Resolves #455 - volumes_from a service with no containers.

Signed-off-by: Daniel Nephin <dnephin@gmail.com>

Author: dnephin

fig/service.py

@@ -5,6 +5,7 @@
 import logging
 import re
 import os
+from operator import attrgetter
 import sys
 from .container import Container
 from .progress_stream import stream_output, StreamOutputError
@@ -285,12 +286,17 @@ def _get_links(self, link_to_self):
 
     def _get_volumes_from(self, intermediate_container=None):
         volumes_from = []
-        for v in self.volumes_from:
-            if isinstance(v, Service):
-                for container in v.containers(stopped=True):
-                    volumes_from.append(container.id)
-            elif isinstance(v, Container):
-                volumes_from.append(v.id)
+        for volume_source in self.volumes_from:
+            if isinstance(volume_source, Service):
+                containers = volume_source.containers(stopped=True)
+
+                if not containers:
+                    volumes_from.append(volume_source.create_container().id)
+                else:
+                    volumes_from.extend(map(attrgetter('id'), containers))
+
+            elif isinstance(volume_source, Container):
+                volumes_from.append(volume_source.id)
 
         if intermediate_container:
             volumes_from.append(intermediate_container.id)

tests/unit/service_test.py

@@ -6,6 +6,7 @@
 import mock
 
 from fig import Service
+from fig.container import Container
 from fig.service import (
     ConfigError,
     split_port,
@@ -38,6 +39,44 @@ def test_config_validation(self):
         self.assertRaises(ConfigError, lambda: Service(name='foo', port=['8000']))
         Service(name='foo', ports=['8000'])
 
+    def test_get_volumes_from_container(self):
+        container_id = 'aabbccddee'
+        service = Service(
+            'test',
+            volumes_from=[mock.Mock(id=container_id, spec=Container)])
+
+        self.assertEqual(service._get_volumes_from(), [container_id])
+
+    def test_get_volumes_from_intermediate_container(self):
+        container_id = 'aabbccddee'
+        service = Service('test')
+        container = mock.Mock(id=container_id, spec=Container)
+
+        self.assertEqual(service._get_volumes_from(container), [container_id])
+
+    def test_get_volumes_from_service_container_exists(self):
+        container_ids = ['aabbccddee', '12345']
+        from_service = mock.create_autospec(Service)
+        from_service.containers.return_value = [
+            mock.Mock(id=container_id, spec=Container)
+            for container_id in container_ids
+        ]
+        service = Service('test', volumes_from=[from_service])
+
+        self.assertEqual(service._get_volumes_from(), container_ids)
+
+    def test_get_volumes_from_service_no_container(self):
+        container_id = 'abababab'
+        from_service = mock.create_autospec(Service)
+        from_service.containers.return_value = []
+        from_service.create_container.return_value = mock.Mock(
+            id=container_id,
+            spec=Container)
+        service = Service('test', volumes_from=[from_service])
+
+        self.assertEqual(service._get_volumes_from(), [container_id])
+        from_service.create_container.assert_called_once_with()
+
     def test_split_port_with_host_ip(self):
         internal_port, external_port = split_port("127.0.0.1:1000:2000")
         self.assertEqual(internal_port, "2000")