Make neutron pecan server an option instead of binary

Launch pecan server instead of home-grown wsgi server using
a new config option. This will make it easier to test out
pecan without invasive changes to devstack.

Related Blueprint: wsgi-pecan-switch
Change-Id: I99261e6bfc9b16c0d601828f97553a9192804216

neutron/cmd/eventlet/server/__init__.py

@@ -10,11 +10,20 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+from oslo_config import cfg
+
 from neutron.server import rpc_eventlet
 from neutron.server import wsgi_eventlet
 from neutron.server import wsgi_pecan
 
 
+def main():
+    if cfg.CONF.web_framework == 'legacy':
+        main_wsgi_eventlet()
+    else:
+        main_wsgi_pecan()
+
+
 def main_wsgi_eventlet():
     wsgi_eventlet.main()
 

neutron/common/config.py

@@ -166,6 +166,11 @@ core_opts = [
     cfg.BoolOpt('vlan_transparent', default=False,
                 help=_('If True, then allow plugins that support it to '
                        'create VLAN transparent networks.')),
+    cfg.StrOpt('web_framework', default='legacy',
+               choices=('legacy', 'pecan'),
+               help=_("This will choose the web framework in which to run "
+                      "the Neutron API server. 'pecan' is a new experiemental "
+                      "rewrite of the API server."))
 ]
 
 core_cli_opts = [

neutron/tests/unit/cmd/server/__init__.py

@@ -0,0 +1,34 @@
+#    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 mock
+from oslo_config import cfg
+
+from neutron.cmd.eventlet import server
+from neutron.tests import base
+
+
+@mock.patch('neutron.cmd.eventlet.server.main_wsgi_eventlet')
+@mock.patch('neutron.cmd.eventlet.server.main_wsgi_pecan')
+class TestNeutronServer(base.BaseTestCase):
+
+    def test_legacy_server(self, pecan_mock, legacy_mock):
+        cfg.CONF.set_override('web_framework', 'legacy')
+        server.main()
+        pecan_mock.assert_not_called()
+        legacy_mock.assert_called_with()
+
+    def test_pecan_server(self, pecan_mock, legacy_mock):
+        cfg.CONF.set_override('web_framework', 'pecan')
+        server.main()
+        pecan_mock.assert_called_with()
+        legacy_mock.assert_not_called()

setup.cfg

@@ -56,8 +56,7 @@ console_scripts =
     neutron-openvswitch-agent = neutron.cmd.eventlet.plugins.ovs_neutron_agent:main
     neutron-ovs-cleanup = neutron.cmd.ovs_cleanup:main
     neutron-pd-notify = neutron.cmd.pd_notify:main
-    neutron-server = neutron.cmd.eventlet.server:main_wsgi_eventlet
-    neutron-dev-server = neutron.cmd.eventlet.server:main_wsgi_pecan
+    neutron-server = neutron.cmd.eventlet.server:main
     neutron-rpc-server = neutron.cmd.eventlet.server:main_rpc_eventlet
     neutron-rootwrap = oslo_rootwrap.cmd:main
     neutron-rootwrap-daemon = oslo_rootwrap.cmd:daemon