def update()

in azurelinuxagent/common/protocol/goal_state.py [0:0]

• 54 lines of code
• 17 McCabe index (conditional complexity)

    def update(self, force_update=False, silent=False):
        """
        Updates the current GoalState instance fetching values from the WireServer/HostGAPlugin as needed
        """
        self.logger.silent = silent

        #
        # Fetch the goal state from both the HGAP and the WireServer
        #
        timestamp = datetime.datetime.utcnow()

        if force_update:
            message = "Refreshing goal state and vmSettings"
            self.logger.info(message)
            add_event(op=WALAEventOperation.GoalState, message=message)

        incarnation, xml_text, xml_doc = GoalState._fetch_goal_state(self._wire_client)
        goal_state_updated = force_update or incarnation != self._incarnation
        if goal_state_updated:
            message = 'Fetched a new incarnation for the WireServer goal state [incarnation {0}]'.format(incarnation)
            self.logger.info(message)
            add_event(op=WALAEventOperation.GoalState, message=message)

        vm_settings, vm_settings_updated = None, False
        if self._goal_state_properties & GoalStateProperties.ExtensionsGoalState:
            try:
                vm_settings, vm_settings_updated = GoalState._fetch_vm_settings(self._wire_client, force_update=force_update)
            except VmSettingsSupportStopped as exception:  # If the HGAP stopped supporting vmSettings, we need to use the goal state from the WireServer
                self._restore_wire_server_goal_state(incarnation, xml_text, xml_doc, exception)
                return

        if vm_settings_updated:
            self.logger.info('')
            message = "Fetched new vmSettings [HostGAPlugin correlation ID: {0} eTag: {1} source: {2}]".format(vm_settings.hostga_plugin_correlation_id, vm_settings.etag, vm_settings.source)
            self.logger.info(message)
            add_event(op=WALAEventOperation.GoalState, message=message)
        # Ignore the vmSettings if their source is Fabric (processing a Fabric goal state may require the tenant certificate and the vmSettings don't include it.)
        if vm_settings is not None and vm_settings.source == GoalStateSource.Fabric:
            if vm_settings_updated:
                message = "The vmSettings originated via Fabric; will ignore them."
                self.logger.info(message)
                add_event(op=WALAEventOperation.GoalState, message=message)
            vm_settings, vm_settings_updated = None, False

        # If neither goal state has changed we are done with the update
        if not goal_state_updated and not vm_settings_updated:
            return

        # Start a new history subdirectory and capture the updated goal state
        tag = "{0}".format(incarnation) if vm_settings is None else "{0}-{1}".format(incarnation, vm_settings.etag)
        if self._save_to_history:
            self._history = GoalStateHistory(timestamp, tag)
            if goal_state_updated:
                self._history.save_goal_state(xml_text)
            if vm_settings_updated:
                self._history.save_vm_settings(vm_settings.get_redacted_text())

        #
        # Continue fetching the rest of the goal state
        #
        extensions_config = None
        if goal_state_updated:
            extensions_config = self._fetch_full_wire_server_goal_state(incarnation, xml_doc)

        #
        # Lastly, decide whether to use the vmSettings or extensionsConfig for the extensions goal state
        #
        if goal_state_updated:
            # On rotation of the tenant certificate the vmSettings and extensionsConfig are not updated. However, the incarnation of the WS goal state is update so 'goal_state_updated' will be True.
            # In this case, we should use the most recent of vmSettigns and extensionsConfig.
            if vm_settings is not None:
                most_recent = vm_settings if vm_settings.created_on_timestamp > extensions_config.created_on_timestamp else extensions_config
            else:
                most_recent = extensions_config
        else:  # vm_settings_updated
            most_recent = vm_settings

        if self._extensions_goal_state is None or most_recent.created_on_timestamp >= self._extensions_goal_state.created_on_timestamp:
            self._extensions_goal_state = most_recent

        #
        # Ensure all certificates are downloaded on Fast Track goal states in order to maintain backwards compatibility with previous
        # versions of the Agent, which used to download certificates from the WireServer on every goal state. Some customer applications
        # depend on this behavior (see https://github.com/Azure/WALinuxAgent/issues/2750).
        #
        if self._extensions_goal_state.source == GoalStateSource.FastTrack and self._goal_state_properties & GoalStateProperties.Certificates:
            self._check_and_download_missing_certs_on_disk()