Fix pull of images

Fix #445

gns3server/modules/docker/docker_vm.py

@@ -150,6 +150,11 @@ class DockerVM(BaseVM):
     def create(self):
         """Creates the Docker container."""
 
+        try:
+            image_infos = yield from self._get_image_informations()
+        except DockerHttp404Error:
+            log.info("Image %s is missing pulling it from docker hub", self._image)
+            yield from self.pull_image(self._image)
             image_infos = yield from self._get_image_informations()
 
         params = {
@@ -173,11 +178,6 @@ class DockerVM(BaseVM):
         if self._environment:
             params.update({"Env": [e.strip() for e in self._environment.split("\n")]})
 
-        images = [i["image"] for i in (yield from self.manager.list_images())]
-        if self._image not in images:
-            log.info("Image %s is missing pulling it from docker hub", self._image)
-            yield from self.pull_image(self._image)
-
         result = yield from self.manager.query("POST", "containers/create", data=params)
         self._cid = result['Id']
         log.info("Docker container '{name}' [{id}] created".format(

tests/modules/docker/test_docker_vm.py

@@ -23,7 +23,7 @@ from tests.utils import asyncio_patch
 
 from gns3server.ubridge.ubridge_error import UbridgeNamespaceError
 from gns3server.modules.docker.docker_vm import DockerVM
-from gns3server.modules.docker.docker_error import DockerError
+from gns3server.modules.docker.docker_error import *
 from gns3server.modules.docker import Docker
 
 
@@ -161,14 +161,28 @@ def test_create_environment(loop, project, manager):
 
 def test_create_image_not_available(loop, project, manager):
 
+    call = 0
+
+    @asyncio.coroutine
+    def informations():
+        nonlocal call
+        if call == 0:
+            call += 1
+            raise DockerHttp404Error("missing")
+        else:
+            return {}
+
     response = {
         "Id": "e90e34656806",
         "Warnings": []
     }
-    with asyncio_patch("gns3server.modules.docker.Docker.list_images", return_value=[]) as mock_list_images:
+
+    vm = DockerVM("test", str(uuid.uuid4()), project, manager, "ubuntu")
+    vm._get_image_informations = MagicMock()
+    vm._get_image_informations.side_effect = informations
+
     with asyncio_patch("gns3server.modules.docker.DockerVM.pull_image", return_value=True) as mock_pull:
         with asyncio_patch("gns3server.modules.docker.Docker.query", return_value=response) as mock:
-                vm = DockerVM("test", str(uuid.uuid4()), project, manager, "ubuntu")
             loop.run_until_complete(asyncio.async(vm.create()))
             mock.assert_called_with("POST", "containers/create", data={
                 "Tty": True,