Add prune_volumes method

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

docker/api/volume.py

@@ -115,6 +115,28 @@ class VolumeApiMixin(object):
         url = self._url('/volumes/{0}', name)
         return self._result(self._get(url), True)
 
+    @utils.minimum_version('1.25')
+    def prune_volumes(self, filters=None):
+        """
+        Delete unused volumes
+
+        Args:
+            filters (dict): Filters to process on the prune list.
+
+        Returns:
+            (dict): A dict containing a list of deleted volume IDs and
+                the amount of disk space reclaimed in bytes.
+
+        Raises:
+            :py:class:`docker.errors.APIError`
+                If the server returns an error.
+        """
+        params = {}
+        if filters:
+            params['filters'] = utils.convert_filters(filters)
+        url = self._url('/volumes/prune')
+        return self._result(self._post(url, params=params), True)
+
     @utils.minimum_version('1.21')
     def remove_volume(self, name, force=False):
         """

docker/models/volumes.py

+from ..api import APIClient
 from .resource import Model, Collection
 
 
@@ -91,3 +92,7 @@ class VolumeCollection(Collection):
         if not resp.get('Volumes'):
             return []
         return [self.prepare_model(obj) for obj in resp['Volumes']]
+
+    def prune(self, filters=None):
+        return self.client.api.prune_volumes(filters=filters)
+    prune.__doc__ = APIClient.prune_volumes.__doc__

tests/integration/api_image_test.py

@@ -299,5 +299,5 @@ class PruneImagesTest(BaseAPIIntegrationTest):
         self.tmp_imgs.append('hello-world')
         img_id = self.client.inspect_image('hello-world')['Id']
         result = self.client.prune_images()
-        assert img_id in result['ImagesDeleted']
+        assert img_id in [img['Deleted'] for img in result['ImagesDeleted']]
         assert result['SpaceReclaimed'] > 0

tests/integration/api_volume_test.py

@@ -56,6 +56,14 @@ class TestVolumes(BaseAPIIntegrationTest):
         self.client.create_volume(name)
         self.client.remove_volume(name, force=True)
 
+    @requires_api_version('1.25')
+    def test_prune_volumes(self):
+        name = 'hopelessmasquerade'
+        self.client.create_volume(name)
+        self.tmp_volumes.append(name)
+        result = self.client.prune_volumes()
+        assert name in result['VolumesDeleted']
+
     def test_remove_nonexistent_volume(self):
         name = 'shootthebullet'
         with pytest.raises(docker.errors.NotFound):