Make server starts and stops idempotent

grpc.go

@@ -53,6 +53,8 @@ type grpcServer struct {
 	opts        server.Options
 	handlers    map[string]server.Handler
 	subscribers map[*subscriber][]broker.Subscriber
+	// marks the serve as started
+	started bool
 	// used for first registration
 	registered bool
 }
@@ -454,7 +456,10 @@ func (g *grpcServer) newCodec(contentType string) (codec.NewCodec, error) {
 }
 
 func (g *grpcServer) Options() server.Options {
+	g.RLock()
 	opts := g.opts
+	g.RUnlock()
+
 	return opts
 }
 
@@ -700,7 +705,14 @@ func (g *grpcServer) Deregister() error {
 }
 
 func (g *grpcServer) Start() error {
-	config := g.opts
+	g.RLock()
+	if g.started {
+		g.RUnlock()
+		return nil
+	}
+	g.RUnlock()
+
+	config := g.Options()
 
 	// micro: config.Transport.Listen(config.Address)
 	ts, err := net.Listen("tcp", config.Address)
@@ -781,13 +793,32 @@ func (g *grpcServer) Start() error {
 		config.Broker.Disconnect()
 	}()
 
+	// mark the server as started
+	g.Lock()
+	g.started = true
+	g.Unlock()
+
 	return nil
 }
 
 func (g *grpcServer) Stop() error {
+	g.RLock()
+	if !g.started {
+		g.RUnlock()
+		return nil
+	}
+	g.RUnlock()
+
 	ch := make(chan error)
 	g.exit <- ch
-	return <-ch
+
+	var err error
+	select {
+	case err = <-ch:
+		g.started = false
+	}
+
+	return err
 }
 
 func (g *grpcServer) String() string {