Use stevedore to load apps

We used to load apps by listing module and class names in a
configuration entry. This patch defines entry points for all present
apps, so we don't have to import them by module path, additionally,
other packages can register new apps, allowing further extensibility.

Closes-Bug: #1702462
Change-Id: Iffa0fea3db36df2f59ef19a621b41838d66cb8d7

devstack/ovs_dpdk_setup.sh

@@ -138,7 +138,7 @@ function configure_ovs {
 
     if is_service_enabled df-controller ; then
         # setup external bridge if necessary
-        check_dnat=$(echo $DF_APPS_LIST | grep "DNATApp")
+        check_dnat=$(echo $DF_APPS_LIST | grep "dnat")
         if [[ "$check_dnat" != "" ]]; then
             echo "Setup external bridge for DNAT"
             sudo ovs-vsctl add-br $PUBLIC_BRIDGE || true

devstack/ovs_setup.sh

@@ -158,7 +158,7 @@ function start_ovs {
 function configure_ovs {
     if is_service_enabled df-controller ; then
         # setup external bridge if necessary
-        check_dnat=$(echo $DF_APPS_LIST | grep "DNATApp")
+        check_dnat=$(echo $DF_APPS_LIST | grep "dnat")
         if [[ "$check_dnat" != "" ]]; then
             echo "Setup external bridge for DNAT"
             sudo ovs-vsctl add-br $PUBLIC_BRIDGE || true

devstack/plugin.sh

@@ -17,36 +17,33 @@ OVS_BRANCH=${OVS_BRANCH:-branch-2.6}
 EXTERNAL_HOST_IP=${EXTERNAL_HOST_IP:-}
 
 DEFAULT_TUNNEL_TYPES="vxlan,geneve,gre"
-DEFAULT_APPS_LIST="l2_app.L2App,l3_proactive_app.L3ProactiveApp,"\
+DEFAULT_APPS_LIST="l2,l3_proactive,dhcp,dnat,sg,portsec,portqos,classifier,tunneling,provider"
-"dhcp_app.DHCPApp,dnat_app.DNATApp,sg_app.SGApp,portsec_app.PortSecApp,"\
-"portqos_app.PortQosApp,classifier_app.ClassifierApp,tunneling_app.TunnelingApp,"\
-"provider_networks_app.ProviderNetworksApp"
 
 if is_service_enabled df-metadata ; then
-    DEFAULT_APPS_LIST="$DEFAULT_APPS_LIST,metadata_service_app.MetadataServiceApp"
+    DEFAULT_APPS_LIST="$DEFAULT_APPS_LIST,metadata_service"
 fi
 
 if is_service_enabled q-trunk ; then
-    DEFAULT_APPS_LIST="$DEFAULT_APPS_LIST,trunk_app.TrunkApp"
+    DEFAULT_APPS_LIST="$DEFAULT_APPS_LIST,trunk"
 fi
 
 ENABLE_ACTIVE_DETECTION=${ENABLE_ACTIVE_DETECTION:-True}
 if [[ "$ENABLE_ACTIVE_DETECTION" == "True" ]]; then
-    DEFAULT_APPS_LIST="$DEFAULT_APPS_LIST,active_port_detection_app.ActivePortDetectionApp"
+    DEFAULT_APPS_LIST="$DEFAULT_APPS_LIST,active_port_detection"
 fi
 
 ENABLE_LIVE_MIGRATION=${ENABLE_LIVE_MIGRATION:-True}
 if [[ "$ENABLE_LIVE_MIGRATION" == "True" ]]; then
-    DEFAULT_APPS_LIST="$DEFAULT_APPS_LIST,migration_app.MigrationApp"
+    DEFAULT_APPS_LIST="$DEFAULT_APPS_LIST,migration"
 fi
 
 if [[ ! -z ${EXTERNAL_HOST_IP} ]]; then
-    DEFAULT_APPS_LIST="$DEFAULT_APPS_LIST,chassis_snat_app.ChassisSNATApp"
+    DEFAULT_APPS_LIST="$DEFAULT_APPS_LIST,chassis_snat"
 fi
 
 ENABLED_AGING_APP=${ENABLE_AGING_APP:-True}
 if [[ "$ENABLE_AGING_APP" == "True" ]]; then
-    DEFAULT_APPS_LIST="aging_app.Aging,$DEFAULT_APPS_LIST"
+    DEFAULT_APPS_LIST="aging,$DEFAULT_APPS_LIST"
 fi
 
 DF_APPS_LIST=${DF_APPS_LIST:-$DEFAULT_APPS_LIST}

doc/source/manual_deployment.rst

@@ -95,7 +95,7 @@ Basic Configurations
     [df]
     metadata_interface = tap-metadata
     enable_selective_topology_distribution = True
-    apps_list = l2_app.L2App,l3_proactive_app.L3ProactiveApp,dhcp_app.DHCPApp,dnat_app.DNATApp,sg_app.SGApp,portsec_app.PortSecApp,portqos_app.PortQosApp
+    apps_list = l2,l3_proactive,dhcp,dnat,sg,portsec,portqos
     integration_bridge = br-int
     tunnel_type = geneve
 

dragonflow/conf/df_common_params.py

@@ -41,9 +41,7 @@ df_opts = [
                 default=False,
                 help=_("Enable dpdk")),
     cfg.StrOpt('apps_list',
-               default='l2_app.L2App,'
+               default='l2,l3_proactive,dhcp',
-                       'l3_proactive_app.L3ProactiveApp,'
-                       'dhcp_app.DHCPApp',
                help=_('List of openflow applications classes to load')),
     cfg.StrOpt('integration_bridge', default='br-int',
                help=_("Integration bridge to use. "

dragonflow/controller/dispatcher.py

@@ -11,9 +11,8 @@
 #    under the License.
 
 from oslo_log import log
-from oslo_utils import importutils
+import stevedore
 
-from dragonflow._i18n import _
 from dragonflow.common import exceptions
 
 LOG = log.getLogger(__name__)
@@ -21,21 +20,21 @@ LOG = log.getLogger(__name__)
 
 class AppDispatcher(object):
 
-    def __init__(self, apps_location_prefix, app_list):
+    def __init__(self, app_list):
-        self.apps_location_prefix = apps_location_prefix
         self.apps_list = app_list.split(',')
         self.apps = []
 
     def load(self, *args, **kwargs):
-        for app in self.apps_list:
+        mgr = stevedore.NamedExtensionManager(
-            app_class_name = self.apps_location_prefix + "." + app
+            'dragonflow.controller.apps',
-            try:
+            self.apps_list,
-                app_class = importutils.import_class(app_class_name)
+            invoke_on_load=True,
-                app = app_class(*args, **kwargs)
+            invoke_args=args,
-                self.apps.append(app)
+            invoke_kwds=kwargs,
-            except ImportError as e:
+        )
-                LOG.exception("Error loading application by class, %s", e)
+
-                raise ImportError(_("Application class not found."))
+        for ext in mgr:
+            self.apps.append(ext.obj)
 
     def dispatch(self, method, *args, **kwargs):
         errors = []

dragonflow/controller/ryu_base_app.py

@@ -39,8 +39,7 @@ class RyuDFAdapter(ofp_handler.OFPHandler):
     def __init__(self, vswitch_api=None, nb_api=None,
                  neutron_server_notifier=None):
         super(RyuDFAdapter, self).__init__()
-        self.dispatcher = dispatcher.AppDispatcher('dragonflow.controller',
+        self.dispatcher = dispatcher.AppDispatcher(cfg.CONF.df.apps_list)
-                                                   cfg.CONF.df.apps_list)
         self.vswitch_api = vswitch_api
         self.nb_api = nb_api
         self.neutron_server_notifier = neutron_server_notifier

dragonflow/db/api_nb.py

@@ -91,7 +91,7 @@ class NbApi(object):
                 # FIXME(nick-ma-z): if active-detection is enabled,
                 # we initialize the publisher here. Make sure it
                 # only supports redis-based pub/sub driver.
-                if "ActivePortDetectionApp" in cfg.CONF.df.apps_list:
+                if "active_port_detection" in cfg.CONF.df.apps_list:
                     self.publisher.initialize()
 
                 # NOTE(gampel) we want to start queuing event as soon

dragonflow/tests/fullstack/test_snat_flows.py

@@ -16,7 +16,7 @@ from dragonflow.tests.common import utils
 from dragonflow.tests.fullstack import test_base
 from dragonflow.tests.fullstack import test_objects as objects
 
-SNAT_APP_NAME = 'chassis_snat_app.ChassisSNATApp'
+SNAT_APP_NAME = 'chassis_snat'
 
 
 class TestSnatFlows(test_base.DFTestBase):

dragonflow/tests/unit/test_chassis_snat_app.py

@@ -21,7 +21,7 @@ from dragonflow.tests.unit import test_app_base
 
 
 class TestChassisSNATApp(test_app_base.DFAppTestBase):
-    apps_list = "chassis_snat_app.ChassisSNATApp"
+    apps_list = "chassis_snat"
     external_host_ip = '172.24.4.100'
 
     def setUp(self):

dragonflow/tests/unit/test_classifier_app.py

@@ -22,7 +22,7 @@ make_fake_local_port = test_app_base.make_fake_local_port
 
 
 class TestClassifierApp(test_app_base.DFAppTestBase):
-    apps_list = "classifier_app.ClassifierApp"
+    apps_list = "classifier"
 
     def setUp(self):
         super(TestClassifierApp, self).setUp()

dragonflow/tests/unit/test_df_local_controller.py

@@ -36,7 +36,7 @@ class _ModelNoEvents(model_framework.ModelBase, mixins.Version):
 
 class DfLocalControllerTestCase(test_app_base.DFAppTestBase):
 
-    apps_list = "l2_app.L2App"
+    apps_list = "l2"
 
     @mock.patch.object(ryu_base_app.RyuDFAdapter, 'notify_ovs_sync_finished')
     def test_ovs_sync_finished(self, mock_notify):

dragonflow/tests/unit/test_dhcp_app.py

@@ -32,7 +32,7 @@ class Option(object):
 
 
 class TestDHCPApp(test_app_base.DFAppTestBase):
-    apps_list = "dhcp_app.DHCPApp"
+    apps_list = "dhcp"
 
     def setUp(self):
         super(TestDHCPApp, self).setUp()

dragonflow/tests/unit/test_dispatcher.py

@@ -30,7 +30,7 @@ class TestAppDispatcher(tests_base.BaseTestCase):
 
     def setUp(self):
         super(TestAppDispatcher, self).setUp()
-        self.dispatcher = dispatcher.AppDispatcher("", "")
+        self.dispatcher = dispatcher.AppDispatcher("")
 
     def test_dispatch_with_exception(self):
         fake_app = mock.MagicMock()

dragonflow/tests/unit/test_dnat_app.py

@@ -46,7 +46,7 @@ remote_lport.is_local = False
 
 
 class TestDNATApp(test_app_base.DFAppTestBase):
-    apps_list = "dnat_app.DNATApp"
+    apps_list = "dnat"
 
     def setUp(self):
         super(TestDNATApp, self).setUp(enable_selective_topo_dist=True)

dragonflow/tests/unit/test_l2_app.py

@@ -21,7 +21,7 @@ from dragonflow.tests.unit import test_app_base
 
 
 class TestL2App(test_app_base.DFAppTestBase):
-    apps_list = "l2_app.L2App"
+    apps_list = "l2"
 
     def setUp(self):
         super(TestL2App, self).setUp()

dragonflow/tests/unit/test_l3_app.py

@@ -23,7 +23,7 @@ from dragonflow.tests.unit import test_app_base
 
 class TestL3App(test_app_base.DFAppTestBase,
                 _test_l3.L3AppTestCaseMixin):
-    apps_list = "l3_app.L3App"
+    apps_list = "l3_reactive"
 
     def setUp(self):
         super(TestL3App, self).setUp()

dragonflow/tests/unit/test_l3_proactive_app.py

@@ -24,7 +24,7 @@ from dragonflow.tests.unit import test_app_base
 
 class TestL3ProactiveApp(test_app_base.DFAppTestBase,
                          _test_l3.L3AppTestCaseMixin):
-    apps_list = "l3_proactive_app.L3ProactiveApp"
+    apps_list = "l3_proactive"
 
     def setUp(self):
         super(TestL3ProactiveApp, self).setUp()

dragonflow/tests/unit/test_legacy_snat.py

@@ -20,7 +20,7 @@ from dragonflow.tests.unit import test_app_base
 
 
 class TestLegacySNatApp(test_app_base.DFAppTestBase):
-    apps_list = "legacy_snat_app.LegacySNatApp"
+    apps_list = "legacy_snat"
 
     def setUp(self):
         super(TestLegacySNatApp, self).setUp()

dragonflow/tests/unit/test_metadata_service_app.py

@@ -25,7 +25,7 @@ from dragonflow.tests.unit import test_app_base
 
 
 class TestMetadataServiceApp(test_app_base.DFAppTestBase):
-    apps_list = "metadata_service_app.MetadataServiceApp"
+    apps_list = "metadata_service"
 
     def setUp(self):
         super(TestMetadataServiceApp, self).setUp()

dragonflow/tests/unit/test_migration_app.py

@@ -18,7 +18,7 @@ from dragonflow.tests.unit import test_app_base
 
 
 class TestMigrationApp(test_app_base.DFAppTestBase):
-    apps_list = "migration_app.MigrationApp"
+    apps_list = "migration"
 
     def test_update_migration_flows(self):
         cfg.CONF.set_override('host', 'fake-local-host')

dragonflow/tests/unit/test_provider_net_app.py

@@ -23,7 +23,7 @@ make_fake_remote_port = test_app_base.make_fake_remote_port
 
 
 class TestProviderNetsApp(test_app_base.DFAppTestBase):
-    apps_list = "provider_networks_app.ProviderNetworksApp"
+    apps_list = "provider"
 
     def setUp(self):
         super(TestProviderNetsApp, self).setUp()

dragonflow/tests/unit/test_sg_app.py

@@ -27,7 +27,7 @@ COMMAND_DELETE = 2
 
 
 class TestSGApp(test_app_base.DFAppTestBase):
-    apps_list = "sg_app.SGApp"
+    apps_list = "sg"
 
     def setUp(self):
         super(TestSGApp, self).setUp()

dragonflow/tests/unit/test_topology.py

@@ -50,7 +50,7 @@ def nb_api_get_all_func(*instances):
 class TestTopology(test_app_base.DFAppTestBase):
     # This is to comply the current code, as the app_list can't be empty.
     # But we don't need any app in this test, acutally.
-    apps_list = "l2_app.L2App"
+    apps_list = "l2"
 
     def setUp(self):
         cfg.CONF.set_override('enable_selective_topology_distribution',

dragonflow/tests/unit/test_trunk_app.py

@@ -41,7 +41,7 @@ class SettingMock(object):
 
 
 class TestTrunkApp(test_app_base.DFAppTestBase):
-    apps_list = "trunk_app.TrunkApp"
+    apps_list = "trunk"
 
     def setUp(self):
         super(TestTrunkApp, self).setUp()

dragonflow/tests/unit/test_tunneling_app.py

@@ -23,7 +23,7 @@ make_fake_remote_port = test_app_base.make_fake_remote_port
 
 
 class TestTunnelingApp(test_app_base.DFAppTestBase):
-    apps_list = "tunneling_app.TunnelingApp"
+    apps_list = "tunneling"
 
     def setUp(self):
         super(TestTunnelingApp, self).setUp()

setup.cfg

@@ -75,3 +75,22 @@ neutron.service_plugins =
     df-bgp = dragonflow.neutron.services.bgp.bgp_plugin:DFBgpPlugin
 oslo.config.opts =
     dragonflow.conf = dragonflow.conf.opts:list_opts
+dragonflow.controller.apps =
+    active_port_detection = dragonflow.controller.active_port_detection_app:ActivePortDetectionApp
+    aging = dragonflow.controller.aging_app:Aging
+    chassis_snat = dragonflow.controller.chassis_snat_app:ChassisSNATApp
+    classifier = dragonflow.controller.classifier_app:ClassifierApp
+    dhcp = dragonflow.controller.dhcp_app:DHCPApp
+    dnat = dragonflow.controller.dnat_app:DNATApp
+    l2 = dragonflow.controller.l2_app:L2App
+    legacy_snat = dragonflow.controller.legacy_snat_app:LegacySNatApp
+    l3_proactive = dragonflow.controller.l3_proactive_app:L3ProactiveApp
+    l3_reactive = dragonflow.controller.l3_app:L3App
+    metadata_service = dragonflow.controller.metadata_service_app:MetadataServiceApp
+    migration = dragonflow.controller.migration_app:MigrationApp
+    portqos = dragonflow.controller.portqos_app:PortQosApp
+    portsec = dragonflow.controller.portsec_app:PortSecApp
+    provider = dragonflow.controller.provider_networks_app:ProviderNetworksApp
+    sg = dragonflow.controller.sg_app:SGApp
+    trunk = dragonflow.controller.trunk_app:TrunkApp
+    tunneling = dragonflow.controller.tunneling_app:TunnelingApp