def handler()

in packages/@aws-cdk/custom-resource-handlers/lib/aws-s3-deployment/bucket-deployment-handler/index.py [0:0]
82 lines of code
40 McCabe index (conditional complexity)

def handler(event, context):

    def cfn_error(message=None):
        if message:
            logger.error("| cfn_error: %s" % message.encode())
        cfn_send(event, context, CFN_FAILED, reason=message, physicalResourceId=event.get('PhysicalResourceId', None))


    try:
        # We are not logging ResponseURL as this is a pre-signed S3 URL, and could be used to tamper
        # with the response CloudFormation sees from this Custom Resource execution.
        logger.info({ key:value for (key, value) in event.items() if key != 'ResponseURL'})

        # cloudformation request type (create/update/delete)
        request_type = event['RequestType']

        # extract resource properties
        props = event['ResourceProperties']
        old_props = event.get('OldResourceProperties', {})
        physical_id = event.get('PhysicalResourceId', None)

        try:
            source_bucket_names = props['SourceBucketNames']
            source_object_keys  = props['SourceObjectKeys']
            source_markers      = props.get('SourceMarkers', None)
            source_markers_config = props.get('SourceMarkersConfig', None)
            dest_bucket_name    = props['DestinationBucketName']
            dest_bucket_prefix  = props.get('DestinationBucketKeyPrefix', '')
            extract             = props.get('Extract', 'true') == 'true'
            retain_on_delete    = props.get('RetainOnDelete', "true") == "true"
            distribution_id     = props.get('DistributionId', '')
            user_metadata       = props.get('UserMetadata', {})
            system_metadata     = props.get('SystemMetadata', {})
            prune               = props.get('Prune', 'true').lower() == 'true'
            exclude             = props.get('Exclude', [])
            include             = props.get('Include', [])
            sign_content        = props.get('SignContent', 'false').lower() == 'true'
            output_object_keys  = props.get('OutputObjectKeys', 'true') == 'true'

            # backwards compatibility - if "SourceMarkers" is not specified,
            # assume all sources have an empty market map
            if source_markers is None:
                source_markers = [{} for i in range(len(source_bucket_names))]
            if source_markers_config is None:
                source_markers_config = [{} for i in range(len(source_bucket_names))]

            default_distribution_path = dest_bucket_prefix
            if not default_distribution_path.endswith("/"):
                default_distribution_path += "/"
            if not default_distribution_path.startswith("/"):
                default_distribution_path = "/" + default_distribution_path
            default_distribution_path += "*"

            distribution_paths = props.get('DistributionPaths', [default_distribution_path])
        except KeyError as e:
            cfn_error("missing request resource property %s. props: %s" % (str(e), props))
            return

        # configure aws cli options after resetting back to the defaults for each request
        if os.path.exists(AWS_CLI_CONFIG_FILE):
                os.remove(AWS_CLI_CONFIG_FILE)
        if sign_content:
                aws_command("configure", "set", "default.s3.payload_signing_enabled", "true")

        # treat "/" as if no prefix was specified
        if dest_bucket_prefix == "/":
            dest_bucket_prefix = ""

        s3_source_zips = list(map(lambda name, key: "s3://%s/%s" % (name, key), source_bucket_names, source_object_keys))
        s3_dest = "s3://%s/%s" % (dest_bucket_name, dest_bucket_prefix)
        old_s3_dest = "s3://%s/%s" % (old_props.get("DestinationBucketName", ""), old_props.get("DestinationBucketKeyPrefix", ""))


        # obviously this is not
        if old_s3_dest == "s3:///":
            old_s3_dest = None

        logger.info("| s3_dest: %s" % sanitize_message(s3_dest))
        logger.info("| old_s3_dest: %s" % sanitize_message(old_s3_dest))

        # if we are creating a new resource, allocate a physical id for it
        # otherwise, we expect physical id to be relayed by cloudformation
        if request_type == "Create":
            physical_id = "aws.cdk.s3deployment.%s" % str(uuid4())
        else:
            if not physical_id:
                cfn_error("invalid request: request type is '%s' but 'PhysicalResourceId' is not defined" % request_type)
                return

        # delete or create/update (only if "retain_on_delete" is false)
        if request_type == "Delete" and not retain_on_delete:
            if not bucket_owned(dest_bucket_name, dest_bucket_prefix):
                aws_command("s3", "rm", s3_dest, "--recursive")

        # if we are updating without retention and the destination changed, delete first
        if request_type == "Update" and not retain_on_delete and old_s3_dest != s3_dest:
            if not old_s3_dest:
                logger.warn("cannot delete old resource without old resource properties")
                return

            aws_command("s3", "rm", old_s3_dest, "--recursive")

        if request_type == "Update" or request_type == "Create":
            s3_deploy(s3_source_zips, s3_dest, user_metadata, system_metadata, prune, exclude, include, source_markers, extract, source_markers_config)

        if distribution_id:
            cloudfront_invalidate(distribution_id, distribution_paths)

        cfn_send(event, context, CFN_SUCCESS, physicalResourceId=physical_id, responseData={
            # Passing through the ARN sequences dependencees on the deployment
            'DestinationBucketArn': props.get('DestinationBucketArn'),
            **({'SourceObjectKeys': props.get('SourceObjectKeys')} if output_object_keys else {'SourceObjectKeys': []})
        })
    except KeyError as e:
        cfn_error("invalid request. Missing key %s" % str(e))
    except Exception as e:
        logger.exception(e)
        cfn_error(str(e))