Isolate eventlet-dependent services for future migration

This commit creates the structure for migrating Designate
services from using eventlet, to using oslo.service threading backend
(standard/native python threading).

Key changes include:
* Eventlet isolation: existing eventlet-dependent service entrypoints
    (central, mdns, producer, sink, worker, manage, status) are moved
    from designate/cmd to a new designate/cmd/eventlet subdirectory.
* Updating their correct path in setup.cfg.

This prepares the codebase for future incremental migrations of
individual services to native threading.

Change-Id: I67941b5c7525d4b9661b30c4cc03dbd061e86083
Signed-off-by: Omer <oschwart@redhat.com>

designate/__init__.py

@@ -17,18 +17,19 @@ import os
 
 # Eventlet's GreenDNS Patching will prevent the resolution of names in
 # the /etc/hosts file, causing problems for installs.
-os.environ['EVENTLET_NO_GREENDNS'] = 'yes'  # noqa
+os.environ['EVENTLET_NO_GREENDNS'] = 'yes'
 
-from oslo_log import log  # noqa
 from oslo_concurrency import lockutils  # noqa
+from oslo_log import log  # noqa
 import oslo_messaging as messaging  # noqa
 
+BASE_PATH = os.path.abspath(os.path.join(os.path.dirname(__file__), '../'))
+
 _EXTRA_DEFAULT_LOG_LEVELS = [
     'kazoo.client=WARN',
     'keystone=INFO',
     'oslo_service.loopingcall=WARN',
 ]
-BASE_PATH = os.path.abspath(os.path.join(os.path.dirname(__file__), '../'))
 
 # Set some Oslo Log defaults
 log.set_defaults(default_log_levels=log.get_default_log_levels() +
@@ -37,5 +38,5 @@ log.set_defaults(default_log_levels=log.get_default_log_levels() +
 # Set some Oslo RPC defaults
 messaging.set_transport_defaults('designate')
 
-# Set some Oslo Oslo Concurrency defaults
+# Set some Oslo Concurrency defaults
 lockutils.set_defaults(lock_path='$state_path')

designate/api/wsgi.py

@@ -13,6 +13,13 @@
 
 import os
 
+# NOTE(oschwart): remove once the default backend is ``BackendType.THREADING``
+import oslo_service.backend as service
+try:
+    service.init_backend(service.BackendType.THREADING)
+except service.exceptions.BackendAlreadySelected:
+    pass
+
 from oslo_config import cfg
 from oslo_log import log as logging
 from paste import deploy
@@ -24,7 +31,6 @@ from designate import heartbeat_emitter
 from designate import policy
 from designate import rpc
 
-
 CONF = designate.conf.CONF
 
 CONFIG_FILES = ['api-paste.ini', 'designate.conf']

designate/cmd/__init__.py

@@ -1,18 +0,0 @@
-# Copyright 2013 Hewlett-Packard Development Company, L.P.
-#
-# Author: Kiall Mac Innes <kiall@hp.com>
-#
-# 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 eventlet
-
-eventlet.monkey_patch(os=False)

designate/cmd/eventlet/__init__.py

@@ -0,0 +1,24 @@
+# Copyright 2012 Managed I.T.
+#
+# Author: Kiall Mac Innes <kiall@managedit.ie>
+#
+# 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 os
+
+# Eventlet's GreenDNS Patching will prevent the resolution of names in
+# the /etc/hosts file, causing problems for installs.
+os.environ['EVENTLET_NO_GREENDNS'] = 'yes'
+
+import eventlet  # noqa
+
+eventlet.monkey_patch(os=False)

designate/cmd/threading/__init__.py

@@ -0,0 +1,22 @@
+# Copyright 2012 Managed I.T.
+#
+# Author: Kiall Mac Innes <kiall@managedit.ie>
+#
+# 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.
+
+# NOTE(oschwart): remove once the default backend is ``BackendType.THREADING``
+import oslo_service.backend as service
+try:
+    service.init_backend(service.BackendType.THREADING)
+except service.exceptions.BackendAlreadySelected:
+    pass

designate/tests/__init__.py

@@ -15,7 +15,10 @@
 # under the License.
 
 
-import eventlet
+import os
+os.environ['EVENTLET_NO_GREENDNS'] = 'yes'
+
+import eventlet # noqa
 
 
-eventlet.monkey_patch(os=False)
+eventlet.monkey_patch(os=False) # noqa

designate/tests/functional/test_upgrade_checks.py

@@ -17,7 +17,7 @@ from oslo_upgradecheck import upgradecheck
 from sqlalchemy.schema import MetaData
 from sqlalchemy.schema import Table
 
-from designate.cmd import status
+from designate.cmd.eventlet import status
 from designate.storage import sql
 import designate.tests.functional
 

designate/tests/unit/cmd/test_cmd.py

@@ -14,12 +14,12 @@ from unittest import mock
 from oslo_config import fixture as cfg_fixture
 import oslotest.base
 
-from designate.cmd import api
-from designate.cmd import central
-from designate.cmd import mdns
-from designate.cmd import producer
-from designate.cmd import sink
-from designate.cmd import worker
+from designate.cmd.eventlet import api
+from designate.cmd.eventlet import central
+from designate.cmd.eventlet import mdns
+from designate.cmd.eventlet import producer
+from designate.cmd.eventlet import sink
+from designate.cmd.eventlet import worker
 import designate.conf
 
 

designate/tests/unit/cmd/test_manage.py

@@ -15,7 +15,7 @@ from unittest import mock
 from oslo_config import fixture as cfg_fixture
 import oslotest.base
 
-from designate.cmd import manage
+from designate.cmd.eventlet import manage
 import designate.conf
 from designate.manage import base
 

setup.cfg

@@ -53,14 +53,14 @@ oslo.policy.enforcer =
 
 console_scripts =
     designate-rootwrap = oslo_rootwrap.cmd:main
-    designate-api = designate.cmd.api:main
-    designate-central = designate.cmd.central:main
-    designate-manage = designate.cmd.manage:main
-    designate-mdns = designate.cmd.mdns:main
-    designate-sink = designate.cmd.sink:main
-    designate-worker = designate.cmd.worker:main
-    designate-producer = designate.cmd.producer:main
-    designate-status = designate.cmd.status:main
+    designate-api = designate.cmd.eventlet.api:main
+    designate-central = designate.cmd.eventlet.central:main
+    designate-manage = designate.cmd.eventlet.manage:main
+    designate-mdns = designate.cmd.eventlet.mdns:main
+    designate-sink = designate.cmd.eventlet.sink:main
+    designate-worker = designate.cmd.eventlet.worker:main
+    designate-producer = designate.cmd.eventlet.producer:main
+    designate-status = designate.cmd.eventlet.status:main
 
 designate.api.admin.extensions =
     reports = designate.api.admin.controllers.extensions.reports:ReportsController