codekingpro/portable-devtools

1# Copyright 2016 Amazon.com, Inc. or its affiliates. All Rights Reserved.2#3# Licensed under the Apache License, Version 2.0 (the "License"). You4# may not use this file except in compliance with the License. A copy of5# the License is located at6#7# http://aws.amazon.com/apache2.0/8#9# or in the "license" file accompanying this file. This file is10# distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF11# ANY KIND, either express or implied. See the License for the specific12# language governing permissions and limitations under the License.13from functools import lru_cache14 15from s3transfer.compat import accepts_kwargs16from s3transfer.exceptions import InvalidSubscriberMethodError17 18 19class BaseSubscriber:20    """The base subscriber class21 22    It is recommended that all subscriber implementations subclass and then23    override the subscription methods (i.e. on_{subsribe_type}() methods).24    """25 26    VALID_SUBSCRIBER_TYPES = ['queued', 'progress', 'done']27 28    def __new__(cls, *args, **kwargs):29        cls._validate_subscriber_methods()30        return super().__new__(cls)31 32    @classmethod33    @lru_cache()34    def _validate_subscriber_methods(cls):35        for subscriber_type in cls.VALID_SUBSCRIBER_TYPES:36            subscriber_method = getattr(cls, 'on_' + subscriber_type)37            if not callable(subscriber_method):38                raise InvalidSubscriberMethodError(39                    'Subscriber method %s must be callable.'40                    % subscriber_method41                )42 43            if not accepts_kwargs(subscriber_method):44                raise InvalidSubscriberMethodError(45                    'Subscriber method %s must accept keyword '46                    'arguments (**kwargs)' % subscriber_method47                )48 49    def on_queued(self, future, **kwargs):50        """Callback to be invoked when transfer request gets queued51 52        This callback can be useful for:53 54            * Keeping track of how many transfers have been requested55            * Providing the expected transfer size through56              future.meta.provide_transfer_size() so a HeadObject would not57              need to be made for copies and downloads.58 59        :type future: s3transfer.futures.TransferFuture60        :param future: The TransferFuture representing the requested transfer.61        """62        pass63 64    def on_progress(self, future, bytes_transferred, **kwargs):65        """Callback to be invoked when progress is made on transfer66 67        This callback can be useful for:68 69            * Recording and displaying progress70 71        :type future: s3transfer.futures.TransferFuture72        :param future: The TransferFuture representing the requested transfer.73 74        :type bytes_transferred: int75        :param bytes_transferred: The number of bytes transferred for that76            invocation of the callback. Note that a negative amount can be77            provided, which usually indicates that an in-progress request78            needed to be retried and thus progress was rewound.79        """80        pass81 82    def on_done(self, future, **kwargs):83        """Callback to be invoked once a transfer is done84 85        This callback can be useful for:86 87            * Recording and displaying whether the transfer succeeded or88              failed using future.result()89            * Running some task after the transfer completed like changing90              the last modified time of a downloaded file.91 92        :type future: s3transfer.futures.TransferFuture93        :param future: The TransferFuture representing the requested transfer.94        """95        pass96