Add version checks and test

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

docker/api/service.py

@@ -18,6 +18,12 @@ def _check_api_features(version, task_template, update_config, endpoint_spec):
             if 'Monitor' in update_config:
                 raise_version_error('UpdateConfig.monitor', '1.25')
 
+        if utils.version_lt(version, '1.28'):
+            if update_config.get('FailureAction') == 'rollback':
+                raise_version_error(
+                    'UpdateConfig.failure_action rollback', '1.28'
+                )
+
         if utils.version_lt(version, '1.29'):
             if 'Order' in update_config:
                 raise_version_error('UpdateConfig.order', '1.29')

docker/types/services.py

@@ -371,7 +371,8 @@ class UpdateConfig(dict):
         delay (int): Amount of time between updates, in nanoseconds.
         failure_action (string): Action to take if an updated task fails to
           run, or stops running during the update. Acceptable values are
-          ``continue``, ``rollback`` and ``pause``. Default: ``continue``
+          ``continue``, ``pause``, as well as ``rollback`` since API v1.28.
+          Default: ``continue``
         monitor (int): Amount of time to monitor each updated task for
           failures, in nanoseconds.
         max_failure_ratio (float): The fraction of tasks that may fail during
@@ -387,7 +388,7 @@ class UpdateConfig(dict):
             self['Delay'] = delay
         if failure_action not in ('pause', 'continue', 'rollback'):
             raise errors.InvalidArgument(
-                'failure_action must be either `pause` or `continue`.'
+                'failure_action must be one of `pause`, `continue`, `rollback`'
             )
         self['FailureAction'] = failure_action
 

tests/integration/api_service_test.py

@@ -281,6 +281,20 @@ class ServiceTest(BaseAPIIntegrationTest):
         assert update_config['Delay'] == uc['Delay']
         assert update_config['FailureAction'] == uc['FailureAction']
 
+    @requires_api_version('1.28')
+    def test_create_service_with_failure_action_rollback(self):
+        container_spec = docker.types.ContainerSpec(BUSYBOX, ['true'])
+        task_tmpl = docker.types.TaskTemplate(container_spec)
+        update_config = docker.types.UpdateConfig(failure_action='rollback')
+        name = self.get_service_name()
+        svc_id = self.client.create_service(
+            task_tmpl, update_config=update_config, name=name
+        )
+        svc_info = self.client.inspect_service(svc_id)
+        assert 'UpdateConfig' in svc_info['Spec']
+        uc = svc_info['Spec']['UpdateConfig']
+        assert update_config['FailureAction'] == uc['FailureAction']
+
     @requires_api_version('1.25')
     def test_create_service_with_update_config_monitor(self):
         container_spec = docker.types.ContainerSpec('busybox', ['true'])