Support no_auth mode in mistral client

Now it is impossible to send requests without authentication.
This patch allows to disable it if user doesn't provide auth_url
to the client.

Change-Id: I3b964e349dd6843ceb022264abe451a1b407786b
Closes-bug: #1730067

mistralclient/api/v2/client.py

@@ -51,8 +51,13 @@ class Client(object):
         if mistral_url and not isinstance(mistral_url, six.string_types):
             raise RuntimeError('Mistral url should be a string.')
 
-        auth_handler = auth.get_auth_handler(auth_type)
-        auth_response = auth_handler.authenticate(req, session=session) or {}
+        # If auth url was provided then we perform an authentication, otherwise
+        # just ignore this step
+        if req.get('auth_url'):
+            auth_handler = auth.get_auth_handler(auth_type)
+            auth_response = auth_handler.authenticate(req, session=session)
+        else:
+            auth_response = {}
 
         # If the session was None and we're using keystone auth, it will be
         # created by the auth_handler.

mistralclient/tests/unit/test_client.py

@@ -141,6 +141,7 @@ class BaseClientTests(base.BaseTestCase):
         auth.get_access = mock.Mock(return_value=mock_access)
 
         client.client(
+            auth_url=AUTH_HTTP_URL_v3,
             username='user',
             api_key='password',
             user_domain_name='Default',
@@ -303,3 +304,16 @@ class BaseClientTests(base.BaseTestCase):
         profiler = osprofiler.profiler.get()
 
         self.assertEqual(profiler.hmac_key, PROFILER_HMAC_KEY)
+
+    @mock.patch('mistralclient.auth.get_auth_handler')
+    def test_mistral_no_auth(self, get_auth_handler_mock):
+        # Test that we don't authenticate if auth url wasn't provided
+
+        client.client(
+            username='mistral',
+            project_name='mistral',
+            api_key='password',
+            service_type='workflowv2'
+        )
+
+        self.assertEqual(0, get_auth_handler_mock.call_count)