[#366] rpc/grpc: Perform read-write message operations with timeout

Remote gRPC server may not return or accept data for a while. gRPC
solves this issue with timeout in context. However, the context is
used for entire gRPC method invocation. Unfortunately the duration
of requests with streams can't be estimated easily.

To solve this issue we can specify timeouts for every message read
and write. Single message has size limit so timeout can be related
to that.

Signed-off-by: Alex Vanin <alexey@nspcc.ru>

rpc/grpc/init.go

@@ -1,7 +1,9 @@
 package grpc
 
 import (
+	"context"
 	"io"
+	"time"
 
 	"github.com/nspcc-dev/neofs-api-go/v2/rpc/common"
 	"google.golang.org/grpc"
@@ -28,18 +30,40 @@ type MessageReadWriter interface {
 
 type streamWrapper struct {
 	grpc.ClientStream
+	timeout time.Duration
+	cancel  context.CancelFunc
 }
 
 func (w streamWrapper) ReadMessage(m Message) error {
+	return w.withTimeout(func() error {
 		return w.ClientStream.RecvMsg(m)
+	})
 }
 
 func (w streamWrapper) WriteMessage(m Message) error {
+	return w.withTimeout(func() error {
 		return w.ClientStream.SendMsg(m)
+	})
 }
 
 func (w *streamWrapper) Close() error {
-	return w.ClientStream.CloseSend()
+	return w.withTimeout(w.ClientStream.CloseSend)
+}
+
+func (w *streamWrapper) withTimeout(closure func() error) error {
+	ch := make(chan error, 1)
+	go func() {
+		ch <- closure()
+		close(ch)
+	}()
+
+	select {
+	case err := <-ch:
+		return err
+	case <-time.After(w.timeout):
+		w.cancel()
+		return context.DeadlineExceeded
+	}
 }
 
 // Init initiates a messaging session within the RPC configured by options.
@@ -50,16 +74,20 @@ func (c *Client) Init(info common.CallMethodInfo, opts ...CallOption) (MessageRe
 		opt(prm)
 	}
 
-	stream, err := c.con.NewStream(prm.ctx, &grpc.StreamDesc{
+	ctx, cancel := context.WithCancel(prm.ctx)
+	stream, err := c.con.NewStream(ctx, &grpc.StreamDesc{
 		StreamName:    info.Name,
 		ServerStreams: info.ServerStream(),
 		ClientStreams: info.ClientStream(),
 	}, toMethodName(info))
 	if err != nil {
+		cancel()
 		return nil, err
 	}
 
 	return &streamWrapper{
 		ClientStream: stream,
+		cancel:       cancel,
+		timeout:      c.rwTimeout,
 	}, nil
 }

rpc/grpc/options.go

@@ -1,15 +1,22 @@
 package grpc
 
 import (
+	"time"
+
 	"google.golang.org/grpc"
 )
 
+const defaultRWTimeout = 1 * time.Minute
+
 type cfg struct {
 	con       *grpc.ClientConn
+	rwTimeout time.Duration
 }
 
 func defaultCfg() *cfg {
-	return new(cfg)
+	return &cfg{
+		rwTimeout: defaultRWTimeout,
+	}
 }
 
 // WithClientConnection returns option to set gRPC connection
@@ -19,3 +26,11 @@ func WithClientConnection(con *grpc.ClientConn) Option {
 		c.con = con
 	}
 }
+
+// WithRWTimeout returns option to specify rwTimeout
+// for reading and writing single gRPC message.
+func WithRWTimeout(t time.Duration) Option {
+	return func(c *cfg) {
+		c.rwTimeout = t
+	}
+}