Fix concurrency on the client (#183)

* reworked peer connection establishment logic eliminating race conditions and deadlocks while running many peers

signal/client/client.go

@@ -45,6 +45,10 @@ type Client struct {
 	status Status
 }
 
+func (c *Client) StreamConnected() bool {
+	return c.status == StreamConnected
+}
+
 func (c *Client) GetStatus() Status {
 	return c.status
 }
@@ -117,7 +121,7 @@ func (c *Client) Receive(msgHandler func(msg *proto.Message) error) error {
 		c.notifyStreamDisconnected()
 
 		log.Debugf("signal connection state %v", c.signalConn.GetState())
-		if !c.ready() {
+		if !c.Ready() {
 			return fmt.Errorf("no connection to signal")
 		}
 
@@ -204,9 +208,9 @@ func (c *Client) connect(key string) (proto.SignalExchange_ConnectStreamClient,
 	return stream, nil
 }
 
-// ready indicates whether the client is okay and ready to be used
+// Ready indicates whether the client is okay and Ready to be used
 // for now it just checks whether gRPC connection to the service is in state Ready
-func (c *Client) ready() bool {
+func (c *Client) Ready() bool {
 	return c.signalConn.GetState() == connectivity.Ready || c.signalConn.GetState() == connectivity.Idle
 }
 
@@ -228,7 +232,7 @@ func (c *Client) WaitStreamConnected() {
 // The Client.Receive method must be called before sending messages to establish initial connection to the Signal Exchange
 // Client.connWg can be used to wait
 func (c *Client) SendToStream(msg *proto.EncryptedMessage) error {
-	if !c.ready() {
+	if !c.Ready() {
 		return fmt.Errorf("no connection to signal")
 	}
 	if c.stream == nil {
@@ -287,7 +291,7 @@ func (c *Client) encryptMessage(msg *proto.Message) (*proto.EncryptedMessage, er
 // Send sends a message to the remote Peer through the Signal Exchange.
 func (c *Client) Send(msg *proto.Message) error {
 
-	if !c.ready() {
+	if !c.Ready() {
 		return fmt.Errorf("no connection to signal")
 	}
 
@@ -295,9 +299,11 @@ func (c *Client) Send(msg *proto.Message) error {
 	if err != nil {
 		return err
 	}
-	_, err = c.realClient.Send(context.TODO(), encryptedMessage)
+
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+	_, err = c.realClient.Send(ctx, encryptedMessage)
 	if err != nil {
-		//log.Errorf("error while sending message to peer [%s] [error: %v]", msg.RemoteKey, err)
 		return err
 	}
 

signal/cmd/run.go

@@ -74,10 +74,6 @@ var (
 				log.Fatalf("failed to listen: %v", err)
 			}
 
-			if err != nil {
-				log.Fatalf("failed to listen: %v", err)
-			}
-
 			proto.RegisterSignalExchangeServer(grpcServer, server.NewServer())
 			log.Printf("started server: localhost:%v", signalPort)
 			if err := grpcServer.Serve(lis); err != nil {

signal/server/signal.go

@@ -29,7 +29,7 @@ func NewServer() *Server {
 func (s *Server) Send(ctx context.Context, msg *proto.EncryptedMessage) (*proto.EncryptedMessage, error) {
 
 	if !s.registry.IsPeerRegistered(msg.Key) {
-		return nil, fmt.Errorf("unknown peer %s", msg.Key)
+		return nil, fmt.Errorf("peer %s is not registered", msg.Key)
 	}
 
 	if dstPeer, found := s.registry.Get(msg.RemoteKey); found {