From 28a43c00327abc29f66688ff1cfa84c46d7d0e0a Mon Sep 17 00:00:00 2001 From: Adam Israel Date: Mon, 23 Apr 2018 16:04:54 -0400 Subject: [PATCH] Improve event monitoring/callbacks Improve the way we monitor changes within the Juju model, by maintaining a single observer with an Application filter. This reduces the number of duplicate callbacks being fired, and decreases the chatter between the controller and client. Signed-off-by: Adam Israel --- n2vc/vnf.py | 77 ++++++++++++++++++++++++++++++++++++++--------------- 1 file changed, 56 insertions(+), 21 deletions(-) diff --git a/n2vc/vnf.py b/n2vc/vnf.py index 7244b22..a457cec 100644 --- a/n2vc/vnf.py +++ b/n2vc/vnf.py @@ -48,40 +48,64 @@ logging.getLogger('juju.machine').setLevel(logging.WARN) class VCAMonitor(ModelObserver): """Monitor state changes within the Juju Model.""" - callback = None - callback_args = None log = None ns_name = None - application_name = None + applications = {} - def __init__(self, ns_name, application_name, callback, *args): + def __init__(self, ns_name): self.log = logging.getLogger(__name__) self.ns_name = ns_name - self.application_name = application_name - self.callback = callback - self.callback_args = args + + def AddApplication(self, application_name, callback, *callback_args): + if application_name not in self.applications: + self.applications[application_name] = { + 'callback': callback, + 'callback_args': callback_args + } + + def RemoveApplication(self, application_name): + if application_name in self.applications: + del self.applications[application_name] async def on_change(self, delta, old, new, model): """React to changes in the Juju model.""" if delta.entity == "unit": + # Ignore change events from other applications + if delta.data['application'] not in self.applications.keys(): + return + try: + + application_name = delta.data['application'] + + callback = self.applications[application_name]['callback'] + callback_args = self.applications[application_name]['callback_args'] + if old and new: old_status = old.workload_status new_status = new.workload_status if old_status == new_status: - """The workload status may fluctuate around certain events, so wait until the status has stabilized before triggering the callback.""" - if self.callback: - self.callback( + if callback: + callback( self.ns_name, - self.application_name, + delta.data['application'], new_status, - *self.callback_args) + *callback_args) + + if old and not new: + # This is a charm being removed + if callback: + callback( + self.ns_name, + delta.data['application'], + "removed", + *callback_args) except Exception as e: self.log.debug("[1] notify_callback exception {}".format(e)) elif delta.entity == "action": @@ -273,13 +297,15 @@ class N2VC: if app: raise JujuApplicationExists("Can't deploy application \"{}\" to model \"{}\" because it already exists.".format(application_name, model)) - ############################################################ - # Create a monitor to watch for application status changes # - ############################################################ + ################################################################ + # Register this application with the model-level event monitor # + ################################################################ if callback: - self.log.debug("Setting monitor<->callback") - self.monitors[application_name] = VCAMonitor(model_name, application_name, callback, *callback_args) - model.add_observer(self.monitors[application_name]) + self.monitors[model_name].AddApplication( + application_name, + callback, + *callback_args + ) ######################################################## # Check for specific machine placement (native charms) # @@ -345,8 +371,6 @@ class N2VC: # This is applied when the Application is deployed pass else: - # TODO: We need to sort by seq, and queue the actions in order. - seq = primitive['seq'] primitives[seq] = { @@ -406,9 +430,16 @@ class N2VC: model = await self.get_model(model_name) app = await self.get_application(model, application_name) if app: - self.notify_callback(model_name, application_name, "removing", callback, *callback_args) + # Remove this application from event monitoring + self.monitors[model_name].RemoveApplication(application_name) + + # self.notify_callback(model_name, application_name, "removing", callback, *callback_args) + self.log.debug("Removing the application {}".format(application_name)) await app.remove() + + # Notify the callback that this charm has been removed. self.notify_callback(model_name, application_name, "removed", callback, *callback_args) + except Exception as e: print("Caught exception: {}".format(e)) self.log.debug(e) @@ -569,6 +600,10 @@ class N2VC: print("connecting to model {}".format(model_name)) self.models[model_name] = await self.controller.get_model(model_name) + # Create an observer for this model + self.monitors[model_name] = VCAMonitor(model_name) + self.models[model_name].add_observer(self.monitors[model_name]) + return self.models[model_name] async def login(self): -- 2.17.1