Fix connstate indication (#732)

Fix the status indication in the client service. The status of the
management server and the signal server was incorrect if the network
connection was broken. Basically the status update was not used by
the management and signal library.

signal/client/grpc.go

@@ -22,6 +22,12 @@ import (
 	"time"
 )
 
+// ConnStateNotifier is a wrapper interface of the status recorder
+type ConnStateNotifier interface {
+	MarkSignalDisconnected()
+	MarkSignalConnected()
+}
+
 // GrpcClient Wraps the Signal Exchange Service gRpc client
 type GrpcClient struct {
 	key        wgtypes.Key
@@ -34,6 +40,9 @@ type GrpcClient struct {
 	mux         sync.Mutex
 	// StreamConnected indicates whether this client is StreamConnected to the Signal stream
 	status Status
+
+	connStateCallback     ConnStateNotifier
+	connStateCallbackLock sync.RWMutex
 }
 
 func (c *GrpcClient) StreamConnected() bool {
@@ -78,15 +87,23 @@ func NewClient(ctx context.Context, addr string, key wgtypes.Key, tlsEnabled boo
 	log.Debugf("connected to Signal Service: %v", conn.Target())
 
 	return &GrpcClient{
-		realClient: proto.NewSignalExchangeClient(conn),
-		ctx:        ctx,
-		signalConn: conn,
-		key:        key,
-		mux:        sync.Mutex{},
-		status:     StreamDisconnected,
+		realClient:            proto.NewSignalExchangeClient(conn),
+		ctx:                   ctx,
+		signalConn:            conn,
+		key:                   key,
+		mux:                   sync.Mutex{},
+		status:                StreamDisconnected,
+		connStateCallbackLock: sync.RWMutex{},
 	}, nil
 }
 
+// SetConnStateListener set the ConnStateNotifier
+func (c *GrpcClient) SetConnStateListener(notifier ConnStateNotifier) {
+	c.connStateCallbackLock.Lock()
+	defer c.connStateCallbackLock.Unlock()
+	c.connStateCallback = notifier
+}
+
 // defaultBackoff is a basic backoff mechanism for general issues
 func defaultBackoff(ctx context.Context) backoff.BackOff {
 	return backoff.WithContext(&backoff.ExponentialBackOff{
@@ -134,13 +151,14 @@ func (c *GrpcClient) Receive(msgHandler func(msg *proto.Message) error) error {
 		c.notifyStreamConnected()
 
 		log.Infof("connected to the Signal Service stream")
-
+		c.notifyConnected()
 		// start receiving messages from the Signal stream (from other peers through signal)
 		err = c.receive(stream, msgHandler)
 		if err != nil {
 			// we need this reset because after a successful connection and a consequent error, backoff lib doesn't
 			// reset times and next try will start with a long delay
 			backOff.Reset()
+			c.notifyDisconnected()
 			log.Warnf("disconnected from the Signal service but will retry silently. Reason: %v", err)
 			return err
 		}
@@ -341,3 +359,23 @@ func (c *GrpcClient) receive(stream proto.SignalExchange_ConnectStreamClient,
 		}
 	}
 }
+
+func (c *GrpcClient) notifyDisconnected() {
+	c.connStateCallbackLock.RLock()
+	defer c.connStateCallbackLock.RUnlock()
+
+	if c.connStateCallback == nil {
+		return
+	}
+	c.connStateCallback.MarkSignalDisconnected()
+}
+
+func (c *GrpcClient) notifyConnected() {
+	c.connStateCallbackLock.RLock()
+	defer c.connStateCallbackLock.RUnlock()
+
+	if c.connStateCallback == nil {
+		return
+	}
+	c.connStateCallback.MarkSignalConnected()
+}