use channel to wait for sockets before looping send frame

.travis.yml

@@ -9,12 +9,8 @@ script:
   - go vet ./...
   - go test ./...
   - curl -sL https://git.io/goreleaser | bash -s check
-  - make install-typescript
-  - git diff
-  - git status
+
 # Create a release using goreleaser when tests pass and revision is tagged.
-before_deploy:
-  - git fetch --unshallow
 deploy:
 - provider: script
   skip_cleanup: true

cmd/managementd/main.go

@@ -45,6 +45,7 @@ const (
 	socketTimeout = 7 * time.Second
 )
 
+var haveClients = make(chan bool)
 var version = "<not set>"
 var sockets = make(map[int64]*WebsocketRegistration)
 var socketsLock sync.RWMutex
@@ -175,12 +176,17 @@ func WebsocketServer(ws *websocket.Conn) {
 			// Occasionally go through the list and cull any that are no-longer sending heart-beats.
 			if message.Type == "Register" {
 				socketsLock.Lock()
+				firstSocket := len(sockets) == 0
 				sockets[message.Uuid] = &WebsocketRegistration{
 					Socket:          ws,
 					LastHeartbeatAt: time.Now(),
 					AtomicLock:      0,
 				}
 				socketsLock.Unlock()
+				if firstSocket {
+					log.Print("Git new client register")
+					haveClients <- true
+				}
 			}
 			if message.Type == "Heartbeat" {
 				if socket, ok := sockets[message.Uuid]; ok {
@@ -281,6 +287,9 @@ func sendFrameToSockets() {
 				}
 				socketsLock.Unlock()
 			}
+		} else {
+			log.Print("Wait for new client camera register")
+			<-haveClients
 		}
 	}
 }