Don't recreate pre-existing volumes.

During the initialize_volumes phase, if a volume using the
non-namespaced name already exists, don't create the namespaced
equivalent.

Signed-off-by: Joffrey F <joffrey@docker.com>

compose/project.py

@@ -235,6 +235,12 @@ class Project(object):
     def initialize_volumes(self):
         try:
             for volume in self.volumes:
+                if volume.is_user_created:
+                    log.info(
+                        'Found user-created volume "{0}". No new namespaced '
+                        'volume will be created.'.format(volume.name)
+                    )
+                    continue
                 volume.create()
         except NotFound:
             raise ConfigurationError(

compose/volume.py

@@ -1,6 +1,8 @@
 from __future__ import absolute_import
 from __future__ import unicode_literals
 
+from docker.errors import NotFound
+
 
 class Volume(object):
     def __init__(self, client, project, name, driver=None, driver_opts=None):
@@ -21,6 +23,15 @@ class Volume(object):
     def inspect(self):
         return self.client.inspect_volume(self.full_name)
 
+    @property
+    def is_user_created(self):
+        try:
+            self.client.inspect_volume(self.name)
+        except NotFound:
+            return False
+
+        return True
+
     @property
     def full_name(self):
         return '{0}_{1}'.format(self.project, self.name)

tests/integration/project_test.py

@@ -4,6 +4,7 @@ from __future__ import unicode_literals
 import random
 
 import py
+from docker.errors import NotFound
 
 from .testcases import DockerClientTestCase
 from compose.config import config
@@ -624,7 +625,7 @@ class ProjectTest(DockerClientTestCase):
         self.assertEqual(volume_data['Name'], full_vol_name)
         self.assertEqual(volume_data['Driver'], 'local')
 
-    def test_project_up_invalid_volume_driver(self):
+    def test_initialize_volumes_invalid_volume_driver(self):
         vol_name = '{0:x}'.format(random.getrandbits(32))
 
         config_data = config.Config(
@@ -642,7 +643,7 @@ class ProjectTest(DockerClientTestCase):
         with self.assertRaises(config.ConfigurationError):
             project.initialize_volumes()
 
-    def test_project_up_updated_driver(self):
+    def test_initialize_volumes_updated_driver(self):
         vol_name = '{0:x}'.format(random.getrandbits(32))
         full_vol_name = 'composetest_{0}'.format(vol_name)
 
@@ -675,3 +676,24 @@ class ProjectTest(DockerClientTestCase):
         assert 'Configuration for volume {0} specifies driver smb'.format(
             vol_name
         ) in str(e.exception)
+
+    def test_initialize_volumes_user_created_volumes(self):
+        # Use composetest_ prefix so it gets garbage-collected in tearDown()
+        vol_name = 'composetest_{0:x}'.format(random.getrandbits(32))
+        full_vol_name = 'composetest_{0}'.format(vol_name)
+        self.client.create_volume(vol_name)
+        config_data = config.Config(
+            version=2, services=[{
+                'name': 'web',
+                'image': 'busybox:latest',
+                'command': 'top'
+            }], volumes={vol_name: {'driver': 'local'}}
+        )
+        project = Project.from_config(
+            name='composetest',
+            config_data=config_data, client=self.client
+        )
+        project.initialize_volumes()
+
+        with self.assertRaises(NotFound):
+            self.client.inspect_volume(full_vol_name)

tests/integration/volume_test.py

@@ -54,3 +54,13 @@ class VolumeTest(DockerClientTestCase):
         vol.remove()
         volumes = self.client.volumes()['Volumes']
         assert len([v for v in volumes if v['Name'] == vol.full_name]) == 0
+
+    def test_is_user_created(self):
+        vol = Volume(self.client, 'composetest', 'uservolume01')
+        try:
+            self.client.create_volume('uservolume01')
+            assert vol.is_user_created is True
+        finally:
+            self.client.remove_volume('uservolume01')
+        vol2 = Volume(self.client, 'composetest', 'volume01')
+        assert vol2.is_user_created is False