Make rpc_backend not engine specific

The rpc_backend with kombu and oslo are being used by the executor
and event engine as well. This patch move the rpc_backend up one
level so it's not engine specific. Also Event engine has its own module
and the EventEngine class is defined in the engine module. This patch
moves the EventEngine to it's own base file in the event_engine module.

Implements: blueprint mistral-actions-run-by-engine

Change-Id: Ie814a26e05f5ca6bfba10f20a7d5921836aa7602

mistral/api/app.py

@@ -22,7 +22,7 @@ from mistral.api import access_control
 from mistral import config as m_config
 from mistral import context as ctx
 from mistral.db.v2 import api as db_api_v2
-from mistral.engine.rpc_backend import rpc
+from mistral.rpc import base as rpc
 from mistral.service import coordination
 from mistral.services import periodic
 

mistral/api/controllers/v2/action_execution.py

@@ -24,8 +24,8 @@ from mistral.api.controllers.v2 import resources
 from mistral.api.controllers.v2 import types
 from mistral import context
 from mistral.db.v2 import api as db_api
-from mistral.engine.rpc_backend import rpc
 from mistral import exceptions as exc
+from mistral.rpc import clients as rpc
 from mistral.utils import filter_utils
 from mistral.utils import rest_utils
 from mistral.workflow import states

mistral/api/controllers/v2/execution.py

@@ -26,8 +26,8 @@ from mistral.api.controllers.v2 import task
 from mistral.api.controllers.v2 import types
 from mistral import context
 from mistral.db.v2 import api as db_api
-from mistral.engine.rpc_backend import rpc
 from mistral import exceptions as exc
+from mistral.rpc import clients as rpc
 from mistral.services import workflows as wf_service
 from mistral.utils import filter_utils
 from mistral.utils import rest_utils

mistral/api/controllers/v2/task.py

@@ -26,9 +26,9 @@ from mistral.api.controllers.v2 import resources
 from mistral.api.controllers.v2 import types
 from mistral import context
 from mistral.db.v2 import api as db_api
-from mistral.engine.rpc_backend import rpc
 from mistral import exceptions as exc
 from mistral.lang import parser as spec_parser
+from mistral.rpc import clients as rpc
 from mistral.utils import filter_utils
 from mistral.utils import rest_utils
 from mistral.workflow import data_flow

mistral/cmd/launch.py

@@ -44,9 +44,9 @@ from oslo_service import service
 from mistral.api import service as api_service
 from mistral import config
 from mistral.engine import engine_server
-from mistral.engine.rpc_backend import rpc
 from mistral.event_engine import event_engine_server
 from mistral.executors import executor_server
+from mistral.rpc import base as rpc
 from mistral import version
 
 

mistral/engine/base.py

@@ -1,4 +1,5 @@
 # Copyright 2014 - Mirantis, Inc.
+# Copyright 2017 - Brocade Communications Systems, Inc.
 #
 #    Licensed under the Apache License, Version 2.0 (the "License");
 #    you may not use this file except in compliance with the License.
@@ -128,19 +129,6 @@ class Engine(object):
         raise NotImplementedError
 
 
-@six.add_metaclass(abc.ABCMeta)
-class EventEngine(object):
-    """Action event trigger interface."""
-
-    @abc.abstractmethod
-    def create_event_trigger(self, trigger, events):
-        raise NotImplementedError()
-
-    @abc.abstractmethod
-    def delete_event_trigger(self, trigger, events):
-        raise NotImplementedError()
-
-
 @six.add_metaclass(abc.ABCMeta)
 class TaskPolicy(object):
     """Task policy.

mistral/engine/engine_server.py

@@ -17,7 +17,7 @@ from oslo_log import log as logging
 from mistral import config as cfg
 from mistral.db.v2 import api as db_api
 from mistral.engine import default_engine
-from mistral.engine.rpc_backend import rpc
+from mistral.rpc import base as rpc
 from mistral.service import base as service_base
 from mistral.services import expiration_policy
 from mistral.services import scheduler

mistral/engine/workflows.py

@@ -22,10 +22,10 @@ import six
 from mistral.db.v2 import api as db_api
 from mistral.db.v2.sqlalchemy import models as db_models
 from mistral.engine import dispatcher
-from mistral.engine.rpc_backend import rpc
 from mistral.engine import utils as engine_utils
 from mistral import exceptions as exc
 from mistral.lang import parser as spec_parser
+from mistral.rpc import clients as rpc
 from mistral.services import scheduler
 from mistral.services import workflows as wf_service
 from mistral import utils

mistral/event_engine/base.py

@@ -0,0 +1,34 @@
+# Copyright 2014 - Mirantis, Inc.
+# Copyright 2017 - Brocade Communications Systems, Inc.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License");
+#    you may not use this file except in compliance with the License.
+#    You may obtain a copy of the License at
+#
+#        http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS,
+#    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#    See the License for the specific language governing permissions and
+#    limitations under the License.
+
+import abc
+import six
+
+
+@six.add_metaclass(abc.ABCMeta)
+class EventEngine(object):
+    """Action event trigger interface."""
+
+    @abc.abstractmethod
+    def create_event_trigger(self, trigger, events):
+        raise NotImplementedError()
+
+    @abc.abstractmethod
+    def update_event_trigger(self, trigger):
+        raise NotImplementedError()
+
+    @abc.abstractmethod
+    def delete_event_trigger(self, trigger, events):
+        raise NotImplementedError()

mistral/event_engine/default_event_engine.py

@@ -1,4 +1,5 @@
 # Copyright 2016 Catalyst IT Ltd
+# Copyright 2017 - Brocade Communications Systems, Inc.
 #
 #    Licensed under the Apache License, Version 2.0 (the "License"); you may
 #    not use this file except in compliance with the License. You may obtain
@@ -25,10 +26,11 @@ import yaml
 
 from mistral import context as auth_ctx
 from mistral.db.v2 import api as db_api
-from mistral.engine.rpc_backend import rpc
+from mistral.event_engine import base
 from mistral import exceptions
 from mistral import expressions
 from mistral import messaging as mistral_messaging
+from mistral.rpc import clients as rpc
 from mistral.services import security
 
 
@@ -126,7 +128,7 @@ class NotificationsConverter(object):
         return edef.convert(event)
 
 
-class EventEngine(object):
+class DefaultEventEngine(base.EventEngine):
     """Event engine server.
 
     A separate service that is responsible for listening event notification

mistral/event_engine/event_engine_server.py

@@ -1,4 +1,5 @@
 # Copyright 2016 - Nokia Networks
+# Copyright 2017 - Brocade Communications Systems, Inc.
 #
 #    Licensed under the Apache License, Version 2.0 (the "License");
 #    you may not use this file except in compliance with the License.
@@ -15,8 +16,8 @@
 from oslo_log import log as logging
 
 from mistral import config as cfg
-from mistral.engine.rpc_backend import rpc
-from mistral.event_engine import event_engine
+from mistral.event_engine import default_event_engine as evt_eng
+from mistral.rpc import base as rpc
 from mistral.service import base as service_base
 from mistral.utils import profiler as profiler_utils
 
@@ -88,4 +89,4 @@ class EventEngineServer(service_base.MistralService):
 
 
 def get_oslo_service():
-    return EventEngineServer(event_engine.EventEngine())
+    return EventEngineServer(evt_eng.DefaultEventEngine())

mistral/executors/default_executor.py

@@ -17,9 +17,9 @@ from oslo_log import log as logging
 from osprofiler import profiler
 
 from mistral.actions import action_factory as a_f
-from mistral.engine.rpc_backend import rpc
 from mistral import exceptions as exc
 from mistral.executors import base
+from mistral.rpc import clients as rpc
 from mistral.utils import inspect_utils as i_u
 from mistral.workflow import utils as wf_utils
 

mistral/executors/executor_server.py

@@ -15,8 +15,8 @@
 from oslo_log import log as logging
 
 from mistral import config as cfg
-from mistral.engine.rpc_backend import rpc
 from mistral.executors import default_executor as exe
+from mistral.rpc import base as rpc
 from mistral.service import base as service_base
 from mistral import utils
 from mistral.utils import profiler as profiler_utils

mistral/executors/remote_executor.py

@@ -15,15 +15,16 @@
 from oslo_config import cfg
 from oslo_log import log as logging
 
-from mistral.engine.rpc_backend import rpc
+from mistral.rpc import base as rpc_base
+from mistral.rpc import clients as rpc_clients
 
 
 LOG = logging.getLogger(__name__)
 
 
-class RemoteExecutor(rpc.ExecutorClient):
+class RemoteExecutor(rpc_clients.ExecutorClient):
     """Executor that passes execution request to a remote executor."""
 
     def __init__(self):
         self.topic = cfg.CONF.executor.topic
-        self._client = rpc.get_rpc_client_driver()(cfg.CONF.executor)
+        self._client = rpc_base.get_rpc_client_driver()(cfg.CONF.executor)

mistral/rpc/base.py

@@ -1,4 +1,5 @@
 # Copyright 2015 - Mirantis, Inc.
+# Copyright 2017 - Brocade Communications Systems, Inc.
 #
 #    Licensed under the Apache License, Version 2.0 (the "License");
 #    you may not use this file except in compliance with the License.
@@ -14,6 +15,101 @@
 
 import abc
 
+from oslo_config import cfg
+from oslo_log import log as logging
+import oslo_messaging as messaging
+from oslo_messaging.rpc import client
+from stevedore import driver
+
+from mistral import exceptions as exc
+
+
+LOG = logging.getLogger(__name__)
+
+
+_IMPL_CLIENT = None
+_IMPL_SERVER = None
+_TRANSPORT = None
+
+
+def cleanup():
+    """Intended to be used by tests to recreate all RPC related objects."""
+
+    global _TRANSPORT
+
+    _TRANSPORT = None
+
+
+# TODO(rakhmerov): This method seems misplaced. Now we have different kind
+# of transports (oslo, kombu) and this module should not have any oslo
+# specific things anymore.
+def get_transport():
+    global _TRANSPORT
+
+    if not _TRANSPORT:
+        _TRANSPORT = messaging.get_transport(cfg.CONF)
+
+    return _TRANSPORT
+
+
+def get_rpc_server_driver():
+    rpc_impl = cfg.CONF.rpc_implementation
+
+    global _IMPL_SERVER
+    if not _IMPL_SERVER:
+        _IMPL_SERVER = driver.DriverManager(
+            'mistral.rpc.backends',
+            '%s_server' % rpc_impl
+        ).driver
+
+    return _IMPL_SERVER
+
+
+def get_rpc_client_driver():
+    rpc_impl = cfg.CONF.rpc_implementation
+
+    global _IMPL_CLIENT
+    if not _IMPL_CLIENT:
+        _IMPL_CLIENT = driver.DriverManager(
+            'mistral.rpc.backends',
+            '%s_client' % rpc_impl
+        ).driver
+
+    return _IMPL_CLIENT
+
+
+def _wrap_exception_and_reraise(exception):
+    message = "%s: %s" % (exception.__class__.__name__, exception.args[0])
+
+    raise exc.MistralException(message)
+
+
+def wrap_messaging_exception(method):
+    """This decorator unwrap remote error in one of MistralException.
+
+    oslo.messaging has different behavior on raising exceptions
+    when fake or rabbit transports are used. In case of rabbit
+    transport it raises wrapped RemoteError which forwards directly
+    to API. Wrapped RemoteError contains one of MistralException raised
+    remotely on Engine and for correct exception interpretation we
+    need to unwrap and raise given exception and manually send it to
+    API layer.
+    """
+    def decorator(*args, **kwargs):
+        try:
+            return method(*args, **kwargs)
+
+        except exc.MistralException:
+            raise
+        except (client.RemoteError, exc.KombuException, Exception) as e:
+            if hasattr(e, 'exc_type') and hasattr(exc, e.exc_type):
+                exc_cls = getattr(exc, e.exc_type)
+                raise exc_cls(e.value)
+
+            _wrap_exception_and_reraise(e)
+
+    return decorator
+
 
 class RPCClient(object):
     def __init__(self, conf):

mistral/rpc/clients.py

@@ -16,24 +16,18 @@
 
 from oslo_config import cfg
 from oslo_log import log as logging
-import oslo_messaging as messaging
-from oslo_messaging.rpc import client
 from osprofiler import profiler
-from stevedore import driver
 
 from mistral import context as auth_ctx
 from mistral.engine import base as eng
-from mistral import exceptions as exc
+from mistral.event_engine import base as evt_eng
 from mistral.executors import base as exe
+from mistral.rpc import base
 
 
 LOG = logging.getLogger(__name__)
 
 
-_IMPL_CLIENT = None
-_IMPL_SERVER = None
-_TRANSPORT = None
-
 _ENGINE_CLIENT = None
 _EXECUTOR_CLIENT = None
 _EVENT_ENGINE_CLIENT = None
@@ -42,29 +36,15 @@ _EVENT_ENGINE_CLIENT = None
 def cleanup():
     """Intended to be used by tests to recreate all RPC related objects."""
 
-    global _TRANSPORT
     global _ENGINE_CLIENT
     global _EXECUTOR_CLIENT
     global _EVENT_ENGINE_CLIENT
 
-    _TRANSPORT = None
     _ENGINE_CLIENT = None
     _EXECUTOR_CLIENT = None
     _EVENT_ENGINE_CLIENT = None
 
 
-# TODO(rakhmerov): This method seems misplaced. Now we have different kind
-# of transports (oslo, kombu) and this module should not have any oslo
-# specific things anymore.
-def get_transport():
-    global _TRANSPORT
-
-    if not _TRANSPORT:
-        _TRANSPORT = messaging.get_transport(cfg.CONF)
-
-    return _TRANSPORT
-
-
 def get_engine_client():
     global _ENGINE_CLIENT
 
@@ -92,65 +72,6 @@ def get_event_engine_client():
     return _EVENT_ENGINE_CLIENT
 
 
-def get_rpc_server_driver():
-    rpc_impl = cfg.CONF.rpc_implementation
-
-    global _IMPL_SERVER
-    if not _IMPL_SERVER:
-        _IMPL_SERVER = driver.DriverManager(
-            'mistral.engine.rpc_backend',
-            '%s_server' % rpc_impl
-        ).driver
-
-    return _IMPL_SERVER
-
-
-def get_rpc_client_driver():
-    rpc_impl = cfg.CONF.rpc_implementation
-
-    global _IMPL_CLIENT
-    if not _IMPL_CLIENT:
-        _IMPL_CLIENT = driver.DriverManager(
-            'mistral.engine.rpc_backend',
-            '%s_client' % rpc_impl
-        ).driver
-
-    return _IMPL_CLIENT
-
-
-def _wrap_exception_and_reraise(exception):
-    message = "%s: %s" % (exception.__class__.__name__, exception.args[0])
-
-    raise exc.MistralException(message)
-
-
-def wrap_messaging_exception(method):
-    """This decorator unwrap remote error in one of MistralException.
-
-    oslo.messaging has different behavior on raising exceptions
-    when fake or rabbit transports are used. In case of rabbit
-    transport it raises wrapped RemoteError which forwards directly
-    to API. Wrapped RemoteError contains one of MistralException raised
-    remotely on Engine and for correct exception interpretation we
-    need to unwrap and raise given exception and manually send it to
-    API layer.
-    """
-    def decorator(*args, **kwargs):
-        try:
-            return method(*args, **kwargs)
-
-        except exc.MistralException:
-            raise
-        except (client.RemoteError, exc.KombuException, Exception) as e:
-            if hasattr(e, 'exc_type') and hasattr(exc, e.exc_type):
-                exc_cls = getattr(exc, e.exc_type)
-                raise exc_cls(e.value)
-
-            _wrap_exception_and_reraise(e)
-
-    return decorator
-
-
 class EngineClient(eng.Engine):
     """RPC Engine client."""
 
@@ -159,9 +80,9 @@ class EngineClient(eng.Engine):
 
         :param rpc_conf_dict: Dict containing RPC configuration.
         """
-        self._client = get_rpc_client_driver()(rpc_conf_dict)
+        self._client = base.get_rpc_client_driver()(rpc_conf_dict)
 
-    @wrap_messaging_exception
+    @base.wrap_messaging_exception
     def start_workflow(self, wf_identifier, wf_input, description='',
                        **params):
         """Starts workflow sending a request to engine over RPC.
@@ -177,7 +98,7 @@ class EngineClient(eng.Engine):
             params=params
         )
 
-    @wrap_messaging_exception
+    @base.wrap_messaging_exception
     def start_action(self, action_name, action_input,
                      description=None, **params):
         """Starts action sending a request to engine over RPC.
@@ -193,7 +114,7 @@ class EngineClient(eng.Engine):
             params=params
         )
 
-    @wrap_messaging_exception
+    @base.wrap_messaging_exception
     @profiler.trace('engine-client-on-action-complete', hide_args=True)
     def on_action_complete(self, action_ex_id, result, wf_action=False,
                            async_=False):
@@ -229,7 +150,7 @@ class EngineClient(eng.Engine):
             wf_action=wf_action
         )
 
-    @wrap_messaging_exception
+    @base.wrap_messaging_exception
     def pause_workflow(self, wf_ex_id):
         """Stops the workflow with the given execution id.
 
@@ -243,7 +164,7 @@ class EngineClient(eng.Engine):
             execution_id=wf_ex_id
         )
 
-    @wrap_messaging_exception
+    @base.wrap_messaging_exception
     def rerun_workflow(self, task_ex_id, reset=True, env=None):
         """Rerun the workflow.
 
@@ -265,7 +186,7 @@ class EngineClient(eng.Engine):
             env=env
         )
 
-    @wrap_messaging_exception
+    @base.wrap_messaging_exception
     def resume_workflow(self, wf_ex_id, env=None):
         """Resumes the workflow with the given execution id.
 
@@ -281,7 +202,7 @@ class EngineClient(eng.Engine):
             env=env
         )
 
-    @wrap_messaging_exception
+    @base.wrap_messaging_exception
     def stop_workflow(self, wf_ex_id, state, message=None):
         """Stops workflow execution with given status.
 
@@ -303,7 +224,7 @@ class EngineClient(eng.Engine):
             message=message
         )
 
-    @wrap_messaging_exception
+    @base.wrap_messaging_exception
     def rollback_workflow(self, wf_ex_id):
         """Rolls back the workflow with the given execution id.
 
@@ -326,7 +247,7 @@ class ExecutorClient(exe.Executor):
         """Constructs an RPC client for the Executor."""
 
         self.topic = cfg.CONF.executor.topic
-        self._client = get_rpc_client_driver()(rpc_conf_dict)
+        self._client = base.get_rpc_client_driver()(rpc_conf_dict)
 
     @profiler.trace('executor-client-run-action')
     def run_action(self, action_ex_id, action_cls_str, action_cls_attrs,
@@ -362,12 +283,12 @@ class ExecutorClient(exe.Executor):
         return rpc_client_method(auth_ctx.ctx(), 'run_action', **rpc_kwargs)
 
 
-class EventEngineClient(eng.EventEngine):
+class EventEngineClient(evt_eng.EventEngine):
     """RPC EventEngine client."""
 
     def __init__(self, rpc_conf_dict):
         """Constructs an RPC client for the EventEngine service."""
-        self._client = get_rpc_client_driver()(rpc_conf_dict)
+        self._client = base.get_rpc_client_driver()(rpc_conf_dict)
 
     def create_event_trigger(self, trigger, events):
         return self._client.sync_call(

mistral/rpc/kombu/examples/client.py

@@ -14,7 +14,7 @@
 
 import sys
 
-from mistral.engine.rpc_backend.kombu import kombu_client
+from mistral.rpc.kombu import kombu_client
 
 
 # Example of using Kombu based RPC client.

mistral/rpc/kombu/examples/server.py

@@ -14,7 +14,7 @@
 
 import sys
 
-from mistral.engine.rpc_backend.kombu import kombu_server
+from mistral.rpc.kombu import kombu_server
 
 
 # Simple example of endpoint of RPC server, which just

mistral/rpc/kombu/kombu_client.py

@@ -19,11 +19,11 @@ from oslo_config import cfg
 from oslo_log import log as logging
 import oslo_messaging as messaging
 
-from mistral.engine.rpc_backend import base as rpc_base
-from mistral.engine.rpc_backend.kombu import base as kombu_base
-from mistral.engine.rpc_backend.kombu import kombu_hosts
-from mistral.engine.rpc_backend.kombu import kombu_listener
 from mistral import exceptions as exc
+from mistral.rpc import base as rpc_base
+from mistral.rpc.kombu import base as kombu_base
+from mistral.rpc.kombu import kombu_hosts
+from mistral.rpc.kombu import kombu_listener
 from mistral import utils
 
 

mistral/rpc/kombu/kombu_listener.py

@@ -20,7 +20,7 @@ import threading
 
 from oslo_log import log as logging
 
-from mistral.engine.rpc_backend.kombu import base as kombu_base
+from mistral.rpc.kombu import base as kombu_base
 
 LOG = logging.getLogger(__name__)
 

mistral/rpc/kombu/kombu_server.py

@@ -24,10 +24,10 @@ import oslo_messaging as messaging
 from stevedore import driver
 
 from mistral import context as auth_ctx
-from mistral.engine.rpc_backend import base as rpc_base
-from mistral.engine.rpc_backend.kombu import base as kombu_base
-from mistral.engine.rpc_backend.kombu import kombu_hosts
 from mistral import exceptions as exc
+from mistral.rpc import base as rpc_base
+from mistral.rpc.kombu import base as kombu_base
+from mistral.rpc.kombu import kombu_hosts
 
 
 LOG = logging.getLogger(__name__)

mistral/rpc/oslo/oslo_client.py

@@ -15,11 +15,10 @@
 import oslo_messaging as messaging
 
 from mistral import context as auth_ctx
-from mistral.engine.rpc_backend import base as rpc_base
-from mistral.engine.rpc_backend import rpc
+from mistral.rpc import base as rpc
 
 
-class OsloRPCClient(rpc_base.RPCClient):
+class OsloRPCClient(rpc.RPCClient):
     def __init__(self, conf):
         super(OsloRPCClient, self).__init__(conf)
         self.topic = conf.topic

mistral/rpc/oslo/oslo_server.py

@@ -16,14 +16,13 @@ from oslo_log import log as logging
 import oslo_messaging as messaging
 
 from mistral import context as ctx
-from mistral.engine.rpc_backend import base as rpc_base
-from mistral.engine.rpc_backend import rpc
+from mistral.rpc import base as rpc
 
 
 LOG = logging.getLogger(__name__)
 
 
-class OsloRPCServer(rpc_base.RPCServer):
+class OsloRPCServer(rpc.RPCServer):
     def __init__(self, conf):
         super(OsloRPCServer, self).__init__(conf)
 

mistral/services/periodic.py

@@ -19,8 +19,8 @@ from oslo_service import threadgroup
 
 from mistral import context as auth_ctx
 from mistral.db.v2 import api as db_api_v2
-from mistral.engine.rpc_backend import rpc
 from mistral import exceptions as exc
+from mistral.rpc import clients as rpc
 from mistral.services import security
 from mistral.services import triggers
 

mistral/services/triggers.py

@@ -18,10 +18,10 @@ import six
 import time
 
 from mistral.db.v2 import api as db_api
-from mistral.engine.rpc_backend import rpc
 from mistral.engine import utils as eng_utils
 from mistral import exceptions as exc
 from mistral.lang import parser
+from mistral.rpc import clients as rpc
 from mistral.services import security
 
 

mistral/tests/unit/api/v2/test_action_executions.py

@@ -25,8 +25,9 @@ import oslo_messaging
 from mistral.api.controllers.v2 import action_execution
 from mistral.db.v2 import api as db_api
 from mistral.db.v2.sqlalchemy import models
-from mistral.engine.rpc_backend import rpc
 from mistral import exceptions as exc
+from mistral.rpc import base as rpc_base
+from mistral.rpc import clients as rpc_clients
 from mistral.tests.unit.api import base
 from mistral.utils import rest_utils
 from mistral.workflow import states
@@ -194,7 +195,7 @@ MOCK_NOT_FOUND = mock.MagicMock(side_effect=exc.DBEntityNotFoundError())
 MOCK_DELETE = mock.MagicMock(return_value=None)
 
 
-@mock.patch.object(rpc, '_IMPL_CLIENT', mock.Mock())
+@mock.patch.object(rpc_base, '_IMPL_CLIENT', mock.Mock())
 class TestActionExecutionsController(base.APITest):
     def setUp(self):
         super(TestActionExecutionsController, self).setUp()
@@ -223,7 +224,7 @@ class TestActionExecutionsController(base.APITest):
 
         self.assertEqual(404, resp.status_int)
 
-    @mock.patch.object(rpc.EngineClient, 'start_action')
+    @mock.patch.object(rpc_clients.EngineClient, 'start_action')
     def test_post(self, f):
         f.return_value = ACTION_EX_DB.to_dict()
 
@@ -251,7 +252,7 @@ class TestActionExecutionsController(base.APITest):
             run_sync=True
         )
 
-    @mock.patch.object(rpc.EngineClient, 'start_action')
+    @mock.patch.object(rpc_clients.EngineClient, 'start_action')
     def test_post_json(self, f):
         f.return_value = ACTION_EX_DB.to_dict()
 
@@ -278,7 +279,7 @@ class TestActionExecutionsController(base.APITest):
             save_result=True
         )
 
-    @mock.patch.object(rpc.EngineClient, 'start_action')
+    @mock.patch.object(rpc_clients.EngineClient, 'start_action')
     def test_post_without_input(self, f):
         f.return_value = ACTION_EX_DB.to_dict()
         f.return_value['output'] = {'result': '123'}
@@ -320,7 +321,7 @@ class TestActionExecutionsController(base.APITest):
 
         self.assertEqual(400, resp.status_int)
 
-    @mock.patch.object(rpc.EngineClient, 'on_action_complete')
+    @mock.patch.object(rpc_clients.EngineClient, 'on_action_complete')
     def test_put(self, f):
         f.return_value = UPDATED_ACTION_EX_DB
 
@@ -334,7 +335,7 @@ class TestActionExecutionsController(base.APITest):
             wf_utils.Result(data=ACTION_EX_DB.output)
         )
 
-    @mock.patch.object(rpc.EngineClient, 'on_action_complete')
+    @mock.patch.object(rpc_clients.EngineClient, 'on_action_complete')
     def test_put_error_with_output(self, f):
         f.return_value = ERROR_ACTION_EX_WITH_OUTPUT
 
@@ -351,7 +352,7 @@ class TestActionExecutionsController(base.APITest):
             wf_utils.Result(error=ERROR_ACTION_RES_WITH_OUTPUT)
         )
 
-    @mock.patch.object(rpc.EngineClient, 'on_action_complete')
+    @mock.patch.object(rpc_clients.EngineClient, 'on_action_complete')
     def test_put_error_with_unknown_reason(self, f):
         f.return_value = ERROR_ACTION_EX_FOR_EMPTY_OUTPUT
         resp = self.app.put_json('/v2/action_executions/123', ERROR_ACTION)
@@ -364,7 +365,7 @@ class TestActionExecutionsController(base.APITest):
             wf_utils.Result(error=DEFAULT_ERROR_OUTPUT)
         )
 
-    @mock.patch.object(rpc.EngineClient, 'on_action_complete')
+    @mock.patch.object(rpc_clients.EngineClient, 'on_action_complete')
     def test_put_error_with_unknown_reason_output_none(self, f):
         f.return_value = ERROR_ACTION_EX_FOR_EMPTY_OUTPUT
         resp = self.app.put_json(
@@ -380,7 +381,7 @@ class TestActionExecutionsController(base.APITest):
             wf_utils.Result(error=DEFAULT_ERROR_OUTPUT)
         )
 
-    @mock.patch.object(rpc.EngineClient, 'on_action_complete')
+    @mock.patch.object(rpc_clients.EngineClient, 'on_action_complete')
     def test_put_cancelled(self, on_action_complete_mock_func):
         on_action_complete_mock_func.return_value = CANCELLED_ACTION_EX_DB
 
@@ -395,7 +396,7 @@ class TestActionExecutionsController(base.APITest):
         )
 
     @mock.patch.object(
-        rpc.EngineClient,
+        rpc_clients.EngineClient,
         'on_action_complete',
         MOCK_NOT_FOUND
     )
@@ -430,7 +431,7 @@ class TestActionExecutionsController(base.APITest):
 
         self.assertEqual(400, resp.status_int)
 
-    @mock.patch.object(rpc.EngineClient, 'on_action_complete')
+    @mock.patch.object(rpc_clients.EngineClient, 'on_action_complete')
     def test_put_without_result(self, f):
         action_ex = copy.deepcopy(UPDATED_ACTION)
         del action_ex['output']

mistral/tests/unit/api/v2/test_event_trigger.py

@@ -85,7 +85,7 @@ class TestEventTriggerController(base.APITest):
     @mock.patch.object(db_api, "get_workflow_definition", MOCK_WF)
     @mock.patch.object(db_api, "create_event_trigger", MOCK_TRIGGER)
     @mock.patch.object(db_api, "get_event_triggers", MOCK_TRIGGERS)
-    @mock.patch('mistral.engine.rpc_backend.rpc.get_event_engine_client')
+    @mock.patch('mistral.rpc.clients.get_event_engine_client')
     def test_post(self, mock_rpc_client):
         client = mock.Mock()
         mock_rpc_client.return_value = client
@@ -134,7 +134,7 @@ class TestEventTriggerController(base.APITest):
         self.assertEqual(404, resp.status_int)
 
     @mock.patch.object(db_api, 'ensure_event_trigger_exists', MOCK_NONE)
-    @mock.patch('mistral.engine.rpc_backend.rpc.get_event_engine_client')
+    @mock.patch('mistral.rpc.clients.get_event_engine_client')
     @mock.patch('mistral.db.v2.api.update_event_trigger')
     def test_put(self, mock_update, mock_rpc_client):
         client = mock.Mock()
@@ -167,7 +167,7 @@ class TestEventTriggerController(base.APITest):
 
         self.assertEqual(400, resp.status_int)
 
-    @mock.patch('mistral.engine.rpc_backend.rpc.get_event_engine_client')
+    @mock.patch('mistral.rpc.clients.get_event_engine_client')
     @mock.patch.object(db_api, "get_event_trigger", MOCK_TRIGGER)
     @mock.patch.object(db_api, "get_event_triggers",
                        mock.MagicMock(return_value=[]))

mistral/tests/unit/api/v2/test_executions.py

@@ -29,8 +29,9 @@ from mistral.api.controllers.v2 import execution
 from mistral.db.v2 import api as db_api
 from mistral.db.v2.sqlalchemy import api as sql_db_api
 from mistral.db.v2.sqlalchemy import models
-from mistral.engine.rpc_backend import rpc
 from mistral import exceptions as exc
+from mistral.rpc import base as rpc_base
+from mistral.rpc import clients as rpc_clients
 from mistral.tests.unit.api import base
 from mistral.tests.unit import base as unit_base
 from mistral import utils
@@ -131,7 +132,7 @@ MOCK_NOT_FOUND = mock.MagicMock(side_effect=exc.DBEntityNotFoundError())
 MOCK_ACTION_EXC = mock.MagicMock(side_effect=exc.ActionException())
 
 
-@mock.patch.object(rpc, '_IMPL_CLIENT', mock.Mock())
+@mock.patch.object(rpc_base, '_IMPL_CLIENT', mock.Mock())
 class TestExecutionsController(base.APITest):
     @mock.patch.object(db_api, 'get_workflow_execution', MOCK_WF_EX)
     def test_get(self):
@@ -159,7 +160,7 @@ class TestExecutionsController(base.APITest):
         mock.MagicMock(return_value=None)
     )
     @mock.patch.object(
-        rpc.EngineClient,
+        rpc_clients.EngineClient,
         'pause_workflow',
         MOCK_UPDATED_WF_EX
     )
@@ -182,7 +183,7 @@ class TestExecutionsController(base.APITest):
         'ensure_workflow_execution_exists',
         mock.MagicMock(return_value=None)
     )
-    @mock.patch.object(rpc.EngineClient, 'stop_workflow')
+    @mock.patch.object(rpc_clients.EngineClient, 'stop_workflow')
     def test_put_state_error(self, mock_stop_wf):
         update_exec = {
             'id': WF_EX['id'],
@@ -210,7 +211,7 @@ class TestExecutionsController(base.APITest):
         'ensure_workflow_execution_exists',
         mock.MagicMock(return_value=None)
     )
-    @mock.patch.object(rpc.EngineClient, 'stop_workflow')
+    @mock.patch.object(rpc_clients.EngineClient, 'stop_workflow')
     def test_put_state_cancelled(self, mock_stop_wf):
         update_exec = {
             'id': WF_EX['id'],
@@ -243,7 +244,7 @@ class TestExecutionsController(base.APITest):
         'ensure_workflow_execution_exists',
         mock.MagicMock(return_value=None)
     )
-    @mock.patch.object(rpc.EngineClient, 'resume_workflow')
+    @mock.patch.object(rpc_clients.EngineClient, 'resume_workflow')
     def test_put_state_resume(self, mock_resume_wf):
         update_exec = {
             'id': WF_EX['id'],
@@ -297,7 +298,7 @@ class TestExecutionsController(base.APITest):
         'ensure_workflow_execution_exists',
         mock.MagicMock(return_value=None)
     )
-    @mock.patch.object(rpc.EngineClient, 'stop_workflow')
+    @mock.patch.object(rpc_clients.EngineClient, 'stop_workflow')
     def test_put_state_info_unset(self, mock_stop_wf):
         update_exec = {
             'id': WF_EX['id'],
@@ -454,7 +455,7 @@ class TestExecutionsController(base.APITest):
 
         self.assertIn(expected_fault, resp.json['faultstring'])
 
-    @mock.patch.object(rpc.EngineClient, 'start_workflow')
+    @mock.patch.object(rpc_clients.EngineClient, 'start_workflow')
     def test_post(self, f):
         f.return_value = WF_EX.to_dict()
 
@@ -472,7 +473,11 @@ class TestExecutionsController(base.APITest):
             **json.loads(exec_dict['params'])
         )
 
-    @mock.patch.object(rpc.EngineClient, 'start_workflow', MOCK_ACTION_EXC)
+    @mock.patch.object(
+        rpc_clients.EngineClient,
+        'start_workflow',
+        MOCK_ACTION_EXC
+    )
     def test_post_throws_exception(self):
         context = self.assertRaises(
             webtest_app.AppError,

mistral/tests/unit/api/v2/test_tasks.py

@@ -20,8 +20,8 @@ import mock
 
 from mistral.db.v2 import api as db_api
 from mistral.db.v2.sqlalchemy import models
-from mistral.engine.rpc_backend import rpc
 from mistral import exceptions as exc
+from mistral.rpc import clients as rpc
 from mistral.tests.unit.api import base
 from mistral.workflow import data_flow
 from mistral.workflow import states

mistral/tests/unit/engine/base.py

@@ -22,9 +22,10 @@ from oslo_service import service
 
 from mistral.db.v2 import api as db_api
 from mistral.engine import engine_server
-from mistral.engine.rpc_backend import rpc
 from mistral.executors import base as exe
 from mistral.executors import executor_server
+from mistral.rpc import base as rpc_base
+from mistral.rpc import clients as rpc_clients
 from mistral.tests.unit import base
 from mistral.workflow import states
 
@@ -57,7 +58,8 @@ class EngineTestCase(base.DbTestCase):
         cfg.CONF.set_default('rpc_backend', 'fake')
 
         # Drop all RPC objects (transport, clients).
-        rpc.cleanup()
+        rpc_base.cleanup()
+        rpc_clients.cleanup()
         exe.cleanup()
 
         self.threads = []
@@ -65,7 +67,7 @@ class EngineTestCase(base.DbTestCase):
         # Start remote executor.
         if cfg.CONF.executor.type == 'remote':
             LOG.info("Starting remote executor threads...")
-            self.executor_client = rpc.get_executor_client()
+            self.executor_client = rpc_clients.get_executor_client()
             exe_svc = executor_server.get_oslo_service(setup_profiler=False)
             self.executor = exe_svc.executor
             self.threads.append(eventlet.spawn(launch_service, exe_svc))
@@ -73,7 +75,7 @@ class EngineTestCase(base.DbTestCase):
 
         # Start engine.
         LOG.info("Starting engine threads...")
-        self.engine_client = rpc.get_engine_client()
+        self.engine_client = rpc_clients.get_engine_client()
         eng_svc = engine_server.get_oslo_service(setup_profiler=False)
         self.engine = eng_svc.engine
         self.threads.append(eventlet.spawn(launch_service, eng_svc))

mistral/tests/unit/rpc/kombu/base.py

@@ -13,8 +13,14 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+from oslo_config import cfg
+
 from mistral.tests.unit import base
 
 
 class KombuTestCase(base.BaseTest):
-    pass
+
+    def setUp(self):
+        super(KombuTestCase, self).setUp()
+
+        cfg.CONF.set_default('rpc_backend', 'kombu')

mistral/tests/unit/rpc/kombu/test_kombu_client.py

@@ -14,15 +14,15 @@
 #    under the License.
 
 from mistral import exceptions as exc
-from mistral.tests.unit.engine.rpc_backend.kombu import base
-from mistral.tests.unit.engine.rpc_backend.kombu import fake_kombu
+from mistral.tests.unit.rpc.kombu import base
+from mistral.tests.unit.rpc.kombu import fake_kombu
 
 import mock
 from six import moves
 
 with mock.patch.dict('sys.modules', kombu=fake_kombu):
-    from mistral.engine.rpc_backend.kombu import base as kombu_base
-    from mistral.engine.rpc_backend.kombu import kombu_client
+    from mistral.rpc.kombu import base as kombu_base
+    from mistral.rpc.kombu import kombu_client
 
 
 class TestException(exc.MistralException):

mistral/tests/unit/rpc/kombu/test_kombu_listener.py

@@ -14,16 +14,16 @@
 #    under the License.
 
 from mistral import exceptions as exc
-from mistral.tests.unit.engine.rpc_backend.kombu import base
-from mistral.tests.unit.engine.rpc_backend.kombu import fake_kombu
+from mistral.tests.unit.rpc.kombu import base
+from mistral.tests.unit.rpc.kombu import fake_kombu
 from mistral import utils
 
 import mock
 from six import moves
 
 with mock.patch.dict('sys.modules', kombu=fake_kombu):
-    from mistral.engine.rpc_backend.kombu import base as kombu_base
-    from mistral.engine.rpc_backend.kombu import kombu_listener
+    from mistral.rpc.kombu import base as kombu_base
+    from mistral.rpc.kombu import kombu_listener
 
 
 class TestException(exc.MistralException):

mistral/tests/unit/rpc/kombu/test_kombu_server.py

@@ -14,15 +14,15 @@
 #    under the License.
 
 from mistral import exceptions as exc
-from mistral.tests.unit.engine.rpc_backend.kombu import base
-from mistral.tests.unit.engine.rpc_backend.kombu import fake_kombu
+from mistral.tests.unit.rpc.kombu import base
+from mistral.tests.unit.rpc.kombu import fake_kombu
 
 import mock
 import socket
 from stevedore import driver
 
 with mock.patch.dict('sys.modules', kombu=fake_kombu):
-    from mistral.engine.rpc_backend.kombu import kombu_server
+    from mistral.rpc.kombu import kombu_server
 
 
 class TestException(exc.MistralError):

mistral/tests/unit/services/test_event_engine.py

@@ -1,4 +1,5 @@
 # Copyright 2016 Catalyst IT Ltd
+# Copyright 2017 Brocade Communications Systems, Inc.
 #
 #    Licensed under the Apache License, Version 2.0 (the "License");
 #    you may not use this file except in compliance with the License.
@@ -18,8 +19,8 @@ import mock
 from oslo_config import cfg
 
 from mistral.db.v2.sqlalchemy import api as db_api
-from mistral.engine.rpc_backend import rpc
-from mistral.event_engine import event_engine
+from mistral.event_engine import default_event_engine as evt_eng
+from mistral.rpc import clients as rpc
 from mistral.services import workflows
 from mistral.tests.unit import base
 
@@ -61,7 +62,7 @@ class EventEngineTest(base.DbTestCase):
 
     @mock.patch.object(rpc, 'get_engine_client', mock.Mock())
     def test_event_engine_start_with_no_triggers(self):
-        e_engine = event_engine.EventEngine()
+        e_engine = evt_eng.DefaultEventEngine()
 
         self.addCleanup(e_engine.handler_tg.stop)
 
@@ -74,7 +75,7 @@ class EventEngineTest(base.DbTestCase):
     def test_event_engine_start_with_triggers(self, mock_start):
         trigger = db_api.create_event_trigger(EVENT_TRIGGER)
 
-        e_engine = event_engine.EventEngine()
+        e_engine = evt_eng.DefaultEventEngine()
 
         self.addCleanup(e_engine.handler_tg.stop)
 
@@ -96,7 +97,7 @@ class EventEngineTest(base.DbTestCase):
     def test_process_event_queue(self, mock_start):
         db_api.create_event_trigger(EVENT_TRIGGER)
 
-        e_engine = event_engine.EventEngine()
+        e_engine = evt_eng.DefaultEventEngine()
 
         self.addCleanup(e_engine.handler_tg.stop)
 
@@ -138,8 +139,8 @@ class NotificationsConverterTest(base.BaseTest):
             }
         ]
 
-        converter = event_engine.NotificationsConverter()
-        converter.definitions = [event_engine.EventDefinition(event_def)
+        converter = evt_eng.NotificationsConverter()
+        converter.definitions = [evt_eng.EventDefinition(event_def)
                                  for event_def in reversed(definition_cfg)]
 
         notification = {
@@ -165,8 +166,8 @@ class NotificationsConverterTest(base.BaseTest):
             }
         ]
 
-        converter = event_engine.NotificationsConverter()
-        converter.definitions = [event_engine.EventDefinition(event_def)
+        converter = evt_eng.NotificationsConverter()
+        converter.definitions = [evt_eng.EventDefinition(event_def)
                                  for event_def in reversed(definition_cfg)]
 
         notification = {

mistral/tests/unit/services/test_trigger_service.py

@@ -18,8 +18,8 @@ import mock
 
 from oslo_config import cfg
 
-from mistral.engine.rpc_backend import rpc
 from mistral import exceptions as exc
+from mistral.rpc import clients as rpc
 from mistral.services import periodic
 from mistral.services import security
 from mistral.services import triggers as t_s

setup.cfg

@@ -40,11 +40,11 @@ console_scripts =
 wsgi_scripts =
     mistral-wsgi-api = mistral.api.wsgi:init_application
 
-mistral.engine.rpc_backend =
-    oslo_client = mistral.engine.rpc_backend.oslo.oslo_client:OsloRPCClient
-    oslo_server = mistral.engine.rpc_backend.oslo.oslo_server:OsloRPCServer
-    kombu_client = mistral.engine.rpc_backend.kombu.kombu_client:KombuRPCClient
-    kombu_server = mistral.engine.rpc_backend.kombu.kombu_server:KombuRPCServer
+mistral.rpc.backends =
+    oslo_client = mistral.rpc.oslo.oslo_client:OsloRPCClient
+    oslo_server = mistral.rpc.oslo.oslo_server:OsloRPCServer
+    kombu_client = mistral.rpc.kombu.kombu_client:KombuRPCClient
+    kombu_server = mistral.rpc.kombu.kombu_server:KombuRPCServer
 
 oslo.config.opts =
     mistral.config = mistral.config:list_opts