feat(live): work on websocket data source, #3455

public/app/core/live/live_srv.ts

@@ -5,24 +5,51 @@ import coreModule from 'app/core/core_module';
 
 export class LiveSrv {
   conn: any;
+  initPromise: any;
+
+  getWebSocketUrl() {
+    var l = window.location;
+    return ((l.protocol === "https:") ? "wss://" : "ws://") + l.host + config.appSubUrl + '/ws';
+  }
 
   init() {
-    this.conn = new WebSocket("ws://localhost:3000/ws");
-    this.conn.onclose = function(evt) {
-      console.log("WebSocket closed");
-    };
-    this.conn.onmessage = function(evt) {
-      console.log("WebSocket message", evt.data);
-    };
-    this.conn.onopen = function(evt) {
-      console.log("Connection opened");
-    };
+    if (this.initPromise) {
+      return this.initPromise;
+    }
+
+    if (this.conn && this.conn.readyState === 1) {
+      return Promise.resolve();
+    }
+
+    this.initPromise = new Promise((resolve, reject) => {
+      console.log('Live: connecting...');
+      this.conn = new WebSocket(this.getWebSocketUrl());
+
+      this.conn.onclose = function(evt) {
+        reject({message: 'Connection closed'});
+      };
+
+      this.conn.onmessage = function(evt) {
+        console.log("Live: message received:", evt.data);
+      };
+
+      this.conn.onopen = function(evt) {
+        console.log('Live: connection open');
+        resolve();
+      };
+    });
+
+    return this.initPromise;
+  }
+
+  send(data) {
+    this.conn.send(JSON.stringify(data));
   }
 
   subscribe(name) {
-    if (!this.conn) {
-      this.init();
-    }
+    return this.init().then(() =>  {
+      this.send({action: 'subscribe', stream: name});
+    });
   }
 
 }