Method TestClientTransportRestartsAfterStreamIDExhausted

test/transport_test.go:85–159

Tests that the client transport drains and restarts when next stream ID exceeds MaxStreamID. This test also verifies that subsequent RPCs use a new client transport and the old transport is closed.

(t *testing.T)

// MaxStreamID. This test also verifies that subsequent RPCs use a new client
// transport and the old transport is closed.
func (s) TestClientTransportRestartsAfterStreamIDExhausted(t *testing.T) {
	// Set the transport's MaxStreamID to 4 to cause connection to drain after 2 RPCs.
	originalMaxStreamID := transport.MaxStreamID
	transport.MaxStreamID = 4
	defer func() {
		transport.MaxStreamID = originalMaxStreamID
	}()

	ss := &stubserver.StubServer{
		FullDuplexCallF: func(stream testgrpc.TestService_FullDuplexCallServer) error {
			if _, err := stream.Recv(); err != nil {
				return status.Errorf(codes.Internal, "unexpected error receiving: %v", err)
			}
			if err := stream.Send(&testpb.StreamingOutputCallResponse{}); err != nil {
				return status.Errorf(codes.Internal, "unexpected error sending: %v", err)
			}
			if recv, err := stream.Recv(); err != io.EOF {
				return status.Errorf(codes.Internal, "Recv = %v, %v; want _, io.EOF", recv, err)
			}
			return nil
		},
	}

	creds := &transportRestartCheckCreds{}
	if err := ss.Start(nil, grpc.WithTransportCredentials(creds)); err != nil {
		t.Fatalf("Starting stubServer: %v", err)
	}
	defer ss.Stop()

	ctx, cancel := context.WithTimeout(context.Background(), defaultTestTimeout)
	defer cancel()

	var streams []testgrpc.TestService_FullDuplexCallClient

	const numStreams = 3
	// expected number of conns when each stream is created i.e., 3rd stream is created
	// on a new connection.
	expectedNumConns := [numStreams]int{1, 1, 2}

	// Set up 3 streams.
	for i := 0; i < numStreams; i++ {
		s, err := ss.Client.FullDuplexCall(ctx)
		if err != nil {
			t.Fatalf("Creating FullDuplex stream: %v", err)
		}
		streams = append(streams, s)
		// Verify expected num of conns after each stream is created.
		if len(creds.connections) != expectedNumConns[i] {
			t.Fatalf("Got number of connections created: %v, want: %v", len(creds.connections), expectedNumConns[i])
		}
	}

	// Verify all streams still work.
	for i, stream := range streams {
		if err := stream.Send(&testpb.StreamingOutputCallRequest{}); err != nil {
			t.Fatalf("Sending on stream %d: %v", i, err)
		}
		if _, err := stream.Recv(); err != nil {