def cfn_handler()

in source/utils/crhelper.py [0:0]

• 30 lines of code
• 10 McCabe index (conditional complexity)

def cfn_handler(event, context, create, update, delete, logger, init_failed):
    """This handler function calls stack creation, update or deletion
       based on request type and also sends status and response data
       from any of the stack operations back to cloudformation,
       as applicable.
    """
    logger.info("Lambda RequestId: %s CloudFormation RequestId: %s" %
                (context.aws_request_id, event['RequestId']))

    # Define an object to place any response information you would like to send
    # back to CloudFormation (these keys can then be used by Fn::GetAttr)
    response_data = {}

    # Define a physicalId for the resource, if the event is an update and the
    # returned phyiscalid changes, cloudformation will then issue a delete
    # against the old id
    physical_resource_id = None

    logger.debug("EVENT: " + str(event))
    # handle init failures
    if init_failed:
        send(event, context, "FAILED", response_data, physical_resource_id,
             logger, reason="Initialization Failed")
        raise Exception("Initialization Failed")

    # Setup timer to catch timeouts
    t = threading.Timer((context.get_remaining_time_in_millis()/1000.00)-0.5,
                        timeout, args=[event, context, logger])
    t.start()

    try:
        # Execute custom resource handlers
        logger.info("Received a %s Request" % event['RequestType'])
        if event['RequestType'] == 'Create':
            physical_resource_id, response_data = create(event, context)
        elif event['RequestType'] == 'Update':
            physical_resource_id, response_data = update(event, context)
        elif event['RequestType'] == 'Delete':
            delete(event, context)

        # Send response back to CloudFormation
        logger.info("Completed successfully, sending response to cfn")
        send(event, context, "SUCCESS", response_data, physical_resource_id,
             logger=logger)

    # Catch any exceptions, log the stacktrace, send a failure back to
    # CloudFormation and then raise an exception
    except Exception as e:
        logger.error(e, exc_info=True)
        send(event, context, "FAILED", response_data, physical_resource_id,
             reason=e, logger=logger)
    finally:
        t.cancel()