Add support for loading kolla config from ENV

Implements: blueprint zookeeper

Change-Id: Ibabcb5d6d304be9290633338c513f16651d4479a

docker/base/set_configs.py

@@ -140,21 +140,38 @@ def set_permissions(data):
 
 
 def load_config():
+    def load_from_env():
+        config_raw = os.environ.get("KOLLA_CONFIG")
+        if config_raw is None:
+            return None
+
+        # Attempt to read config
+        try:
+            return json.loads(config_raw)
+        except ValueError:
+            LOG.error('Invalid json for Kolla config')
+            sys.exit(1)
+
+    def load_from_file():
         config_file = '/var/lib/kolla/config_files/config.json'
         LOG.info('Loading config file at {}'.format(config_file))
 
         # Attempt to read config file
         with open(config_file) as f:
             try:
-            config = json.load(f)
+                return json.load(f)
             except ValueError:
                 LOG.error('Invalid json file found at {}'.format(config_file))
                 sys.exit(1)
             except IOError as e:
-            LOG.error('Could not read file {}. Failed with error {}'.format(
+                LOG.error('Could not read file {}. Failed with error {}'
-                config_file, e))
+                          .format(config_file, e))
                 sys.exit(1)
 
+    config = load_from_env()
+    if config is None:
+        config = load_from_file()
+
     LOG.info('Validating config file')
     validate_config(config)
 

tests/test_set_config.py

@@ -45,3 +45,20 @@ class LoadFromFile(base.BaseTestCase):
                 mock.call().__enter__(),
                 mock.call().write(u'/bin/true'),
                 mock.call().__exit__(None, None, None)], mo.mock_calls)
+
+
+class LoadFromEnv(base.BaseTestCase):
+
+    def test_load_ok(self):
+        in_config = json.dumps({'command': '/bin/true',
+                                'config_files': {}})
+
+        mo = mock.mock_open()
+        with mock.patch.object(set_configs, 'open', mo):
+            with mock.patch.dict('os.environ', {'KOLLA_CONFIG': in_config}):
+                set_configs.load_config()
+                self.assertEqual([mock.call('/run_command', 'w+'),
+                                  mock.call().__enter__(),
+                                  mock.call().write(u'/bin/true'),
+                                  mock.call().__exit__(None, None, None)],
+                                 mo.mock_calls)