# Copyright 2016 Amazon.com, Inc. or its affiliates. All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"). You
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# may not use this file except in compliance with the License. A copy of
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# the License is located at
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#
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# http://aws.amazon.com/apache2.0/
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#
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# or in the "license" file accompanying this file. This file is
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# distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF
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# ANY KIND, either express or implied. See the License for the specific
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# language governing permissions and limitations under the License.
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from botocore.compat import six
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from s3transfer.compat import accepts_kwargs
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from s3transfer.exceptions import InvalidSubscriberMethodError
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class BaseSubscriber(object):
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"""The base subscriber class
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It is recommended that all subscriber implementations subclass and then
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override the subscription methods (i.e. on_{subsribe_type}() methods).
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"""
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VALID_SUBSCRIBER_TYPES = [
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'queued',
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'progress',
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'done'
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]
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def __new__(cls, *args, **kwargs):
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cls._validate_subscriber_methods()
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return super(BaseSubscriber, cls).__new__(cls)
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@classmethod
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def _validate_subscriber_methods(cls):
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for subscriber_type in cls.VALID_SUBSCRIBER_TYPES:
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subscriber_method = getattr(cls, 'on_' + subscriber_type)
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if not six.callable(subscriber_method):
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raise InvalidSubscriberMethodError(
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'Subscriber method %s must be callable.' %
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subscriber_method)
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if not accepts_kwargs(subscriber_method):
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raise InvalidSubscriberMethodError(
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'Subscriber method %s must accept keyword '
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'arguments (**kwargs)' % subscriber_method)
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def on_queued(self, future, **kwargs):
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"""Callback to be invoked when transfer request gets queued
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This callback can be useful for:
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* Keeping track of how many transfers have been requested
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* Providing the expected transfer size through
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future.meta.provide_transfer_size() so a HeadObject would not
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need to be made for copies and downloads.
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:type future: s3transfer.futures.TransferFuture
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:param future: The TransferFuture representing the requested transfer.
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"""
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pass
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def on_progress(self, future, bytes_transferred, **kwargs):
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"""Callback to be invoked when progress is made on transfer
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This callback can be useful for:
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* Recording and displaying progress
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:type future: s3transfer.futures.TransferFuture
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:param future: The TransferFuture representing the requested transfer.
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:type bytes_transferred: int
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:param bytes_transferred: The number of bytes transferred for that
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invocation of the callback. Note that a negative amount can be
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provided, which usually indicates that an in-progress request
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needed to be retried and thus progress was rewound.
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"""
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pass
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def on_done(self, future, **kwargs):
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"""Callback to be invoked once a transfer is done
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This callback can be useful for:
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* Recording and displaying whether the transfer succeeded or
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failed using future.result()
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* Running some task after the transfer completed like changing
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the last modified time of a downloaded file.
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:type future: s3transfer.futures.TransferFuture
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:param future: The TransferFuture representing the requested transfer.
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"""
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pass
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