Implement extends

Signed-off-by: Aanand Prasad <aanand.prasad@gmail.com>

tests/fixtures/extends/circle-1.yml

@@ -0,0 +1,12 @@
+foo:
+  image: busybox
+bar:
+  image: busybox
+web:
+  extends:
+    file: circle-2.yml
+    service: web
+baz:
+  image: busybox
+quux:
+  image: busybox

tests/fixtures/extends/circle-2.yml

@@ -0,0 +1,12 @@
+foo:
+  image: busybox
+bar:
+  image: busybox
+web:
+  extends:
+    file: circle-1.yml
+    service: web
+baz:
+  image: busybox
+quux:
+  image: busybox

tests/fixtures/extends/common.yml

@@ -0,0 +1,6 @@
+web:
+  image: busybox
+  command: /bin/true
+  environment:
+    - FOO=1
+    - BAR=1

tests/fixtures/extends/docker-compose.yml

@@ -0,0 +1,16 @@
+myweb:
+  extends:
+    file: common.yml
+    service: web
+  command: sleep 300
+  links:
+    - "mydb:db"
+  environment:
+    # leave FOO alone
+    # override BAR
+    BAR: "2"
+    # add BAZ
+    BAZ: "2"
+mydb:
+  image: busybox
+  command: sleep 300

tests/fixtures/extends/nested-intermediate.yml

@@ -0,0 +1,6 @@
+webintermediate:
+  extends:
+    file: common.yml
+    service: web
+  environment:
+    - "FOO=2"

tests/fixtures/extends/nested.yml

@@ -0,0 +1,6 @@
+myweb:
+  extends:
+    file: nested-intermediate.yml
+    service: webintermediate
+  environment:
+    - "BAR=2"

tests/integration/cli_test.py

@@ -427,3 +427,30 @@ class CLITestCase(DockerClientTestCase):
         containers = self.project.containers(stopped=True)
         self.assertEqual(len(containers), 1)
         self.assertIn("FOO=1", containers[0].get('Config.Env'))
+
+    def test_up_with_extends(self):
+        self.command.base_dir = 'tests/fixtures/extends'
+        self.command.dispatch(['up', '-d'], None)
+
+        self.assertEqual(
+            set([s.name for s in self.project.services]),
+            set(['mydb', 'myweb']),
+        )
+
+        # Sort by name so we get [db, web]
+        containers = sorted(
+            self.project.containers(stopped=True),
+            key=lambda c: c.name,
+        )
+
+        self.assertEqual(len(containers), 2)
+        web = containers[1]
+
+        self.assertEqual(set(web.links()), set(['db', 'mydb_1', 'extends_mydb_1']))
+
+        expected_env = set([
+            "FOO=1",
+            "BAR=2",
+            "BAZ=2",
+        ])
+        self.assertTrue(expected_env <= set(web.get('Config.Env')))

tests/unit/config_test.py

@@ -38,6 +38,8 @@ class ConfigTest(unittest.TestCase):
         )
         config.make_service_dict('foo', {'ports': ['8000']})
 
+
+class EnvTest(unittest.TestCase):
     def test_parse_environment_as_list(self):
         environment =[
             'NORMAL=F1',
@@ -130,3 +132,112 @@ class ConfigTest(unittest.TestCase):
             service_dict['environment'],
             {'FILE_DEF': 'F1', 'FILE_DEF_EMPTY': '', 'ENV_DEF': 'E3', 'NO_DEF': ''},
         )
+
+
+class ExtendsTest(unittest.TestCase):
+    def test_extends(self):
+        service_dicts = config.load('tests/fixtures/extends/docker-compose.yml')
+
+        service_dicts = sorted(
+            service_dicts,
+            key=lambda sd: sd['name'],
+        )
+
+        self.assertEqual(service_dicts, [
+            {
+                'name': 'mydb',
+                'image': 'busybox',
+                'command': 'sleep 300',
+            },
+            {
+                'name': 'myweb',
+                'image': 'busybox',
+                'command': 'sleep 300',
+                'links': ['mydb:db'],
+                'environment': {
+                    "FOO": "1",
+                    "BAR": "2",
+                    "BAZ": "2",
+                },
+            }
+        ])
+
+    def test_nested(self):
+        service_dicts = config.load('tests/fixtures/extends/nested.yml')
+
+        self.assertEqual(service_dicts, [
+            {
+                'name': 'myweb',
+                'image': 'busybox',
+                'command': '/bin/true',
+                'environment': {
+                    "FOO": "2",
+                    "BAR": "2",
+                },
+            },
+        ])
+
+    def test_circular(self):
+        try:
+            config.load('tests/fixtures/extends/circle-1.yml')
+            raise Exception("Expected config.CircularReference to be raised")
+        except config.CircularReference as e:
+            self.assertEqual(
+                [(os.path.basename(filename), service_name) for (filename, service_name) in e.trail],
+                [
+                    ('circle-1.yml', 'web'),
+                    ('circle-2.yml', 'web'),
+                    ('circle-1.yml', 'web'),
+                ],
+            )
+
+
+    def test_extends_validation(self):
+        dictionary = {'extends': None}
+        load_config = lambda: config.make_service_dict('myweb', dictionary, working_dir='tests/fixtures/extends')
+
+        self.assertRaisesRegexp(config.ConfigurationError, 'dictionary', load_config)
+
+        dictionary['extends'] = {}
+        self.assertRaises(config.ConfigurationError, load_config)
+
+        dictionary['extends']['file'] = 'common.yml'
+        self.assertRaisesRegexp(config.ConfigurationError, 'service', load_config)
+
+        dictionary['extends']['service'] = 'web'
+        self.assertIsInstance(load_config(), dict)
+
+        dictionary['extends']['what'] = 'is this'
+        self.assertRaisesRegexp(config.ConfigurationError, 'what', load_config)
+
+    def test_blacklisted_options(self):
+        def load_config():
+            return config.make_service_dict('myweb', {
+                'extends': {
+                    'file': 'whatever',
+                    'service': 'web',
+                }
+            }, '.')
+
+        with self.assertRaisesRegexp(config.ConfigurationError, 'links'):
+            other_config = {'web': {'links': ['db']}}
+
+            with mock.patch.object(config, 'load_yaml', return_value=other_config):
+                print load_config()
+
+        with self.assertRaisesRegexp(config.ConfigurationError, 'volumes_from'):
+            other_config = {'web': {'volumes_from': ['db']}}
+
+            with mock.patch.object(config, 'load_yaml', return_value=other_config):
+                print load_config()
+
+        with self.assertRaisesRegexp(config.ConfigurationError, 'net'):
+            other_config = {'web': {'net': 'container:db'}}
+
+            with mock.patch.object(config, 'load_yaml', return_value=other_config):
+                print load_config()
+
+        other_config = {'web': {'net': 'host'}}
+
+        with mock.patch.object(config, 'load_yaml', return_value=other_config):
+            print load_config()