Flow extension uses extension manager from agent

Removed creating separate extension manager for flow extension.
Instead, have made flow extension using the same extension manager
instance which is initialized in agent. It fixes circular
extension loading in stevedore.

Closes-Bug: #1316145
Change-Id: Id339f1876168a41ca43ba7473f3ff6949a233ef3

ironic_python_agent/agent.py

@@ -102,6 +102,11 @@ class IronicPythonAgent(base.ExecuteCommandMixin):
     def __init__(self, api_url, advertise_address, listen_address,
                  lookup_timeout, lookup_interval, driver_name):
         super(IronicPythonAgent, self).__init__()
+        self.ext_mgr = extension.ExtensionManager(
+            namespace='ironic_python_agent.extensions',
+            invoke_on_load=True,
+            propagate_map_exceptions=True,
+        )
         self.api_url = api_url
         self.driver_name = driver_name
         self.api_client = ironic_api_client.APIClient(self.api_url,
@@ -121,13 +126,6 @@ class IronicPythonAgent(base.ExecuteCommandMixin):
         self.lookup_timeout = lookup_timeout
         self.lookup_interval = lookup_interval
 
-    def get_extension_manager(self):
-        return extension.ExtensionManager(
-            namespace='ironic_python_agent.extensions',
-            invoke_on_load=True,
-            propagate_map_exceptions=True,
-        )
-
     def get_status(self):
         """Retrieve a serializable status."""
         return IronicPythonAgentStatus(

ironic_python_agent/errors.py

@@ -182,3 +182,7 @@ class SystemRebootError(RESTError):
         super(SystemRebootError, self).__init__()
         self.details = 'Reboot script failed with exit code {0}.'
         self.details = self.details.format(exit_code)
+
+
+class ExtensionError(Exception):
+    pass

ironic_python_agent/extensions/base.py

@@ -131,11 +131,14 @@ class ExecuteCommandMixin(object):
     def __init__(self):
         self.command_lock = threading.Lock()
         self.command_results = utils.get_ordereddict()
-        self.ext_mgr = self.get_extension_manager()
+        self.ext_mgr = None
 
-    def get_extension_manager(self):
-        raise NotImplementedError(
-            'get_extension_manager should be implemented in successor class')
+    def get_extension(self, extension_name):
+        if self.ext_mgr is None:
+            raise errors.ExtensionError('Extension manager is not initialized')
+        ext = self.ext_mgr[extension_name].obj
+        ext.ext_mgr = self.ext_mgr
+        return ext
 
     def split_command(self, command_name):
         command_parts = command_name.split('.', 1)
@@ -156,7 +159,7 @@ class ExecuteCommandMixin(object):
                     raise errors.CommandExecutionError('agent is busy')
 
             try:
-                ext = self.ext_mgr[extension_part].obj
+                ext = self.get_extension(extension_part)
                 result = ext.execute(command_part, **kwargs)
             except KeyError:
                 # Extension Not found

ironic_python_agent/extensions/flow.py

@@ -12,8 +12,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from stevedore import enabled
-
 from ironic_python_agent import errors
 from ironic_python_agent.extensions import base
 from ironic_python_agent.openstack.common import log
@@ -21,11 +19,6 @@ from ironic_python_agent.openstack.common import log
 LOG = log.getLogger(__name__)
 
 
-def _load_extension(ext):
-    disabled_extension_list = ['flow']
-    return ext.name not in disabled_extension_list
-
-
 def _validate_exts(ext, flow=None):
     for task in flow:
         for method in task:
@@ -42,14 +35,6 @@ class FlowExtension(base.BaseAgentExtension, base.ExecuteCommandMixin):
         super(FlowExtension, self).__init__()
         self.command_map['start_flow'] = self.start_flow
 
-    def get_extension_manager(self):
-        return enabled.EnabledExtensionManager(
-            'ironic_python_agent.extensions',
-            _load_extension,
-            invoke_on_load=True,
-            propagate_map_exceptions=True,
-        )
-
     @base.async_command(_validate_exts)
     def start_flow(self, flow=None):
         for task in flow:

ironic_python_agent/tests/agent.py

@@ -125,15 +125,10 @@ class TestHeartbeater(test_base.BaseTestCase):
 
 class TestBaseAgent(test_base.BaseTestCase):
 
-    @mock.patch.object(agent.IronicPythonAgent, 'get_extension_manager')
-    def setUp(self, fake_ext_mgr):
+    def setUp(self):
         super(TestBaseAgent, self).setUp()
         self.encoder = encoding.RESTJSONEncoder(indent=4)
 
-        fake_ext_mgr.return_value = extension.ExtensionManager.\
-            make_test_instance([extension.Extension('fake', None,
-                                                    FakeExtension,
-                                                    FakeExtension())])
         self.agent = agent.IronicPythonAgent('https://fake_api.example.'
                                              'org:8081/',
                                              ('203.0.113.1', 9990),
@@ -141,6 +136,10 @@ class TestBaseAgent(test_base.BaseTestCase):
                                              300,
                                              1,
                                              'agent_ipmitool')
+        self.agent.ext_mgr = extension.ExtensionManager.\
+            make_test_instance([extension.Extension('fake', None,
+                                                    FakeExtension,
+                                                    FakeExtension())])
 
     def assertEqualEncoded(self, a, b):
         # Evidently JSONEncoder.default() can't handle None (??) so we have to

ironic_python_agent/tests/extensions/base.py

@@ -52,9 +52,7 @@ class FakeExtension(base.BaseAgentExtension):
 class FakeAgent(base.ExecuteCommandMixin):
     def __init__(self):
         super(FakeAgent, self).__init__()
-
-    def get_extension_manager(self):
-        return extension.ExtensionManager.make_test_instance(
+        self.ext_mgr = extension.ExtensionManager.make_test_instance(
             [extension.Extension('fake', None, FakeExtension,
                                  FakeExtension())])
 
@@ -88,7 +86,7 @@ class TestExecuteCommandMixin(test_base.BaseTestCase):
 
     def test_execute_command_success(self):
         expected_result = base.SyncCommandResult('fake', None, True, None)
-        fake_ext = self.agent.ext_mgr['fake'].obj
+        fake_ext = self.agent.get_extension('fake')
         fake_ext.execute = mock.Mock()
         fake_ext.execute.return_value = expected_result
         result = self.agent.execute_command('fake.sleep',