Store driver objects in a global dict

When security group support is added, device objects need to be shared
between the existing mechanism driver and also a service plugin. This
change invokes drivers and stores them in a single global DEVICES dict.

Change-Id: I5cd5880cded950cd5f3cfff6c77750f44e92618e
Related-Bug: #2110760

Author: steveb

networking_generic_switch/devices/__init__.py

@@ -15,10 +15,12 @@
 import abc
 
 from neutron_lib.utils.helpers import parse_mappings
+from oslo_concurrency import lockutils
 from oslo_log import log as logging
 from oslo_utils import strutils
 import stevedore
 
+from networking_generic_switch import config as gsw_conf
 from networking_generic_switch import exceptions as gsw_exc
 
 GENERIC_SWITCH_NAMESPACE = 'generic_switch.devices'
@@ -60,6 +62,20 @@
     {'name': 'ngs_allowed_ports'},
 ]
 
+EM_SEMAPHORE = 'ngs_device_manager'
+DEVICES = {}
+
+
+@lockutils.synchronized(EM_SEMAPHORE)
+def get_devices():
+    global DEVICES
+    gsw_devices = gsw_conf.get_devices()
+    for device_name, device_cfg in gsw_devices.items():
+        if device_name in DEVICES:
+            continue
+        DEVICES[device_name] = device_manager(device_cfg, device_name)
+    return DEVICES
+
 
 def device_manager(device_cfg, device_name=""):
     device_type = device_cfg.get('device_type', '')

networking_generic_switch/generic_switch_mech.py

@@ -22,7 +22,6 @@
 from neutron_lib.plugins.ml2 import api
 from oslo_log import log as logging
 
-from networking_generic_switch import config as gsw_conf
 from networking_generic_switch import devices
 from networking_generic_switch.devices import utils as device_utils
 from networking_generic_switch import exceptions as ngs_exc
@@ -51,11 +50,7 @@ def initialize(self):
         self.vif_details = {portbindings.VIF_DETAILS_CONNECTIVITY:
                             portbindings.CONNECTIVITY_L2}
 
-        gsw_devices = gsw_conf.get_devices()
-        self.switches = {}
-        for switch_info, device_cfg in gsw_devices.items():
-            switch = devices.device_manager(device_cfg, switch_info)
-            self.switches[switch_info] = switch
+        self.switches = devices.get_devices()
 
         LOG.info('Devices %s have been loaded', self.switches.keys())
         if not self.switches:

networking_generic_switch/tests/unit/test_generic_switch_mech.py

@@ -21,6 +21,7 @@
 from neutron_lib.callbacks import resources
 from neutron_lib.plugins import directory
 
+from networking_generic_switch import devices
 from networking_generic_switch.devices import utils as device_utils
 from networking_generic_switch import exceptions
 from networking_generic_switch import generic_switch_mech as gsm
@@ -32,6 +33,7 @@
 class TestGenericSwitchDriver(unittest.TestCase):
     def setUp(self):
         super(TestGenericSwitchDriver, self).setUp()
+        devices.DEVICES.clear()
         self.switch_mock = mock.Mock()
         self.switch_mock.config = {'device_type': 'bar', 'spam': 'ham',
                                    'ip': 'ip'}