Merge pull request #198 from fcoelho/fix-volumes-from

Sanitize create_container input for volumes_from

docker/client.py

@@ -121,8 +121,12 @@ class Client(requests.Session):
                 volumes_dict[vol] = {}
             volumes = volumes_dict
 
-        if volumes_from and not isinstance(volumes_from, six.string_types):
+        if volumes_from:
+            if not isinstance(volumes_from, six.string_types):
                 volumes_from = ','.join(volumes_from)
+        else:
+            # Force None, an empty list or dict causes client.start to fail
+            volumes_from = None
 
         attach_stdin = False
         attach_stdout = False

tests/test.py

@@ -342,6 +342,16 @@ class DockerClientTest(unittest.TestCase):
         self.assertEqual(args[1]['headers'],
                          {'Content-Type': 'application/json'})
 
+    def test_create_container_empty_volumes_from(self):
+        try:
+            self.client.create_container('busybox', 'true', volumes_from=[])
+        except Exception as e:
+            self.fail('Command should not raise exception: {0}'.format(e))
+
+        args = fake_request.call_args
+        data = json.loads(args[1]['data'])
+        self.assertTrue('VolumesFrom' not in data)
+
     def test_create_named_container(self):
         try:
             self.client.create_container('busybox', 'true',