Use asyncio.ensure_future() instead of asyncio.async() with conservative approach to support Python < 3.4.4. Fixes https://github.com/GNS3/gns3-gui/issues/2566

gns3server/handlers/api/controller/project_handler.py

@@ -25,6 +25,7 @@ from gns3server.controller import Controller
 from gns3server.controller.import_project import import_project
 from gns3server.controller.export_project import export_project
 from gns3server.config import Config
+from gns3server.utils.asyncio import asyncio_ensure_future
 
 
 from gns3server.schemas.project import (
@@ -246,7 +247,7 @@ class ProjectHandler:
         ws = aiohttp.web.WebSocketResponse()
         yield from ws.prepare(request)
 
-        asyncio.async(process_websocket(ws))
+        asyncio_ensure_future(process_websocket(ws))
 
         with controller.notification.queue(project) as queue:
             while True:

gns3server/handlers/api/controller/server_handler.py

@@ -20,6 +20,7 @@ from gns3server.config import Config
 from gns3server.controller import Controller
 from gns3server.schemas.version import VERSION_SCHEMA
 from gns3server.version import __version__
+from gns3server.utils.asyncio import asyncio_ensure_future
 
 from aiohttp.web import HTTPConflict, HTTPForbidden
 
@@ -57,7 +58,7 @@ class ServerHandler:
 
         tasks = []
         for project in projects:
-            tasks.append(asyncio.async(project.close()))
+            tasks.append(asyncio_ensure_future(project.close()))
 
         if tasks:
             done, _ = yield from asyncio.wait(tasks)
@@ -71,7 +72,7 @@ class ServerHandler:
         # then shutdown the server itself
         from gns3server.web.web_server import WebServer
         server = WebServer.instance()
-        asyncio.async(server.shutdown_server())
+        asyncio_ensure_future(server.shutdown_server())
         response.set_status(201)
 
     @Route.get(