clientv3: only retry mutable KV RPCs if no endpoints found

Was retrying when it shouldn't, causing multiple puts

clientv3/client.go

@@ -52,11 +52,9 @@ type Client struct {
 	conn     *grpc.ClientConn
 	dialerrc chan error
 
-	cfg              Config
-	creds            *credentials.TransportCredentials
-	balancer         *simpleBalancer
-	retryWrapper     retryRpcFunc
-	retryAuthWrapper retryRpcFunc
+	cfg      Config
+	creds    *credentials.TransportCredentials
+	balancer *simpleBalancer
 
 	ctx    context.Context
 	cancel context.CancelFunc
@@ -387,8 +385,6 @@ func newClient(cfg *Config) (*Client, error) {
 		return nil, err
 	}
 	client.conn = conn
-	client.retryWrapper = client.newRetryWrapper()
-	client.retryAuthWrapper = client.newAuthRetryWrapper()
 
 	// wait for a connection
 	if cfg.DialTimeout > 0 {
@@ -510,7 +506,6 @@ func toErr(ctx context.Context, err error) error {
 			err = ctx.Err()
 		}
 	case codes.Unavailable:
-		err = ErrNoAvailableEndpoints
 	case codes.FailedPrecondition:
 		err = grpc.ErrClientConnClosing
 	}

clientv3/retry.go

@@ -24,26 +24,29 @@ import (
 
 type rpcFunc func(ctx context.Context) error
 type retryRpcFunc func(context.Context, rpcFunc) error
+type retryStopErrFunc func(error) bool
 
-func (c *Client) newRetryWrapper() retryRpcFunc {
-	return func(rpcCtx context.Context, f rpcFunc) error {
-		for {
-			err := f(rpcCtx)
-			if err == nil {
-				return nil
-			}
+func isReadStopError(err error) bool {
+	eErr := rpctypes.Error(err)
+	// always stop retry on etcd errors
+	if _, ok := eErr.(rpctypes.EtcdError); ok {
+		return true
+	}
+	// only retry if unavailable
+	return grpc.Code(err) != codes.Unavailable
+}
 
-			eErr := rpctypes.Error(err)
-			// always stop retry on etcd errors
-			if _, ok := eErr.(rpctypes.EtcdError); ok {
-				return err
-			}
+func isWriteStopError(err error) bool {
+	return grpc.Code(err) != codes.Unavailable ||
+		grpc.ErrorDesc(err) != "there is no address available"
+}
 
-			// only retry if unavailable
-			if grpc.Code(err) != codes.Unavailable {
+func (c *Client) newRetryWrapper(isStop retryStopErrFunc) retryRpcFunc {
+	return func(rpcCtx context.Context, f rpcFunc) error {
+		for {
+			if err := f(rpcCtx); err == nil || isStop(err) {
 				return err
 			}
-
 			select {
 			case <-c.balancer.ConnectNotify():
 			case <-rpcCtx.Done():
@@ -79,17 +82,24 @@ func (c *Client) newAuthRetryWrapper() retryRpcFunc {
 
 // RetryKVClient implements a KVClient that uses the client's FailFast retry policy.
 func RetryKVClient(c *Client) pb.KVClient {
-	retryWrite := &retryWriteKVClient{pb.NewKVClient(c.conn), c.retryWrapper}
-	return &retryKVClient{&retryWriteKVClient{retryWrite, c.retryAuthWrapper}}
+	readRetry := c.newRetryWrapper(isReadStopError)
+	writeRetry := c.newRetryWrapper(isWriteStopError)
+	conn := pb.NewKVClient(c.conn)
+	retryBasic := &retryKVClient{&retryWriteKVClient{conn, writeRetry}, readRetry}
+	retryAuthWrapper := c.newAuthRetryWrapper()
+	return &retryKVClient{
+		&retryWriteKVClient{retryBasic, retryAuthWrapper},
+		retryAuthWrapper}
 }
 
 type retryKVClient struct {
 	*retryWriteKVClient
+	readRetry retryRpcFunc
 }
 
 func (rkv *retryKVClient) Range(ctx context.Context, in *pb.RangeRequest, opts ...grpc.CallOption) (resp *pb.RangeResponse, err error) {
-	err = rkv.retryf(ctx, func(rctx context.Context) error {
-		resp, err = rkv.retryWriteKVClient.Range(rctx, in, opts...)
+	err = rkv.readRetry(ctx, func(rctx context.Context) error {
+		resp, err = rkv.KVClient.Range(rctx, in, opts...)
 		return err
 	})
 	return resp, err
@@ -139,8 +149,11 @@ type retryLeaseClient struct {
 
 // RetryLeaseClient implements a LeaseClient that uses the client's FailFast retry policy.
 func RetryLeaseClient(c *Client) pb.LeaseClient {
-	retry := &retryLeaseClient{pb.NewLeaseClient(c.conn), c.retryWrapper}
-	return &retryLeaseClient{retry, c.retryAuthWrapper}
+	retry := &retryLeaseClient{
+		pb.NewLeaseClient(c.conn),
+		c.newRetryWrapper(isReadStopError),
+	}
+	return &retryLeaseClient{retry, c.newAuthRetryWrapper()}
 }
 
 func (rlc *retryLeaseClient) LeaseGrant(ctx context.Context, in *pb.LeaseGrantRequest, opts ...grpc.CallOption) (resp *pb.LeaseGrantResponse, err error) {
@@ -167,7 +180,7 @@ type retryClusterClient struct {
 
 // RetryClusterClient implements a ClusterClient that uses the client's FailFast retry policy.
 func RetryClusterClient(c *Client) pb.ClusterClient {
-	return &retryClusterClient{pb.NewClusterClient(c.conn), c.retryWrapper}
+	return &retryClusterClient{pb.NewClusterClient(c.conn), c.newRetryWrapper(isWriteStopError)}
 }
 
 func (rcc *retryClusterClient) MemberAdd(ctx context.Context, in *pb.MemberAddRequest, opts ...grpc.CallOption) (resp *pb.MemberAddResponse, err error) {
@@ -201,7 +214,7 @@ type retryAuthClient struct {
 
 // RetryAuthClient implements a AuthClient that uses the client's FailFast retry policy.
 func RetryAuthClient(c *Client) pb.AuthClient {
-	return &retryAuthClient{pb.NewAuthClient(c.conn), c.retryWrapper}
+	return &retryAuthClient{pb.NewAuthClient(c.conn), c.newRetryWrapper(isWriteStopError)}
 }
 
 func (rac *retryAuthClient) AuthEnable(ctx context.Context, in *pb.AuthEnableRequest, opts ...grpc.CallOption) (resp *pb.AuthEnableResponse, err error) {