Force heartbeat immediately after async command completes

This change passes the agent object into extensions, such that
they may call agent methods as needed. It also causes async
commands to force a heartbeat immediately after completing the
command. This allows Ironic to get a heartbeat and continue
work as quickly as possible, while also allowing deployers to
configure Ironic (agent) to heartbeat less often.

Change-Id: Ib3c3a43dfd0ed4ed51b7d52ac099f01181ca822f

ironic_python_agent/agent.py

@@ -121,6 +121,9 @@ class IronicPythonAgentHeartbeater(threading.Thread):
             self.error_delay = min(self.error_delay * self.backoff_factor,
                                    self.max_delay)
 
+    def force_heartbeat(self):
+        os.write(self.writer, 'b')
+
     def stop(self):
         """Stop the heartbeat thread."""
         if self.writer is not None:
@@ -140,6 +143,7 @@ class IronicPythonAgent(base.ExecuteCommandMixin):
             namespace='ironic_python_agent.extensions',
             invoke_on_load=True,
             propagate_map_exceptions=True,
+            invoke_kwds={'agent': self},
         )
         self.api_url = api_url
         self.driver_name = driver_name
@@ -262,6 +266,9 @@ class IronicPythonAgent(base.ExecuteCommandMixin):
             raise errors.RequestedObjectNotFoundError('Command Result',
                                                       result_id)
 
+    def force_heartbeat(self):
+        self.heartbeater.force_heartbeat()
+
     def run(self):
         """Run the Ironic Python Agent."""
         # Get the UUID so we can heartbeat to Ironic. Raises LookupNodeError

ironic_python_agent/extensions/base.py

@@ -67,8 +67,10 @@ class AsyncCommandResult(BaseCommandResult):
 
     :param execute_method: a callable to be executed asynchronously
     """
-    def __init__(self, command_name, command_params, execute_method):
+    def __init__(self, command_name, command_params, execute_method,
+                 agent=None):
         super(AsyncCommandResult, self).__init__(command_name, command_params)
+        self.agent = agent
         self.execute_method = execute_method
         self.command_state_lock = threading.Lock()
 
@@ -98,7 +100,6 @@ class AsyncCommandResult(BaseCommandResult):
             with self.command_state_lock:
                 self.command_result = result
                 self.command_status = AgentCommandStatus.SUCCEEDED
-
         except Exception as e:
             if not isinstance(e, errors.RESTError):
                 e = errors.CommandExecutionError(str(e))
@@ -106,11 +107,15 @@ class AsyncCommandResult(BaseCommandResult):
             with self.command_state_lock:
                 self.command_error = e
                 self.command_status = AgentCommandStatus.FAILED
+        finally:
+            if self.agent:
+                self.agent.force_heartbeat()
 
 
 class BaseAgentExtension(object):
-    def __init__(self):
+    def __init__(self, agent=None):
         super(BaseAgentExtension, self).__init__()
+        self.agent = agent
         self.log = log.getLogger(__name__)
         self.command_map = dict(
             (v.command_name, v)
@@ -207,7 +212,8 @@ def async_command(command_name, validator=None):
 
             return AsyncCommandResult(command_name,
                                       command_params,
-                                      bound_func).start()
+                                      bound_func,
+                                      agent=self.agent).start()
         return wrapper
     return async_decorator
 

ironic_python_agent/extensions/standby.py

@@ -172,8 +172,8 @@ def _validate_image_info(ext, image_info=None, **kwargs):
 
 
 class StandbyExtension(base.BaseAgentExtension):
-    def __init__(self):
+    def __init__(self, agent=None):
-        super(StandbyExtension, self).__init__()
+        super(StandbyExtension, self).__init__(agent=agent)
 
         self.cached_image_id = None
 

ironic_python_agent/tests/agent.py

@@ -49,8 +49,7 @@ def foo_execute(*args, **kwargs):
 
 
 class FakeExtension(base.BaseAgentExtension):
-    def __init__(self):
+    pass
-        super(FakeExtension, self).__init__()
 
 
 class TestHeartbeater(test_base.BaseTestCase):

ironic_python_agent/tests/extensions/base.py

@@ -120,7 +120,9 @@ class TestExecuteCommandMixin(test_base.BaseTestCase):
 class TestExtensionDecorators(test_base.BaseTestCase):
     def setUp(self):
         super(TestExtensionDecorators, self).setUp()
-        self.extension = FakeExtension()
+        self.agent = FakeAgent()
+        self.agent.force_heartbeat = mock.Mock()
+        self.extension = FakeExtension(agent=self.agent)
 
     def test_async_command_success(self):
         result = self.extension.execute('fake_async_command', param='v1')
@@ -132,12 +134,27 @@ class TestExtensionDecorators(test_base.BaseTestCase):
                          result.command_status)
         self.assertEqual(None, result.command_error)
         self.assertEqual('v1', result.command_result)
+        self.agent.force_heartbeat.assert_called_once_with()
+
+    def test_async_command_success_without_agent(self):
+        extension = FakeExtension(agent=None)
+        result = extension.execute('fake_async_command', param='v1')
+        self.assertIsInstance(result, base.AsyncCommandResult)
+        result.join()
+        self.assertEqual('fake_async_command', result.command_name)
+        self.assertEqual({'param': 'v1'}, result.command_params)
+        self.assertEqual(base.AgentCommandStatus.SUCCEEDED,
+                         result.command_status)
+        self.assertEqual(None, result.command_error)
+        self.assertEqual('v1', result.command_result)
 
     def test_async_command_validation_failure(self):
         self.assertRaises(errors.InvalidCommandParamsError,
                           self.extension.execute,
                           'fake_async_command',
                           is_valid=False)
+        # validation is synchronous, no need to force a heartbeat
+        self.assertEqual(0, self.agent.force_heartbeat.call_count)
 
     def test_async_command_execution_failure(self):
         result = self.extension.execute('fake_async_command', param='v2')
@@ -149,6 +166,7 @@ class TestExtensionDecorators(test_base.BaseTestCase):
                          result.command_status)
         self.assertIsInstance(result.command_error, ExecutionError)
         self.assertEqual(None, result.command_result)
+        self.agent.force_heartbeat.assert_called_once_with()
 
     def test_async_command_name(self):
         self.assertEqual(
@@ -164,18 +182,24 @@ class TestExtensionDecorators(test_base.BaseTestCase):
                          result.command_status)
         self.assertEqual(None, result.command_error)
         self.assertEqual('v1', result.command_result)
+        # no need to force heartbeat on a sync command
+        self.assertEqual(0, self.agent.force_heartbeat.call_count)
 
     def test_sync_command_validation_failure(self):
         self.assertRaises(errors.InvalidCommandParamsError,
                           self.extension.execute,
                           'fake_sync_command',
                           is_valid=False)
+        # validation is synchronous, no need to force a heartbeat
+        self.assertEqual(0, self.agent.force_heartbeat.call_count)
 
     def test_sync_command_execution_failure(self):
         self.assertRaises(ExecutionError,
                           self.extension.execute,
                           'fake_sync_command',
                           param='v2')
+        # no need to force heartbeat on a sync command
+        self.assertEqual(0, self.agent.force_heartbeat.call_count)
 
     def test_sync_command_name(self):
         self.assertEqual(