clientv3: configure gRPC message limits in Config

Signed-off-by: Gyuho Lee <gyuhox@gmail.com>

clientv3/client.go

@@ -67,6 +67,8 @@ type Client struct {
 	Password string
 	// tokenCred is an instance of WithPerRPCCredentials()'s argument
 	tokenCred *authTokenCredential
+
+	callOpts []grpc.CallOption
 }
 
 // New creates a new etcdv3 client from a given configuration.
@@ -386,11 +388,29 @@ func newClient(cfg *Config) (*Client, error) {
 		ctx:      ctx,
 		cancel:   cancel,
 		mu:       new(sync.Mutex),
+		callOpts: defaultCallOpts,
 	}
 	if cfg.Username != "" && cfg.Password != "" {
 		client.Username = cfg.Username
 		client.Password = cfg.Password
 	}
+	if cfg.MaxCallSendMsgSize > 0 || cfg.MaxCallRecvMsgSize > 0 {
+		if cfg.MaxCallRecvMsgSize > 0 && cfg.MaxCallSendMsgSize > cfg.MaxCallRecvMsgSize {
+			return nil, fmt.Errorf("gRPC message recv limit (%d bytes) must be greater than send limit (%d bytes)", cfg.MaxCallRecvMsgSize, cfg.MaxCallSendMsgSize)
+		}
+		callOpts := []grpc.CallOption{
+			defaultFailFast,
+			defaultMaxCallSendMsgSize,
+			defaultMaxCallRecvMsgSize,
+		}
+		if cfg.MaxCallSendMsgSize > 0 {
+			callOpts[1] = grpc.MaxCallSendMsgSize(cfg.MaxCallSendMsgSize)
+		}
+		if cfg.MaxCallRecvMsgSize > 0 {
+			callOpts[2] = grpc.MaxCallRecvMsgSize(cfg.MaxCallRecvMsgSize)
+		}
+		client.callOpts = callOpts
+	}
 
 	client.balancer = newHealthBalancer(cfg.Endpoints, cfg.DialTimeout, func(ep string) (bool, error) {
 		return grpcHealthCheck(client, ep)

clientv3/config.go

@@ -41,6 +41,19 @@ type Config struct {
 	// keep-alive probe. If the response is not received in this time, the connection is closed.
 	DialKeepAliveTimeout time.Duration `json:"dial-keep-alive-timeout"`
 
+	// MaxCallSendMsgSize is the client-side request send limit in bytes.
+	// If 0, it defaults to 2.0 MiB (2 * 1024 * 1024).
+	// Make sure that "MaxCallSendMsgSize" < server-side default send/recv limit.
+	// ("--max-request-bytes" flag to etcd or "embed.Config.MaxRequestBytes").
+	MaxCallSendMsgSize int
+
+	// MaxCallRecvMsgSize is the client-side response receive limit.
+	// If 0, it defaults to "math.MaxInt32", because range response can
+	// easily exceed request send limits.
+	// Make sure that "MaxCallRecvMsgSize" >= server-side default send/recv limit.
+	// ("--max-request-bytes" flag to etcd or "embed.Config.MaxRequestBytes").
+	MaxCallRecvMsgSize int
+
 	// TLS holds the client secure credentials, if any.
 	TLS *tls.Config
 

clientv3/grpc_options.go

@@ -0,0 +1,46 @@
+// 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.
+// 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 (
+	"math"
+
+	"google.golang.org/grpc"
+)
+
+var (
+	// Disable gRPC internal retrial logic
+	// TODO: enable when gRPC retry is stable (FailFast=false)
+	// Reference:
+	//  - https://github.com/grpc/grpc-go/issues/1532
+	//  - https://github.com/grpc/proposal/blob/master/A6-client-retries.md
+	defaultFailFast = grpc.FailFast(true)
+
+	// client-side request send limit, gRPC default is math.MaxInt32
+	// Make sure that "client-side send limit < server-side default send/recv limit"
+	// Same value as "embed.DefaultMaxRequestBytes" plus gRPC overhead bytes
+	defaultMaxCallSendMsgSize = grpc.MaxCallSendMsgSize(2 * 1024 * 1024)
+
+	// client-side response receive limit, gRPC default is 4MB
+	// Make sure that "client-side receive limit >= server-side default send/recv limit"
+	// because range response can easily exceed request send limits
+	// Default to math.MaxInt32; writes exceeding server-side send limit fails anyway
+	defaultMaxCallRecvMsgSize = grpc.MaxCallRecvMsgSize(math.MaxInt32)
+)
+
+// defaultCallOpts defines a list of default "gRPC.CallOption".
+// Some options are exposed to "clientv3.Config".
+// Defaults will be overridden by the settings in "clientv3.Config".
+var defaultCallOpts = []grpc.CallOption{defaultFailFast, defaultMaxCallSendMsgSize, defaultMaxCallRecvMsgSize}