ashb commented on a change in pull request #8701: URL: https://github.com/apache/airflow/pull/8701#discussion_r426578726
########## File path: airflow/providers/amazon/aws/hooks/elasticache.py ########## @@ -0,0 +1,259 @@ +# +# Licensed to the Apache Software Foundation (ASF) under one +# or more contributor license agreements. See the NOTICE file +# distributed with this work for additional information +# regarding copyright ownership. The ASF licenses this file +# to you under the Apache License, Version 2.0 (the +# "License"); you may not use this file except in compliance +# with the License. You may obtain a copy of the License at +# +# http://www.apache.org/licenses/LICENSE-2.0 +# +# Unless required by applicable law or agreed to in writing, +# software distributed under the License is distributed on an +# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +# KIND, either express or implied. See the License for the +# specific language governing permissions and limitations +# under the License. + +import re +from time import sleep + +from airflow.exceptions import AirflowException +from airflow.providers.amazon.aws.hooks.base_aws import AwsBaseHook + + +class ElastiCacheHook(AwsBaseHook): + """ + Interact with AWS ElastiCache + """ + + # Constants for ElastiCache describe API response keys + REPLICATION_GROUPS = 'ReplicationGroups' + REPLICATION_GROUP = 'ReplicationGroup' + STATUS = 'Status' + + # Constants for ElastiCache delete API response messages + RESPONSE_NOT_VALID_STATE = 'not in a valid state to be deleted' + RESPONSE_DELETING_STATE = 'has status deleting which is not valid for deletion' + RESPONSE_MODIFYING_STATE = 'has status modifying which is not valid for deletion' + + # Constants for ElastiCache replication group status + STATUS_CREATING = 'creating' + STATUS_AVAILABLE = 'available' + STATUS_DELETING = 'deleting' + STATUS_CREATE_FAILED = 'create-failed' + + def __init__( + self, max_retries=10, exponential_back_off_factor=1, initial_poke_interval=60, *args, **kwargs + ): + """ + :param max_retries: Max tries for checking availability of and deleting replication group + :param exponential_back_off_factor: Factor for deciding next sleep time + :param initial_poke_interval: Initial sleep time in seconds + """ + self.max_retries = max_retries + self.exponential_back_off_factor = exponential_back_off_factor + self.initial_poke_interval = initial_poke_interval + + super().__init__(client_type='elasticache', *args, **kwargs) + + def create_replication_group(self, config): + """ + Call ElastiCache API for creating a replication group + :param config: Python dictionary to use as config for creating replication group + :return: Response from ElastiCache create replication group API + """ + return self.conn.create_replication_group(**config) + + def delete_replication_group(self, replication_group_id): + """ + Call ElastiCache API for deleting a replication group + :param replication_group_id: ID of replication group to delete + :return: Response from ElastiCache delete replication group API + """ + return self.conn.delete_replication_group(ReplicationGroupId=replication_group_id) + + def describe_replication_group(self, replication_group_id): + """ + Call ElastiCache API for describing a replication group + :param replication_group_id: ID of replication group to describe + :return: Response from ElastiCache describe replication group API + """ + return self.conn.describe_replication_groups(ReplicationGroupId=replication_group_id) + + def get_replication_group_status(self, replication_group_id): + """ + Get current status of replication group + :param replication_group_id: ID of replication group to check for status + :return: Current status of replication group + """ + return self.describe_replication_group(replication_group_id)[self.REPLICATION_GROUPS][0][self.STATUS] + + def is_replication_group_available(self, replication_group_id): + """ + Helper for checking if replication is available or not + :param replication_group_id: ID of replication group to check for availability + :return: True if available else False + replication group + """ + return self.get_replication_group_status( + replication_group_id=replication_group_id + ) == self.STATUS_AVAILABLE + + def should_stop_poking(self, replication_group_id): + """ + Helper for checking if we should stop poking replication group for availability or not + :param replication_group_id: ID of replication group to check + :return: Flag to check if availability check should be stopped or not and current status of + replication group + """ + status = self.get_replication_group_status(replication_group_id=replication_group_id) + + return status in ( + self.STATUS_AVAILABLE, + self.STATUS_CREATE_FAILED, + self.STATUS_DELETING + ), status + + def wait_for_availability( + self, + replication_group_id, + initial_sleep_time=None, + exponential_back_off_factor=None, + max_retries=None + ): + """ + Check if replication is available or not by performing a describe over it + :param max_retries: Max tries for checking availability of replication group + :param exponential_back_off_factor: Factor for deciding next sleep time + :param initial_sleep_time: Initial sleep time in seconds + :param replication_group_id: ID of replication group to check for availability + :return: True if replication is available else False + """ + sleep_time = initial_sleep_time or self.initial_poke_interval + exponential_back_off_factor = exponential_back_off_factor or self.exponential_back_off_factor + max_retries = max_retries or self.max_retries + num_retries = 0 + status = self.STATUS_CREATE_FAILED + + while num_retries < max_retries: + stop_poking, status = self.should_stop_poking(replication_group_id=replication_group_id) + + self.log.info('Status : %s', status) + + if stop_poking: + self.log.info('Received signal to stop poking. Current status : "%s"', status) + break + + num_retries += 1 + + self.log.info('Poke retry: %s. Sleep time: %s. Sleeping...', num_retries, sleep_time) + + sleep(sleep_time) + + sleep_time = sleep_time * exponential_back_off_factor + + if status != self.STATUS_AVAILABLE: + self.log.warning('Replication group is not available. Current status : "%s"', status) + + return False + + return True + + def wait_for_deletion( + self, + replication_group_id, + initial_sleep_time=None, + exponential_back_off_factor=None, + max_retries=None + ): + """ + Helper for deleting a replication group ensuring it is either deleted or can't be deleted + :param replication_group_id: ID of replication to delete + :param max_retries: Max tries for checking availability of replication group + :param exponential_back_off_factor: Factor for deciding next sleep time + :param initial_sleep_time: Initial sleep time in second + :return: Response from ElastiCache delete replication group API and flag to identify if deleted or not + """ + response = None + deleted = False + sleep_time = initial_sleep_time or self.initial_poke_interval + exponential_back_off_factor = exponential_back_off_factor or self.exponential_back_off_factor + max_retries = max_retries or self.max_retries + num_retries = 0 + + while not deleted and num_retries < max_retries: + try: + response = self.delete_replication_group(replication_group_id=replication_group_id) + + self.log.info('Replication group with ID : %s : is being deleted...', replication_group_id) + + except self.conn.exceptions.ReplicationGroupNotFoundFault: + self.log.info("Replication group with ID : '%s' does not exist", replication_group_id) + + deleted = True + + except self.conn.exceptions.InvalidReplicationGroupStateFault as exp: + message = exp.response['Error']['Message'] + + self.log.info('Received message : %s', message) + + if re.search(self.RESPONSE_NOT_VALID_STATE, message) \ + or re.search(self.RESPONSE_MODIFYING_STATE, message): + + self.log.info( + 'Replication group with ID : %s : is not in valid state to be deleted', + replication_group_id + ) + + elif re.search(self.RESPONSE_DELETING_STATE, message): + self.log.info( Review comment: Wait, we try and delete it every time around the loop? That seems.... odd. Why not 1) issue delete request, 2) describe/sleep until it is eventually deleted. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected]
