Merge pull request #8840 from gyuho/health-balancer

*: refactor clientv3 balancer, upgrade gRPC to v1.7.2

clientv3/balancer.go

@@ -1,439 +0,0 @@
-// Copyright 2016 The etcd Authors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package clientv3
-
-import (
-	"context"
-	"net/url"
-	"strings"
-	"sync"
-
-	"google.golang.org/grpc"
-	"google.golang.org/grpc/codes"
-	"google.golang.org/grpc/status"
-)
-
-// ErrNoAddrAvilable is returned by Get() when the balancer does not have
-// any active connection to endpoints at the time.
-// This error is returned only when opts.BlockingWait is true.
-var ErrNoAddrAvilable = status.Error(codes.Unavailable, "there is no address available")
-
-type notifyMsg int
-
-const (
-	notifyReset notifyMsg = iota
-	notifyNext
-)
-
-// simpleBalancer does the bare minimum to expose multiple eps
-// to the grpc reconnection code path
-type simpleBalancer struct {
-	// addrs are the client's endpoint addresses for grpc
-	addrs []grpc.Address
-
-	// eps holds the raw endpoints from the client
-	eps []string
-
-	// notifyCh notifies grpc of the set of addresses for connecting
-	notifyCh chan []grpc.Address
-
-	// readyc closes once the first connection is up
-	readyc    chan struct{}
-	readyOnce sync.Once
-
-	// mu protects all fields below.
-	mu sync.RWMutex
-
-	// upc closes when pinAddr transitions from empty to non-empty or the balancer closes.
-	upc chan struct{}
-
-	// downc closes when grpc calls down() on pinAddr
-	downc chan struct{}
-
-	// stopc is closed to signal updateNotifyLoop should stop.
-	stopc chan struct{}
-
-	// donec closes when all goroutines are exited
-	donec chan struct{}
-
-	// updateAddrsC notifies updateNotifyLoop to update addrs.
-	updateAddrsC chan notifyMsg
-
-	// grpc issues TLS cert checks using the string passed into dial so
-	// that string must be the host. To recover the full scheme://host URL,
-	// have a map from hosts to the original endpoint.
-	hostPort2ep map[string]string
-
-	// pinAddr is the currently pinned address; set to the empty string on
-	// initialization and shutdown.
-	pinAddr string
-
-	closed bool
-}
-
-func newSimpleBalancer(eps []string) *simpleBalancer {
-	notifyCh := make(chan []grpc.Address)
-	addrs := eps2addrs(eps)
-	sb := &simpleBalancer{
-		addrs:        addrs,
-		eps:          eps,
-		notifyCh:     notifyCh,
-		readyc:       make(chan struct{}),
-		upc:          make(chan struct{}),
-		stopc:        make(chan struct{}),
-		downc:        make(chan struct{}),
-		donec:        make(chan struct{}),
-		updateAddrsC: make(chan notifyMsg),
-		hostPort2ep:  getHostPort2ep(eps),
-	}
-	close(sb.downc)
-	go sb.updateNotifyLoop()
-	return sb
-}
-
-func (b *simpleBalancer) Start(target string, config grpc.BalancerConfig) error { return nil }
-
-func (b *simpleBalancer) ConnectNotify() <-chan struct{} {
-	b.mu.Lock()
-	defer b.mu.Unlock()
-	return b.upc
-}
-
-func (b *simpleBalancer) ready() <-chan struct{} { return b.readyc }
-
-func (b *simpleBalancer) endpoint(hostPort string) string {
-	b.mu.Lock()
-	defer b.mu.Unlock()
-	return b.hostPort2ep[hostPort]
-}
-
-func (b *simpleBalancer) endpoints() []string {
-	b.mu.RLock()
-	defer b.mu.RUnlock()
-	return b.eps
-}
-
-func (b *simpleBalancer) pinned() string {
-	b.mu.RLock()
-	defer b.mu.RUnlock()
-	return b.pinAddr
-}
-
-func getHostPort2ep(eps []string) map[string]string {
-	hm := make(map[string]string, len(eps))
-	for i := range eps {
-		_, host, _ := parseEndpoint(eps[i])
-		hm[host] = eps[i]
-	}
-	return hm
-}
-
-func (b *simpleBalancer) updateAddrs(eps ...string) {
-	np := getHostPort2ep(eps)
-
-	b.mu.Lock()
-
-	match := len(np) == len(b.hostPort2ep)
-	for k, v := range np {
-		if b.hostPort2ep[k] != v {
-			match = false
-			break
-		}
-	}
-	if match {
-		// same endpoints, so no need to update address
-		b.mu.Unlock()
-		return
-	}
-
-	b.hostPort2ep = np
-	b.addrs, b.eps = eps2addrs(eps), eps
-
-	// updating notifyCh can trigger new connections,
-	// only update addrs if all connections are down
-	// or addrs does not include pinAddr.
-	update := !hasAddr(b.addrs, b.pinAddr)
-	b.mu.Unlock()
-
-	if update {
-		select {
-		case b.updateAddrsC <- notifyNext:
-		case <-b.stopc:
-		}
-	}
-}
-
-func (b *simpleBalancer) next() {
-	b.mu.RLock()
-	downc := b.downc
-	b.mu.RUnlock()
-	select {
-	case b.updateAddrsC <- notifyNext:
-	case <-b.stopc:
-	}
-	// wait until disconnect so new RPCs are not issued on old connection
-	select {
-	case <-downc:
-	case <-b.stopc:
-	}
-}
-
-func hasAddr(addrs []grpc.Address, targetAddr string) bool {
-	for _, addr := range addrs {
-		if targetAddr == addr.Addr {
-			return true
-		}
-	}
-	return false
-}
-
-func (b *simpleBalancer) updateNotifyLoop() {
-	defer close(b.donec)
-
-	for {
-		b.mu.RLock()
-		upc, downc, addr := b.upc, b.downc, b.pinAddr
-		b.mu.RUnlock()
-		// downc or upc should be closed
-		select {
-		case <-downc:
-			downc = nil
-		default:
-		}
-		select {
-		case <-upc:
-			upc = nil
-		default:
-		}
-		switch {
-		case downc == nil && upc == nil:
-			// stale
-			select {
-			case <-b.stopc:
-				return
-			default:
-			}
-		case downc == nil:
-			b.notifyAddrs(notifyReset)
-			select {
-			case <-upc:
-			case msg := <-b.updateAddrsC:
-				b.notifyAddrs(msg)
-			case <-b.stopc:
-				return
-			}
-		case upc == nil:
-			select {
-			// close connections that are not the pinned address
-			case b.notifyCh <- []grpc.Address{{Addr: addr}}:
-			case <-downc:
-			case <-b.stopc:
-				return
-			}
-			select {
-			case <-downc:
-				b.notifyAddrs(notifyReset)
-			case msg := <-b.updateAddrsC:
-				b.notifyAddrs(msg)
-			case <-b.stopc:
-				return
-			}
-		}
-	}
-}
-
-func (b *simpleBalancer) notifyAddrs(msg notifyMsg) {
-	if msg == notifyNext {
-		select {
-		case b.notifyCh <- []grpc.Address{}:
-		case <-b.stopc:
-			return
-		}
-	}
-	b.mu.RLock()
-	addrs := b.addrs
-	pinAddr := b.pinAddr
-	downc := b.downc
-	b.mu.RUnlock()
-
-	var waitDown bool
-	if pinAddr != "" {
-		waitDown = true
-		for _, a := range addrs {
-			if a.Addr == pinAddr {
-				waitDown = false
-			}
-		}
-	}
-
-	select {
-	case b.notifyCh <- addrs:
-		if waitDown {
-			select {
-			case <-downc:
-			case <-b.stopc:
-			}
-		}
-	case <-b.stopc:
-	}
-}
-
-func (b *simpleBalancer) Up(addr grpc.Address) func(error) {
-	f, _ := b.up(addr)
-	return f
-}
-
-func (b *simpleBalancer) up(addr grpc.Address) (func(error), bool) {
-	b.mu.Lock()
-	defer b.mu.Unlock()
-
-	// gRPC might call Up after it called Close. We add this check
-	// to "fix" it up at application layer. Otherwise, will panic
-	// if b.upc is already closed.
-	if b.closed {
-		return func(err error) {}, false
-	}
-	// gRPC might call Up on a stale address.
-	// Prevent updating pinAddr with a stale address.
-	if !hasAddr(b.addrs, addr.Addr) {
-		return func(err error) {}, false
-	}
-	if b.pinAddr != "" {
-		if logger.V(4) {
-			logger.Infof("clientv3/balancer: %q is up but not pinned (already pinned %q)", addr.Addr, b.pinAddr)
-		}
-		return func(err error) {}, false
-	}
-	// notify waiting Get()s and pin first connected address
-	close(b.upc)
-	b.downc = make(chan struct{})
-	b.pinAddr = addr.Addr
-	if logger.V(4) {
-		logger.Infof("clientv3/balancer: pin %q", addr.Addr)
-	}
-	// notify client that a connection is up
-	b.readyOnce.Do(func() { close(b.readyc) })
-	return func(err error) {
-		b.mu.Lock()
-		b.upc = make(chan struct{})
-		close(b.downc)
-		b.pinAddr = ""
-		b.mu.Unlock()
-		if logger.V(4) {
-			logger.Infof("clientv3/balancer: unpin %q (%q)", addr.Addr, err.Error())
-		}
-	}, true
-}
-
-func (b *simpleBalancer) Get(ctx context.Context, opts grpc.BalancerGetOptions) (grpc.Address, func(), error) {
-	var (
-		addr   string
-		closed bool
-	)
-
-	// If opts.BlockingWait is false (for fail-fast RPCs), it should return
-	// an address it has notified via Notify immediately instead of blocking.
-	if !opts.BlockingWait {
-		b.mu.RLock()
-		closed = b.closed
-		addr = b.pinAddr
-		b.mu.RUnlock()
-		if closed {
-			return grpc.Address{Addr: ""}, nil, grpc.ErrClientConnClosing
-		}
-		if addr == "" {
-			return grpc.Address{Addr: ""}, nil, ErrNoAddrAvilable
-		}
-		return grpc.Address{Addr: addr}, func() {}, nil
-	}
-
-	for {
-		b.mu.RLock()
-		ch := b.upc
-		b.mu.RUnlock()
-		select {
-		case <-ch:
-		case <-b.donec:
-			return grpc.Address{Addr: ""}, nil, grpc.ErrClientConnClosing
-		case <-ctx.Done():
-			return grpc.Address{Addr: ""}, nil, ctx.Err()
-		}
-		b.mu.RLock()
-		closed = b.closed
-		addr = b.pinAddr
-		b.mu.RUnlock()
-		// Close() which sets b.closed = true can be called before Get(), Get() must exit if balancer is closed.
-		if closed {
-			return grpc.Address{Addr: ""}, nil, grpc.ErrClientConnClosing
-		}
-		if addr != "" {
-			break
-		}
-	}
-	return grpc.Address{Addr: addr}, func() {}, nil
-}
-
-func (b *simpleBalancer) Notify() <-chan []grpc.Address { return b.notifyCh }
-
-func (b *simpleBalancer) Close() error {
-	b.mu.Lock()
-	// In case gRPC calls close twice. TODO: remove the checking
-	// when we are sure that gRPC wont call close twice.
-	if b.closed {
-		b.mu.Unlock()
-		<-b.donec
-		return nil
-	}
-	b.closed = true
-	close(b.stopc)
-	b.pinAddr = ""
-
-	// In the case of following scenario:
-	//	1. upc is not closed; no pinned address
-	// 	2. client issues an RPC, calling invoke(), which calls Get(), enters for loop, blocks
-	// 	3. client.conn.Close() calls balancer.Close(); closed = true
-	// 	4. for loop in Get() never exits since ctx is the context passed in by the client and may not be canceled
-	// we must close upc so Get() exits from blocking on upc
-	select {
-	case <-b.upc:
-	default:
-		// terminate all waiting Get()s
-		close(b.upc)
-	}
-
-	b.mu.Unlock()
-
-	// wait for updateNotifyLoop to finish
-	<-b.donec
-	close(b.notifyCh)
-
-	return nil
-}
-
-func getHost(ep string) string {
-	url, uerr := url.Parse(ep)
-	if uerr != nil || !strings.Contains(ep, "://") {
-		return ep
-	}
-	return url.Host
-}
-
-func eps2addrs(eps []string) []grpc.Address {
-	addrs := make([]grpc.Address, len(eps))
-	for i := range eps {
-		addrs[i].Addr = getHost(eps[i])
-	}
-	return addrs
-}

clientv3/client.go

@@ -121,6 +121,19 @@ func (c *Client) SetEndpoints(eps ...string) {
 	c.cfg.Endpoints = eps
 	c.mu.Unlock()
 	c.balancer.updateAddrs(eps...)
+
+	// updating notifyCh can trigger new connections,
+	// need update addrs if all connections are down
+	// or addrs does not include pinAddr.
+	c.balancer.mu.RLock()
+	update := !hasAddr(c.balancer.addrs, c.balancer.pinAddr)
+	c.balancer.mu.RUnlock()
+	if update {
+		select {
+		case c.balancer.updateAddrsC <- notifyNext:
+		case <-c.balancer.stopc:
+		}
+	}
 }
 
 // Sync synchronizes client's endpoints with the known endpoints from the etcd membership.
@@ -378,9 +391,9 @@ func newClient(cfg *Config) (*Client, error) {
 		client.Password = cfg.Password
 	}
 
-	sb := newSimpleBalancer(cfg.Endpoints)
-	hc := func(ep string) (bool, error) { return grpcHealthCheck(client, ep) }
-	client.balancer = newHealthBalancer(sb, cfg.DialTimeout, hc)
+	client.balancer = newHealthBalancer(cfg.Endpoints, cfg.DialTimeout, func(ep string) (bool, error) {
+		return grpcHealthCheck(client, ep)
+	})
 
 	// use Endpoints[0] so that for https:// without any tls config given, then
 	// grpc will assume the certificate server name is the endpoint host.

clientv3/health_balancer.go

@@ -16,6 +16,9 @@ package clientv3
 
 import (
 	"context"
+	"errors"
+	"net/url"
+	"strings"
 	"sync"
 	"time"
 
@@ -25,207 +28,549 @@ import (
 	"google.golang.org/grpc/status"
 )
 
-const minHealthRetryDuration = 3 * time.Second
-const unknownService = "unknown service grpc.health.v1.Health"
+const (
+	minHealthRetryDuration = 3 * time.Second
+	unknownService         = "unknown service grpc.health.v1.Health"
+)
+
+// ErrNoAddrAvilable is returned by Get() when the balancer does not have
+// any active connection to endpoints at the time.
+// This error is returned only when opts.BlockingWait is true.
+var ErrNoAddrAvilable = status.Error(codes.Unavailable, "there is no address available")
 
 type healthCheckFunc func(ep string) (bool, error)
 
-// healthBalancer wraps a balancer so that it uses health checking
-// to choose its endpoints.
+type notifyMsg int
+
+const (
+	notifyReset notifyMsg = iota
+	notifyNext
+)
+
+// healthBalancer does the bare minimum to expose multiple eps
+// to the grpc reconnection code path
 type healthBalancer struct {
-	*simpleBalancer
+	// addrs are the client's endpoint addresses for grpc
+	addrs []grpc.Address
+
+	// eps holds the raw endpoints from the client
+	eps []string
+
+	// notifyCh notifies grpc of the set of addresses for connecting
+	notifyCh chan []grpc.Address
+
+	// readyc closes once the first connection is up
+	readyc    chan struct{}
+	readyOnce sync.Once
 
 	// healthCheck checks an endpoint's health.
 	healthCheck        healthCheckFunc
 	healthCheckTimeout time.Duration
 
-	// mu protects addrs, eps, unhealthy map, and stopc.
+	unhealthyMu        sync.RWMutex
+	unhealthyHostPorts map[string]time.Time
+
+	// mu protects all fields below.
 	mu sync.RWMutex
 
-	// addrs stores all grpc addresses associated with the balancer.
-	addrs []grpc.Address
+	// upc closes when pinAddr transitions from empty to non-empty or the balancer closes.
+	upc chan struct{}
 
-	// eps stores all client endpoints
-	eps []string
-
-	// unhealthy tracks the last unhealthy time of endpoints.
-	unhealthy map[string]time.Time
+	// downc closes when grpc calls down() on pinAddr
+	downc chan struct{}
 
+	// stopc is closed to signal updateNotifyLoop should stop.
 	stopc    chan struct{}
 	stopOnce sync.Once
+	wg       sync.WaitGroup
+
+	// donec closes when all goroutines are exited
+	donec chan struct{}
 
+	// updateAddrsC notifies updateNotifyLoop to update addrs.
+	updateAddrsC chan notifyMsg
+
+	// grpc issues TLS cert checks using the string passed into dial so
+	// that string must be the host. To recover the full scheme://host URL,
+	// have a map from hosts to the original endpoint.
 	hostPort2ep map[string]string
 
-	wg sync.WaitGroup
+	// pinAddr is the currently pinned address; set to the empty string on
+	// initialization and shutdown.
+	pinAddr string
+
+	closed bool
 }
 
-func newHealthBalancer(b *simpleBalancer, timeout time.Duration, hc healthCheckFunc) *healthBalancer {
+func newHealthBalancer(eps []string, timeout time.Duration, hc healthCheckFunc) *healthBalancer {
+	notifyCh := make(chan []grpc.Address)
+	addrs := eps2addrs(eps)
 	hb := &healthBalancer{
-		simpleBalancer: b,
-		healthCheck:    hc,
-		eps:            b.endpoints(),
-		addrs:          eps2addrs(b.endpoints()),
-		hostPort2ep:    getHostPort2ep(b.endpoints()),
-		unhealthy:      make(map[string]time.Time),
-		stopc:          make(chan struct{}),
+		addrs:              addrs,
+		eps:                eps,
+		notifyCh:           notifyCh,
+		readyc:             make(chan struct{}),
+		healthCheck:        hc,
+		unhealthyHostPorts: make(map[string]time.Time),
+		upc:                make(chan struct{}),
+		stopc:              make(chan struct{}),
+		downc:              make(chan struct{}),
+		donec:              make(chan struct{}),
+		updateAddrsC:       make(chan notifyMsg),
+		hostPort2ep:        getHostPort2ep(eps),
 	}
 	if timeout < minHealthRetryDuration {
 		timeout = minHealthRetryDuration
 	}
 	hb.healthCheckTimeout = timeout
 
+	close(hb.downc)
+	go hb.updateNotifyLoop()
 	hb.wg.Add(1)
 	go func() {
 		defer hb.wg.Done()
-		hb.updateUnhealthy(timeout)
+		hb.updateUnhealthy()
 	}()
-
 	return hb
 }
 
-func (hb *healthBalancer) Up(addr grpc.Address) func(error) {
-	f, used := hb.up(addr)
-	if !used {
-		return f
+func (b *healthBalancer) Start(target string, config grpc.BalancerConfig) error { return nil }
+
+func (b *healthBalancer) ConnectNotify() <-chan struct{} {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+	return b.upc
+}
+
+func (b *healthBalancer) ready() <-chan struct{} { return b.readyc }
+
+func (b *healthBalancer) endpoint(hostPort string) string {
+	b.mu.RLock()
+	defer b.mu.RUnlock()
+	return b.hostPort2ep[hostPort]
+}
+
+func (b *healthBalancer) pinned() string {
+	b.mu.RLock()
+	defer b.mu.RUnlock()
+	return b.pinAddr
+}
+
+func (b *healthBalancer) hostPortError(hostPort string, err error) {
+	if b.endpoint(hostPort) == "" {
+		if logger.V(4) {
+			logger.Infof("clientv3/balancer: %q is stale (skip marking as unhealthy on %q)", hostPort, err.Error())
+		}
+		return
 	}
-	return func(err error) {
-		// If connected to a black hole endpoint or a killed server, the gRPC ping
-		// timeout will induce a network I/O error, and retrying until success;
-		// finding healthy endpoint on retry could take several timeouts and redials.
-		// To avoid wasting retries, gray-list unhealthy endpoints.
-		hb.hostPortError(addr.Addr, err)
-		f(err)
+
+	b.unhealthyMu.Lock()
+	b.unhealthyHostPorts[hostPort] = time.Now()
+	b.unhealthyMu.Unlock()
+	if logger.V(4) {
+		logger.Infof("clientv3/balancer: %q is marked unhealthy (%q)", hostPort, err.Error())
 	}
 }
 
-func (hb *healthBalancer) up(addr grpc.Address) (func(error), bool) {
-	if !hb.mayPin(addr) {
-		return func(err error) {}, false
+func (b *healthBalancer) removeUnhealthy(hostPort, msg string) {
+	if b.endpoint(hostPort) == "" {
+		if logger.V(4) {
+			logger.Infof("clientv3/balancer: %q was not in unhealthy (%q)", hostPort, msg)
+		}
+		return
+	}
+
+	b.unhealthyMu.Lock()
+	delete(b.unhealthyHostPorts, hostPort)
+	b.unhealthyMu.Unlock()
+	if logger.V(4) {
+		logger.Infof("clientv3/balancer: %q is removed from unhealthy (%q)", hostPort, msg)
 	}
-	return hb.simpleBalancer.up(addr)
 }
 
-func (hb *healthBalancer) Close() error {
-	hb.stopOnce.Do(func() { close(hb.stopc) })
-	hb.wg.Wait()
-	return hb.simpleBalancer.Close()
+func (b *healthBalancer) countUnhealthy() (count int) {
+	b.unhealthyMu.RLock()
+	count = len(b.unhealthyHostPorts)
+	b.unhealthyMu.RUnlock()
+	return count
 }
 
-func (hb *healthBalancer) updateAddrs(eps ...string) {
-	addrs, hostPort2ep := eps2addrs(eps), getHostPort2ep(eps)
-	hb.mu.Lock()
-	hb.addrs, hb.eps, hb.hostPort2ep = addrs, eps, hostPort2ep
-	hb.unhealthy = make(map[string]time.Time)
-	hb.mu.Unlock()
-	hb.simpleBalancer.updateAddrs(eps...)
+func (b *healthBalancer) isUnhealthy(hostPort string) (unhealthy bool) {
+	b.unhealthyMu.RLock()
+	_, unhealthy = b.unhealthyHostPorts[hostPort]
+	b.unhealthyMu.RUnlock()
+	return unhealthy
 }
 
-func (hb *healthBalancer) endpoint(host string) string {
-	hb.mu.RLock()
-	defer hb.mu.RUnlock()
-	return hb.hostPort2ep[host]
+func (b *healthBalancer) cleanupUnhealthy() {
+	b.unhealthyMu.Lock()
+	for k, v := range b.unhealthyHostPorts {
+		if time.Since(v) > b.healthCheckTimeout {
+			delete(b.unhealthyHostPorts, k)
+			if logger.V(4) {
+				logger.Infof("clientv3/balancer: removed %q from unhealthy after %v", k, b.healthCheckTimeout)
+			}
+		}
+	}
+	b.unhealthyMu.Unlock()
 }
 
-func (hb *healthBalancer) endpoints() []string {
-	hb.mu.RLock()
-	defer hb.mu.RUnlock()
-	return hb.eps
+func (b *healthBalancer) liveAddrs() ([]grpc.Address, map[string]struct{}) {
+	unhealthyCnt := b.countUnhealthy()
+
+	b.mu.RLock()
+	defer b.mu.RUnlock()
+
+	hbAddrs := b.addrs
+	if len(b.addrs) == 1 || unhealthyCnt == 0 || unhealthyCnt == len(b.addrs) {
+		liveHostPorts := make(map[string]struct{}, len(b.hostPort2ep))
+		for k := range b.hostPort2ep {
+			liveHostPorts[k] = struct{}{}
+		}
+		return hbAddrs, liveHostPorts
+	}
+
+	addrs := make([]grpc.Address, 0, len(b.addrs)-unhealthyCnt)
+	liveHostPorts := make(map[string]struct{}, len(addrs))
+	for _, addr := range b.addrs {
+		if !b.isUnhealthy(addr.Addr) {
+			addrs = append(addrs, addr)
+			liveHostPorts[addr.Addr] = struct{}{}
+		}
+	}
+	return addrs, liveHostPorts
 }
 
-func (hb *healthBalancer) updateUnhealthy(timeout time.Duration) {
+func (b *healthBalancer) updateUnhealthy() {
 	for {
 		select {
-		case <-time.After(timeout):
-			hb.mu.Lock()
-			for k, v := range hb.unhealthy {
-				if time.Since(v) > timeout {
-					delete(hb.unhealthy, k)
-					if logger.V(4) {
-						logger.Infof("clientv3/health-balancer: removes %q from unhealthy after %v", k, timeout)
-					}
+		case <-time.After(b.healthCheckTimeout):
+			b.cleanupUnhealthy()
+			pinned := b.pinned()
+			if pinned == "" || b.isUnhealthy(pinned) {
+				select {
+				case b.updateAddrsC <- notifyNext:
+				case <-b.stopc:
+					return
 				}
 			}
-			hb.mu.Unlock()
-			eps := []string{}
-			for _, addr := range hb.liveAddrs() {
-				eps = append(eps, hb.endpoint(addr.Addr))
-			}
-			hb.simpleBalancer.updateAddrs(eps...)
-		case <-hb.stopc:
+		case <-b.stopc:
 			return
 		}
 	}
 }
 
-func (hb *healthBalancer) liveAddrs() []grpc.Address {
-	hb.mu.RLock()
-	defer hb.mu.RUnlock()
-	hbAddrs := hb.addrs
-	if len(hb.addrs) == 1 || len(hb.unhealthy) == 0 || len(hb.unhealthy) == len(hb.addrs) {
-		return hbAddrs
+func (b *healthBalancer) updateAddrs(eps ...string) {
+	np := getHostPort2ep(eps)
+
+	b.mu.Lock()
+	defer b.mu.Unlock()
+
+	match := len(np) == len(b.hostPort2ep)
+	if match {
+		for k, v := range np {
+			if b.hostPort2ep[k] != v {
+				match = false
+				break
+			}
+		}
 	}
-	addrs := make([]grpc.Address, 0, len(hb.addrs)-len(hb.unhealthy))
-	for _, addr := range hb.addrs {
-		if _, unhealthy := hb.unhealthy[addr.Addr]; !unhealthy {
-			addrs = append(addrs, addr)
+	if match {
+		// same endpoints, so no need to update address
+		return
+	}
+
+	b.hostPort2ep = np
+	b.addrs, b.eps = eps2addrs(eps), eps
+
+	b.unhealthyMu.Lock()
+	b.unhealthyHostPorts = make(map[string]time.Time)
+	b.unhealthyMu.Unlock()
+}
+
+func (b *healthBalancer) next() {
+	b.mu.RLock()
+	downc := b.downc
+	b.mu.RUnlock()
+	select {
+	case b.updateAddrsC <- notifyNext:
+	case <-b.stopc:
+	}
+	// wait until disconnect so new RPCs are not issued on old connection
+	select {
+	case <-downc:
+	case <-b.stopc:
+	}
+}
+
+func (b *healthBalancer) updateNotifyLoop() {
+	defer close(b.donec)
+
+	for {
+		b.mu.RLock()
+		upc, downc, addr := b.upc, b.downc, b.pinAddr
+		b.mu.RUnlock()
+		// downc or upc should be closed
+		select {
+		case <-downc:
+			downc = nil
+		default:
+		}
+		select {
+		case <-upc:
+			upc = nil
+		default:
+		}
+		switch {
+		case downc == nil && upc == nil:
+			// stale
+			select {
+			case <-b.stopc:
+				return
+			default:
+			}
+		case downc == nil:
+			b.notifyAddrs(notifyReset)
+			select {
+			case <-upc:
+			case msg := <-b.updateAddrsC:
+				b.notifyAddrs(msg)
+			case <-b.stopc:
+				return
+			}
+		case upc == nil:
+			select {
+			// close connections that are not the pinned address
+			case b.notifyCh <- []grpc.Address{{Addr: addr}}:
+			case <-downc:
+			case <-b.stopc:
+				return
+			}
+			select {
+			case <-downc:
+				b.notifyAddrs(notifyReset)
+			case msg := <-b.updateAddrsC:
+				b.notifyAddrs(msg)
+			case <-b.stopc:
+				return
+			}
 		}
 	}
-	return addrs
 }
 
-func (hb *healthBalancer) hostPortError(hostPort string, err error) {
-	hb.mu.Lock()
-	if _, ok := hb.hostPort2ep[hostPort]; ok {
-		hb.unhealthy[hostPort] = time.Now()
+func (b *healthBalancer) notifyAddrs(msg notifyMsg) {
+	if msg == notifyNext {
+		select {
+		case b.notifyCh <- []grpc.Address{}:
+		case <-b.stopc:
+			return
+		}
+	}
+	b.mu.RLock()
+	pinAddr := b.pinAddr
+	downc := b.downc
+	b.mu.RUnlock()
+	addrs, hostPorts := b.liveAddrs()
+
+	var waitDown bool
+	if pinAddr != "" {
+		_, ok := hostPorts[pinAddr]
+		waitDown = !ok
+	}
+
+	select {
+	case b.notifyCh <- addrs:
+		if waitDown {
+			select {
+			case <-downc:
+			case <-b.stopc:
+			}
+		}
+	case <-b.stopc:
+	}
+}
+
+func (b *healthBalancer) Up(addr grpc.Address) func(error) {
+	if !b.mayPin(addr) {
+		return func(err error) {}
+	}
+
+	b.mu.Lock()
+	defer b.mu.Unlock()
+
+	// gRPC might call Up after it called Close. We add this check
+	// to "fix" it up at application layer. Otherwise, will panic
+	// if b.upc is already closed.
+	if b.closed {
+		return func(err error) {}
+	}
+
+	// gRPC might call Up on a stale address.
+	// Prevent updating pinAddr with a stale address.
+	if !hasAddr(b.addrs, addr.Addr) {
+		return func(err error) {}
+	}
+
+	if b.pinAddr != "" {
 		if logger.V(4) {
-			logger.Infof("clientv3/health-balancer: marking %q as unhealthy (%q)", hostPort, err.Error())
+			logger.Infof("clientv3/balancer: %q is up but not pinned (already pinned %q)", addr.Addr, b.pinAddr)
+		}
+		return func(err error) {}
+	}
+
+	// notify waiting Get()s and pin first connected address
+	close(b.upc)
+	b.downc = make(chan struct{})
+	b.pinAddr = addr.Addr
+	if logger.V(4) {
+		logger.Infof("clientv3/balancer: pin %q", addr.Addr)
+	}
+
+	// notify client that a connection is up
+	b.readyOnce.Do(func() { close(b.readyc) })
+
+	return func(err error) {
+		// If connected to a black hole endpoint or a killed server, the gRPC ping
+		// timeout will induce a network I/O error, and retrying until success;
+		// finding healthy endpoint on retry could take several timeouts and redials.
+		// To avoid wasting retries, gray-list unhealthy endpoints.
+		b.hostPortError(addr.Addr, err)
+
+		b.mu.Lock()
+		b.upc = make(chan struct{})
+		close(b.downc)
+		b.pinAddr = ""
+		b.mu.Unlock()
+		if logger.V(4) {
+			logger.Infof("clientv3/balancer: unpin %q (%q)", addr.Addr, err.Error())
 		}
 	}
-	hb.mu.Unlock()
 }
 
-func (hb *healthBalancer) mayPin(addr grpc.Address) bool {
-	hb.mu.RLock()
-	if _, ok := hb.hostPort2ep[addr.Addr]; !ok { // stale host:port
-		hb.mu.RUnlock()
+func (b *healthBalancer) mayPin(addr grpc.Address) bool {
+	if b.endpoint(addr.Addr) == "" { // stale host:port
 		return false
 	}
-	skip := len(hb.addrs) == 1 || len(hb.unhealthy) == 0 || len(hb.addrs) == len(hb.unhealthy)
-	failedTime, bad := hb.unhealthy[addr.Addr]
-	dur := hb.healthCheckTimeout
-	hb.mu.RUnlock()
+
+	b.unhealthyMu.RLock()
+	unhealthyCnt := len(b.unhealthyHostPorts)
+	failedTime, bad := b.unhealthyHostPorts[addr.Addr]
+	b.unhealthyMu.RUnlock()
+
+	b.mu.RLock()
+	skip := len(b.addrs) == 1 || unhealthyCnt == 0 || len(b.addrs) == unhealthyCnt
+	b.mu.RUnlock()
 	if skip || !bad {
 		return true
 	}
+
 	// prevent isolated member's endpoint from being infinitely retried, as follows:
 	//   1. keepalive pings detects GoAway with http2.ErrCodeEnhanceYourCalm
 	//   2. balancer 'Up' unpins with grpc: failed with network I/O error
 	//   3. grpc-healthcheck still SERVING, thus retry to pin
 	// instead, return before grpc-healthcheck if failed within healthcheck timeout
-	if elapsed := time.Since(failedTime); elapsed < dur {
+	if elapsed := time.Since(failedTime); elapsed < b.healthCheckTimeout {
 		if logger.V(4) {
-			logger.Infof("clientv3/health-balancer: %q is up but not pinned (failed %v ago, require minimum %v after failure)", addr.Addr, elapsed, dur)
+			logger.Infof("clientv3/balancer: %q is up but not pinned (failed %v ago, require minimum %v after failure)", addr.Addr, elapsed, b.healthCheckTimeout)
 		}
 		return false
 	}
-	if ok, _ := hb.healthCheck(addr.Addr); ok {
-		hb.mu.Lock()
-		delete(hb.unhealthy, addr.Addr)
-		hb.mu.Unlock()
-		if logger.V(4) {
-			logger.Infof("clientv3/health-balancer: %q is healthy (health check success)", addr.Addr)
-		}
+
+	if ok, _ := b.healthCheck(addr.Addr); ok {
+		b.removeUnhealthy(addr.Addr, "health check success")
 		return true
 	}
-	hb.mu.Lock()
-	hb.unhealthy[addr.Addr] = time.Now()
-	hb.mu.Unlock()
-	if logger.V(4) {
-		logger.Infof("clientv3/health-balancer: %q becomes unhealthy (health check failed)", addr.Addr)
-	}
+
+	b.hostPortError(addr.Addr, errors.New("health check failed"))
 	return false
 }
 
+func (b *healthBalancer) Get(ctx context.Context, opts grpc.BalancerGetOptions) (grpc.Address, func(), error) {
+	var (
+		addr   string
+		closed bool
+	)
+
+	// If opts.BlockingWait is false (for fail-fast RPCs), it should return
+	// an address it has notified via Notify immediately instead of blocking.
+	if !opts.BlockingWait {
+		b.mu.RLock()
+		closed = b.closed
+		addr = b.pinAddr
+		b.mu.RUnlock()
+		if closed {
+			return grpc.Address{Addr: ""}, nil, grpc.ErrClientConnClosing
+		}
+		if addr == "" {
+			return grpc.Address{Addr: ""}, nil, ErrNoAddrAvilable
+		}
+		return grpc.Address{Addr: addr}, func() {}, nil
+	}
+
+	for {
+		b.mu.RLock()
+		ch := b.upc
+		b.mu.RUnlock()
+		select {
+		case <-ch:
+		case <-b.donec:
+			return grpc.Address{Addr: ""}, nil, grpc.ErrClientConnClosing
+		case <-ctx.Done():
+			return grpc.Address{Addr: ""}, nil, ctx.Err()
+		}
+		b.mu.RLock()
+		closed = b.closed
+		addr = b.pinAddr
+		b.mu.RUnlock()
+		// Close() which sets b.closed = true can be called before Get(), Get() must exit if balancer is closed.
+		if closed {
+			return grpc.Address{Addr: ""}, nil, grpc.ErrClientConnClosing
+		}
+		if addr != "" {
+			break
+		}
+	}
+	return grpc.Address{Addr: addr}, func() {}, nil
+}
+
+func (b *healthBalancer) Notify() <-chan []grpc.Address { return b.notifyCh }
+
+func (b *healthBalancer) Close() error {
+	b.mu.Lock()
+	// In case gRPC calls close twice. TODO: remove the checking
+	// when we are sure that gRPC wont call close twice.
+	if b.closed {
+		b.mu.Unlock()
+		<-b.donec
+		return nil
+	}
+	b.closed = true
+	b.stopOnce.Do(func() { close(b.stopc) })
+	b.pinAddr = ""
+
+	// In the case of following scenario:
+	//	1. upc is not closed; no pinned address
+	// 	2. client issues an RPC, calling invoke(), which calls Get(), enters for loop, blocks
+	// 	3. client.conn.Close() calls balancer.Close(); closed = true
+	// 	4. for loop in Get() never exits since ctx is the context passed in by the client and may not be canceled
+	// we must close upc so Get() exits from blocking on upc
+	select {
+	case <-b.upc:
+	default:
+		// terminate all waiting Get()s
+		close(b.upc)
+	}
+
+	b.mu.Unlock()
+	b.wg.Wait()
+
+	// wait for updateNotifyLoop to finish
+	<-b.donec
+	close(b.notifyCh)
+
+	return nil
+}
+
 func grpcHealthCheck(client *Client, ep string) (bool, error) {
 	conn, err := client.dial(ep)
 	if err != nil {
@@ -238,8 +583,7 @@ func grpcHealthCheck(client *Client, ep string) (bool, error) {
 	cancel()
 	if err != nil {
 		if s, ok := status.FromError(err); ok && s.Code() == codes.Unavailable {
-			if s.Message() == unknownService {
-				// etcd < v3.3.0
+			if s.Message() == unknownService { // etcd < v3.3.0
 				return true, nil
 			}
 		}
@@ -247,3 +591,37 @@ func grpcHealthCheck(client *Client, ep string) (bool, error) {
 	}
 	return resp.Status == healthpb.HealthCheckResponse_SERVING, nil
 }
+
+func hasAddr(addrs []grpc.Address, targetAddr string) bool {
+	for _, addr := range addrs {
+		if targetAddr == addr.Addr {
+			return true
+		}
+	}
+	return false
+}
+
+func getHost(ep string) string {
+	url, uerr := url.Parse(ep)
+	if uerr != nil || !strings.Contains(ep, "://") {
+		return ep
+	}
+	return url.Host
+}
+
+func eps2addrs(eps []string) []grpc.Address {
+	addrs := make([]grpc.Address, len(eps))
+	for i := range eps {
+		addrs[i].Addr = getHost(eps[i])
+	}
+	return addrs
+}
+
+func getHostPort2ep(eps []string) map[string]string {
+	hm := make(map[string]string, len(eps))
+	for i := range eps {
+		_, host, _ := parseEndpoint(eps[i])
+		hm[host] = eps[i]
+	}
+	return hm
+}

clientv3/balancer_test.go → clientv3/health_balancer_test.go

@@ -1,4 +1,4 @@
-// Copyright 2016 The etcd Authors
+// Copyright 2017 The etcd Authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -28,29 +28,27 @@ import (
 	"google.golang.org/grpc"
 )
 
-var (
-	endpoints = []string{"localhost:2379", "localhost:22379", "localhost:32379"}
-)
+var endpoints = []string{"localhost:2379", "localhost:22379", "localhost:32379"}
 
 func TestBalancerGetUnblocking(t *testing.T) {
-	sb := newSimpleBalancer(endpoints)
-	defer sb.Close()
-	if addrs := <-sb.Notify(); len(addrs) != len(endpoints) {
-		t.Errorf("Initialize newSimpleBalancer should have triggered Notify() chan, but it didn't")
+	hb := newHealthBalancer(endpoints, minHealthRetryDuration, func(string) (bool, error) { return true, nil })
+	defer hb.Close()
+	if addrs := <-hb.Notify(); len(addrs) != len(endpoints) {
+		t.Errorf("Initialize newHealthBalancer should have triggered Notify() chan, but it didn't")
 	}
 	unblockingOpts := grpc.BalancerGetOptions{BlockingWait: false}
 
-	_, _, err := sb.Get(context.Background(), unblockingOpts)
+	_, _, err := hb.Get(context.Background(), unblockingOpts)
 	if err != ErrNoAddrAvilable {
 		t.Errorf("Get() with no up endpoints should return ErrNoAddrAvailable, got: %v", err)
 	}
 
-	down1 := sb.Up(grpc.Address{Addr: endpoints[1]})
-	if addrs := <-sb.Notify(); len(addrs) != 1 {
+	down1 := hb.Up(grpc.Address{Addr: endpoints[1]})
+	if addrs := <-hb.Notify(); len(addrs) != 1 {
 		t.Errorf("first Up() should have triggered balancer to send the first connected address via Notify chan so that other connections can be closed")
 	}
-	down2 := sb.Up(grpc.Address{Addr: endpoints[2]})
-	addrFirst, putFun, err := sb.Get(context.Background(), unblockingOpts)
+	down2 := hb.Up(grpc.Address{Addr: endpoints[2]})
+	addrFirst, putFun, err := hb.Get(context.Background(), unblockingOpts)
 	if err != nil {
 		t.Errorf("Get() with up endpoints should success, got %v", err)
 	}
@@ -60,32 +58,32 @@ func TestBalancerGetUnblocking(t *testing.T) {
 	if putFun == nil {
 		t.Errorf("Get() returned unexpected nil put function")
 	}
-	addrSecond, _, _ := sb.Get(context.Background(), unblockingOpts)
+	addrSecond, _, _ := hb.Get(context.Background(), unblockingOpts)
 	if addrFirst.Addr != addrSecond.Addr {
 		t.Errorf("Get() didn't return the same address as previous call, got %v and %v", addrFirst, addrSecond)
 	}
 
 	down1(errors.New("error"))
-	if addrs := <-sb.Notify(); len(addrs) != len(endpoints) {
-		t.Errorf("closing the only connection should triggered balancer to send the all endpoints via Notify chan so that we can establish a connection")
+	if addrs := <-hb.Notify(); len(addrs) != len(endpoints)-1 { // we call down on one endpoint
+		t.Errorf("closing the only connection should triggered balancer to send the %d endpoints via Notify chan so that we can establish a connection", len(endpoints)-1)
 	}
 	down2(errors.New("error"))
-	_, _, err = sb.Get(context.Background(), unblockingOpts)
+	_, _, err = hb.Get(context.Background(), unblockingOpts)
 	if err != ErrNoAddrAvilable {
 		t.Errorf("Get() with no up endpoints should return ErrNoAddrAvailable, got: %v", err)
 	}
 }
 
 func TestBalancerGetBlocking(t *testing.T) {
-	sb := newSimpleBalancer(endpoints)
-	defer sb.Close()
-	if addrs := <-sb.Notify(); len(addrs) != len(endpoints) {
-		t.Errorf("Initialize newSimpleBalancer should have triggered Notify() chan, but it didn't")
+	hb := newHealthBalancer(endpoints, minHealthRetryDuration, func(string) (bool, error) { return true, nil })
+	defer hb.Close()
+	if addrs := <-hb.Notify(); len(addrs) != len(endpoints) {
+		t.Errorf("Initialize newHealthBalancer should have triggered Notify() chan, but it didn't")
 	}
 	blockingOpts := grpc.BalancerGetOptions{BlockingWait: true}
 
 	ctx, cancel := context.WithTimeout(context.Background(), time.Millisecond*100)
-	_, _, err := sb.Get(ctx, blockingOpts)
+	_, _, err := hb.Get(ctx, blockingOpts)
 	cancel()
 	if err != context.DeadlineExceeded {
 		t.Errorf("Get() with no up endpoints should timeout, got %v", err)
@@ -94,15 +92,15 @@ func TestBalancerGetBlocking(t *testing.T) {
 	downC := make(chan func(error), 1)
 
 	go func() {
-		// ensure sb.Up() will be called after sb.Get() to see if Up() releases blocking Get()
+		// ensure hb.Up() will be called after hb.Get() to see if Up() releases blocking Get()
 		time.Sleep(time.Millisecond * 100)
-		f := sb.Up(grpc.Address{Addr: endpoints[1]})
-		if addrs := <-sb.Notify(); len(addrs) != 1 {
+		f := hb.Up(grpc.Address{Addr: endpoints[1]})
+		if addrs := <-hb.Notify(); len(addrs) != 1 {
 			t.Errorf("first Up() should have triggered balancer to send the first connected address via Notify chan so that other connections can be closed")
 		}
 		downC <- f
 	}()
-	addrFirst, putFun, err := sb.Get(context.Background(), blockingOpts)
+	addrFirst, putFun, err := hb.Get(context.Background(), blockingOpts)
 	if err != nil {
 		t.Errorf("Get() with up endpoints should success, got %v", err)
 	}
@@ -114,19 +112,19 @@ func TestBalancerGetBlocking(t *testing.T) {
 	}
 	down1 := <-downC
 
-	down2 := sb.Up(grpc.Address{Addr: endpoints[2]})
-	addrSecond, _, _ := sb.Get(context.Background(), blockingOpts)
+	down2 := hb.Up(grpc.Address{Addr: endpoints[2]})
+	addrSecond, _, _ := hb.Get(context.Background(), blockingOpts)
 	if addrFirst.Addr != addrSecond.Addr {
 		t.Errorf("Get() didn't return the same address as previous call, got %v and %v", addrFirst, addrSecond)
 	}
 
 	down1(errors.New("error"))
-	if addrs := <-sb.Notify(); len(addrs) != len(endpoints) {
-		t.Errorf("closing the only connection should triggered balancer to send the all endpoints via Notify chan so that we can establish a connection")
+	if addrs := <-hb.Notify(); len(addrs) != len(endpoints)-1 { // we call down on one endpoint
+		t.Errorf("closing the only connection should triggered balancer to send the %d endpoints via Notify chan so that we can establish a connection", len(endpoints)-1)
 	}
 	down2(errors.New("error"))
 	ctx, cancel = context.WithTimeout(context.Background(), time.Millisecond*100)
-	_, _, err = sb.Get(ctx, blockingOpts)
+	_, _, err = hb.Get(ctx, blockingOpts)
 	cancel()
 	if err != context.DeadlineExceeded {
 		t.Errorf("Get() with no up endpoints should timeout, got %v", err)
@@ -168,9 +166,8 @@ func TestHealthBalancerGraylist(t *testing.T) {
 		}()
 	}
 
-	sb := newSimpleBalancer(eps)
 	tf := func(s string) (bool, error) { return false, nil }
-	hb := newHealthBalancer(sb, 5*time.Second, tf)
+	hb := newHealthBalancer(eps, 5*time.Second, tf)
 
 	conn, err := grpc.Dial("", grpc.WithInsecure(), grpc.WithBalancer(hb))
 	testutil.AssertNil(t, err)
@@ -203,13 +200,13 @@ func TestBalancerDoNotBlockOnClose(t *testing.T) {
 	defer kcl.close()
 
 	for i := 0; i < 5; i++ {
-		sb := newSimpleBalancer(kcl.endpoints())
-		conn, err := grpc.Dial("", grpc.WithInsecure(), grpc.WithBalancer(sb))
+		hb := newHealthBalancer(kcl.endpoints(), minHealthRetryDuration, func(string) (bool, error) { return true, nil })
+		conn, err := grpc.Dial("", grpc.WithInsecure(), grpc.WithBalancer(hb))
 		if err != nil {
 			t.Fatal(err)
 		}
 		kvc := pb.NewKVClient(conn)
-		<-sb.readyc
+		<-hb.readyc
 
 		var wg sync.WaitGroup
 		wg.Add(100)
@@ -225,7 +222,7 @@ func TestBalancerDoNotBlockOnClose(t *testing.T) {
 		bclosec, cclosec := make(chan struct{}), make(chan struct{})
 		go func() {
 			defer close(bclosec)
-			sb.Close()
+			hb.Close()
 		}()
 		go func() {
 			defer close(cclosec)

clientv3/integration/kv_test.go

@@ -472,8 +472,9 @@ func TestKVNewAfterClose(t *testing.T) {
 
 	donec := make(chan struct{})
 	go func() {
-		if _, err := cli.Get(context.TODO(), "foo"); err != context.Canceled {
-			t.Fatalf("expected %v, got %v", context.Canceled, err)
+		_, err := cli.Get(context.TODO(), "foo")
+		if err != context.Canceled && err != grpc.ErrClientConnClosing {
+			t.Fatalf("expected %v or %v, got %v", context.Canceled, grpc.ErrClientConnClosing, err)
 		}
 		close(donec)
 	}()

clientv3/retry.go

@@ -45,7 +45,8 @@ func isNonRepeatableStopError(err error) bool {
 	if ev.Code() != codes.Unavailable {
 		return true
 	}
-	return rpctypes.ErrorDesc(err) != "there is no address available"
+	desc := rpctypes.ErrorDesc(err)
+	return desc != "there is no address available" && desc != "there is no connection available"
 }
 
 func (c *Client) newRetryWrapper(isStop retryStopErrFunc) retryRPCFunc {

cmd/vendor/google.golang.org/grpc/balancer.go

@@ -403,6 +403,6 @@ type pickFirst struct {
 	*roundRobin
 }
 
-func pickFirstBalancer(r naming.Resolver) Balancer {
+func pickFirstBalancerV1(r naming.Resolver) Balancer {
 	return &pickFirst{&roundRobin{r: r}}
 }

cmd/vendor/google.golang.org/grpc/balancer/balancer.go

@@ -0,0 +1,206 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package balancer defines APIs for load balancing in gRPC.
+// All APIs in this package are experimental.
+package balancer
+
+import (
+	"errors"
+	"net"
+
+	"golang.org/x/net/context"
+	"google.golang.org/grpc/connectivity"
+	"google.golang.org/grpc/credentials"
+	"google.golang.org/grpc/resolver"
+)
+
+var (
+	// m is a map from name to balancer builder.
+	m = make(map[string]Builder)
+	// defaultBuilder is the default balancer to use.
+	defaultBuilder Builder // TODO(bar) install pickfirst as default.
+)
+
+// Register registers the balancer builder to the balancer map.
+// b.Name will be used as the name registered with this builder.
+func Register(b Builder) {
+	m[b.Name()] = b
+}
+
+// Get returns the resolver builder registered with the given name.
+// If no builder is register with the name, the default pickfirst will
+// be used.
+func Get(name string) Builder {
+	if b, ok := m[name]; ok {
+		return b
+	}
+	return defaultBuilder
+}
+
+// SubConn represents a gRPC sub connection.
+// Each sub connection contains a list of addresses. gRPC will
+// try to connect to them (in sequence), and stop trying the
+// remainder once one connection is successful.
+//
+// The reconnect backoff will be applied on the list, not a single address.
+// For example, try_on_all_addresses -> backoff -> try_on_all_addresses.
+//
+// All SubConns start in IDLE, and will not try to connect. To trigger
+// the connecting, Balancers must call Connect.
+// When the connection encounters an error, it will reconnect immediately.
+// When the connection becomes IDLE, it will not reconnect unless Connect is
+// called.
+type SubConn interface {
+	// UpdateAddresses updates the addresses used in this SubConn.
+	// gRPC checks if currently-connected address is still in the new list.
+	// If it's in the list, the connection will be kept.
+	// If it's not in the list, the connection will gracefully closed, and
+	// a new connection will be created.
+	//
+	// This will trigger a state transition for the SubConn.
+	UpdateAddresses([]resolver.Address)
+	// Connect starts the connecting for this SubConn.
+	Connect()
+}
+
+// NewSubConnOptions contains options to create new SubConn.
+type NewSubConnOptions struct{}
+
+// ClientConn represents a gRPC ClientConn.
+type ClientConn interface {
+	// NewSubConn is called by balancer to create a new SubConn.
+	// It doesn't block and wait for the connections to be established.
+	// Behaviors of the SubConn can be controlled by options.
+	NewSubConn([]resolver.Address, NewSubConnOptions) (SubConn, error)
+	// RemoveSubConn removes the SubConn from ClientConn.
+	// The SubConn will be shutdown.
+	RemoveSubConn(SubConn)
+
+	// UpdateBalancerState is called by balancer to nofity gRPC that some internal
+	// state in balancer has changed.
+	//
+	// gRPC will update the connectivity state of the ClientConn, and will call pick
+	// on the new picker to pick new SubConn.
+	UpdateBalancerState(s connectivity.State, p Picker)
+
+	// Target returns the dial target for this ClientConn.
+	Target() string
+}
+
+// BuildOptions contains additional information for Build.
+type BuildOptions struct {
+	// DialCreds is the transport credential the Balancer implementation can
+	// use to dial to a remote load balancer server. The Balancer implementations
+	// can ignore this if it does not need to talk to another party securely.
+	DialCreds credentials.TransportCredentials
+	// Dialer is the custom dialer the Balancer implementation can use to dial
+	// to a remote load balancer server. The Balancer implementations
+	// can ignore this if it doesn't need to talk to remote balancer.
+	Dialer func(context.Context, string) (net.Conn, error)
+}
+
+// Builder creates a balancer.
+type Builder interface {
+	// Build creates a new balancer with the ClientConn.
+	Build(cc ClientConn, opts BuildOptions) Balancer
+	// Name returns the name of balancers built by this builder.
+	// It will be used to pick balancers (for example in service config).
+	Name() string
+}
+
+// PickOptions contains addition information for the Pick operation.
+type PickOptions struct{}
+
+// DoneInfo contains additional information for done.
+type DoneInfo struct {
+	// Err is the rpc error the RPC finished with. It could be nil.
+	Err error
+}
+
+var (
+	// ErrNoSubConnAvailable indicates no SubConn is available for pick().
+	// gRPC will block the RPC until a new picker is available via UpdateBalancerState().
+	ErrNoSubConnAvailable = errors.New("no SubConn is available")
+	// ErrTransientFailure indicates all SubConns are in TransientFailure.
+	// WaitForReady RPCs will block, non-WaitForReady RPCs will fail.
+	ErrTransientFailure = errors.New("all SubConns are in TransientFailure")
+)
+
+// Picker is used by gRPC to pick a SubConn to send an RPC.
+// Balancer is expected to generate a new picker from its snapshot everytime its
+// internal state has changed.
+//
+// The pickers used by gRPC can be updated by ClientConn.UpdateBalancerState().
+type Picker interface {
+	// Pick returns the SubConn to be used to send the RPC.
+	// The returned SubConn must be one returned by NewSubConn().
+	//
+	// This functions is expected to return:
+	// - a SubConn that is known to be READY;
+	// - ErrNoSubConnAvailable if no SubConn is available, but progress is being
+	//   made (for example, some SubConn is in CONNECTING mode);
+	// - other errors if no active connecting is happening (for example, all SubConn
+	//   are in TRANSIENT_FAILURE mode).
+	//
+	// If a SubConn is returned:
+	// - If it is READY, gRPC will send the RPC on it;
+	// - If it is not ready, or becomes not ready after it's returned, gRPC will block
+	//   this call until a new picker is updated and will call pick on the new picker.
+	//
+	// If the returned error is not nil:
+	// - If the error is ErrNoSubConnAvailable, gRPC will block until UpdateBalancerState()
+	// - If the error is ErrTransientFailure:
+	//   - If the RPC is wait-for-ready, gRPC will block until UpdateBalancerState()
+	//     is called to pick again;
+	//   - Otherwise, RPC will fail with unavailable error.
+	// - Else (error is other non-nil error):
+	//   - The RPC will fail with unavailable error.
+	//
+	// The returned done() function will be called once the rpc has finished, with the
+	// final status of that RPC.
+	// done may be nil if balancer doesn't care about the RPC status.
+	Pick(ctx context.Context, opts PickOptions) (conn SubConn, done func(DoneInfo), err error)
+}
+
+// Balancer takes input from gRPC, manages SubConns, and collects and aggregates
+// the connectivity states.
+//
+// It also generates and updates the Picker used by gRPC to pick SubConns for RPCs.
+//
+// HandleSubConnectionStateChange, HandleResolvedAddrs and Close are guaranteed
+// to be called synchronously from the same goroutine.
+// There's no guarantee on picker.Pick, it may be called anytime.
+type Balancer interface {
+	// HandleSubConnStateChange is called by gRPC when the connectivity state
+	// of sc has changed.
+	// Balancer is expected to aggregate all the state of SubConn and report
+	// that back to gRPC.
+	// Balancer should also generate and update Pickers when its internal state has
+	// been changed by the new state.
+	HandleSubConnStateChange(sc SubConn, state connectivity.State)
+	// HandleResolvedAddrs is called by gRPC to send updated resolved addresses to
+	// balancers.
+	// Balancer can create new SubConn or remove SubConn with the addresses.
+	// An empty address slice and a non-nil error will be passed if the resolver returns
+	// non-nil error to gRPC.
+	HandleResolvedAddrs([]resolver.Address, error)
+	// Close closes the balancer. The balancer is not required to call
+	// ClientConn.RemoveSubConn for its existing SubConns.
+	Close()
+}

cmd/vendor/google.golang.org/grpc/balancer_conn_wrappers.go

@@ -0,0 +1,248 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package grpc
+
+import (
+	"sync"
+
+	"google.golang.org/grpc/balancer"
+	"google.golang.org/grpc/connectivity"
+	"google.golang.org/grpc/grpclog"
+	"google.golang.org/grpc/resolver"
+)
+
+// scStateUpdate contains the subConn and the new state it changed to.
+type scStateUpdate struct {
+	sc    balancer.SubConn
+	state connectivity.State
+}
+
+// scStateUpdateBuffer is an unbounded channel for scStateChangeTuple.
+// TODO make a general purpose buffer that uses interface{}.
+type scStateUpdateBuffer struct {
+	c       chan *scStateUpdate
+	mu      sync.Mutex
+	backlog []*scStateUpdate
+}
+
+func newSCStateUpdateBuffer() *scStateUpdateBuffer {
+	return &scStateUpdateBuffer{
+		c: make(chan *scStateUpdate, 1),
+	}
+}
+
+func (b *scStateUpdateBuffer) put(t *scStateUpdate) {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+	if len(b.backlog) == 0 {
+		select {
+		case b.c <- t:
+			return
+		default:
+		}
+	}
+	b.backlog = append(b.backlog, t)
+}
+
+func (b *scStateUpdateBuffer) load() {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+	if len(b.backlog) > 0 {
+		select {
+		case b.c <- b.backlog[0]:
+			b.backlog[0] = nil
+			b.backlog = b.backlog[1:]
+		default:
+		}
+	}
+}
+
+// get returns the channel that receives a recvMsg in the buffer.
+//
+// Upon receiving, the caller should call load to send another
+// scStateChangeTuple onto the channel if there is any.
+func (b *scStateUpdateBuffer) get() <-chan *scStateUpdate {
+	return b.c
+}
+
+// resolverUpdate contains the new resolved addresses or error if there's
+// any.
+type resolverUpdate struct {
+	addrs []resolver.Address
+	err   error
+}
+
+// ccBalancerWrapper is a wrapper on top of cc for balancers.
+// It implements balancer.ClientConn interface.
+type ccBalancerWrapper struct {
+	cc               *ClientConn
+	balancer         balancer.Balancer
+	stateChangeQueue *scStateUpdateBuffer
+	resolverUpdateCh chan *resolverUpdate
+	done             chan struct{}
+}
+
+func newCCBalancerWrapper(cc *ClientConn, b balancer.Builder, bopts balancer.BuildOptions) *ccBalancerWrapper {
+	ccb := &ccBalancerWrapper{
+		cc:               cc,
+		stateChangeQueue: newSCStateUpdateBuffer(),
+		resolverUpdateCh: make(chan *resolverUpdate, 1),
+		done:             make(chan struct{}),
+	}
+	go ccb.watcher()
+	ccb.balancer = b.Build(ccb, bopts)
+	return ccb
+}
+
+// watcher balancer functions sequencially, so the balancer can be implemeneted
+// lock-free.
+func (ccb *ccBalancerWrapper) watcher() {
+	for {
+		select {
+		case t := <-ccb.stateChangeQueue.get():
+			ccb.stateChangeQueue.load()
+			ccb.balancer.HandleSubConnStateChange(t.sc, t.state)
+		case t := <-ccb.resolverUpdateCh:
+			ccb.balancer.HandleResolvedAddrs(t.addrs, t.err)
+		case <-ccb.done:
+		}
+
+		select {
+		case <-ccb.done:
+			ccb.balancer.Close()
+			return
+		default:
+		}
+	}
+}
+
+func (ccb *ccBalancerWrapper) close() {
+	close(ccb.done)
+}
+
+func (ccb *ccBalancerWrapper) handleSubConnStateChange(sc balancer.SubConn, s connectivity.State) {
+	// When updating addresses for a SubConn, if the address in use is not in
+	// the new addresses, the old ac will be tearDown() and a new ac will be
+	// created. tearDown() generates a state change with Shutdown state, we
+	// don't want the balancer to receive this state change. So before
+	// tearDown() on the old ac, ac.acbw (acWrapper) will be set to nil, and
+	// this function will be called with (nil, Shutdown). We don't need to call
+	// balancer method in this case.
+	if sc == nil {
+		return
+	}
+	ccb.stateChangeQueue.put(&scStateUpdate{
+		sc:    sc,
+		state: s,
+	})
+}
+
+func (ccb *ccBalancerWrapper) handleResolvedAddrs(addrs []resolver.Address, err error) {
+	select {
+	case <-ccb.resolverUpdateCh:
+	default:
+	}
+	ccb.resolverUpdateCh <- &resolverUpdate{
+		addrs: addrs,
+		err:   err,
+	}
+}
+
+func (ccb *ccBalancerWrapper) NewSubConn(addrs []resolver.Address, opts balancer.NewSubConnOptions) (balancer.SubConn, error) {
+	grpclog.Infof("ccBalancerWrapper: new subconn: %v", addrs)
+	ac, err := ccb.cc.newAddrConn(addrs)
+	if err != nil {
+		return nil, err
+	}
+	acbw := &acBalancerWrapper{ac: ac}
+	ac.acbw = acbw
+	return acbw, nil
+}
+
+func (ccb *ccBalancerWrapper) RemoveSubConn(sc balancer.SubConn) {
+	grpclog.Infof("ccBalancerWrapper: removing subconn")
+	acbw, ok := sc.(*acBalancerWrapper)
+	if !ok {
+		return
+	}
+	ccb.cc.removeAddrConn(acbw.getAddrConn(), errConnDrain)
+}
+
+func (ccb *ccBalancerWrapper) UpdateBalancerState(s connectivity.State, p balancer.Picker) {
+	grpclog.Infof("ccBalancerWrapper: updating state and picker called by balancer: %v, %p", s, p)
+	ccb.cc.csMgr.updateState(s)
+	ccb.cc.blockingpicker.updatePicker(p)
+}
+
+func (ccb *ccBalancerWrapper) Target() string {
+	return ccb.cc.target
+}
+
+// acBalancerWrapper is a wrapper on top of ac for balancers.
+// It implements balancer.SubConn interface.
+type acBalancerWrapper struct {
+	mu sync.Mutex
+	ac *addrConn
+}
+
+func (acbw *acBalancerWrapper) UpdateAddresses(addrs []resolver.Address) {
+	grpclog.Infof("acBalancerWrapper: UpdateAddresses called with %v", addrs)
+	acbw.mu.Lock()
+	defer acbw.mu.Unlock()
+	if !acbw.ac.tryUpdateAddrs(addrs) {
+		cc := acbw.ac.cc
+		acbw.ac.mu.Lock()
+		// Set old ac.acbw to nil so the Shutdown state update will be ignored
+		// by balancer.
+		//
+		// TODO(bar) the state transition could be wrong when tearDown() old ac
+		// and creating new ac, fix the transition.
+		acbw.ac.acbw = nil
+		acbw.ac.mu.Unlock()
+		acState := acbw.ac.getState()
+		acbw.ac.tearDown(errConnDrain)
+
+		if acState == connectivity.Shutdown {
+			return
+		}
+
+		ac, err := cc.newAddrConn(addrs)
+		if err != nil {
+			grpclog.Warningf("acBalancerWrapper: UpdateAddresses: failed to newAddrConn: %v", err)
+			return
+		}
+		acbw.ac = ac
+		ac.acbw = acbw
+		if acState != connectivity.Idle {
+			ac.connect(false)
+		}
+	}
+}
+
+func (acbw *acBalancerWrapper) Connect() {
+	acbw.mu.Lock()
+	defer acbw.mu.Unlock()
+	acbw.ac.connect(false)
+}
+
+func (acbw *acBalancerWrapper) getAddrConn() *addrConn {
+	acbw.mu.Lock()
+	defer acbw.mu.Unlock()
+	return acbw.ac
+}

cmd/vendor/google.golang.org/grpc/balancer_v1_wrapper.go

@@ -0,0 +1,367 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package grpc
+
+import (
+	"sync"
+
+	"golang.org/x/net/context"
+	"google.golang.org/grpc/balancer"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/connectivity"
+	"google.golang.org/grpc/grpclog"
+	"google.golang.org/grpc/resolver"
+)
+
+type balancerWrapperBuilder struct {
+	b Balancer // The v1 balancer.
+}
+
+func (bwb *balancerWrapperBuilder) Build(cc balancer.ClientConn, opts balancer.BuildOptions) balancer.Balancer {
+	bwb.b.Start(cc.Target(), BalancerConfig{
+		DialCreds: opts.DialCreds,
+		Dialer:    opts.Dialer,
+	})
+	_, pickfirst := bwb.b.(*pickFirst)
+	bw := &balancerWrapper{
+		balancer:  bwb.b,
+		pickfirst: pickfirst,
+		cc:        cc,
+		startCh:   make(chan struct{}),
+		conns:     make(map[resolver.Address]balancer.SubConn),
+		connSt:    make(map[balancer.SubConn]*scState),
+		csEvltr:   &connectivityStateEvaluator{},
+		state:     connectivity.Idle,
+	}
+	cc.UpdateBalancerState(connectivity.Idle, bw)
+	go bw.lbWatcher()
+	return bw
+}
+
+func (bwb *balancerWrapperBuilder) Name() string {
+	return "wrapper"
+}
+
+type scState struct {
+	addr Address // The v1 address type.
+	s    connectivity.State
+	down func(error)
+}
+
+type balancerWrapper struct {
+	balancer  Balancer // The v1 balancer.
+	pickfirst bool
+
+	cc balancer.ClientConn
+
+	// To aggregate the connectivity state.
+	csEvltr *connectivityStateEvaluator
+	state   connectivity.State
+
+	mu     sync.Mutex
+	conns  map[resolver.Address]balancer.SubConn
+	connSt map[balancer.SubConn]*scState
+	// This channel is closed when handling the first resolver result.
+	// lbWatcher blocks until this is closed, to avoid race between
+	// - NewSubConn is created, cc wants to notify balancer of state changes;
+	// - Build hasn't return, cc doesn't have access to balancer.
+	startCh chan struct{}
+}
+
+// lbWatcher watches the Notify channel of the balancer and manages
+// connections accordingly.
+func (bw *balancerWrapper) lbWatcher() {
+	<-bw.startCh
+	grpclog.Infof("balancerWrapper: is pickfirst: %v\n", bw.pickfirst)
+	notifyCh := bw.balancer.Notify()
+	if notifyCh == nil {
+		// There's no resolver in the balancer. Connect directly.
+		a := resolver.Address{
+			Addr: bw.cc.Target(),
+			Type: resolver.Backend,
+		}
+		sc, err := bw.cc.NewSubConn([]resolver.Address{a}, balancer.NewSubConnOptions{})
+		if err != nil {
+			grpclog.Warningf("Error creating connection to %v. Err: %v", a, err)
+		} else {
+			bw.mu.Lock()
+			bw.conns[a] = sc
+			bw.connSt[sc] = &scState{
+				addr: Address{Addr: bw.cc.Target()},
+				s:    connectivity.Idle,
+			}
+			bw.mu.Unlock()
+			sc.Connect()
+		}
+		return
+	}
+
+	for addrs := range notifyCh {
+		grpclog.Infof("balancerWrapper: got update addr from Notify: %v\n", addrs)
+		if bw.pickfirst {
+			var (
+				oldA  resolver.Address
+				oldSC balancer.SubConn
+			)
+			bw.mu.Lock()
+			for oldA, oldSC = range bw.conns {
+				break
+			}
+			bw.mu.Unlock()
+			if len(addrs) <= 0 {
+				if oldSC != nil {
+					// Teardown old sc.
+					bw.mu.Lock()
+					delete(bw.conns, oldA)
+					delete(bw.connSt, oldSC)
+					bw.mu.Unlock()
+					bw.cc.RemoveSubConn(oldSC)
+				}
+				continue
+			}
+
+			var newAddrs []resolver.Address
+			for _, a := range addrs {
+				newAddr := resolver.Address{
+					Addr:       a.Addr,
+					Type:       resolver.Backend, // All addresses from balancer are all backends.
+					ServerName: "",
+					Metadata:   a.Metadata,
+				}
+				newAddrs = append(newAddrs, newAddr)
+			}
+			if oldSC == nil {
+				// Create new sc.
+				sc, err := bw.cc.NewSubConn(newAddrs, balancer.NewSubConnOptions{})
+				if err != nil {
+					grpclog.Warningf("Error creating connection to %v. Err: %v", newAddrs, err)
+				} else {
+					bw.mu.Lock()
+					// For pickfirst, there should be only one SubConn, so the
+					// address doesn't matter. All states updating (up and down)
+					// and picking should all happen on that only SubConn.
+					bw.conns[resolver.Address{}] = sc
+					bw.connSt[sc] = &scState{
+						addr: addrs[0], // Use the first address.
+						s:    connectivity.Idle,
+					}
+					bw.mu.Unlock()
+					sc.Connect()
+				}
+			} else {
+				oldSC.UpdateAddresses(newAddrs)
+				bw.mu.Lock()
+				bw.connSt[oldSC].addr = addrs[0]
+				bw.mu.Unlock()
+			}
+		} else {
+			var (
+				add []resolver.Address // Addresses need to setup connections.
+				del []balancer.SubConn // Connections need to tear down.
+			)
+			resAddrs := make(map[resolver.Address]Address)
+			for _, a := range addrs {
+				resAddrs[resolver.Address{
+					Addr:       a.Addr,
+					Type:       resolver.Backend, // All addresses from balancer are all backends.
+					ServerName: "",
+					Metadata:   a.Metadata,
+				}] = a
+			}
+			bw.mu.Lock()
+			for a := range resAddrs {
+				if _, ok := bw.conns[a]; !ok {
+					add = append(add, a)
+				}
+			}
+			for a, c := range bw.conns {
+				if _, ok := resAddrs[a]; !ok {
+					del = append(del, c)
+					delete(bw.conns, a)
+					// Keep the state of this sc in bw.connSt until its state becomes Shutdown.
+				}
+			}
+			bw.mu.Unlock()
+			for _, a := range add {
+				sc, err := bw.cc.NewSubConn([]resolver.Address{a}, balancer.NewSubConnOptions{})
+				if err != nil {
+					grpclog.Warningf("Error creating connection to %v. Err: %v", a, err)
+				} else {
+					bw.mu.Lock()
+					bw.conns[a] = sc
+					bw.connSt[sc] = &scState{
+						addr: resAddrs[a],
+						s:    connectivity.Idle,
+					}
+					bw.mu.Unlock()
+					sc.Connect()
+				}
+			}
+			for _, c := range del {
+				bw.cc.RemoveSubConn(c)
+			}
+		}
+	}
+}
+
+func (bw *balancerWrapper) HandleSubConnStateChange(sc balancer.SubConn, s connectivity.State) {
+	grpclog.Infof("balancerWrapper: handle subconn state change: %p, %v", sc, s)
+	bw.mu.Lock()
+	defer bw.mu.Unlock()
+	scSt, ok := bw.connSt[sc]
+	if !ok {
+		return
+	}
+	if s == connectivity.Idle {
+		sc.Connect()
+	}
+	oldS := scSt.s
+	scSt.s = s
+	if oldS != connectivity.Ready && s == connectivity.Ready {
+		scSt.down = bw.balancer.Up(scSt.addr)
+	} else if oldS == connectivity.Ready && s != connectivity.Ready {
+		if scSt.down != nil {
+			scSt.down(errConnClosing)
+		}
+	}
+	sa := bw.csEvltr.recordTransition(oldS, s)
+	if bw.state != sa {
+		bw.state = sa
+	}
+	bw.cc.UpdateBalancerState(bw.state, bw)
+	if s == connectivity.Shutdown {
+		// Remove state for this sc.
+		delete(bw.connSt, sc)
+	}
+	return
+}
+
+func (bw *balancerWrapper) HandleResolvedAddrs([]resolver.Address, error) {
+	bw.mu.Lock()
+	defer bw.mu.Unlock()
+	select {
+	case <-bw.startCh:
+	default:
+		close(bw.startCh)
+	}
+	// There should be a resolver inside the balancer.
+	// All updates here, if any, are ignored.
+	return
+}
+
+func (bw *balancerWrapper) Close() {
+	bw.mu.Lock()
+	defer bw.mu.Unlock()
+	select {
+	case <-bw.startCh:
+	default:
+		close(bw.startCh)
+	}
+	bw.balancer.Close()
+	return
+}
+
+// The picker is the balancerWrapper itself.
+// Pick should never return ErrNoSubConnAvailable.
+// It either blocks or returns error, consistent with v1 balancer Get().
+func (bw *balancerWrapper) Pick(ctx context.Context, opts balancer.PickOptions) (balancer.SubConn, func(balancer.DoneInfo), error) {
+	failfast := true // Default failfast is true.
+	if ss, ok := rpcInfoFromContext(ctx); ok {
+		failfast = ss.failfast
+	}
+	a, p, err := bw.balancer.Get(ctx, BalancerGetOptions{BlockingWait: !failfast})
+	if err != nil {
+		return nil, nil, err
+	}
+	var done func(balancer.DoneInfo)
+	if p != nil {
+		done = func(i balancer.DoneInfo) { p() }
+	}
+	var sc balancer.SubConn
+	bw.mu.Lock()
+	defer bw.mu.Unlock()
+	if bw.pickfirst {
+		// Get the first sc in conns.
+		for _, sc = range bw.conns {
+			break
+		}
+	} else {
+		var ok bool
+		sc, ok = bw.conns[resolver.Address{
+			Addr:       a.Addr,
+			Type:       resolver.Backend,
+			ServerName: "",
+			Metadata:   a.Metadata,
+		}]
+		if !ok && failfast {
+			return nil, nil, Errorf(codes.Unavailable, "there is no connection available")
+		}
+		if s, ok := bw.connSt[sc]; failfast && (!ok || s.s != connectivity.Ready) {
+			// If the returned sc is not ready and RPC is failfast,
+			// return error, and this RPC will fail.
+			return nil, nil, Errorf(codes.Unavailable, "there is no connection available")
+		}
+	}
+
+	return sc, done, nil
+}
+
+// connectivityStateEvaluator gets updated by addrConns when their
+// states transition, based on which it evaluates the state of
+// ClientConn.
+type connectivityStateEvaluator struct {
+	mu                  sync.Mutex
+	numReady            uint64 // Number of addrConns in ready state.
+	numConnecting       uint64 // Number of addrConns in connecting state.
+	numTransientFailure uint64 // Number of addrConns in transientFailure.
+}
+
+// recordTransition records state change happening in every subConn and based on
+// that it evaluates what aggregated state should be.
+// It can only transition between Ready, Connecting and TransientFailure. Other states,
+// Idle and Shutdown are transitioned into by ClientConn; in the beginning of the connection
+// before any subConn is created ClientConn is in idle state. In the end when ClientConn
+// closes it is in Shutdown state.
+// TODO Note that in later releases, a ClientConn with no activity will be put into an Idle state.
+func (cse *connectivityStateEvaluator) recordTransition(oldState, newState connectivity.State) connectivity.State {
+	cse.mu.Lock()
+	defer cse.mu.Unlock()
+
+	// Update counters.
+	for idx, state := range []connectivity.State{oldState, newState} {
+		updateVal := 2*uint64(idx) - 1 // -1 for oldState and +1 for new.
+		switch state {
+		case connectivity.Ready:
+			cse.numReady += updateVal
+		case connectivity.Connecting:
+			cse.numConnecting += updateVal
+		case connectivity.TransientFailure:
+			cse.numTransientFailure += updateVal
+		}
+	}
+
+	// Evaluate.
+	if cse.numReady > 0 {
+		return connectivity.Ready
+	}
+	if cse.numConnecting > 0 {
+		return connectivity.Connecting
+	}
+	return connectivity.TransientFailure
+}

cmd/vendor/google.golang.org/grpc/call.go

@@ -25,6 +25,7 @@ import (
 
 	"golang.org/x/net/context"
 	"golang.org/x/net/trace"
+	"google.golang.org/grpc/balancer"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/peer"
 	"google.golang.org/grpc/stats"
@@ -135,7 +136,7 @@ func Invoke(ctx context.Context, method string, args, reply interface{}, cc *Cli
 }
 
 func invoke(ctx context.Context, method string, args, reply interface{}, cc *ClientConn, opts ...CallOption) (e error) {
-	c := defaultCallInfo
+	c := defaultCallInfo()
 	mc := cc.GetMethodConfig(method)
 	if mc.WaitForReady != nil {
 		c.failFast = !*mc.WaitForReady
@@ -149,13 +150,13 @@ func invoke(ctx context.Context, method string, args, reply interface{}, cc *Cli
 
 	opts = append(cc.dopts.callOptions, opts...)
 	for _, o := range opts {
-		if err := o.before(&c); err != nil {
+		if err := o.before(c); err != nil {
 			return toRPCErr(err)
 		}
 	}
 	defer func() {
 		for _, o := range opts {
-			o.after(&c)
+			o.after(c)
 		}
 	}()
 
@@ -178,7 +179,7 @@ func invoke(ctx context.Context, method string, args, reply interface{}, cc *Cli
 			}
 		}()
 	}
-	ctx = newContextWithRPCInfo(ctx)
+	ctx = newContextWithRPCInfo(ctx, c.failFast)
 	sh := cc.dopts.copts.StatsHandler
 	if sh != nil {
 		ctx = sh.TagRPC(ctx, &stats.RPCTagInfo{FullMethodName: method, FailFast: c.failFast})
@@ -206,9 +207,9 @@ func invoke(ctx context.Context, method string, args, reply interface{}, cc *Cli
 			err    error
 			t      transport.ClientTransport
 			stream *transport.Stream
-			// Record the put handler from Balancer.Get(...). It is called once the
+			// Record the done handler from Balancer.Get(...). It is called once the
 			// RPC has completed or failed.
-			put func()
+			done func(balancer.DoneInfo)
 		)
 		// TODO(zhaoq): Need a formal spec of fail-fast.
 		callHdr := &transport.CallHdr{
@@ -222,10 +223,7 @@ func invoke(ctx context.Context, method string, args, reply interface{}, cc *Cli
 			callHdr.Creds = c.creds
 		}
 
-		gopts := BalancerGetOptions{
-			BlockingWait: !c.failFast,
-		}
-		t, put, err = cc.getTransport(ctx, gopts)
+		t, done, err = cc.getTransport(ctx, c.failFast)
 		if err != nil {
 			// TODO(zhaoq): Probably revisit the error handling.
 			if _, ok := status.FromError(err); ok {
@@ -245,14 +243,14 @@ func invoke(ctx context.Context, method string, args, reply interface{}, cc *Cli
 		}
 		stream, err = t.NewStream(ctx, callHdr)
 		if err != nil {
-			if put != nil {
+			if done != nil {
 				if _, ok := err.(transport.ConnectionError); ok {
 					// If error is connection error, transport was sending data on wire,
 					// and we are not sure if anything has been sent on wire.
 					// If error is not connection error, we are sure nothing has been sent.
 					updateRPCInfoInContext(ctx, rpcInfo{bytesSent: true, bytesReceived: false})
 				}
-				put()
+				done(balancer.DoneInfo{Err: err})
 			}
 			if _, ok := err.(transport.ConnectionError); (ok || err == transport.ErrStreamDrain) && !c.failFast {
 				continue
@@ -262,14 +260,14 @@ func invoke(ctx context.Context, method string, args, reply interface{}, cc *Cli
 		if peer, ok := peer.FromContext(stream.Context()); ok {
 			c.peer = peer
 		}
-		err = sendRequest(ctx, cc.dopts, cc.dopts.cp, &c, callHdr, stream, t, args, topts)
+		err = sendRequest(ctx, cc.dopts, cc.dopts.cp, c, callHdr, stream, t, args, topts)
 		if err != nil {
-			if put != nil {
+			if done != nil {
 				updateRPCInfoInContext(ctx, rpcInfo{
 					bytesSent:     stream.BytesSent(),
 					bytesReceived: stream.BytesReceived(),
 				})
-				put()
+				done(balancer.DoneInfo{Err: err})
 			}
 			// Retry a non-failfast RPC when
 			// i) there is a connection error; or
@@ -279,14 +277,14 @@ func invoke(ctx context.Context, method string, args, reply interface{}, cc *Cli
 			}
 			return toRPCErr(err)
 		}
-		err = recvResponse(ctx, cc.dopts, t, &c, stream, reply)
+		err = recvResponse(ctx, cc.dopts, t, c, stream, reply)
 		if err != nil {
-			if put != nil {
+			if done != nil {
 				updateRPCInfoInContext(ctx, rpcInfo{
 					bytesSent:     stream.BytesSent(),
 					bytesReceived: stream.BytesReceived(),
 				})
-				put()
+				done(balancer.DoneInfo{Err: err})
 			}
 			if _, ok := err.(transport.ConnectionError); (ok || err == transport.ErrStreamDrain) && !c.failFast {
 				continue
@@ -297,12 +295,12 @@ func invoke(ctx context.Context, method string, args, reply interface{}, cc *Cli
 			c.traceInfo.tr.LazyLog(&payload{sent: false, msg: reply}, true)
 		}
 		t.CloseStream(stream, nil)
-		if put != nil {
+		if done != nil {
 			updateRPCInfoInContext(ctx, rpcInfo{
 				bytesSent:     stream.BytesSent(),
 				bytesReceived: stream.BytesReceived(),
 			})
-			put()
+			done(balancer.DoneInfo{Err: err})
 		}
 		return stream.Status().Err()
 	}

cmd/vendor/google.golang.org/grpc/go16.go

@@ -1,98 +0,0 @@
-// +build go1.6,!go1.7
-
-/*
- *
- * Copyright 2016 gRPC authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- */
-
-package grpc
-
-import (
-	"fmt"
-	"io"
-	"net"
-	"net/http"
-	"os"
-
-	"golang.org/x/net/context"
-	"google.golang.org/grpc/codes"
-	"google.golang.org/grpc/status"
-	"google.golang.org/grpc/transport"
-)
-
-// dialContext connects to the address on the named network.
-func dialContext(ctx context.Context, network, address string) (net.Conn, error) {
-	return (&net.Dialer{Cancel: ctx.Done()}).Dial(network, address)
-}
-
-func sendHTTPRequest(ctx context.Context, req *http.Request, conn net.Conn) error {
-	req.Cancel = ctx.Done()
-	if err := req.Write(conn); err != nil {
-		return fmt.Errorf("failed to write the HTTP request: %v", err)
-	}
-	return nil
-}
-
-// toRPCErr converts an error into an error from the status package.
-func toRPCErr(err error) error {
-	if _, ok := status.FromError(err); ok {
-		return err
-	}
-	switch e := err.(type) {
-	case transport.StreamError:
-		return status.Error(e.Code, e.Desc)
-	case transport.ConnectionError:
-		return status.Error(codes.Unavailable, e.Desc)
-	default:
-		switch err {
-		case context.DeadlineExceeded:
-			return status.Error(codes.DeadlineExceeded, err.Error())
-		case context.Canceled:
-			return status.Error(codes.Canceled, err.Error())
-		case ErrClientConnClosing:
-			return status.Error(codes.FailedPrecondition, err.Error())
-		}
-	}
-	return status.Error(codes.Unknown, err.Error())
-}
-
-// convertCode converts a standard Go error into its canonical code. Note that
-// this is only used to translate the error returned by the server applications.
-func convertCode(err error) codes.Code {
-	switch err {
-	case nil:
-		return codes.OK
-	case io.EOF:
-		return codes.OutOfRange
-	case io.ErrClosedPipe, io.ErrNoProgress, io.ErrShortBuffer, io.ErrShortWrite, io.ErrUnexpectedEOF:
-		return codes.FailedPrecondition
-	case os.ErrInvalid:
-		return codes.InvalidArgument
-	case context.Canceled:
-		return codes.Canceled
-	case context.DeadlineExceeded:
-		return codes.DeadlineExceeded
-	}
-	switch {
-	case os.IsExist(err):
-		return codes.AlreadyExists
-	case os.IsNotExist(err):
-		return codes.NotFound
-	case os.IsPermission(err):
-		return codes.PermissionDenied
-	}
-	return codes.Unknown
-}

cmd/vendor/google.golang.org/grpc/go17.go

@@ -1,98 +0,0 @@
-// +build go1.7
-
-/*
- *
- * Copyright 2016 gRPC authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- */
-
-package grpc
-
-import (
-	"context"
-	"io"
-	"net"
-	"net/http"
-	"os"
-
-	netctx "golang.org/x/net/context"
-	"google.golang.org/grpc/codes"
-	"google.golang.org/grpc/status"
-	"google.golang.org/grpc/transport"
-)
-
-// dialContext connects to the address on the named network.
-func dialContext(ctx context.Context, network, address string) (net.Conn, error) {
-	return (&net.Dialer{}).DialContext(ctx, network, address)
-}
-
-func sendHTTPRequest(ctx context.Context, req *http.Request, conn net.Conn) error {
-	req = req.WithContext(ctx)
-	if err := req.Write(conn); err != nil {
-		return err
-	}
-	return nil
-}
-
-// toRPCErr converts an error into an error from the status package.
-func toRPCErr(err error) error {
-	if _, ok := status.FromError(err); ok {
-		return err
-	}
-	switch e := err.(type) {
-	case transport.StreamError:
-		return status.Error(e.Code, e.Desc)
-	case transport.ConnectionError:
-		return status.Error(codes.Unavailable, e.Desc)
-	default:
-		switch err {
-		case context.DeadlineExceeded, netctx.DeadlineExceeded:
-			return status.Error(codes.DeadlineExceeded, err.Error())
-		case context.Canceled, netctx.Canceled:
-			return status.Error(codes.Canceled, err.Error())
-		case ErrClientConnClosing:
-			return status.Error(codes.FailedPrecondition, err.Error())
-		}
-	}
-	return status.Error(codes.Unknown, err.Error())
-}
-
-// convertCode converts a standard Go error into its canonical code. Note that
-// this is only used to translate the error returned by the server applications.
-func convertCode(err error) codes.Code {
-	switch err {
-	case nil:
-		return codes.OK
-	case io.EOF:
-		return codes.OutOfRange
-	case io.ErrClosedPipe, io.ErrNoProgress, io.ErrShortBuffer, io.ErrShortWrite, io.ErrUnexpectedEOF:
-		return codes.FailedPrecondition
-	case os.ErrInvalid:
-		return codes.InvalidArgument
-	case context.Canceled, netctx.Canceled:
-		return codes.Canceled
-	case context.DeadlineExceeded, netctx.DeadlineExceeded:
-		return codes.DeadlineExceeded
-	}
-	switch {
-	case os.IsExist(err):
-		return codes.AlreadyExists
-	case os.IsNotExist(err):
-		return codes.NotFound
-	case os.IsPermission(err):
-		return codes.PermissionDenied
-	}
-	return codes.Unknown
-}

cmd/vendor/google.golang.org/grpc/grpclb.go

@@ -73,7 +73,7 @@ func (x *balanceLoadClientStream) Recv() (*lbmpb.LoadBalanceResponse, error) {
 
 // NewGRPCLBBalancer creates a grpclb load balancer.
 func NewGRPCLBBalancer(r naming.Resolver) Balancer {
-	return &balancer{
+	return &grpclbBalancer{
 		r: r,
 	}
 }
@@ -96,7 +96,7 @@ type grpclbAddrInfo struct {
 	dropForLoadBalancing bool
 }
 
-type balancer struct {
+type grpclbBalancer struct {
 	r      naming.Resolver
 	target string
 	mu     sync.Mutex
@@ -113,7 +113,7 @@ type balancer struct {
 	clientStats lbmpb.ClientStats
 }
 
-func (b *balancer) watchAddrUpdates(w naming.Watcher, ch chan []remoteBalancerInfo) error {
+func (b *grpclbBalancer) watchAddrUpdates(w naming.Watcher, ch chan []remoteBalancerInfo) error {
 	updates, err := w.Next()
 	if err != nil {
 		grpclog.Warningf("grpclb: failed to get next addr update from watcher: %v", err)
@@ -187,7 +187,7 @@ func convertDuration(d *lbmpb.Duration) time.Duration {
 	return time.Duration(d.Seconds)*time.Second + time.Duration(d.Nanos)*time.Nanosecond
 }
 
-func (b *balancer) processServerList(l *lbmpb.ServerList, seq int) {
+func (b *grpclbBalancer) processServerList(l *lbmpb.ServerList, seq int) {
 	if l == nil {
 		return
 	}
@@ -230,7 +230,7 @@ func (b *balancer) processServerList(l *lbmpb.ServerList, seq int) {
 	return
 }
 
-func (b *balancer) sendLoadReport(s *balanceLoadClientStream, interval time.Duration, done <-chan struct{}) {
+func (b *grpclbBalancer) sendLoadReport(s *balanceLoadClientStream, interval time.Duration, done <-chan struct{}) {
 	ticker := time.NewTicker(interval)
 	defer ticker.Stop()
 	for {
@@ -259,7 +259,7 @@ func (b *balancer) sendLoadReport(s *balanceLoadClientStream, interval time.Dura
 	}
 }
 
-func (b *balancer) callRemoteBalancer(lbc *loadBalancerClient, seq int) (retry bool) {
+func (b *grpclbBalancer) callRemoteBalancer(lbc *loadBalancerClient, seq int) (retry bool) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
 	stream, err := lbc.BalanceLoad(ctx)
@@ -332,7 +332,7 @@ func (b *balancer) callRemoteBalancer(lbc *loadBalancerClient, seq int) (retry b
 	return true
 }
 
-func (b *balancer) Start(target string, config BalancerConfig) error {
+func (b *grpclbBalancer) Start(target string, config BalancerConfig) error {
 	b.rand = rand.New(rand.NewSource(time.Now().Unix()))
 	// TODO: Fall back to the basic direct connection if there is no name resolver.
 	if b.r == nil {
@@ -461,8 +461,11 @@ func (b *balancer) Start(target string, config BalancerConfig) error {
 				// WithDialer takes a different type of function, so we instead use a special DialOption here.
 				dopts = append(dopts, func(o *dialOptions) { o.copts.Dialer = dialer })
 			}
+			dopts = append(dopts, WithBlock())
 			ccError = make(chan struct{})
-			cc, err = Dial(rb.addr, dopts...)
+			ctx, cancel := context.WithTimeout(context.Background(), time.Second)
+			cc, err = DialContext(ctx, rb.addr, dopts...)
+			cancel()
 			if err != nil {
 				grpclog.Warningf("grpclb: failed to setup a connection to the remote balancer %v: %v", rb.addr, err)
 				close(ccError)
@@ -488,7 +491,7 @@ func (b *balancer) Start(target string, config BalancerConfig) error {
 	return nil
 }
 
-func (b *balancer) down(addr Address, err error) {
+func (b *grpclbBalancer) down(addr Address, err error) {
 	b.mu.Lock()
 	defer b.mu.Unlock()
 	for _, a := range b.addrs {
@@ -499,7 +502,7 @@ func (b *balancer) down(addr Address, err error) {
 	}
 }
 
-func (b *balancer) Up(addr Address) func(error) {
+func (b *grpclbBalancer) Up(addr Address) func(error) {
 	b.mu.Lock()
 	defer b.mu.Unlock()
 	if b.done {
@@ -527,7 +530,7 @@ func (b *balancer) Up(addr Address) func(error) {
 	}
 }
 
-func (b *balancer) Get(ctx context.Context, opts BalancerGetOptions) (addr Address, put func(), err error) {
+func (b *grpclbBalancer) Get(ctx context.Context, opts BalancerGetOptions) (addr Address, put func(), err error) {
 	var ch chan struct{}
 	b.mu.Lock()
 	if b.done {
@@ -597,17 +600,10 @@ func (b *balancer) Get(ctx context.Context, opts BalancerGetOptions) (addr Addre
 		}
 	}
 	if !opts.BlockingWait {
-		if len(b.addrs) == 0 {
-			b.clientStats.NumCallsFinished++
-			b.clientStats.NumCallsFinishedWithClientFailedToSend++
-			b.mu.Unlock()
-			err = Errorf(codes.Unavailable, "there is no address available")
-			return
-		}
-		// Returns the next addr on b.addrs for a failfast RPC.
-		addr = b.addrs[b.next].addr
-		b.next++
+		b.clientStats.NumCallsFinished++
+		b.clientStats.NumCallsFinishedWithClientFailedToSend++
 		b.mu.Unlock()
+		err = Errorf(codes.Unavailable, "there is no address available")
 		return
 	}
 	// Wait on b.waitCh for non-failfast RPCs.
@@ -684,11 +680,11 @@ func (b *balancer) Get(ctx context.Context, opts BalancerGetOptions) (addr Addre
 	}
 }
 
-func (b *balancer) Notify() <-chan []Address {
+func (b *grpclbBalancer) Notify() <-chan []Address {
 	return b.addrCh
 }
 
-func (b *balancer) Close() error {
+func (b *grpclbBalancer) Close() error {
 	b.mu.Lock()
 	defer b.mu.Unlock()
 	if b.done {

cmd/vendor/google.golang.org/grpc/naming/go17.go

@@ -1,4 +1,4 @@
-// +build go1.6, !go1.8
+// +build go1.7, !go1.8
 
 /*
  *

cmd/vendor/google.golang.org/grpc/picker_wrapper.go

@@ -0,0 +1,141 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package grpc
+
+import (
+	"sync"
+
+	"golang.org/x/net/context"
+	"google.golang.org/grpc/balancer"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/grpclog"
+	"google.golang.org/grpc/status"
+	"google.golang.org/grpc/transport"
+)
+
+// pickerWrapper is a wrapper of balancer.Picker. It blocks on certain pick
+// actions and unblock when there's a picker update.
+type pickerWrapper struct {
+	mu         sync.Mutex
+	done       bool
+	blockingCh chan struct{}
+	picker     balancer.Picker
+}
+
+func newPickerWrapper() *pickerWrapper {
+	bp := &pickerWrapper{blockingCh: make(chan struct{})}
+	return bp
+}
+
+// updatePicker is called by UpdateBalancerState. It unblocks all blocked pick.
+func (bp *pickerWrapper) updatePicker(p balancer.Picker) {
+	bp.mu.Lock()
+	if bp.done {
+		bp.mu.Unlock()
+		return
+	}
+	bp.picker = p
+	// bp.blockingCh should never be nil.
+	close(bp.blockingCh)
+	bp.blockingCh = make(chan struct{})
+	bp.mu.Unlock()
+}
+
+// pick returns the transport that will be used for the RPC.
+// It may block in the following cases:
+// - there's no picker
+// - the current picker returns ErrNoSubConnAvailable
+// - the current picker returns other errors and failfast is false.
+// - the subConn returned by the current picker is not READY
+// When one of these situations happens, pick blocks until the picker gets updated.
+func (bp *pickerWrapper) pick(ctx context.Context, failfast bool, opts balancer.PickOptions) (transport.ClientTransport, func(balancer.DoneInfo), error) {
+	var (
+		p  balancer.Picker
+		ch chan struct{}
+	)
+
+	for {
+		bp.mu.Lock()
+		if bp.done {
+			bp.mu.Unlock()
+			return nil, nil, ErrClientConnClosing
+		}
+
+		if bp.picker == nil {
+			ch = bp.blockingCh
+		}
+		if ch == bp.blockingCh {
+			// This could happen when either:
+			// - bp.picker is nil (the previous if condition), or
+			// - has called pick on the current picker.
+			bp.mu.Unlock()
+			select {
+			case <-ctx.Done():
+				return nil, nil, ctx.Err()
+			case <-ch:
+			}
+			continue
+		}
+
+		ch = bp.blockingCh
+		p = bp.picker
+		bp.mu.Unlock()
+
+		subConn, put, err := p.Pick(ctx, opts)
+
+		if err != nil {
+			switch err {
+			case balancer.ErrNoSubConnAvailable:
+				continue
+			case balancer.ErrTransientFailure:
+				if !failfast {
+					continue
+				}
+				return nil, nil, status.Errorf(codes.Unavailable, "%v", err)
+			default:
+				// err is some other error.
+				return nil, nil, toRPCErr(err)
+			}
+		}
+
+		acw, ok := subConn.(*acBalancerWrapper)
+		if !ok {
+			grpclog.Infof("subconn returned from pick is not *acBalancerWrapper")
+			continue
+		}
+		if t, ok := acw.getAddrConn().getReadyTransport(); ok {
+			return t, put, nil
+		}
+		grpclog.Infof("blockingPicker: the picked transport is not ready, loop back to repick")
+		// If ok == false, ac.state is not READY.
+		// A valid picker always returns READY subConn. This means the state of ac
+		// just changed, and picker will be updated shortly.
+		// continue back to the beginning of the for loop to repick.
+	}
+}
+
+func (bp *pickerWrapper) close() {
+	bp.mu.Lock()
+	defer bp.mu.Unlock()
+	if bp.done {
+		return
+	}
+	bp.done = true
+	close(bp.blockingCh)
+}

cmd/vendor/google.golang.org/grpc/pickfirst.go

@@ -0,0 +1,95 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package grpc
+
+import (
+	"golang.org/x/net/context"
+	"google.golang.org/grpc/balancer"
+	"google.golang.org/grpc/connectivity"
+	"google.golang.org/grpc/grpclog"
+	"google.golang.org/grpc/resolver"
+)
+
+func newPickfirstBuilder() balancer.Builder {
+	return &pickfirstBuilder{}
+}
+
+type pickfirstBuilder struct{}
+
+func (*pickfirstBuilder) Build(cc balancer.ClientConn, opt balancer.BuildOptions) balancer.Balancer {
+	return &pickfirstBalancer{cc: cc}
+}
+
+func (*pickfirstBuilder) Name() string {
+	return "pickfirst"
+}
+
+type pickfirstBalancer struct {
+	cc balancer.ClientConn
+	sc balancer.SubConn
+}
+
+func (b *pickfirstBalancer) HandleResolvedAddrs(addrs []resolver.Address, err error) {
+	if err != nil {
+		grpclog.Infof("pickfirstBalancer: HandleResolvedAddrs called with error %v", err)
+		return
+	}
+	if b.sc == nil {
+		b.sc, err = b.cc.NewSubConn(addrs, balancer.NewSubConnOptions{})
+		if err != nil {
+			grpclog.Errorf("pickfirstBalancer: failed to NewSubConn: %v", err)
+			return
+		}
+		b.cc.UpdateBalancerState(connectivity.Idle, &picker{sc: b.sc})
+	} else {
+		b.sc.UpdateAddresses(addrs)
+	}
+}
+
+func (b *pickfirstBalancer) HandleSubConnStateChange(sc balancer.SubConn, s connectivity.State) {
+	grpclog.Infof("pickfirstBalancer: HandleSubConnStateChange: %p, %v", sc, s)
+	if b.sc != sc || s == connectivity.Shutdown {
+		b.sc = nil
+		return
+	}
+
+	switch s {
+	case connectivity.Ready, connectivity.Idle:
+		b.cc.UpdateBalancerState(s, &picker{sc: sc})
+	case connectivity.Connecting:
+		b.cc.UpdateBalancerState(s, &picker{err: balancer.ErrNoSubConnAvailable})
+	case connectivity.TransientFailure:
+		b.cc.UpdateBalancerState(s, &picker{err: balancer.ErrTransientFailure})
+	}
+}
+
+func (b *pickfirstBalancer) Close() {
+}
+
+type picker struct {
+	err error
+	sc  balancer.SubConn
+}
+
+func (p *picker) Pick(ctx context.Context, opts balancer.PickOptions) (balancer.SubConn, func(balancer.DoneInfo), error) {
+	if p.err != nil {
+		return nil, nil, p.err
+	}
+	return p.sc, nil, nil
+}

cmd/vendor/google.golang.org/grpc/proxy.go

@@ -82,7 +82,8 @@ func doHTTPConnectHandshake(ctx context.Context, conn net.Conn, addr string) (_
 		Header: map[string][]string{"User-Agent": {grpcUA}},
 	})
 
-	if err := sendHTTPRequest(ctx, req, conn); err != nil {
+	req = req.WithContext(ctx)
+	if err := req.Write(conn); err != nil {
 		return nil, fmt.Errorf("failed to write the HTTP request: %v", err)
 	}
 

cmd/vendor/google.golang.org/grpc/resolver/resolver.go

@@ -0,0 +1,143 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package resolver defines APIs for name resolution in gRPC.
+// All APIs in this package are experimental.
+package resolver
+
+var (
+	// m is a map from scheme to resolver builder.
+	m = make(map[string]Builder)
+	// defaultScheme is the default scheme to use.
+	defaultScheme string
+)
+
+// TODO(bar) install dns resolver in init(){}.
+
+// Register registers the resolver builder to the resolver map.
+// b.Scheme will be used as the scheme registered with this builder.
+func Register(b Builder) {
+	m[b.Scheme()] = b
+}
+
+// Get returns the resolver builder registered with the given scheme.
+// If no builder is register with the scheme, the default scheme will
+// be used.
+// If the default scheme is not modified, "dns" will be the default
+// scheme, and the preinstalled dns resolver will be used.
+// If the default scheme is modified, and a resolver is registered with
+// the scheme, that resolver will be returned.
+// If the default scheme is modified, and no resolver is registered with
+// the scheme, nil will be returned.
+func Get(scheme string) Builder {
+	if b, ok := m[scheme]; ok {
+		return b
+	}
+	if b, ok := m[defaultScheme]; ok {
+		return b
+	}
+	return nil
+}
+
+// SetDefaultScheme sets the default scheme that will be used.
+// The default default scheme is "dns".
+func SetDefaultScheme(scheme string) {
+	defaultScheme = scheme
+}
+
+// AddressType indicates the address type returned by name resolution.
+type AddressType uint8
+
+const (
+	// Backend indicates the address is for a backend server.
+	Backend AddressType = iota
+	// GRPCLB indicates the address is for a grpclb load balancer.
+	GRPCLB
+)
+
+// Address represents a server the client connects to.
+// This is the EXPERIMENTAL API and may be changed or extended in the future.
+type Address struct {
+	// Addr is the server address on which a connection will be established.
+	Addr string
+	// Type is the type of this address.
+	Type AddressType
+	// ServerName is the name of this address.
+	// It's the name of the grpc load balancer, which will be used for authentication.
+	ServerName string
+	// Metadata is the information associated with Addr, which may be used
+	// to make load balancing decision.
+	Metadata interface{}
+}
+
+// BuildOption includes additional information for the builder to create
+// the resolver.
+type BuildOption struct {
+}
+
+// ClientConn contains the callbacks for resolver to notify any updates
+// to the gRPC ClientConn.
+type ClientConn interface {
+	// NewAddress is called by resolver to notify ClientConn a new list
+	// of resolved addresses.
+	// The address list should be the complete list of resolved addresses.
+	NewAddress(addresses []Address)
+	// NewServiceConfig is called by resolver to notify ClientConn a new
+	// service config. The service config should be provided as a json string.
+	NewServiceConfig(serviceConfig string)
+}
+
+// Target represents a target for gRPC, as specified in:
+// https://github.com/grpc/grpc/blob/master/doc/naming.md.
+type Target struct {
+	Scheme    string
+	Authority string
+	Endpoint  string
+}
+
+// Builder creates a resolver that will be used to watch name resolution updates.
+type Builder interface {
+	// Build creates a new resolver for the given target.
+	//
+	// gRPC dial calls Build synchronously, and fails if the returned error is
+	// not nil.
+	Build(target Target, cc ClientConn, opts BuildOption) (Resolver, error)
+	// Scheme returns the scheme supported by this resolver.
+	// Scheme is defined at https://github.com/grpc/grpc/blob/master/doc/naming.md.
+	Scheme() string
+}
+
+// ResolveNowOption includes additional information for ResolveNow.
+type ResolveNowOption struct{}
+
+// Resolver watches for the updates on the specified target.
+// Updates include address updates and service config updates.
+type Resolver interface {
+	// ResolveNow will be called by gRPC to try to resolve the target name again.
+	// It's just a hint, resolver can ignore this if it's not necessary.
+	ResolveNow(ResolveNowOption)
+	// Close closes the resolver.
+	Close()
+}
+
+// UnregisterForTesting removes the resolver builder with the given scheme from the
+// resolver map.
+// This function is for testing only.
+func UnregisterForTesting(scheme string) {
+	delete(m, scheme)
+}

cmd/vendor/google.golang.org/grpc/resolver_conn_wrapper.go

@@ -0,0 +1,139 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package grpc
+
+import (
+	"strings"
+
+	"google.golang.org/grpc/grpclog"
+	"google.golang.org/grpc/resolver"
+)
+
+// ccResolverWrapper is a wrapper on top of cc for resolvers.
+// It implements resolver.ClientConnection interface.
+type ccResolverWrapper struct {
+	cc       *ClientConn
+	resolver resolver.Resolver
+	addrCh   chan []resolver.Address
+	scCh     chan string
+	done     chan struct{}
+}
+
+// split2 returns the values from strings.SplitN(s, sep, 2).
+// If sep is not found, it returns "", s instead.
+func split2(s, sep string) (string, string) {
+	spl := strings.SplitN(s, sep, 2)
+	if len(spl) < 2 {
+		return "", s
+	}
+	return spl[0], spl[1]
+}
+
+// parseTarget splits target into a struct containing scheme, authority and
+// endpoint.
+func parseTarget(target string) (ret resolver.Target) {
+	ret.Scheme, ret.Endpoint = split2(target, "://")
+	ret.Authority, ret.Endpoint = split2(ret.Endpoint, "/")
+	return ret
+}
+
+// newCCResolverWrapper parses cc.target for scheme and gets the resolver
+// builder for this scheme. It then builds the resolver and starts the
+// monitoring goroutine for it.
+//
+// This function could return nil, nil, in tests for old behaviors.
+// TODO(bar) never return nil, nil when DNS becomes the default resolver.
+func newCCResolverWrapper(cc *ClientConn) (*ccResolverWrapper, error) {
+	target := parseTarget(cc.target)
+	grpclog.Infof("dialing to target with scheme: %q", target.Scheme)
+
+	rb := resolver.Get(target.Scheme)
+	if rb == nil {
+		// TODO(bar) return error when DNS becomes the default (implemented and
+		// registered by DNS package).
+		grpclog.Infof("could not get resolver for scheme: %q", target.Scheme)
+		return nil, nil
+	}
+
+	ccr := &ccResolverWrapper{
+		cc:     cc,
+		addrCh: make(chan []resolver.Address, 1),
+		scCh:   make(chan string, 1),
+		done:   make(chan struct{}),
+	}
+
+	var err error
+	ccr.resolver, err = rb.Build(target, ccr, resolver.BuildOption{})
+	if err != nil {
+		return nil, err
+	}
+	go ccr.watcher()
+	return ccr, nil
+}
+
+// watcher processes address updates and service config updates sequencially.
+// Otherwise, we need to resolve possible races between address and service
+// config (e.g. they specify different balancer types).
+func (ccr *ccResolverWrapper) watcher() {
+	for {
+		select {
+		case <-ccr.done:
+			return
+		default:
+		}
+
+		select {
+		case addrs := <-ccr.addrCh:
+			grpclog.Infof("ccResolverWrapper: sending new addresses to balancer wrapper: %v", addrs)
+			// TODO(bar switching) this should never be nil. Pickfirst should be default.
+			if ccr.cc.balancerWrapper != nil {
+				// TODO(bar switching) create balancer if it's nil?
+				ccr.cc.balancerWrapper.handleResolvedAddrs(addrs, nil)
+			}
+		case sc := <-ccr.scCh:
+			grpclog.Infof("ccResolverWrapper: got new service config: %v", sc)
+		case <-ccr.done:
+			return
+		}
+	}
+}
+
+func (ccr *ccResolverWrapper) close() {
+	ccr.resolver.Close()
+	close(ccr.done)
+}
+
+// NewAddress is called by the resolver implemenetion to send addresses to gRPC.
+func (ccr *ccResolverWrapper) NewAddress(addrs []resolver.Address) {
+	select {
+	case <-ccr.addrCh:
+	default:
+	}
+	ccr.addrCh <- addrs
+}
+
+// NewServiceConfig is called by the resolver implemenetion to send service
+// configs to gPRC.
+func (ccr *ccResolverWrapper) NewServiceConfig(sc string) {
+	select {
+	case <-ccr.scCh:
+	default:
+	}
+	ccr.scCh <- sc
+}

cmd/vendor/google.golang.org/grpc/rpc_util.go

@@ -21,10 +21,12 @@ package grpc
 import (
 	"bytes"
 	"compress/gzip"
+	stdctx "context"
 	"encoding/binary"
 	"io"
 	"io/ioutil"
 	"math"
+	"os"
 	"sync"
 	"time"
 
@@ -132,7 +134,9 @@ type callInfo struct {
 	creds                 credentials.PerRPCCredentials
 }
 
-var defaultCallInfo = callInfo{failFast: true}
+func defaultCallInfo() *callInfo {
+	return &callInfo{failFast: true}
+}
 
 // CallOption configures a Call before it starts or extracts information from
 // a Call after it completes.
@@ -384,14 +388,15 @@ func recv(p *parser, c Codec, s *transport.Stream, dc Decompressor, m interface{
 }
 
 type rpcInfo struct {
+	failfast      bool
 	bytesSent     bool
 	bytesReceived bool
 }
 
 type rpcInfoContextKey struct{}
 
-func newContextWithRPCInfo(ctx context.Context) context.Context {
-	return context.WithValue(ctx, rpcInfoContextKey{}, &rpcInfo{})
+func newContextWithRPCInfo(ctx context.Context, failfast bool) context.Context {
+	return context.WithValue(ctx, rpcInfoContextKey{}, &rpcInfo{failfast: failfast})
 }
 
 func rpcInfoFromContext(ctx context.Context) (s *rpcInfo, ok bool) {
@@ -401,11 +406,63 @@ func rpcInfoFromContext(ctx context.Context) (s *rpcInfo, ok bool) {
 
 func updateRPCInfoInContext(ctx context.Context, s rpcInfo) {
 	if ss, ok := rpcInfoFromContext(ctx); ok {
-		*ss = s
+		ss.bytesReceived = s.bytesReceived
+		ss.bytesSent = s.bytesSent
 	}
 	return
 }
 
+// toRPCErr converts an error into an error from the status package.
+func toRPCErr(err error) error {
+	if _, ok := status.FromError(err); ok {
+		return err
+	}
+	switch e := err.(type) {
+	case transport.StreamError:
+		return status.Error(e.Code, e.Desc)
+	case transport.ConnectionError:
+		return status.Error(codes.Unavailable, e.Desc)
+	default:
+		switch err {
+		case context.DeadlineExceeded, stdctx.DeadlineExceeded:
+			return status.Error(codes.DeadlineExceeded, err.Error())
+		case context.Canceled, stdctx.Canceled:
+			return status.Error(codes.Canceled, err.Error())
+		case ErrClientConnClosing:
+			return status.Error(codes.FailedPrecondition, err.Error())
+		}
+	}
+	return status.Error(codes.Unknown, err.Error())
+}
+
+// convertCode converts a standard Go error into its canonical code. Note that
+// this is only used to translate the error returned by the server applications.
+func convertCode(err error) codes.Code {
+	switch err {
+	case nil:
+		return codes.OK
+	case io.EOF:
+		return codes.OutOfRange
+	case io.ErrClosedPipe, io.ErrNoProgress, io.ErrShortBuffer, io.ErrShortWrite, io.ErrUnexpectedEOF:
+		return codes.FailedPrecondition
+	case os.ErrInvalid:
+		return codes.InvalidArgument
+	case context.Canceled, stdctx.Canceled:
+		return codes.Canceled
+	case context.DeadlineExceeded, stdctx.DeadlineExceeded:
+		return codes.DeadlineExceeded
+	}
+	switch {
+	case os.IsExist(err):
+		return codes.AlreadyExists
+	case os.IsNotExist(err):
+		return codes.NotFound
+	case os.IsPermission(err):
+		return codes.PermissionDenied
+	}
+	return codes.Unknown
+}
+
 // Code returns the error code for err if it was produced by the rpc system.
 // Otherwise, it returns codes.Unknown.
 //
@@ -452,7 +509,7 @@ type MethodConfig struct {
 	// MaxReqSize is the maximum allowed payload size for an individual request in a
 	// stream (client->server) in bytes. The size which is measured is the serialized
 	// payload after per-message compression (but before stream compression) in bytes.
-	// The actual value used is the minumum of the value specified here and the value set
+	// The actual value used is the minimum of the value specified here and the value set
 	// by the application via the gRPC client API. If either one is not set, then the other
 	// will be used.  If neither is set, then the built-in default is used.
 	MaxReqSize *int
@@ -497,7 +554,7 @@ func getMaxSize(mcMax, doptMax *int, defaultVal int) *int {
 
 // SupportPackageIsVersion3 is referenced from generated protocol buffer files.
 // The latest support package version is 4.
-// SupportPackageIsVersion3 is kept for compability. It will be removed in the
+// SupportPackageIsVersion3 is kept for compatibility. It will be removed in the
 // next support package version update.
 const SupportPackageIsVersion3 = true
 
@@ -510,6 +567,6 @@ const SupportPackageIsVersion3 = true
 const SupportPackageIsVersion4 = true
 
 // Version is the current grpc version.
-const Version = "1.6.0"
+const Version = "1.7.2"
 
 const grpcUA = "grpc-go/" + Version

cmd/vendor/google.golang.org/grpc/server.go

@@ -116,6 +116,8 @@ type options struct {
 	keepalivePolicy       keepalive.EnforcementPolicy
 	initialWindowSize     int32
 	initialConnWindowSize int32
+	writeBufferSize       int
+	readBufferSize        int
 }
 
 var defaultServerOptions = options{
@@ -126,6 +128,22 @@ var defaultServerOptions = options{
 // A ServerOption sets options such as credentials, codec and keepalive parameters, etc.
 type ServerOption func(*options)
 
+// WriteBufferSize lets you set the size of write buffer, this determines how much data can be batched
+// before doing a write on the wire.
+func WriteBufferSize(s int) ServerOption {
+	return func(o *options) {
+		o.writeBufferSize = s
+	}
+}
+
+// ReadBufferSize lets you set the size of read buffer, this determines how much data can be read at most
+// for one read syscall.
+func ReadBufferSize(s int) ServerOption {
+	return func(o *options) {
+		o.readBufferSize = s
+	}
+}
+
 // InitialWindowSize returns a ServerOption that sets window size for stream.
 // The lower bound for window size is 64K and any value smaller than that will be ignored.
 func InitialWindowSize(s int32) ServerOption {
@@ -260,7 +278,7 @@ func StatsHandler(h stats.Handler) ServerOption {
 // handler that will be invoked instead of returning the "unimplemented" gRPC
 // error whenever a request is received for an unregistered service or method.
 // The handling function has full access to the Context of the request and the
-// stream, and the invocation passes through interceptors.
+// stream, and the invocation bypasses interceptors.
 func UnknownServiceHandler(streamHandler StreamHandler) ServerOption {
 	return func(o *options) {
 		o.unknownStreamDesc = &StreamDesc{
@@ -524,6 +542,8 @@ func (s *Server) serveHTTP2Transport(c net.Conn, authInfo credentials.AuthInfo)
 		KeepalivePolicy:       s.opts.keepalivePolicy,
 		InitialWindowSize:     s.opts.initialWindowSize,
 		InitialConnWindowSize: s.opts.initialConnWindowSize,
+		WriteBufferSize:       s.opts.writeBufferSize,
+		ReadBufferSize:        s.opts.readBufferSize,
 	}
 	st, err := transport.NewServerTransport("http2", c, config)
 	if err != nil {
@@ -891,9 +911,6 @@ func (s *Server) processStreamingRPC(t transport.ServerTransport, stream *transp
 		trInfo:                trInfo,
 		statsHandler:          sh,
 	}
-	if ss.cp != nil {
-		ss.cbuf = new(bytes.Buffer)
-	}
 	if trInfo != nil {
 		trInfo.tr.LazyLog(&trInfo.firstLine, false)
 		defer func() {

cmd/vendor/google.golang.org/grpc/stats/stats.go

@@ -135,8 +135,6 @@ func (s *OutPayload) isRPCStats() {}
 type OutHeader struct {
 	// Client is true if this OutHeader is from client side.
 	Client bool
-	// WireLength is the wire length of header.
-	WireLength int
 
 	// The following fields are valid only if Client is true.
 	// FullMethod is the full RPC method string, i.e., /package.service/method.
@@ -220,7 +218,7 @@ type outgoingTagsKey struct{}
 // the outgoing RPC with the header grpc-tags-bin.  Subsequent calls to
 // SetTags will overwrite the values from earlier calls.
 //
-// NOTE: this is provided only for backward compatibilty with existing clients
+// NOTE: this is provided only for backward compatibility with existing clients
 // and will likely be removed in an upcoming release.  New uses should transmit
 // this type of data using metadata with a different, non-reserved (i.e. does
 // not begin with "grpc-") header name.
@@ -230,7 +228,7 @@ func SetTags(ctx context.Context, b []byte) context.Context {
 
 // Tags returns the tags from the context for the inbound RPC.
 //
-// NOTE: this is provided only for backward compatibilty with existing clients
+// NOTE: this is provided only for backward compatibility with existing clients
 // and will likely be removed in an upcoming release.  New uses should transmit
 // this type of data using metadata with a different, non-reserved (i.e. does
 // not begin with "grpc-") header name.
@@ -262,7 +260,7 @@ type outgoingTraceKey struct{}
 // the outgoing RPC with the header grpc-trace-bin.  Subsequent calls to
 // SetTrace will overwrite the values from earlier calls.
 //
-// NOTE: this is provided only for backward compatibilty with existing clients
+// NOTE: this is provided only for backward compatibility with existing clients
 // and will likely be removed in an upcoming release.  New uses should transmit
 // this type of data using metadata with a different, non-reserved (i.e. does
 // not begin with "grpc-") header name.
@@ -272,7 +270,7 @@ func SetTrace(ctx context.Context, b []byte) context.Context {
 
 // Trace returns the trace from the context for the inbound RPC.
 //
-// NOTE: this is provided only for backward compatibilty with existing clients
+// NOTE: this is provided only for backward compatibility with existing clients
 // and will likely be removed in an upcoming release.  New uses should transmit
 // this type of data using metadata with a different, non-reserved (i.e. does
 // not begin with "grpc-") header name.

cmd/vendor/google.golang.org/grpc/stream.go

@@ -27,6 +27,7 @@ import (
 
 	"golang.org/x/net/context"
 	"golang.org/x/net/trace"
+	"google.golang.org/grpc/balancer"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/metadata"
 	"google.golang.org/grpc/peer"
@@ -106,10 +107,10 @@ func newClientStream(ctx context.Context, desc *StreamDesc, cc *ClientConn, meth
 	var (
 		t      transport.ClientTransport
 		s      *transport.Stream
-		put    func()
+		done   func(balancer.DoneInfo)
 		cancel context.CancelFunc
 	)
-	c := defaultCallInfo
+	c := defaultCallInfo()
 	mc := cc.GetMethodConfig(method)
 	if mc.WaitForReady != nil {
 		c.failFast = !*mc.WaitForReady
@@ -126,7 +127,7 @@ func newClientStream(ctx context.Context, desc *StreamDesc, cc *ClientConn, meth
 
 	opts = append(cc.dopts.callOptions, opts...)
 	for _, o := range opts {
-		if err := o.before(&c); err != nil {
+		if err := o.before(c); err != nil {
 			return nil, toRPCErr(err)
 		}
 	}
@@ -167,7 +168,7 @@ func newClientStream(ctx context.Context, desc *StreamDesc, cc *ClientConn, meth
 			}
 		}()
 	}
-	ctx = newContextWithRPCInfo(ctx)
+	ctx = newContextWithRPCInfo(ctx, c.failFast)
 	sh := cc.dopts.copts.StatsHandler
 	if sh != nil {
 		ctx = sh.TagRPC(ctx, &stats.RPCTagInfo{FullMethodName: method, FailFast: c.failFast})
@@ -188,11 +189,8 @@ func newClientStream(ctx context.Context, desc *StreamDesc, cc *ClientConn, meth
 			}
 		}()
 	}
-	gopts := BalancerGetOptions{
-		BlockingWait: !c.failFast,
-	}
 	for {
-		t, put, err = cc.getTransport(ctx, gopts)
+		t, done, err = cc.getTransport(ctx, c.failFast)
 		if err != nil {
 			// TODO(zhaoq): Probably revisit the error handling.
 			if _, ok := status.FromError(err); ok {
@@ -210,15 +208,15 @@ func newClientStream(ctx context.Context, desc *StreamDesc, cc *ClientConn, meth
 
 		s, err = t.NewStream(ctx, callHdr)
 		if err != nil {
-			if _, ok := err.(transport.ConnectionError); ok && put != nil {
+			if _, ok := err.(transport.ConnectionError); ok && done != nil {
 				// If error is connection error, transport was sending data on wire,
 				// and we are not sure if anything has been sent on wire.
 				// If error is not connection error, we are sure nothing has been sent.
 				updateRPCInfoInContext(ctx, rpcInfo{bytesSent: true, bytesReceived: false})
 			}
-			if put != nil {
-				put()
-				put = nil
+			if done != nil {
+				done(balancer.DoneInfo{Err: err})
+				done = nil
 			}
 			if _, ok := err.(transport.ConnectionError); (ok || err == transport.ErrStreamDrain) && !c.failFast {
 				continue
@@ -240,10 +238,10 @@ func newClientStream(ctx context.Context, desc *StreamDesc, cc *ClientConn, meth
 		dc:     cc.dopts.dc,
 		cancel: cancel,
 
-		put: put,
-		t:   t,
-		s:   s,
-		p:   &parser{r: s},
+		done: done,
+		t:    t,
+		s:    s,
+		p:    &parser{r: s},
 
 		tracing: EnableTracing,
 		trInfo:  trInfo,
@@ -251,9 +249,6 @@ func newClientStream(ctx context.Context, desc *StreamDesc, cc *ClientConn, meth
 		statsCtx:     ctx,
 		statsHandler: cc.dopts.copts.StatsHandler,
 	}
-	if cc.dopts.cp != nil {
-		cs.cbuf = new(bytes.Buffer)
-	}
 	// Listen on ctx.Done() to detect cancellation and s.Done() to detect normal termination
 	// when there is no pending I/O operations on this stream.
 	go func() {
@@ -283,21 +278,20 @@ func newClientStream(ctx context.Context, desc *StreamDesc, cc *ClientConn, meth
 // clientStream implements a client side Stream.
 type clientStream struct {
 	opts   []CallOption
-	c      callInfo
+	c      *callInfo
 	t      transport.ClientTransport
 	s      *transport.Stream
 	p      *parser
 	desc   *StreamDesc
 	codec  Codec
 	cp     Compressor
-	cbuf   *bytes.Buffer
 	dc     Decompressor
 	cancel context.CancelFunc
 
 	tracing bool // set to EnableTracing when the clientStream is created.
 
 	mu       sync.Mutex
-	put      func()
+	done     func(balancer.DoneInfo)
 	closed   bool
 	finished bool
 	// trInfo.tr is set when the clientStream is created (if EnableTracing is true),
@@ -367,12 +361,7 @@ func (cs *clientStream) SendMsg(m interface{}) (err error) {
 			Client: true,
 		}
 	}
-	hdr, data, err := encode(cs.codec, m, cs.cp, cs.cbuf, outPayload)
-	defer func() {
-		if cs.cbuf != nil {
-			cs.cbuf.Reset()
-		}
-	}()
+	hdr, data, err := encode(cs.codec, m, cs.cp, bytes.NewBuffer([]byte{}), outPayload)
 	if err != nil {
 		return err
 	}
@@ -494,15 +483,15 @@ func (cs *clientStream) finish(err error) {
 		}
 	}()
 	for _, o := range cs.opts {
-		o.after(&cs.c)
+		o.after(cs.c)
 	}
-	if cs.put != nil {
+	if cs.done != nil {
 		updateRPCInfoInContext(cs.s.Context(), rpcInfo{
 			bytesSent:     cs.s.BytesSent(),
 			bytesReceived: cs.s.BytesReceived(),
 		})
-		cs.put()
-		cs.put = nil
+		cs.done(balancer.DoneInfo{Err: err})
+		cs.done = nil
 	}
 	if cs.statsHandler != nil {
 		end := &stats.End{
@@ -557,7 +546,6 @@ type serverStream struct {
 	codec                 Codec
 	cp                    Compressor
 	dc                    Decompressor
-	cbuf                  *bytes.Buffer
 	maxReceiveMessageSize int
 	maxSendMessageSize    int
 	trInfo                *traceInfo
@@ -613,12 +601,7 @@ func (ss *serverStream) SendMsg(m interface{}) (err error) {
 	if ss.statsHandler != nil {
 		outPayload = &stats.OutPayload{}
 	}
-	hdr, data, err := encode(ss.codec, m, ss.cp, ss.cbuf, outPayload)
-	defer func() {
-		if ss.cbuf != nil {
-			ss.cbuf.Reset()
-		}
-	}()
+	hdr, data, err := encode(ss.codec, m, ss.cp, bytes.NewBuffer([]byte{}), outPayload)
 	if err != nil {
 		return err
 	}

cmd/vendor/google.golang.org/grpc/trace.go

@@ -31,7 +31,7 @@ import (
 
 // EnableTracing controls whether to trace RPCs using the golang.org/x/net/trace package.
 // This should only be set before any RPCs are sent or received by this program.
-var EnableTracing = true
+var EnableTracing bool
 
 // methodFamily returns the trace family for the given method.
 // It turns "/pkg.Service/GetFoo" into "pkg.Service".
@@ -76,6 +76,15 @@ func (f *firstLine) String() string {
 	return line.String()
 }
 
+const truncateSize = 100
+
+func truncate(x string, l int) string {
+	if l > len(x) {
+		return x
+	}
+	return x[:l]
+}
+
 // payload represents an RPC request or response payload.
 type payload struct {
 	sent bool        // whether this is an outgoing payload
@@ -85,9 +94,9 @@ type payload struct {
 
 func (p payload) String() string {
 	if p.sent {
-		return fmt.Sprintf("sent: %v", p.msg)
+		return truncate(fmt.Sprintf("sent: %v", p.msg), truncateSize)
 	}
-	return fmt.Sprintf("recv: %v", p.msg)
+	return truncate(fmt.Sprintf("recv: %v", p.msg), truncateSize)
 }
 
 type fmtStringer struct {

cmd/vendor/google.golang.org/grpc/transport/bdp_estimator.go

@@ -59,7 +59,7 @@ type bdpEstimator struct {
 	sample uint32
 	// bwMax is the maximum bandwidth noted so far (bytes/sec).
 	bwMax float64
-	// bool to keep track of the begining of a new measurement cycle.
+	// bool to keep track of the beginning of a new measurement cycle.
 	isSent bool
 	// Callback to update the window sizes.
 	updateFlowControl func(n uint32)
@@ -70,7 +70,7 @@ type bdpEstimator struct {
 }
 
 // timesnap registers the time bdp ping was sent out so that
-// network rtt can be calculated when its ack is recieved.
+// network rtt can be calculated when its ack is received.
 // It is called (by controller) when the bdpPing is
 // being written on the wire.
 func (b *bdpEstimator) timesnap(d [8]byte) {
@@ -119,7 +119,7 @@ func (b *bdpEstimator) calculate(d [8]byte) {
 		b.rtt += (rttSample - b.rtt) * float64(alpha)
 	}
 	b.isSent = false
-	// The number of bytes accumalated so far in the sample is smaller
+	// The number of bytes accumulated so far in the sample is smaller
 	// than or equal to 1.5 times the real BDP on a saturated connection.
 	bwCurrent := float64(b.sample) / (b.rtt * float64(1.5))
 	if bwCurrent > b.bwMax {

cmd/vendor/google.golang.org/grpc/transport/control.go

@@ -22,9 +22,11 @@ import (
 	"fmt"
 	"math"
 	"sync"
+	"sync/atomic"
 	"time"
 
 	"golang.org/x/net/http2"
+	"golang.org/x/net/http2/hpack"
 )
 
 const (
@@ -44,15 +46,44 @@ const (
 	defaultKeepalivePolicyMinTime = time.Duration(5 * time.Minute)
 	// max window limit set by HTTP2 Specs.
 	maxWindowSize = math.MaxInt32
+	// defaultLocalSendQuota sets is default value for number of data
+	// bytes that each stream can schedule before some of it being
+	// flushed out.
+	defaultLocalSendQuota = 64 * 1024
 )
 
 // The following defines various control items which could flow through
 // the control buffer of transport. They represent different aspects of
 // control tasks, e.g., flow control, settings, streaming resetting, etc.
+
+type headerFrame struct {
+	streamID  uint32
+	hf        []hpack.HeaderField
+	endStream bool
+}
+
+func (*headerFrame) item() {}
+
+type continuationFrame struct {
+	streamID            uint32
+	endHeaders          bool
+	headerBlockFragment []byte
+}
+
+type dataFrame struct {
+	streamID  uint32
+	endStream bool
+	d         []byte
+	f         func()
+}
+
+func (*dataFrame) item() {}
+
+func (*continuationFrame) item() {}
+
 type windowUpdate struct {
 	streamID  uint32
 	increment uint32
-	flush     bool
 }
 
 func (*windowUpdate) item() {}
@@ -97,8 +128,9 @@ func (*ping) item() {}
 type quotaPool struct {
 	c chan int
 
-	mu    sync.Mutex
-	quota int
+	mu      sync.Mutex
+	version uint32
+	quota   int
 }
 
 // newQuotaPool creates a quotaPool which has quota q available to consume.
@@ -119,6 +151,10 @@ func newQuotaPool(q int) *quotaPool {
 func (qb *quotaPool) add(v int) {
 	qb.mu.Lock()
 	defer qb.mu.Unlock()
+	qb.lockedAdd(v)
+}
+
+func (qb *quotaPool) lockedAdd(v int) {
 	select {
 	case n := <-qb.c:
 		qb.quota += n
@@ -139,6 +175,35 @@ func (qb *quotaPool) add(v int) {
 	}
 }
 
+func (qb *quotaPool) addAndUpdate(v int) {
+	qb.mu.Lock()
+	defer qb.mu.Unlock()
+	qb.lockedAdd(v)
+	// Update the version only after having added to the quota
+	// so that if acquireWithVesrion sees the new vesrion it is
+	// guaranteed to have seen the updated quota.
+	// Also, still keep this inside of the lock, so that when
+	// compareAndExecute is processing, this function doesn't
+	// get executed partially (quota gets updated but the version
+	// doesn't).
+	atomic.AddUint32(&(qb.version), 1)
+}
+
+func (qb *quotaPool) acquireWithVersion() (<-chan int, uint32) {
+	return qb.c, atomic.LoadUint32(&(qb.version))
+}
+
+func (qb *quotaPool) compareAndExecute(version uint32, success, failure func()) bool {
+	qb.mu.Lock()
+	defer qb.mu.Unlock()
+	if version == atomic.LoadUint32(&(qb.version)) {
+		success()
+		return true
+	}
+	failure()
+	return false
+}
+
 // acquire returns the channel on which available quota amounts are sent.
 func (qb *quotaPool) acquire() <-chan int {
 	return qb.c

cmd/vendor/google.golang.org/grpc/transport/go16.go

@@ -1,45 +0,0 @@
-// +build go1.6,!go1.7
-
-/*
- *
- * Copyright 2016 gRPC authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- */
-
-package transport
-
-import (
-	"net"
-
-	"google.golang.org/grpc/codes"
-
-	"golang.org/x/net/context"
-)
-
-// dialContext connects to the address on the named network.
-func dialContext(ctx context.Context, network, address string) (net.Conn, error) {
-	return (&net.Dialer{Cancel: ctx.Done()}).Dial(network, address)
-}
-
-// ContextErr converts the error from context package into a StreamError.
-func ContextErr(err error) StreamError {
-	switch err {
-	case context.DeadlineExceeded:
-		return streamErrorf(codes.DeadlineExceeded, "%v", err)
-	case context.Canceled:
-		return streamErrorf(codes.Canceled, "%v", err)
-	}
-	return streamErrorf(codes.Internal, "Unexpected error from context packet: %v", err)
-}

cmd/vendor/google.golang.org/grpc/transport/go17.go

@@ -1,46 +0,0 @@
-// +build go1.7
-
-/*
- *
- * Copyright 2016 gRPC authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- */
-
-package transport
-
-import (
-	"context"
-	"net"
-
-	"google.golang.org/grpc/codes"
-
-	netctx "golang.org/x/net/context"
-)
-
-// dialContext connects to the address on the named network.
-func dialContext(ctx context.Context, network, address string) (net.Conn, error) {
-	return (&net.Dialer{}).DialContext(ctx, network, address)
-}
-
-// ContextErr converts the error from context package into a StreamError.
-func ContextErr(err error) StreamError {
-	switch err {
-	case context.DeadlineExceeded, netctx.DeadlineExceeded:
-		return streamErrorf(codes.DeadlineExceeded, "%v", err)
-	case context.Canceled, netctx.Canceled:
-		return streamErrorf(codes.Canceled, "%v", err)
-	}
-	return streamErrorf(codes.Internal, "Unexpected error from context packet: %v", err)
-}

cmd/vendor/google.golang.org/grpc/transport/handler_server.go

@@ -173,7 +173,6 @@ func (ht *serverHandlerTransport) do(fn func()) error {
 		case <-ht.closedCh:
 			return ErrConnClosing
 		}
-
 	}
 }
 
@@ -183,6 +182,7 @@ func (ht *serverHandlerTransport) WriteStatus(s *Stream, st *status.Status) erro
 		ht.mu.Unlock()
 		return nil
 	}
+	ht.streamDone = true
 	ht.mu.Unlock()
 	err := ht.do(func() {
 		ht.writeCommonHeaders(s)
@@ -223,9 +223,6 @@ func (ht *serverHandlerTransport) WriteStatus(s *Stream, st *status.Status) erro
 		}
 	})
 	close(ht.writes)
-	ht.mu.Lock()
-	ht.streamDone = true
-	ht.mu.Unlock()
 	return err
 }
 

cmd/vendor/google.golang.org/grpc/transport/http2_client.go

@@ -43,6 +43,7 @@ import (
 // http2Client implements the ClientTransport interface with HTTP2.
 type http2Client struct {
 	ctx        context.Context
+	cancel     context.CancelFunc
 	target     string // server name/addr
 	userAgent  string
 	md         interface{}
@@ -52,17 +53,6 @@ type http2Client struct {
 	authInfo   credentials.AuthInfo // auth info about the connection
 	nextID     uint32               // the next stream ID to be used
 
-	// writableChan synchronizes write access to the transport.
-	// A writer acquires the write lock by sending a value on writableChan
-	// and releases it by receiving from writableChan.
-	writableChan chan int
-	// shutdownChan is closed when Close is called.
-	// Blocking operations should select on shutdownChan to avoid
-	// blocking forever after Close.
-	// TODO(zhaoq): Maybe have a channel context?
-	shutdownChan chan struct{}
-	// errorChan is closed to notify the I/O error to the caller.
-	errorChan chan struct{}
 	// goAway is closed to notify the upper layer (i.e., addrConn.transportMonitor)
 	// that the server sent GoAway on this transport.
 	goAway chan struct{}
@@ -119,7 +109,7 @@ func dial(ctx context.Context, fn func(context.Context, string) (net.Conn, error
 	if fn != nil {
 		return fn(ctx, addr)
 	}
-	return dialContext(ctx, "tcp", addr)
+	return (&net.Dialer{}).DialContext(ctx, "tcp", addr)
 }
 
 func isTemporary(err error) bool {
@@ -153,9 +143,18 @@ func isTemporary(err error) bool {
 // newHTTP2Client constructs a connected ClientTransport to addr based on HTTP2
 // and starts to receive messages on it. Non-nil error returns if construction
 // fails.
-func newHTTP2Client(ctx context.Context, addr TargetInfo, opts ConnectOptions) (_ ClientTransport, err error) {
+func newHTTP2Client(ctx context.Context, addr TargetInfo, opts ConnectOptions, timeout time.Duration) (_ ClientTransport, err error) {
 	scheme := "http"
-	conn, err := dial(ctx, opts.Dialer, addr.Addr)
+	ctx, cancel := context.WithCancel(ctx)
+	connectCtx, connectCancel := context.WithTimeout(ctx, timeout)
+	defer func() {
+		connectCancel()
+		if err != nil {
+			cancel()
+		}
+	}()
+
+	conn, err := dial(connectCtx, opts.Dialer, addr.Addr)
 	if err != nil {
 		if opts.FailOnNonTempDialError {
 			return nil, connectionErrorf(isTemporary(err), err, "transport: error while dialing: %v", err)
@@ -174,7 +173,7 @@ func newHTTP2Client(ctx context.Context, addr TargetInfo, opts ConnectOptions) (
 	)
 	if creds := opts.TransportCredentials; creds != nil {
 		scheme = "https"
-		conn, authInfo, err = creds.ClientHandshake(ctx, addr.Addr, conn)
+		conn, authInfo, err = creds.ClientHandshake(connectCtx, addr.Addr, conn)
 		if err != nil {
 			// Credentials handshake errors are typically considered permanent
 			// to avoid retrying on e.g. bad certificates.
@@ -198,8 +197,17 @@ func newHTTP2Client(ctx context.Context, addr TargetInfo, opts ConnectOptions) (
 		dynamicWindow = false
 	}
 	var buf bytes.Buffer
+	writeBufSize := defaultWriteBufSize
+	if opts.WriteBufferSize > 0 {
+		writeBufSize = opts.WriteBufferSize
+	}
+	readBufSize := defaultReadBufSize
+	if opts.ReadBufferSize > 0 {
+		readBufSize = opts.ReadBufferSize
+	}
 	t := &http2Client{
 		ctx:        ctx,
+		cancel:     cancel,
 		target:     addr.Addr,
 		userAgent:  opts.UserAgent,
 		md:         addr.Metadata,
@@ -209,14 +217,11 @@ func newHTTP2Client(ctx context.Context, addr TargetInfo, opts ConnectOptions) (
 		authInfo:   authInfo,
 		// The client initiated stream id is odd starting from 1.
 		nextID:            1,
-		writableChan:      make(chan int, 1),
-		shutdownChan:      make(chan struct{}),
-		errorChan:         make(chan struct{}),
 		goAway:            make(chan struct{}),
 		awakenKeepalive:   make(chan struct{}, 1),
-		framer:            newFramer(conn),
 		hBuf:              &buf,
 		hEnc:              hpack.NewEncoder(&buf),
+		framer:            newFramer(conn, writeBufSize, readBufSize),
 		controlBuf:        newControlBuffer(),
 		fc:                &inFlow{limit: uint32(icwz)},
 		sendQuotaPool:     newQuotaPool(defaultWindowSize),
@@ -270,12 +275,12 @@ func newHTTP2Client(ctx context.Context, addr TargetInfo, opts ConnectOptions) (
 		return nil, connectionErrorf(true, err, "transport: preface mismatch, wrote %d bytes; want %d", n, len(clientPreface))
 	}
 	if t.initialWindowSize != defaultWindowSize {
-		err = t.framer.writeSettings(true, http2.Setting{
+		err = t.framer.fr.WriteSettings(http2.Setting{
 			ID:  http2.SettingInitialWindowSize,
 			Val: uint32(t.initialWindowSize),
 		})
 	} else {
-		err = t.framer.writeSettings(true)
+		err = t.framer.fr.WriteSettings()
 	}
 	if err != nil {
 		t.Close()
@@ -283,31 +288,35 @@ func newHTTP2Client(ctx context.Context, addr TargetInfo, opts ConnectOptions) (
 	}
 	// Adjust the connection flow control window if needed.
 	if delta := uint32(icwz - defaultWindowSize); delta > 0 {
-		if err := t.framer.writeWindowUpdate(true, 0, delta); err != nil {
+		if err := t.framer.fr.WriteWindowUpdate(0, delta); err != nil {
 			t.Close()
 			return nil, connectionErrorf(true, err, "transport: failed to write window update: %v", err)
 		}
 	}
-	go t.controller()
+	t.framer.writer.Flush()
+	go func() {
+		loopyWriter(t.ctx, t.controlBuf, t.itemHandler)
+		t.Close()
+	}()
 	if t.kp.Time != infinity {
 		go t.keepalive()
 	}
-	t.writableChan <- 0
 	return t, nil
 }
 
 func (t *http2Client) newStream(ctx context.Context, callHdr *CallHdr) *Stream {
 	// TODO(zhaoq): Handle uint32 overflow of Stream.id.
 	s := &Stream{
-		id:            t.nextID,
-		done:          make(chan struct{}),
-		goAway:        make(chan struct{}),
-		method:        callHdr.Method,
-		sendCompress:  callHdr.SendCompress,
-		buf:           newRecvBuffer(),
-		fc:            &inFlow{limit: uint32(t.initialWindowSize)},
-		sendQuotaPool: newQuotaPool(int(t.streamSendQuota)),
-		headerChan:    make(chan struct{}),
+		id:             t.nextID,
+		done:           make(chan struct{}),
+		goAway:         make(chan struct{}),
+		method:         callHdr.Method,
+		sendCompress:   callHdr.SendCompress,
+		buf:            newRecvBuffer(),
+		fc:             &inFlow{limit: uint32(t.initialWindowSize)},
+		sendQuotaPool:  newQuotaPool(int(t.streamSendQuota)),
+		localSendQuota: newQuotaPool(defaultLocalSendQuota),
+		headerChan:     make(chan struct{}),
 	}
 	t.nextID += 2
 	s.requestRead = func(n int) {
@@ -368,13 +377,13 @@ func (t *http2Client) NewStream(ctx context.Context, callHdr *CallHdr) (_ *Strea
 			authData[k] = v
 		}
 	}
-	callAuthData := make(map[string]string)
+	callAuthData := map[string]string{}
 	// Check if credentials.PerRPCCredentials were provided via call options.
 	// Note: if these credentials are provided both via dial options and call
 	// options, then both sets of credentials will be applied.
 	if callCreds := callHdr.Creds; callCreds != nil {
 		if !t.isSecure && callCreds.RequireTransportSecurity() {
-			return nil, streamErrorf(codes.Unauthenticated, "transport: cannot send secure credentials on an insecure conneciton")
+			return nil, streamErrorf(codes.Unauthenticated, "transport: cannot send secure credentials on an insecure connection")
 		}
 		data, err := callCreds.GetRequestMetadata(ctx, audience)
 		if err != nil {
@@ -400,7 +409,7 @@ func (t *http2Client) NewStream(ctx context.Context, callHdr *CallHdr) (_ *Strea
 		return nil, ErrConnClosing
 	}
 	t.mu.Unlock()
-	sq, err := wait(ctx, nil, nil, t.shutdownChan, t.streamsQuota.acquire())
+	sq, err := wait(ctx, t.ctx, nil, nil, t.streamsQuota.acquire())
 	if err != nil {
 		return nil, err
 	}
@@ -408,78 +417,40 @@ func (t *http2Client) NewStream(ctx context.Context, callHdr *CallHdr) (_ *Strea
 	if sq > 1 {
 		t.streamsQuota.add(sq - 1)
 	}
-	if _, err := wait(ctx, nil, nil, t.shutdownChan, t.writableChan); err != nil {
-		// Return the quota back now because there is no stream returned to the caller.
-		if _, ok := err.(StreamError); ok {
-			t.streamsQuota.add(1)
-		}
-		return nil, err
-	}
-	t.mu.Lock()
-	if t.state == draining {
-		t.mu.Unlock()
-		t.streamsQuota.add(1)
-		// Need to make t writable again so that the rpc in flight can still proceed.
-		t.writableChan <- 0
-		return nil, ErrStreamDrain
-	}
-	if t.state != reachable {
-		t.mu.Unlock()
-		return nil, ErrConnClosing
-	}
-	s := t.newStream(ctx, callHdr)
-	t.activeStreams[s.id] = s
-	// If the number of active streams change from 0 to 1, then check if keepalive
-	// has gone dormant. If so, wake it up.
-	if len(t.activeStreams) == 1 {
-		select {
-		case t.awakenKeepalive <- struct{}{}:
-			t.framer.writePing(false, false, [8]byte{})
-			// Fill the awakenKeepalive channel again as this channel must be
-			// kept non-writable except at the point that the keepalive()
-			// goroutine is waiting either to be awaken or shutdown.
-			t.awakenKeepalive <- struct{}{}
-		default:
-		}
-	}
-
-	t.mu.Unlock()
-
-	// HPACK encodes various headers. Note that once WriteField(...) is
-	// called, the corresponding headers/continuation frame has to be sent
-	// because hpack.Encoder is stateful.
-	t.hBuf.Reset()
-	t.hEnc.WriteField(hpack.HeaderField{Name: ":method", Value: "POST"})
-	t.hEnc.WriteField(hpack.HeaderField{Name: ":scheme", Value: t.scheme})
-	t.hEnc.WriteField(hpack.HeaderField{Name: ":path", Value: callHdr.Method})
-	t.hEnc.WriteField(hpack.HeaderField{Name: ":authority", Value: callHdr.Host})
-	t.hEnc.WriteField(hpack.HeaderField{Name: "content-type", Value: "application/grpc"})
-	t.hEnc.WriteField(hpack.HeaderField{Name: "user-agent", Value: t.userAgent})
-	t.hEnc.WriteField(hpack.HeaderField{Name: "te", Value: "trailers"})
+	// TODO(mmukhi): Benchmark if the perfomance gets better if count the metadata and other header fields
+	// first and create a slice of that exact size.
+	// Make the slice of certain predictable size to reduce allocations made by append.
+	hfLen := 7 // :method, :scheme, :path, :authority, content-type, user-agent, te
+	hfLen += len(authData) + len(callAuthData)
+	headerFields := make([]hpack.HeaderField, 0, hfLen)
+	headerFields = append(headerFields, hpack.HeaderField{Name: ":method", Value: "POST"})
+	headerFields = append(headerFields, hpack.HeaderField{Name: ":scheme", Value: t.scheme})
+	headerFields = append(headerFields, hpack.HeaderField{Name: ":path", Value: callHdr.Method})
+	headerFields = append(headerFields, hpack.HeaderField{Name: ":authority", Value: callHdr.Host})
+	headerFields = append(headerFields, hpack.HeaderField{Name: "content-type", Value: "application/grpc"})
+	headerFields = append(headerFields, hpack.HeaderField{Name: "user-agent", Value: t.userAgent})
+	headerFields = append(headerFields, hpack.HeaderField{Name: "te", Value: "trailers"})
 
 	if callHdr.SendCompress != "" {
-		t.hEnc.WriteField(hpack.HeaderField{Name: "grpc-encoding", Value: callHdr.SendCompress})
+		headerFields = append(headerFields, hpack.HeaderField{Name: "grpc-encoding", Value: callHdr.SendCompress})
 	}
 	if dl, ok := ctx.Deadline(); ok {
 		// Send out timeout regardless its value. The server can detect timeout context by itself.
+		// TODO(mmukhi): Perhaps this field should be updated when actually writing out to the wire.
 		timeout := dl.Sub(time.Now())
-		t.hEnc.WriteField(hpack.HeaderField{Name: "grpc-timeout", Value: encodeTimeout(timeout)})
+		headerFields = append(headerFields, hpack.HeaderField{Name: "grpc-timeout", Value: encodeTimeout(timeout)})
 	}
-
 	for k, v := range authData {
-		t.hEnc.WriteField(hpack.HeaderField{Name: k, Value: encodeMetadataHeader(k, v)})
+		headerFields = append(headerFields, hpack.HeaderField{Name: k, Value: encodeMetadataHeader(k, v)})
 	}
 	for k, v := range callAuthData {
-		t.hEnc.WriteField(hpack.HeaderField{Name: k, Value: encodeMetadataHeader(k, v)})
+		headerFields = append(headerFields, hpack.HeaderField{Name: k, Value: encodeMetadataHeader(k, v)})
 	}
-	var (
-		endHeaders bool
-	)
 	if b := stats.OutgoingTags(ctx); b != nil {
-		t.hEnc.WriteField(hpack.HeaderField{Name: "grpc-tags-bin", Value: encodeBinHeader(b)})
+		headerFields = append(headerFields, hpack.HeaderField{Name: "grpc-tags-bin", Value: encodeBinHeader(b)})
 	}
 	if b := stats.OutgoingTrace(ctx); b != nil {
-		t.hEnc.WriteField(hpack.HeaderField{Name: "grpc-trace-bin", Value: encodeBinHeader(b)})
+		headerFields = append(headerFields, hpack.HeaderField{Name: "grpc-trace-bin", Value: encodeBinHeader(b)})
 	}
 	if md, ok := metadata.FromOutgoingContext(ctx); ok {
 		for k, vv := range md {
@@ -488,7 +459,7 @@ func (t *http2Client) NewStream(ctx context.Context, callHdr *CallHdr) (_ *Strea
 				continue
 			}
 			for _, v := range vv {
-				t.hEnc.WriteField(hpack.HeaderField{Name: k, Value: encodeMetadataHeader(k, v)})
+				headerFields = append(headerFields, hpack.HeaderField{Name: k, Value: encodeMetadataHeader(k, v)})
 			}
 		}
 	}
@@ -498,46 +469,42 @@ func (t *http2Client) NewStream(ctx context.Context, callHdr *CallHdr) (_ *Strea
 				continue
 			}
 			for _, v := range vv {
-				t.hEnc.WriteField(hpack.HeaderField{Name: k, Value: encodeMetadataHeader(k, v)})
+				headerFields = append(headerFields, hpack.HeaderField{Name: k, Value: encodeMetadataHeader(k, v)})
 			}
 		}
 	}
-	first := true
-	bufLen := t.hBuf.Len()
-	// Sends the headers in a single batch even when they span multiple frames.
-	for !endHeaders {
-		size := t.hBuf.Len()
-		if size > http2MaxFrameLen {
-			size = http2MaxFrameLen
-		} else {
-			endHeaders = true
-		}
-		var flush bool
-		if callHdr.Flush && endHeaders {
-			flush = true
-		}
-		if first {
-			// Sends a HeadersFrame to server to start a new stream.
-			p := http2.HeadersFrameParam{
-				StreamID:      s.id,
-				BlockFragment: t.hBuf.Next(size),
-				EndStream:     false,
-				EndHeaders:    endHeaders,
-			}
-			// Do a force flush for the buffered frames iff it is the last headers frame
-			// and there is header metadata to be sent. Otherwise, there is flushing until
-			// the corresponding data frame is written.
-			err = t.framer.writeHeaders(flush, p)
-			first = false
-		} else {
-			// Sends Continuation frames for the leftover headers.
-			err = t.framer.writeContinuation(flush, s.id, endHeaders, t.hBuf.Next(size))
-		}
-		if err != nil {
-			t.notifyError(err)
-			return nil, connectionErrorf(true, err, "transport: %v", err)
+	t.mu.Lock()
+	if t.state == draining {
+		t.mu.Unlock()
+		t.streamsQuota.add(1)
+		return nil, ErrStreamDrain
+	}
+	if t.state != reachable {
+		t.mu.Unlock()
+		return nil, ErrConnClosing
+	}
+	s := t.newStream(ctx, callHdr)
+	t.activeStreams[s.id] = s
+	// If the number of active streams change from 0 to 1, then check if keepalive
+	// has gone dormant. If so, wake it up.
+	if len(t.activeStreams) == 1 {
+		select {
+		case t.awakenKeepalive <- struct{}{}:
+			t.controlBuf.put(&ping{data: [8]byte{}})
+			// Fill the awakenKeepalive channel again as this channel must be
+			// kept non-writable except at the point that the keepalive()
+			// goroutine is waiting either to be awaken or shutdown.
+			t.awakenKeepalive <- struct{}{}
+		default:
 		}
 	}
+	t.controlBuf.put(&headerFrame{
+		streamID:  s.id,
+		hf:        headerFields,
+		endStream: false,
+	})
+	t.mu.Unlock()
+
 	s.mu.Lock()
 	s.bytesSent = true
 	s.mu.Unlock()
@@ -545,7 +512,6 @@ func (t *http2Client) NewStream(ctx context.Context, callHdr *CallHdr) (_ *Strea
 	if t.statsHandler != nil {
 		outHeader := &stats.OutHeader{
 			Client:      true,
-			WireLength:  bufLen,
 			FullMethod:  callHdr.Method,
 			RemoteAddr:  t.remoteAddr,
 			LocalAddr:   t.localAddr,
@@ -553,7 +519,6 @@ func (t *http2Client) NewStream(ctx context.Context, callHdr *CallHdr) (_ *Strea
 		}
 		t.statsHandler.HandleRPC(s.ctx, outHeader)
 	}
-	t.writableChan <- 0
 	return s, nil
 }
 
@@ -623,12 +588,9 @@ func (t *http2Client) Close() (err error) {
 		t.mu.Unlock()
 		return
 	}
-	if t.state == reachable || t.state == draining {
-		close(t.errorChan)
-	}
 	t.state = closing
 	t.mu.Unlock()
-	close(t.shutdownChan)
+	t.cancel()
 	err = t.conn.Close()
 	t.mu.Lock()
 	streams := t.activeStreams
@@ -650,23 +612,18 @@ func (t *http2Client) Close() (err error) {
 		}
 		t.statsHandler.HandleConn(t.ctx, connEnd)
 	}
-	return
+	return err
 }
 
+// GracefulClose sets the state to draining, which prevents new streams from
+// being created and causes the transport to be closed when the last active
+// stream is closed.  If there are no active streams, the transport is closed
+// immediately.  This does nothing if the transport is already draining or
+// closing.
 func (t *http2Client) GracefulClose() error {
 	t.mu.Lock()
 	switch t.state {
-	case unreachable:
-		// The server may close the connection concurrently. t is not available for
-		// any streams. Close it now.
-		t.mu.Unlock()
-		t.Close()
-		return nil
-	case closing:
-		t.mu.Unlock()
-		return nil
-	}
-	if t.state == draining {
+	case closing, draining:
 		t.mu.Unlock()
 		return nil
 	}
@@ -681,32 +638,38 @@ func (t *http2Client) GracefulClose() error {
 
 // Write formats the data into HTTP2 data frame(s) and sends it out. The caller
 // should proceed only if Write returns nil.
-// TODO(zhaoq): opts.Delay is ignored in this implementation. Support it later
-// if it improves the performance.
 func (t *http2Client) Write(s *Stream, hdr []byte, data []byte, opts *Options) error {
-	secondStart := http2MaxFrameLen - len(hdr)%http2MaxFrameLen
-	if len(data) < secondStart {
-		secondStart = len(data)
-	}
-	hdr = append(hdr, data[:secondStart]...)
-	data = data[secondStart:]
-	isLastSlice := (len(data) == 0)
-	r := bytes.NewBuffer(hdr)
-	var (
-		p   []byte
-		oqv uint32
-	)
-	for {
-		oqv = atomic.LoadUint32(&t.outQuotaVersion)
-		if r.Len() > 0 || p != nil {
+	select {
+	case <-s.ctx.Done():
+		return ContextErr(s.ctx.Err())
+	case <-t.ctx.Done():
+		return ErrConnClosing
+	default:
+	}
+
+	if hdr == nil && data == nil && opts.Last {
+		// stream.CloseSend uses this to send an empty frame with endStream=True
+		t.controlBuf.put(&dataFrame{streamID: s.id, endStream: true, f: func() {}})
+		return nil
+	}
+	// Add data to header frame so that we can equally distribute data across frames.
+	emptyLen := http2MaxFrameLen - len(hdr)
+	if emptyLen > len(data) {
+		emptyLen = len(data)
+	}
+	hdr = append(hdr, data[:emptyLen]...)
+	data = data[emptyLen:]
+	for idx, r := range [][]byte{hdr, data} {
+		for len(r) > 0 {
 			size := http2MaxFrameLen
 			// Wait until the stream has some quota to send the data.
-			sq, err := wait(s.ctx, s.done, s.goAway, t.shutdownChan, s.sendQuotaPool.acquire())
+			quotaChan, quotaVer := s.sendQuotaPool.acquireWithVersion()
+			sq, err := wait(s.ctx, t.ctx, s.done, s.goAway, quotaChan)
 			if err != nil {
 				return err
 			}
 			// Wait until the transport has some quota to send the data.
-			tq, err := wait(s.ctx, s.done, s.goAway, t.shutdownChan, t.sendQuotaPool.acquire())
+			tq, err := wait(s.ctx, t.ctx, s.done, s.goAway, t.sendQuotaPool.acquire())
 			if err != nil {
 				return err
 			}
@@ -716,94 +679,52 @@ func (t *http2Client) Write(s *Stream, hdr []byte, data []byte, opts *Options) e
 			if tq < size {
 				size = tq
 			}
-			if p == nil {
-				p = r.Next(size)
+			if size > len(r) {
+				size = len(r)
 			}
+			p := r[:size]
 			ps := len(p)
-			if ps < sq {
-				// Overbooked stream quota. Return it back.
-				s.sendQuotaPool.add(sq - ps)
-			}
 			if ps < tq {
 				// Overbooked transport quota. Return it back.
 				t.sendQuotaPool.add(tq - ps)
 			}
-		}
-		var (
-			endStream  bool
-			forceFlush bool
-		)
-		// Indicate there is a writer who is about to write a data frame.
-		t.framer.adjustNumWriters(1)
-		// Got some quota. Try to acquire writing privilege on the transport.
-		if _, err := wait(s.ctx, s.done, s.goAway, t.shutdownChan, t.writableChan); err != nil {
-			if _, ok := err.(StreamError); ok || err == io.EOF {
-				// Return the connection quota back.
-				t.sendQuotaPool.add(len(p))
+			// Acquire local send quota to be able to write to the controlBuf.
+			ltq, err := wait(s.ctx, t.ctx, s.done, s.goAway, s.localSendQuota.acquire())
+			if err != nil {
+				if _, ok := err.(ConnectionError); !ok {
+					t.sendQuotaPool.add(ps)
+				}
+				return err
 			}
-			if t.framer.adjustNumWriters(-1) == 0 {
-				// This writer is the last one in this batch and has the
-				// responsibility to flush the buffered frames. It queues
-				// a flush request to controlBuf instead of flushing directly
-				// in order to avoid the race with other writing or flushing.
-				t.controlBuf.put(&flushIO{})
+			s.localSendQuota.add(ltq - ps) // It's ok if we make it negative.
+			var endStream bool
+			// See if this is the last frame to be written.
+			if opts.Last {
+				if len(r)-size == 0 { // No more data in r after this iteration.
+					if idx == 0 { // We're writing data header.
+						if len(data) == 0 { // There's no data to follow.
+							endStream = true
+						}
+					} else { // We're writing data.
+						endStream = true
+					}
+				}
 			}
-			return err
-		}
-		select {
-		case <-s.ctx.Done():
-			t.sendQuotaPool.add(len(p))
-			if t.framer.adjustNumWriters(-1) == 0 {
-				t.controlBuf.put(&flushIO{})
+			success := func() {
+				t.controlBuf.put(&dataFrame{streamID: s.id, endStream: endStream, d: p, f: func() { s.localSendQuota.add(ps) }})
+				if ps < sq {
+					s.sendQuotaPool.lockedAdd(sq - ps)
+				}
+				r = r[ps:]
 			}
-			t.writableChan <- 0
-			return ContextErr(s.ctx.Err())
-		default:
-		}
-		if oqv != atomic.LoadUint32(&t.outQuotaVersion) {
-			// InitialWindowSize settings frame must have been received after we
-			// acquired send quota but before we got the writable channel.
-			// We must forsake this write.
-			t.sendQuotaPool.add(len(p))
-			s.sendQuotaPool.add(len(p))
-			if t.framer.adjustNumWriters(-1) == 0 {
-				t.controlBuf.put(&flushIO{})
+			failure := func() {
+				s.sendQuotaPool.lockedAdd(sq)
 			}
-			t.writableChan <- 0
-			continue
-		}
-		if r.Len() == 0 {
-			if isLastSlice {
-				if opts.Last {
-					endStream = true
-				}
-				if t.framer.adjustNumWriters(0) == 1 {
-					// Do a force flush iff this is last frame for the entire gRPC message
-					// and the caller is the only writer at this moment.
-					forceFlush = true
-				}
-			} else {
-				isLastSlice = true
-				if len(data) != 0 {
-					r = bytes.NewBuffer(data)
-				}
+			if !s.sendQuotaPool.compareAndExecute(quotaVer, success, failure) {
+				t.sendQuotaPool.add(ps)
+				s.localSendQuota.add(ps)
 			}
 		}
-		// If WriteData fails, all the pending streams will be handled
-		// by http2Client.Close(). No explicit CloseStream() needs to be
-		// invoked.
-		if err := t.framer.writeData(forceFlush, s.id, endStream, p); err != nil {
-			t.notifyError(err)
-			return connectionErrorf(true, err, "transport: %v", err)
-		}
-		p = nil
-		if t.framer.adjustNumWriters(-1) == 0 {
-			t.framer.flushWrite()
-		}
-		t.writableChan <- 0
-		if r.Len() == 0 {
-			break
-		}
 	}
 	if !opts.Last {
 		return nil
@@ -833,11 +754,11 @@ func (t *http2Client) adjustWindow(s *Stream, n uint32) {
 		return
 	}
 	if w := s.fc.maybeAdjust(n); w > 0 {
-		// Piggyback conneciton's window update along.
+		// Piggyback connection's window update along.
 		if cw := t.fc.resetPendingUpdate(); cw > 0 {
-			t.controlBuf.put(&windowUpdate{0, cw, false})
+			t.controlBuf.put(&windowUpdate{0, cw})
 		}
-		t.controlBuf.put(&windowUpdate{s.id, w, true})
+		t.controlBuf.put(&windowUpdate{s.id, w})
 	}
 }
 
@@ -852,9 +773,9 @@ func (t *http2Client) updateWindow(s *Stream, n uint32) {
 	}
 	if w := s.fc.onRead(n); w > 0 {
 		if cw := t.fc.resetPendingUpdate(); cw > 0 {
-			t.controlBuf.put(&windowUpdate{0, cw, false})
+			t.controlBuf.put(&windowUpdate{0, cw})
 		}
-		t.controlBuf.put(&windowUpdate{s.id, w, true})
+		t.controlBuf.put(&windowUpdate{s.id, w})
 	}
 }
 
@@ -868,7 +789,7 @@ func (t *http2Client) updateFlowControl(n uint32) {
 	}
 	t.initialWindowSize = int32(n)
 	t.mu.Unlock()
-	t.controlBuf.put(&windowUpdate{0, t.fc.newLimit(n), false})
+	t.controlBuf.put(&windowUpdate{0, t.fc.newLimit(n)})
 	t.controlBuf.put(&settings{
 		ack: false,
 		ss: []http2.Setting{
@@ -898,15 +819,17 @@ func (t *http2Client) handleData(f *http2.DataFrame) {
 	// Furthermore, if a bdpPing is being sent out we can piggyback
 	// connection's window update for the bytes we just received.
 	if sendBDPPing {
-		t.controlBuf.put(&windowUpdate{0, uint32(size), false})
+		if size != 0 { // Could've been an empty data frame.
+			t.controlBuf.put(&windowUpdate{0, uint32(size)})
+		}
 		t.controlBuf.put(bdpPing)
 	} else {
 		if err := t.fc.onData(uint32(size)); err != nil {
-			t.notifyError(connectionErrorf(true, err, "%v", err))
+			t.Close()
 			return
 		}
 		if w := t.fc.onRead(uint32(size)); w > 0 {
-			t.controlBuf.put(&windowUpdate{0, w, true})
+			t.controlBuf.put(&windowUpdate{0, w})
 		}
 	}
 	// Select the right stream to dispatch.
@@ -930,7 +853,7 @@ func (t *http2Client) handleData(f *http2.DataFrame) {
 		}
 		if f.Header().Flags.Has(http2.FlagDataPadded) {
 			if w := s.fc.onRead(uint32(size) - uint32(len(f.Data()))); w > 0 {
-				t.controlBuf.put(&windowUpdate{s.id, w, true})
+				t.controlBuf.put(&windowUpdate{s.id, w})
 			}
 		}
 		s.mu.Unlock()
@@ -1019,10 +942,10 @@ func (t *http2Client) handleGoAway(f *http2.GoAwayFrame) {
 	id := f.LastStreamID
 	if id > 0 && id%2 != 1 {
 		t.mu.Unlock()
-		t.notifyError(connectionErrorf(true, nil, "received illegal http2 GOAWAY frame: stream ID %d is even", f.LastStreamID))
+		t.Close()
 		return
 	}
-	// A client can recieve multiple GoAways from server (look at https://github.com/grpc/grpc-go/issues/1387).
+	// A client can receive multiple GoAways from server (look at https://github.com/grpc/grpc-go/issues/1387).
 	// The idea is that the first GoAway will be sent with an ID of MaxInt32 and the second GoAway will be sent after an RTT delay
 	// with the ID of the last stream the server will process.
 	// Therefore, when we get the first GoAway we don't really close any streams. While in case of second GoAway we
@@ -1033,7 +956,7 @@ func (t *http2Client) handleGoAway(f *http2.GoAwayFrame) {
 		// If there are multiple GoAways the first one should always have an ID greater than the following ones.
 		if id > t.prevGoAwayID {
 			t.mu.Unlock()
-			t.notifyError(connectionErrorf(true, nil, "received illegal http2 GOAWAY frame: previously recv GOAWAY frame with LastStramID %d, currently recv %d", id, f.LastStreamID))
+			t.Close()
 			return
 		}
 	default:
@@ -1177,22 +1100,22 @@ func handleMalformedHTTP2(s *Stream, err error) {
 // TODO(zhaoq): Check the validity of the incoming frame sequence.
 func (t *http2Client) reader() {
 	// Check the validity of server preface.
-	frame, err := t.framer.readFrame()
+	frame, err := t.framer.fr.ReadFrame()
 	if err != nil {
-		t.notifyError(err)
+		t.Close()
 		return
 	}
 	atomic.CompareAndSwapUint32(&t.activity, 0, 1)
 	sf, ok := frame.(*http2.SettingsFrame)
 	if !ok {
-		t.notifyError(err)
+		t.Close()
 		return
 	}
 	t.handleSettings(sf)
 
 	// loop to keep reading incoming messages on this transport.
 	for {
-		frame, err := t.framer.readFrame()
+		frame, err := t.framer.fr.ReadFrame()
 		atomic.CompareAndSwapUint32(&t.activity, 0, 1)
 		if err != nil {
 			// Abort an active stream if the http2.Framer returns a
@@ -1204,12 +1127,12 @@ func (t *http2Client) reader() {
 				t.mu.Unlock()
 				if s != nil {
 					// use error detail to provide better err message
-					handleMalformedHTTP2(s, streamErrorf(http2ErrConvTab[se.Code], "%v", t.framer.errorDetail()))
+					handleMalformedHTTP2(s, streamErrorf(http2ErrConvTab[se.Code], "%v", t.framer.fr.ErrorDetail()))
 				}
 				continue
 			} else {
 				// Transport error.
-				t.notifyError(err)
+				t.Close()
 				return
 			}
 		}
@@ -1253,61 +1176,86 @@ func (t *http2Client) applySettings(ss []http2.Setting) {
 			t.mu.Lock()
 			for _, stream := range t.activeStreams {
 				// Adjust the sending quota for each stream.
-				stream.sendQuotaPool.add(int(s.Val) - int(t.streamSendQuota))
+				stream.sendQuotaPool.addAndUpdate(int(s.Val) - int(t.streamSendQuota))
 			}
 			t.streamSendQuota = s.Val
 			t.mu.Unlock()
-			atomic.AddUint32(&t.outQuotaVersion, 1)
 		}
 	}
 }
 
-// controller running in a separate goroutine takes charge of sending control
-// frames (e.g., window update, reset stream, setting, etc.) to the server.
-func (t *http2Client) controller() {
-	for {
-		select {
-		case i := <-t.controlBuf.get():
-			t.controlBuf.load()
-			select {
-			case <-t.writableChan:
-				switch i := i.(type) {
-				case *windowUpdate:
-					t.framer.writeWindowUpdate(i.flush, i.streamID, i.increment)
-				case *settings:
-					if i.ack {
-						t.framer.writeSettingsAck(true)
-						t.applySettings(i.ss)
-					} else {
-						t.framer.writeSettings(true, i.ss...)
-					}
-				case *resetStream:
-					// If the server needs to be to intimated about stream closing,
-					// then we need to make sure the RST_STREAM frame is written to
-					// the wire before the headers of the next stream waiting on
-					// streamQuota. We ensure this by adding to the streamsQuota pool
-					// only after having acquired the writableChan to send RST_STREAM.
-					t.streamsQuota.add(1)
-					t.framer.writeRSTStream(true, i.streamID, i.code)
-				case *flushIO:
-					t.framer.flushWrite()
-				case *ping:
-					if !i.ack {
-						t.bdpEst.timesnap(i.data)
-					}
-					t.framer.writePing(true, i.ack, i.data)
-				default:
-					errorf("transport: http2Client.controller got unexpected item type %v\n", i)
-				}
-				t.writableChan <- 0
-				continue
-			case <-t.shutdownChan:
-				return
+// TODO(mmukhi): A lot of this code(and code in other places in the tranpsort layer)
+// is duplicated between the client and the server.
+// The transport layer needs to be refactored to take care of this.
+func (t *http2Client) itemHandler(i item) error {
+	var err error
+	switch i := i.(type) {
+	case *dataFrame:
+		err = t.framer.fr.WriteData(i.streamID, i.endStream, i.d)
+		if err == nil {
+			i.f()
+		}
+	case *headerFrame:
+		t.hBuf.Reset()
+		for _, f := range i.hf {
+			t.hEnc.WriteField(f)
+		}
+		endHeaders := false
+		first := true
+		for !endHeaders {
+			size := t.hBuf.Len()
+			if size > http2MaxFrameLen {
+				size = http2MaxFrameLen
+			} else {
+				endHeaders = true
 			}
-		case <-t.shutdownChan:
-			return
+			if first {
+				first = false
+				err = t.framer.fr.WriteHeaders(http2.HeadersFrameParam{
+					StreamID:      i.streamID,
+					BlockFragment: t.hBuf.Next(size),
+					EndStream:     i.endStream,
+					EndHeaders:    endHeaders,
+				})
+			} else {
+				err = t.framer.fr.WriteContinuation(
+					i.streamID,
+					endHeaders,
+					t.hBuf.Next(size),
+				)
+			}
+			if err != nil {
+				return err
+			}
+		}
+	case *windowUpdate:
+		err = t.framer.fr.WriteWindowUpdate(i.streamID, i.increment)
+	case *settings:
+		if i.ack {
+			t.applySettings(i.ss)
+			err = t.framer.fr.WriteSettingsAck()
+		} else {
+			err = t.framer.fr.WriteSettings(i.ss...)
+		}
+	case *resetStream:
+		// If the server needs to be to intimated about stream closing,
+		// then we need to make sure the RST_STREAM frame is written to
+		// the wire before the headers of the next stream waiting on
+		// streamQuota. We ensure this by adding to the streamsQuota pool
+		// only after having acquired the writableChan to send RST_STREAM.
+		err = t.framer.fr.WriteRSTStream(i.streamID, i.code)
+		t.streamsQuota.add(1)
+	case *flushIO:
+		err = t.framer.writer.Flush()
+	case *ping:
+		if !i.ack {
+			t.bdpEst.timesnap(i.data)
 		}
+		err = t.framer.fr.WritePing(i.ack, i.data)
+	default:
+		errorf("transport: http2Client.controller got unexpected item type %v\n", i)
 	}
+	return err
 }
 
 // keepalive running in a separate goroutune makes sure the connection is alive by sending pings.
@@ -1331,7 +1279,7 @@ func (t *http2Client) keepalive() {
 				case <-t.awakenKeepalive:
 					// If the control gets here a ping has been sent
 					// need to reset the timer with keepalive.Timeout.
-				case <-t.shutdownChan:
+				case <-t.ctx.Done():
 					return
 				}
 			} else {
@@ -1350,13 +1298,13 @@ func (t *http2Client) keepalive() {
 				}
 				t.Close()
 				return
-			case <-t.shutdownChan:
+			case <-t.ctx.Done():
 				if !timer.Stop() {
 					<-timer.C
 				}
 				return
 			}
-		case <-t.shutdownChan:
+		case <-t.ctx.Done():
 			if !timer.Stop() {
 				<-timer.C
 			}
@@ -1366,25 +1314,9 @@ func (t *http2Client) keepalive() {
 }
 
 func (t *http2Client) Error() <-chan struct{} {
-	return t.errorChan
+	return t.ctx.Done()
 }
 
 func (t *http2Client) GoAway() <-chan struct{} {
 	return t.goAway
 }
-
-func (t *http2Client) notifyError(err error) {
-	t.mu.Lock()
-	// make sure t.errorChan is closed only once.
-	if t.state == draining {
-		t.mu.Unlock()
-		t.Close()
-		return
-	}
-	if t.state == reachable {
-		t.state = unreachable
-		close(t.errorChan)
-		infof("transport: http2Client.notifyError got notified that the client transport was broken %v.", err)
-	}
-	t.mu.Unlock()
-}

cmd/vendor/google.golang.org/grpc/transport/http2_server.go

@@ -21,6 +21,7 @@ package transport
 import (
 	"bytes"
 	"errors"
+	"fmt"
 	"io"
 	"math"
 	"math/rand"
@@ -51,23 +52,16 @@ var ErrIllegalHeaderWrite = errors.New("transport: the stream is done or WriteHe
 // http2Server implements the ServerTransport interface with HTTP2.
 type http2Server struct {
 	ctx         context.Context
+	cancel      context.CancelFunc
 	conn        net.Conn
 	remoteAddr  net.Addr
 	localAddr   net.Addr
 	maxStreamID uint32               // max stream ID ever seen
 	authInfo    credentials.AuthInfo // auth info about the connection
 	inTapHandle tap.ServerInHandle
-	// writableChan synchronizes write access to the transport.
-	// A writer acquires the write lock by receiving a value on writableChan
-	// and releases it by sending on writableChan.
-	writableChan chan int
-	// shutdownChan is closed when Close is called.
-	// Blocking operations should select on shutdownChan to avoid
-	// blocking forever after Close.
-	shutdownChan chan struct{}
-	framer       *framer
-	hBuf         *bytes.Buffer  // the buffer for HPACK encoding
-	hEnc         *hpack.Encoder // HPACK encoder
+	framer      *framer
+	hBuf        *bytes.Buffer  // the buffer for HPACK encoding
+	hEnc        *hpack.Encoder // HPACK encoder
 	// The max number of concurrent streams.
 	maxStreams uint32
 	// controlBuf delivers all the control related tasks (e.g., window
@@ -96,8 +90,6 @@ type http2Server struct {
 	initialWindowSize int32
 	bdpEst            *bdpEstimator
 
-	outQuotaVersion uint32
-
 	mu sync.Mutex // guard the following
 
 	// drainChan is initialized when drain(...) is called the first time.
@@ -112,7 +104,7 @@ type http2Server struct {
 	// the per-stream outbound flow control window size set by the peer.
 	streamSendQuota uint32
 	// idle is the time instant when the connection went idle.
-	// This is either the begining of the connection or when the number of
+	// This is either the beginning of the connection or when the number of
 	// RPCs go down to 0.
 	// When the connection is busy, this value is set to 0.
 	idle time.Time
@@ -121,7 +113,15 @@ type http2Server struct {
 // newHTTP2Server constructs a ServerTransport based on HTTP2. ConnectionError is
 // returned if something goes wrong.
 func newHTTP2Server(conn net.Conn, config *ServerConfig) (_ ServerTransport, err error) {
-	framer := newFramer(conn)
+	writeBufSize := defaultWriteBufSize
+	if config.WriteBufferSize > 0 {
+		writeBufSize = config.WriteBufferSize
+	}
+	readBufSize := defaultReadBufSize
+	if config.ReadBufferSize > 0 {
+		readBufSize = config.ReadBufferSize
+	}
+	framer := newFramer(conn, writeBufSize, readBufSize)
 	// Send initial settings as connection preface to client.
 	var isettings []http2.Setting
 	// TODO(zhaoq): Have a better way to signal "no limit" because 0 is
@@ -151,12 +151,12 @@ func newHTTP2Server(conn net.Conn, config *ServerConfig) (_ ServerTransport, err
 			ID:  http2.SettingInitialWindowSize,
 			Val: uint32(iwz)})
 	}
-	if err := framer.writeSettings(true, isettings...); err != nil {
+	if err := framer.fr.WriteSettings(isettings...); err != nil {
 		return nil, connectionErrorf(true, err, "transport: %v", err)
 	}
 	// Adjust the connection flow control window if needed.
 	if delta := uint32(icwz - defaultWindowSize); delta > 0 {
-		if err := framer.writeWindowUpdate(true, 0, delta); err != nil {
+		if err := framer.fr.WriteWindowUpdate(0, delta); err != nil {
 			return nil, connectionErrorf(true, err, "transport: %v", err)
 		}
 	}
@@ -183,8 +183,10 @@ func newHTTP2Server(conn net.Conn, config *ServerConfig) (_ ServerTransport, err
 		kep.MinTime = defaultKeepalivePolicyMinTime
 	}
 	var buf bytes.Buffer
+	ctx, cancel := context.WithCancel(context.Background())
 	t := &http2Server{
-		ctx:               context.Background(),
+		ctx:               ctx,
+		cancel:            cancel,
 		conn:              conn,
 		remoteAddr:        conn.RemoteAddr(),
 		localAddr:         conn.LocalAddr(),
@@ -198,8 +200,6 @@ func newHTTP2Server(conn net.Conn, config *ServerConfig) (_ ServerTransport, err
 		fc:                &inFlow{limit: uint32(icwz)},
 		sendQuotaPool:     newQuotaPool(defaultWindowSize),
 		state:             reachable,
-		writableChan:      make(chan int, 1),
-		shutdownChan:      make(chan struct{}),
 		activeStreams:     make(map[uint32]*Stream),
 		streamSendQuota:   defaultWindowSize,
 		stats:             config.StatsHandler,
@@ -222,9 +222,12 @@ func newHTTP2Server(conn net.Conn, config *ServerConfig) (_ ServerTransport, err
 		connBegin := &stats.ConnBegin{}
 		t.stats.HandleConn(t.ctx, connBegin)
 	}
-	go t.controller()
+	t.framer.writer.Flush()
+	go func() {
+		loopyWriter(t.ctx, t.controlBuf, t.itemHandler)
+		t.Close()
+	}()
 	go t.keepalive()
-	t.writableChan <- 0
 	return t, nil
 }
 
@@ -313,6 +316,7 @@ func (t *http2Server) operateHeaders(frame *http2.MetaHeadersFrame, handle func(
 	}
 	t.maxStreamID = streamID
 	s.sendQuotaPool = newQuotaPool(int(t.streamSendQuota))
+	s.localSendQuota = newQuotaPool(defaultLocalSendQuota)
 	t.activeStreams[streamID] = s
 	if len(t.activeStreams) == 1 {
 		t.idle = time.Time{}
@@ -366,7 +370,7 @@ func (t *http2Server) HandleStreams(handle func(*Stream), traceCtx func(context.
 		return
 	}
 
-	frame, err := t.framer.readFrame()
+	frame, err := t.framer.fr.ReadFrame()
 	if err == io.EOF || err == io.ErrUnexpectedEOF {
 		t.Close()
 		return
@@ -386,7 +390,7 @@ func (t *http2Server) HandleStreams(handle func(*Stream), traceCtx func(context.
 	t.handleSettings(sf)
 
 	for {
-		frame, err := t.framer.readFrame()
+		frame, err := t.framer.fr.ReadFrame()
 		atomic.StoreUint32(&t.activity, 1)
 		if err != nil {
 			if se, ok := err.(http2.StreamError); ok {
@@ -457,9 +461,9 @@ func (t *http2Server) adjustWindow(s *Stream, n uint32) {
 	}
 	if w := s.fc.maybeAdjust(n); w > 0 {
 		if cw := t.fc.resetPendingUpdate(); cw > 0 {
-			t.controlBuf.put(&windowUpdate{0, cw, false})
+			t.controlBuf.put(&windowUpdate{0, cw})
 		}
-		t.controlBuf.put(&windowUpdate{s.id, w, true})
+		t.controlBuf.put(&windowUpdate{s.id, w})
 	}
 }
 
@@ -474,9 +478,9 @@ func (t *http2Server) updateWindow(s *Stream, n uint32) {
 	}
 	if w := s.fc.onRead(n); w > 0 {
 		if cw := t.fc.resetPendingUpdate(); cw > 0 {
-			t.controlBuf.put(&windowUpdate{0, cw, false})
+			t.controlBuf.put(&windowUpdate{0, cw})
 		}
-		t.controlBuf.put(&windowUpdate{s.id, w, true})
+		t.controlBuf.put(&windowUpdate{s.id, w})
 	}
 }
 
@@ -490,7 +494,7 @@ func (t *http2Server) updateFlowControl(n uint32) {
 	}
 	t.initialWindowSize = int32(n)
 	t.mu.Unlock()
-	t.controlBuf.put(&windowUpdate{0, t.fc.newLimit(n), false})
+	t.controlBuf.put(&windowUpdate{0, t.fc.newLimit(n)})
 	t.controlBuf.put(&settings{
 		ack: false,
 		ss: []http2.Setting{
@@ -521,7 +525,9 @@ func (t *http2Server) handleData(f *http2.DataFrame) {
 	// Furthermore, if a bdpPing is being sent out we can piggyback
 	// connection's window update for the bytes we just received.
 	if sendBDPPing {
-		t.controlBuf.put(&windowUpdate{0, uint32(size), false})
+		if size != 0 { // Could be an empty frame.
+			t.controlBuf.put(&windowUpdate{0, uint32(size)})
+		}
 		t.controlBuf.put(bdpPing)
 	} else {
 		if err := t.fc.onData(uint32(size)); err != nil {
@@ -530,7 +536,7 @@ func (t *http2Server) handleData(f *http2.DataFrame) {
 			return
 		}
 		if w := t.fc.onRead(uint32(size)); w > 0 {
-			t.controlBuf.put(&windowUpdate{0, w, true})
+			t.controlBuf.put(&windowUpdate{0, w})
 		}
 	}
 	// Select the right stream to dispatch.
@@ -552,7 +558,7 @@ func (t *http2Server) handleData(f *http2.DataFrame) {
 		}
 		if f.Header().Flags.Has(http2.FlagDataPadded) {
 			if w := s.fc.onRead(uint32(size) - uint32(len(f.Data()))); w > 0 {
-				t.controlBuf.put(&windowUpdate{s.id, w, true})
+				t.controlBuf.put(&windowUpdate{s.id, w})
 			}
 		}
 		s.mu.Unlock()
@@ -593,10 +599,23 @@ func (t *http2Server) handleSettings(f *http2.SettingsFrame) {
 		ss = append(ss, s)
 		return nil
 	})
-	// The settings will be applied once the ack is sent.
 	t.controlBuf.put(&settings{ack: true, ss: ss})
 }
 
+func (t *http2Server) applySettings(ss []http2.Setting) {
+	for _, s := range ss {
+		if s.ID == http2.SettingInitialWindowSize {
+			t.mu.Lock()
+			for _, stream := range t.activeStreams {
+				stream.sendQuotaPool.addAndUpdate(int(s.Val) - int(t.streamSendQuota))
+			}
+			t.streamSendQuota = s.Val
+			t.mu.Unlock()
+		}
+
+	}
+}
+
 const (
 	maxPingStrikes     = 2
 	defaultPingTimeout = 2 * time.Hour
@@ -634,7 +653,7 @@ func (t *http2Server) handlePing(f *http2.PingFrame) {
 	t.mu.Unlock()
 	if ns < 1 && !t.kep.PermitWithoutStream {
 		// Keepalive shouldn't be active thus, this new ping should
-		// have come after atleast defaultPingTimeout.
+		// have come after at least defaultPingTimeout.
 		if t.lastPingAt.Add(defaultPingTimeout).After(now) {
 			t.pingStrikes++
 		}
@@ -647,6 +666,7 @@ func (t *http2Server) handlePing(f *http2.PingFrame) {
 
 	if t.pingStrikes > maxPingStrikes {
 		// Send goaway and close the connection.
+		errorf("transport: Got to too many pings from the client, closing the connection.")
 		t.controlBuf.put(&goAway{code: http2.ErrCodeEnhanceYourCalm, debugData: []byte("too_many_pings"), closeConn: true})
 	}
 }
@@ -663,47 +683,16 @@ func (t *http2Server) handleWindowUpdate(f *http2.WindowUpdateFrame) {
 	}
 }
 
-func (t *http2Server) writeHeaders(s *Stream, b *bytes.Buffer, endStream bool) error {
-	first := true
-	endHeaders := false
-	var err error
-	defer func() {
-		if err == nil {
-			// Reset ping strikes when seding headers since that might cause the
-			// peer to send ping.
-			atomic.StoreUint32(&t.resetPingStrikes, 1)
-		}
-	}()
-	// Sends the headers in a single batch.
-	for !endHeaders {
-		size := t.hBuf.Len()
-		if size > http2MaxFrameLen {
-			size = http2MaxFrameLen
-		} else {
-			endHeaders = true
-		}
-		if first {
-			p := http2.HeadersFrameParam{
-				StreamID:      s.id,
-				BlockFragment: b.Next(size),
-				EndStream:     endStream,
-				EndHeaders:    endHeaders,
-			}
-			err = t.framer.writeHeaders(endHeaders, p)
-			first = false
-		} else {
-			err = t.framer.writeContinuation(endHeaders, s.id, endHeaders, b.Next(size))
-		}
-		if err != nil {
-			t.Close()
-			return connectionErrorf(true, err, "transport: %v", err)
-		}
-	}
-	return nil
-}
-
 // WriteHeader sends the header metedata md back to the client.
 func (t *http2Server) WriteHeader(s *Stream, md metadata.MD) error {
+	select {
+	case <-s.ctx.Done():
+		return ContextErr(s.ctx.Err())
+	case <-t.ctx.Done():
+		return ErrConnClosing
+	default:
+	}
+
 	s.mu.Lock()
 	if s.headerOk || s.state == streamDone {
 		s.mu.Unlock()
@@ -719,14 +708,13 @@ func (t *http2Server) WriteHeader(s *Stream, md metadata.MD) error {
 	}
 	md = s.header
 	s.mu.Unlock()
-	if _, err := wait(s.ctx, nil, nil, t.shutdownChan, t.writableChan); err != nil {
-		return err
-	}
-	t.hBuf.Reset()
-	t.hEnc.WriteField(hpack.HeaderField{Name: ":status", Value: "200"})
-	t.hEnc.WriteField(hpack.HeaderField{Name: "content-type", Value: "application/grpc"})
+	// TODO(mmukhi): Benchmark if the perfomance gets better if count the metadata and other header fields
+	// first and create a slice of that exact size.
+	headerFields := make([]hpack.HeaderField, 0, 2) // at least :status, content-type will be there if none else.
+	headerFields = append(headerFields, hpack.HeaderField{Name: ":status", Value: "200"})
+	headerFields = append(headerFields, hpack.HeaderField{Name: "content-type", Value: "application/grpc"})
 	if s.sendCompress != "" {
-		t.hEnc.WriteField(hpack.HeaderField{Name: "grpc-encoding", Value: s.sendCompress})
+		headerFields = append(headerFields, hpack.HeaderField{Name: "grpc-encoding", Value: s.sendCompress})
 	}
 	for k, vv := range md {
 		if isReservedHeader(k) {
@@ -734,20 +722,20 @@ func (t *http2Server) WriteHeader(s *Stream, md metadata.MD) error {
 			continue
 		}
 		for _, v := range vv {
-			t.hEnc.WriteField(hpack.HeaderField{Name: k, Value: encodeMetadataHeader(k, v)})
+			headerFields = append(headerFields, hpack.HeaderField{Name: k, Value: encodeMetadataHeader(k, v)})
 		}
 	}
-	bufLen := t.hBuf.Len()
-	if err := t.writeHeaders(s, t.hBuf, false); err != nil {
-		return err
-	}
+	t.controlBuf.put(&headerFrame{
+		streamID:  s.id,
+		hf:        headerFields,
+		endStream: false,
+	})
 	if t.stats != nil {
 		outHeader := &stats.OutHeader{
-			WireLength: bufLen,
+		//WireLength: // TODO(mmukhi): Revisit this later, if needed.
 		}
 		t.stats.HandleRPC(s.Context(), outHeader)
 	}
-	t.writableChan <- 0
 	return nil
 }
 
@@ -756,6 +744,12 @@ func (t *http2Server) WriteHeader(s *Stream, md metadata.MD) error {
 // TODO(zhaoq): Now it indicates the end of entire stream. Revisit if early
 // OK is adopted.
 func (t *http2Server) WriteStatus(s *Stream, st *status.Status) error {
+	select {
+	case <-t.ctx.Done():
+		return ErrConnClosing
+	default:
+	}
+
 	var headersSent, hasHeader bool
 	s.mu.Lock()
 	if s.state == streamDone {
@@ -775,25 +769,15 @@ func (t *http2Server) WriteStatus(s *Stream, st *status.Status) error {
 		headersSent = true
 	}
 
-	// Always write a status regardless of context cancellation unless the stream
-	// is terminated (e.g. by a RST_STREAM, GOAWAY, or transport error).  The
-	// server's application code is already done so it is fine to ignore s.ctx.
-	select {
-	case <-t.shutdownChan:
-		return ErrConnClosing
-	case <-t.writableChan:
-	}
-	t.hBuf.Reset()
+	// TODO(mmukhi): Benchmark if the perfomance gets better if count the metadata and other header fields
+	// first and create a slice of that exact size.
+	headerFields := make([]hpack.HeaderField, 0, 2) // grpc-status and grpc-message will be there if none else.
 	if !headersSent {
-		t.hEnc.WriteField(hpack.HeaderField{Name: ":status", Value: "200"})
-		t.hEnc.WriteField(hpack.HeaderField{Name: "content-type", Value: "application/grpc"})
+		headerFields = append(headerFields, hpack.HeaderField{Name: ":status", Value: "200"})
+		headerFields = append(headerFields, hpack.HeaderField{Name: "content-type", Value: "application/grpc"})
 	}
-	t.hEnc.WriteField(
-		hpack.HeaderField{
-			Name:  "grpc-status",
-			Value: strconv.Itoa(int(st.Code())),
-		})
-	t.hEnc.WriteField(hpack.HeaderField{Name: "grpc-message", Value: encodeGrpcMessage(st.Message())})
+	headerFields = append(headerFields, hpack.HeaderField{Name: "grpc-status", Value: strconv.Itoa(int(st.Code()))})
+	headerFields = append(headerFields, hpack.HeaderField{Name: "grpc-message", Value: encodeGrpcMessage(st.Message())})
 
 	if p := st.Proto(); p != nil && len(p.Details) > 0 {
 		stBytes, err := proto.Marshal(p)
@@ -802,7 +786,7 @@ func (t *http2Server) WriteStatus(s *Stream, st *status.Status) error {
 			panic(err)
 		}
 
-		t.hEnc.WriteField(hpack.HeaderField{Name: "grpc-status-details-bin", Value: encodeBinHeader(stBytes)})
+		headerFields = append(headerFields, hpack.HeaderField{Name: "grpc-status-details-bin", Value: encodeBinHeader(stBytes)})
 	}
 
 	// Attach the trailer metadata.
@@ -812,36 +796,32 @@ func (t *http2Server) WriteStatus(s *Stream, st *status.Status) error {
 			continue
 		}
 		for _, v := range vv {
-			t.hEnc.WriteField(hpack.HeaderField{Name: k, Value: encodeMetadataHeader(k, v)})
+			headerFields = append(headerFields, hpack.HeaderField{Name: k, Value: encodeMetadataHeader(k, v)})
 		}
 	}
-	bufLen := t.hBuf.Len()
-	if err := t.writeHeaders(s, t.hBuf, true); err != nil {
-		t.Close()
-		return err
-	}
+	t.controlBuf.put(&headerFrame{
+		streamID:  s.id,
+		hf:        headerFields,
+		endStream: true,
+	})
 	if t.stats != nil {
-		outTrailer := &stats.OutTrailer{
-			WireLength: bufLen,
-		}
-		t.stats.HandleRPC(s.Context(), outTrailer)
+		t.stats.HandleRPC(s.Context(), &stats.OutTrailer{})
 	}
 	t.closeStream(s)
-	t.writableChan <- 0
 	return nil
 }
 
 // Write converts the data into HTTP2 data frame and sends it out. Non-nil error
 // is returns if it fails (e.g., framing error, transport error).
 func (t *http2Server) Write(s *Stream, hdr []byte, data []byte, opts *Options) (err error) {
-	// TODO(zhaoq): Support multi-writers for a single stream.
-	secondStart := http2MaxFrameLen - len(hdr)%http2MaxFrameLen
-	if len(data) < secondStart {
-		secondStart = len(data)
-	}
-	hdr = append(hdr, data[:secondStart]...)
-	data = data[secondStart:]
-	isLastSlice := (len(data) == 0)
+	select {
+	case <-s.ctx.Done():
+		return ContextErr(s.ctx.Err())
+	case <-t.ctx.Done():
+		return ErrConnClosing
+	default:
+	}
+
 	var writeHeaderFrame bool
 	s.mu.Lock()
 	if s.state == streamDone {
@@ -855,124 +835,74 @@ func (t *http2Server) Write(s *Stream, hdr []byte, data []byte, opts *Options) (
 	if writeHeaderFrame {
 		t.WriteHeader(s, nil)
 	}
-	r := bytes.NewBuffer(hdr)
-	var (
-		p   []byte
-		oqv uint32
-	)
-	for {
-		if r.Len() == 0 && p == nil {
-			return nil
-		}
-		oqv = atomic.LoadUint32(&t.outQuotaVersion)
-		size := http2MaxFrameLen
-		// Wait until the stream has some quota to send the data.
-		sq, err := wait(s.ctx, nil, nil, t.shutdownChan, s.sendQuotaPool.acquire())
-		if err != nil {
-			return err
-		}
-		// Wait until the transport has some quota to send the data.
-		tq, err := wait(s.ctx, nil, nil, t.shutdownChan, t.sendQuotaPool.acquire())
-		if err != nil {
-			return err
-		}
-		if sq < size {
-			size = sq
-		}
-		if tq < size {
-			size = tq
-		}
-		if p == nil {
-			p = r.Next(size)
-		}
-		ps := len(p)
-		if ps < sq {
-			// Overbooked stream quota. Return it back.
-			s.sendQuotaPool.add(sq - ps)
-		}
-		if ps < tq {
-			// Overbooked transport quota. Return it back.
-			t.sendQuotaPool.add(tq - ps)
-		}
-		t.framer.adjustNumWriters(1)
-		// Got some quota. Try to acquire writing privilege on the
-		// transport.
-		if _, err := wait(s.ctx, nil, nil, t.shutdownChan, t.writableChan); err != nil {
-			if _, ok := err.(StreamError); ok {
-				// Return the connection quota back.
-				t.sendQuotaPool.add(ps)
+	// Add data to header frame so that we can equally distribute data across frames.
+	emptyLen := http2MaxFrameLen - len(hdr)
+	if emptyLen > len(data) {
+		emptyLen = len(data)
+	}
+	hdr = append(hdr, data[:emptyLen]...)
+	data = data[emptyLen:]
+	for _, r := range [][]byte{hdr, data} {
+		for len(r) > 0 {
+			size := http2MaxFrameLen
+			// Wait until the stream has some quota to send the data.
+			quotaChan, quotaVer := s.sendQuotaPool.acquireWithVersion()
+			sq, err := wait(s.ctx, t.ctx, nil, nil, quotaChan)
+			if err != nil {
+				return err
 			}
-			if t.framer.adjustNumWriters(-1) == 0 {
-				// This writer is the last one in this batch and has the
-				// responsibility to flush the buffered frames. It queues
-				// a flush request to controlBuf instead of flushing directly
-				// in order to avoid the race with other writing or flushing.
-				t.controlBuf.put(&flushIO{})
+			// Wait until the transport has some quota to send the data.
+			tq, err := wait(s.ctx, t.ctx, nil, nil, t.sendQuotaPool.acquire())
+			if err != nil {
+				return err
 			}
-			return err
-		}
-		select {
-		case <-s.ctx.Done():
-			t.sendQuotaPool.add(ps)
-			if t.framer.adjustNumWriters(-1) == 0 {
-				t.controlBuf.put(&flushIO{})
+			if sq < size {
+				size = sq
 			}
-			t.writableChan <- 0
-			return ContextErr(s.ctx.Err())
-		default:
-		}
-		if oqv != atomic.LoadUint32(&t.outQuotaVersion) {
-			// InitialWindowSize settings frame must have been received after we
-			// acquired send quota but before we got the writable channel.
-			// We must forsake this write.
-			t.sendQuotaPool.add(ps)
-			s.sendQuotaPool.add(ps)
-			if t.framer.adjustNumWriters(-1) == 0 {
-				t.controlBuf.put(&flushIO{})
+			if tq < size {
+				size = tq
 			}
-			t.writableChan <- 0
-			continue
-		}
-		var forceFlush bool
-		if r.Len() == 0 {
-			if isLastSlice {
-				if t.framer.adjustNumWriters(0) == 1 && !opts.Last {
-					forceFlush = true
+			if size > len(r) {
+				size = len(r)
+			}
+			p := r[:size]
+			ps := len(p)
+			if ps < tq {
+				// Overbooked transport quota. Return it back.
+				t.sendQuotaPool.add(tq - ps)
+			}
+			// Acquire local send quota to be able to write to the controlBuf.
+			ltq, err := wait(s.ctx, t.ctx, nil, nil, s.localSendQuota.acquire())
+			if err != nil {
+				if _, ok := err.(ConnectionError); !ok {
+					t.sendQuotaPool.add(ps)
 				}
-			} else {
-				r = bytes.NewBuffer(data)
-				isLastSlice = true
+				return err
 			}
-		}
-		// Reset ping strikes when sending data since this might cause
-		// the peer to send ping.
-		atomic.StoreUint32(&t.resetPingStrikes, 1)
-		if err := t.framer.writeData(forceFlush, s.id, false, p); err != nil {
-			t.Close()
-			return connectionErrorf(true, err, "transport: %v", err)
-		}
-		p = nil
-		if t.framer.adjustNumWriters(-1) == 0 {
-			t.framer.flushWrite()
-		}
-		t.writableChan <- 0
-	}
-
-}
-
-func (t *http2Server) applySettings(ss []http2.Setting) {
-	for _, s := range ss {
-		if s.ID == http2.SettingInitialWindowSize {
-			t.mu.Lock()
-			defer t.mu.Unlock()
-			for _, stream := range t.activeStreams {
-				stream.sendQuotaPool.add(int(s.Val) - int(t.streamSendQuota))
+			s.localSendQuota.add(ltq - ps) // It's ok we make this negative.
+			// Reset ping strikes when sending data since this might cause
+			// the peer to send ping.
+			atomic.StoreUint32(&t.resetPingStrikes, 1)
+			success := func() {
+				t.controlBuf.put(&dataFrame{streamID: s.id, endStream: false, d: p, f: func() {
+					s.localSendQuota.add(ps)
+				}})
+				if ps < sq {
+					// Overbooked stream quota. Return it back.
+					s.sendQuotaPool.lockedAdd(sq - ps)
+				}
+				r = r[ps:]
+			}
+			failure := func() {
+				s.sendQuotaPool.lockedAdd(sq)
+			}
+			if !s.sendQuotaPool.compareAndExecute(quotaVer, success, failure) {
+				t.sendQuotaPool.add(ps)
+				s.localSendQuota.add(ps)
 			}
-			t.streamSendQuota = s.Val
-			atomic.AddUint32(&t.outQuotaVersion, 1)
 		}
-
 	}
+	return nil
 }
 
 // keepalive running in a separate goroutine does the following:
@@ -988,7 +918,7 @@ func (t *http2Server) keepalive() {
 	maxAge := time.NewTimer(t.kp.MaxConnectionAge)
 	keepalive := time.NewTimer(t.kp.Time)
 	// NOTE: All exit paths of this function should reset their
-	// respecitve timers. A failure to do so will cause the
+	// respective timers. A failure to do so will cause the
 	// following clean-up to deadlock and eventually leak.
 	defer func() {
 		if !maxIdle.Stop() {
@@ -1031,7 +961,7 @@ func (t *http2Server) keepalive() {
 				t.Close()
 				// Reseting the timer so that the clean-up doesn't deadlock.
 				maxAge.Reset(infinity)
-			case <-t.shutdownChan:
+			case <-t.ctx.Done():
 			}
 			return
 		case <-keepalive.C:
@@ -1049,7 +979,7 @@ func (t *http2Server) keepalive() {
 			pingSent = true
 			t.controlBuf.put(p)
 			keepalive.Reset(t.kp.Timeout)
-		case <-t.shutdownChan:
+		case <-t.ctx.Done():
 			return
 		}
 	}
@@ -1057,93 +987,129 @@ func (t *http2Server) keepalive() {
 
 var goAwayPing = &ping{data: [8]byte{1, 6, 1, 8, 0, 3, 3, 9}}
 
-// controller running in a separate goroutine takes charge of sending control
-// frames (e.g., window update, reset stream, setting, etc.) to the server.
-func (t *http2Server) controller() {
-	for {
-		select {
-		case i := <-t.controlBuf.get():
-			t.controlBuf.load()
+// TODO(mmukhi): A lot of this code(and code in other places in the tranpsort layer)
+// is duplicated between the client and the server.
+// The transport layer needs to be refactored to take care of this.
+func (t *http2Server) itemHandler(i item) error {
+	switch i := i.(type) {
+	case *dataFrame:
+		if err := t.framer.fr.WriteData(i.streamID, i.endStream, i.d); err != nil {
+			return err
+		}
+		i.f()
+		return nil
+	case *headerFrame:
+		t.hBuf.Reset()
+		for _, f := range i.hf {
+			t.hEnc.WriteField(f)
+		}
+		first := true
+		endHeaders := false
+		for !endHeaders {
+			size := t.hBuf.Len()
+			if size > http2MaxFrameLen {
+				size = http2MaxFrameLen
+			} else {
+				endHeaders = true
+			}
+			var err error
+			if first {
+				first = false
+				err = t.framer.fr.WriteHeaders(http2.HeadersFrameParam{
+					StreamID:      i.streamID,
+					BlockFragment: t.hBuf.Next(size),
+					EndStream:     i.endStream,
+					EndHeaders:    endHeaders,
+				})
+			} else {
+				err = t.framer.fr.WriteContinuation(
+					i.streamID,
+					endHeaders,
+					t.hBuf.Next(size),
+				)
+			}
+			if err != nil {
+				return err
+			}
+		}
+		atomic.StoreUint32(&t.resetPingStrikes, 1)
+		return nil
+	case *windowUpdate:
+		return t.framer.fr.WriteWindowUpdate(i.streamID, i.increment)
+	case *settings:
+		if i.ack {
+			t.applySettings(i.ss)
+			return t.framer.fr.WriteSettingsAck()
+		}
+		return t.framer.fr.WriteSettings(i.ss...)
+	case *resetStream:
+		return t.framer.fr.WriteRSTStream(i.streamID, i.code)
+	case *goAway:
+		t.mu.Lock()
+		if t.state == closing {
+			t.mu.Unlock()
+			// The transport is closing.
+			return fmt.Errorf("transport: Connection closing")
+		}
+		sid := t.maxStreamID
+		if !i.headsUp {
+			// Stop accepting more streams now.
+			t.state = draining
+			t.mu.Unlock()
+			if err := t.framer.fr.WriteGoAway(sid, i.code, i.debugData); err != nil {
+				return err
+			}
+			if i.closeConn {
+				// Abruptly close the connection following the GoAway (via
+				// loopywriter).  But flush out what's inside the buffer first.
+				t.framer.writer.Flush()
+				return fmt.Errorf("transport: Connection closing")
+			}
+			return nil
+		}
+		t.mu.Unlock()
+		// For a graceful close, send out a GoAway with stream ID of MaxUInt32,
+		// Follow that with a ping and wait for the ack to come back or a timer
+		// to expire. During this time accept new streams since they might have
+		// originated before the GoAway reaches the client.
+		// After getting the ack or timer expiration send out another GoAway this
+		// time with an ID of the max stream server intends to process.
+		if err := t.framer.fr.WriteGoAway(math.MaxUint32, http2.ErrCodeNo, []byte{}); err != nil {
+			return err
+		}
+		if err := t.framer.fr.WritePing(false, goAwayPing.data); err != nil {
+			return err
+		}
+		go func() {
+			timer := time.NewTimer(time.Minute)
+			defer timer.Stop()
 			select {
-			case <-t.writableChan:
-				switch i := i.(type) {
-				case *windowUpdate:
-					t.framer.writeWindowUpdate(i.flush, i.streamID, i.increment)
-				case *settings:
-					if i.ack {
-						t.framer.writeSettingsAck(true)
-						t.applySettings(i.ss)
-					} else {
-						t.framer.writeSettings(true, i.ss...)
-					}
-				case *resetStream:
-					t.framer.writeRSTStream(true, i.streamID, i.code)
-				case *goAway:
-					t.mu.Lock()
-					if t.state == closing {
-						t.mu.Unlock()
-						// The transport is closing.
-						return
-					}
-					sid := t.maxStreamID
-					if !i.headsUp {
-						// Stop accepting more streams now.
-						t.state = draining
-						activeStreams := len(t.activeStreams)
-						t.mu.Unlock()
-						t.framer.writeGoAway(true, sid, i.code, i.debugData)
-						if i.closeConn || activeStreams == 0 {
-							// Abruptly close the connection following the GoAway.
-							t.Close()
-						}
-						t.writableChan <- 0
-						continue
-					}
-					t.mu.Unlock()
-					// For a graceful close, send out a GoAway with stream ID of MaxUInt32,
-					// Follow that with a ping and wait for the ack to come back or a timer
-					// to expire. During this time accept new streams since they might have
-					// originated before the GoAway reaches the client.
-					// After getting the ack or timer expiration send out another GoAway this
-					// time with an ID of the max stream server intends to process.
-					t.framer.writeGoAway(true, math.MaxUint32, http2.ErrCodeNo, []byte{})
-					t.framer.writePing(true, false, goAwayPing.data)
-					go func() {
-						timer := time.NewTimer(time.Minute)
-						defer timer.Stop()
-						select {
-						case <-t.drainChan:
-						case <-timer.C:
-						case <-t.shutdownChan:
-							return
-						}
-						t.controlBuf.put(&goAway{code: i.code, debugData: i.debugData})
-					}()
-				case *flushIO:
-					t.framer.flushWrite()
-				case *ping:
-					if !i.ack {
-						t.bdpEst.timesnap(i.data)
-					}
-					t.framer.writePing(true, i.ack, i.data)
-				default:
-					errorf("transport: http2Server.controller got unexpected item type %v\n", i)
-				}
-				t.writableChan <- 0
-				continue
-			case <-t.shutdownChan:
+			case <-t.drainChan:
+			case <-timer.C:
+			case <-t.ctx.Done():
 				return
 			}
-		case <-t.shutdownChan:
-			return
+			t.controlBuf.put(&goAway{code: i.code, debugData: i.debugData})
+		}()
+		return nil
+	case *flushIO:
+		return t.framer.writer.Flush()
+	case *ping:
+		if !i.ack {
+			t.bdpEst.timesnap(i.data)
 		}
+		return t.framer.fr.WritePing(i.ack, i.data)
+	default:
+		err := status.Errorf(codes.Internal, "transport: http2Server.controller got unexpected item type %t", i)
+		errorf("%v", err)
+		return err
 	}
 }
 
 // Close starts shutting down the http2Server transport.
 // TODO(zhaoq): Now the destruction is not blocked on any pending streams. This
 // could cause some resource issue. Revisit this later.
-func (t *http2Server) Close() (err error) {
+func (t *http2Server) Close() error {
 	t.mu.Lock()
 	if t.state == closing {
 		t.mu.Unlock()
@@ -1153,8 +1119,8 @@ func (t *http2Server) Close() (err error) {
 	streams := t.activeStreams
 	t.activeStreams = nil
 	t.mu.Unlock()
-	close(t.shutdownChan)
-	err = t.conn.Close()
+	t.cancel()
+	err := t.conn.Close()
 	// Cancel all active streams.
 	for _, s := range streams {
 		s.cancel()
@@ -1163,7 +1129,7 @@ func (t *http2Server) Close() (err error) {
 		connEnd := &stats.ConnEnd{}
 		t.stats.HandleConn(t.ctx, connEnd)
 	}
-	return
+	return err
 }
 
 // closeStream clears the footprint of a stream when the stream is not needed

cmd/vendor/google.golang.org/grpc/transport/http_util.go

@@ -28,7 +28,6 @@ import (
 	"net/http"
 	"strconv"
 	"strings"
-	"sync/atomic"
 	"time"
 
 	"github.com/golang/protobuf/proto"
@@ -45,7 +44,8 @@ const (
 	// http://http2.github.io/http2-spec/#SettingValues
 	http2InitHeaderTableSize = 4096
 	// http2IOBufSize specifies the buffer size for sending frames.
-	http2IOBufSize = 32 * 1024
+	defaultWriteBufSize = 32 * 1024
+	defaultReadBufSize  = 32 * 1024
 )
 
 var (
@@ -475,10 +475,10 @@ type framer struct {
 	fr         *http2.Framer
 }
 
-func newFramer(conn net.Conn) *framer {
+func newFramer(conn net.Conn, writeBufferSize, readBufferSize int) *framer {
 	f := &framer{
-		reader: bufio.NewReaderSize(conn, http2IOBufSize),
-		writer: bufio.NewWriterSize(conn, http2IOBufSize),
+		reader: bufio.NewReaderSize(conn, readBufferSize),
+		writer: bufio.NewWriterSize(conn, writeBufferSize),
 	}
 	f.fr = http2.NewFramer(f.writer, f.reader)
 	// Opt-in to Frame reuse API on framer to reduce garbage.
@@ -487,132 +487,3 @@ func newFramer(conn net.Conn) *framer {
 	f.fr.ReadMetaHeaders = hpack.NewDecoder(http2InitHeaderTableSize, nil)
 	return f
 }
-
-func (f *framer) adjustNumWriters(i int32) int32 {
-	return atomic.AddInt32(&f.numWriters, i)
-}
-
-// The following writeXXX functions can only be called when the caller gets
-// unblocked from writableChan channel (i.e., owns the privilege to write).
-
-func (f *framer) writeContinuation(forceFlush bool, streamID uint32, endHeaders bool, headerBlockFragment []byte) error {
-	if err := f.fr.WriteContinuation(streamID, endHeaders, headerBlockFragment); err != nil {
-		return err
-	}
-	if forceFlush {
-		return f.writer.Flush()
-	}
-	return nil
-}
-
-func (f *framer) writeData(forceFlush bool, streamID uint32, endStream bool, data []byte) error {
-	if err := f.fr.WriteData(streamID, endStream, data); err != nil {
-		return err
-	}
-	if forceFlush {
-		return f.writer.Flush()
-	}
-	return nil
-}
-
-func (f *framer) writeGoAway(forceFlush bool, maxStreamID uint32, code http2.ErrCode, debugData []byte) error {
-	if err := f.fr.WriteGoAway(maxStreamID, code, debugData); err != nil {
-		return err
-	}
-	if forceFlush {
-		return f.writer.Flush()
-	}
-	return nil
-}
-
-func (f *framer) writeHeaders(forceFlush bool, p http2.HeadersFrameParam) error {
-	if err := f.fr.WriteHeaders(p); err != nil {
-		return err
-	}
-	if forceFlush {
-		return f.writer.Flush()
-	}
-	return nil
-}
-
-func (f *framer) writePing(forceFlush, ack bool, data [8]byte) error {
-	if err := f.fr.WritePing(ack, data); err != nil {
-		return err
-	}
-	if forceFlush {
-		return f.writer.Flush()
-	}
-	return nil
-}
-
-func (f *framer) writePriority(forceFlush bool, streamID uint32, p http2.PriorityParam) error {
-	if err := f.fr.WritePriority(streamID, p); err != nil {
-		return err
-	}
-	if forceFlush {
-		return f.writer.Flush()
-	}
-	return nil
-}
-
-func (f *framer) writePushPromise(forceFlush bool, p http2.PushPromiseParam) error {
-	if err := f.fr.WritePushPromise(p); err != nil {
-		return err
-	}
-	if forceFlush {
-		return f.writer.Flush()
-	}
-	return nil
-}
-
-func (f *framer) writeRSTStream(forceFlush bool, streamID uint32, code http2.ErrCode) error {
-	if err := f.fr.WriteRSTStream(streamID, code); err != nil {
-		return err
-	}
-	if forceFlush {
-		return f.writer.Flush()
-	}
-	return nil
-}
-
-func (f *framer) writeSettings(forceFlush bool, settings ...http2.Setting) error {
-	if err := f.fr.WriteSettings(settings...); err != nil {
-		return err
-	}
-	if forceFlush {
-		return f.writer.Flush()
-	}
-	return nil
-}
-
-func (f *framer) writeSettingsAck(forceFlush bool) error {
-	if err := f.fr.WriteSettingsAck(); err != nil {
-		return err
-	}
-	if forceFlush {
-		return f.writer.Flush()
-	}
-	return nil
-}
-
-func (f *framer) writeWindowUpdate(forceFlush bool, streamID, incr uint32) error {
-	if err := f.fr.WriteWindowUpdate(streamID, incr); err != nil {
-		return err
-	}
-	if forceFlush {
-		return f.writer.Flush()
-	}
-	return nil
-}
-
-func (f *framer) flushWrite() error {
-	return f.writer.Flush()
-}
-
-func (f *framer) readFrame() (http2.Frame, error) {
-	return f.fr.ReadFrame()
-}
-
-func (f *framer) errorDetail() error {
-	return f.fr.ErrorDetail()
-}

cmd/vendor/google.golang.org/grpc/transport/transport.go

@@ -21,10 +21,12 @@
 package transport // import "google.golang.org/grpc/transport"
 
 import (
+	stdctx "context"
 	"fmt"
 	"io"
 	"net"
 	"sync"
+	"time"
 
 	"golang.org/x/net/context"
 	"golang.org/x/net/http2"
@@ -67,20 +69,20 @@ func newRecvBuffer() *recvBuffer {
 
 func (b *recvBuffer) put(r recvMsg) {
 	b.mu.Lock()
-	defer b.mu.Unlock()
 	if len(b.backlog) == 0 {
 		select {
 		case b.c <- r:
+			b.mu.Unlock()
 			return
 		default:
 		}
 	}
 	b.backlog = append(b.backlog, r)
+	b.mu.Unlock()
 }
 
 func (b *recvBuffer) load() {
 	b.mu.Lock()
-	defer b.mu.Unlock()
 	if len(b.backlog) > 0 {
 		select {
 		case b.c <- b.backlog[0]:
@@ -89,6 +91,7 @@ func (b *recvBuffer) load() {
 		default:
 		}
 	}
+	b.mu.Unlock()
 }
 
 // get returns the channel that receives a recvMsg in the buffer.
@@ -164,20 +167,20 @@ func newControlBuffer() *controlBuffer {
 
 func (b *controlBuffer) put(r item) {
 	b.mu.Lock()
-	defer b.mu.Unlock()
 	if len(b.backlog) == 0 {
 		select {
 		case b.c <- r:
+			b.mu.Unlock()
 			return
 		default:
 		}
 	}
 	b.backlog = append(b.backlog, r)
+	b.mu.Unlock()
 }
 
 func (b *controlBuffer) load() {
 	b.mu.Lock()
-	defer b.mu.Unlock()
 	if len(b.backlog) > 0 {
 		select {
 		case b.c <- b.backlog[0]:
@@ -186,6 +189,7 @@ func (b *controlBuffer) load() {
 		default:
 		}
 	}
+	b.mu.Unlock()
 }
 
 // get returns the channel that receives an item in the buffer.
@@ -235,7 +239,8 @@ type Stream struct {
 	// is used to adjust flow control, if need be.
 	requestRead func(int)
 
-	sendQuotaPool *quotaPool
+	sendQuotaPool  *quotaPool
+	localSendQuota *quotaPool
 	// Close headerChan to indicate the end of reception of header metadata.
 	headerChan chan struct{}
 	// header caches the received header metadata.
@@ -313,8 +318,9 @@ func (s *Stream) Header() (metadata.MD, error) {
 // side only.
 func (s *Stream) Trailer() metadata.MD {
 	s.mu.RLock()
-	defer s.mu.RUnlock()
-	return s.trailer.Copy()
+	c := s.trailer.Copy()
+	s.mu.RUnlock()
+	return c
 }
 
 // ServerTransport returns the underlying ServerTransport for the stream.
@@ -342,14 +348,16 @@ func (s *Stream) Status() *status.Status {
 // Server side only.
 func (s *Stream) SetHeader(md metadata.MD) error {
 	s.mu.Lock()
-	defer s.mu.Unlock()
 	if s.headerOk || s.state == streamDone {
+		s.mu.Unlock()
 		return ErrIllegalHeaderWrite
 	}
 	if md.Len() == 0 {
+		s.mu.Unlock()
 		return nil
 	}
 	s.header = metadata.Join(s.header, md)
+	s.mu.Unlock()
 	return nil
 }
 
@@ -360,8 +368,8 @@ func (s *Stream) SetTrailer(md metadata.MD) error {
 		return nil
 	}
 	s.mu.Lock()
-	defer s.mu.Unlock()
 	s.trailer = metadata.Join(s.trailer, md)
+	s.mu.Unlock()
 	return nil
 }
 
@@ -412,15 +420,17 @@ func (s *Stream) finish(st *status.Status) {
 // BytesSent indicates whether any bytes have been sent on this stream.
 func (s *Stream) BytesSent() bool {
 	s.mu.Lock()
-	defer s.mu.Unlock()
-	return s.bytesSent
+	bs := s.bytesSent
+	s.mu.Unlock()
+	return bs
 }
 
 // BytesReceived indicates whether any bytes have been received on this stream.
 func (s *Stream) BytesReceived() bool {
 	s.mu.Lock()
-	defer s.mu.Unlock()
-	return s.bytesReceived
+	br := s.bytesReceived
+	s.mu.Unlock()
+	return br
 }
 
 // GoString is implemented by Stream so context.String() won't
@@ -449,7 +459,6 @@ type transportState int
 
 const (
 	reachable transportState = iota
-	unreachable
 	closing
 	draining
 )
@@ -464,6 +473,8 @@ type ServerConfig struct {
 	KeepalivePolicy       keepalive.EnforcementPolicy
 	InitialWindowSize     int32
 	InitialConnWindowSize int32
+	WriteBufferSize       int
+	ReadBufferSize        int
 }
 
 // NewServerTransport creates a ServerTransport with conn or non-nil error
@@ -491,10 +502,14 @@ type ConnectOptions struct {
 	KeepaliveParams keepalive.ClientParameters
 	// StatsHandler stores the handler for stats.
 	StatsHandler stats.Handler
-	// InitialWindowSize sets the intial window size for a stream.
+	// InitialWindowSize sets the initial window size for a stream.
 	InitialWindowSize int32
-	// InitialConnWindowSize sets the intial window size for a connection.
+	// InitialConnWindowSize sets the initial window size for a connection.
 	InitialConnWindowSize int32
+	// WriteBufferSize sets the size of write buffer which in turn determines how much data can be batched before it's written on the wire.
+	WriteBufferSize int
+	// ReadBufferSize sets the size of read buffer, which in turn determines how much data can be read at most for one read syscall.
+	ReadBufferSize int
 }
 
 // TargetInfo contains the information of the target such as network address and metadata.
@@ -505,8 +520,8 @@ type TargetInfo struct {
 
 // NewClientTransport establishes the transport with the required ConnectOptions
 // and returns it to the caller.
-func NewClientTransport(ctx context.Context, target TargetInfo, opts ConnectOptions) (ClientTransport, error) {
-	return newHTTP2Client(ctx, target, opts)
+func NewClientTransport(ctx context.Context, target TargetInfo, opts ConnectOptions, timeout time.Duration) (ClientTransport, error) {
+	return newHTTP2Client(ctx, target, opts, timeout)
 }
 
 // Options provides additional hints and information for message
@@ -518,7 +533,7 @@ type Options struct {
 
 	// Delay is a hint to the transport implementation for whether
 	// the data could be buffered for a batching write. The
-	// Transport implementation may ignore the hint.
+	// transport implementation may ignore the hint.
 	Delay bool
 }
 
@@ -688,34 +703,33 @@ func (e StreamError) Error() string {
 	return fmt.Sprintf("stream error: code = %s desc = %q", e.Code, e.Desc)
 }
 
-// wait blocks until it can receive from ctx.Done, closing, or proceed.
-// If it receives from ctx.Done, it returns 0, the StreamError for ctx.Err.
-// If it receives from done, it returns 0, io.EOF if ctx is not done; otherwise
-// it return the StreamError for ctx.Err.
-// If it receives from goAway, it returns 0, ErrStreamDrain.
-// If it receives from closing, it returns 0, ErrConnClosing.
-// If it receives from proceed, it returns the received integer, nil.
-func wait(ctx context.Context, done, goAway, closing <-chan struct{}, proceed <-chan int) (int, error) {
+// wait blocks until it can receive from one of the provided contexts or channels
+func wait(ctx, tctx context.Context, done, goAway <-chan struct{}, proceed <-chan int) (int, error) {
 	select {
 	case <-ctx.Done():
 		return 0, ContextErr(ctx.Err())
 	case <-done:
-		// User cancellation has precedence.
-		select {
-		case <-ctx.Done():
-			return 0, ContextErr(ctx.Err())
-		default:
-		}
 		return 0, io.EOF
 	case <-goAway:
 		return 0, ErrStreamDrain
-	case <-closing:
+	case <-tctx.Done():
 		return 0, ErrConnClosing
 	case i := <-proceed:
 		return i, nil
 	}
 }
 
+// ContextErr converts the error from context package into a StreamError.
+func ContextErr(err error) StreamError {
+	switch err {
+	case context.DeadlineExceeded, stdctx.DeadlineExceeded:
+		return streamErrorf(codes.DeadlineExceeded, "%v", err)
+	case context.Canceled, stdctx.Canceled:
+		return streamErrorf(codes.Canceled, "%v", err)
+	}
+	return streamErrorf(codes.Internal, "Unexpected error from context packet: %v", err)
+}
+
 // GoAwayReason contains the reason for the GoAway frame received.
 type GoAwayReason uint8
 
@@ -725,6 +739,39 @@ const (
 	// NoReason is the default value when GoAway frame is received.
 	NoReason GoAwayReason = 1
 	// TooManyPings indicates that a GoAway frame with ErrCodeEnhanceYourCalm
-	// was recieved and that the debug data said "too_many_pings".
+	// was received and that the debug data said "too_many_pings".
 	TooManyPings GoAwayReason = 2
 )
+
+// loopyWriter is run in a separate go routine. It is the single code path that will
+// write data on wire.
+func loopyWriter(ctx context.Context, cbuf *controlBuffer, handler func(item) error) {
+	for {
+		select {
+		case i := <-cbuf.get():
+			cbuf.load()
+			if err := handler(i); err != nil {
+				return
+			}
+		case <-ctx.Done():
+			return
+		}
+	hasData:
+		for {
+			select {
+			case i := <-cbuf.get():
+				cbuf.load()
+				if err := handler(i); err != nil {
+					return
+				}
+			case <-ctx.Done():
+				return
+			default:
+				if err := handler(&flushIO{}); err != nil {
+					return
+				}
+				break hasData
+			}
+		}
+	}
+}

glide.lock

@@ -1,5 +1,5 @@
-hash: cff74aae5a6b8c11816c9994dedfdfdcd9f4137d61d8ed8ba0bf623f0ff21d50
-updated: 2017-11-10T09:46:28.3753-08:00
+hash: 8d556efcf8d917aba74445bd98eb9de3abcf981ca70adb53276026c4c3ecfcfd
+updated: 2017-11-10T12:07:01.187305-08:00
 imports:
 - name: github.com/beorn7/perks
   version: 4c0e84591b9aa9e6dcfdf3e020114cd81f89d5f9
@@ -158,8 +158,9 @@ imports:
   subpackages:
   - googleapis/rpc/status
 - name: google.golang.org/grpc
-  version: f92cdcd7dcdc69e81b2d7b338479a19a8723cfa3
+  version: 5ffe3083946d5603a0578721101dc8165b1d5b5f
   subpackages:
+  - balancer
   - codes
   - connectivity
   - credentials
@@ -172,6 +173,7 @@ imports:
   - metadata
   - naming
   - peer
+  - resolver
   - stats
   - status
   - tap

glide.yaml

@@ -108,7 +108,7 @@ import:
   subpackages:
   - rate
 - package: google.golang.org/grpc
-  version: v1.6.0
+  version: v1.7.2
   subpackages:
   - codes
   - credentials