mirror of
https://github.com/matrix-org/synapse-s3-storage-provider.git
synced 2024-10-23 07:29:40 +00:00
280 lines
8.8 KiB
Python
280 lines
8.8 KiB
Python
# -*- coding: utf-8 -*-
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# Copyright 2018 New Vector Ltd
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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from twisted.internet import defer, reactor
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from twisted.python.failure import Failure
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from synapse.rest.media.v1.storage_provider import StorageProvider
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from synapse.rest.media.v1._base import Responder
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from synapse.util.logcontext import make_deferred_yieldable
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import boto3
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import botocore
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import logging
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import threading
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import os
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logger = logging.getLogger("synapse.s3")
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# The list of valid AWS storage class names
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_VALID_STORAGE_CLASSES = ('STANDARD', 'REDUCED_REDUNDANCY', 'STANDARD_IA')
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# Chunk size to use when reading from s3 connection in bytes
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READ_CHUNK_SIZE = 16 * 1024
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class S3StorageProviderBackend(StorageProvider):
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"""
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Args:
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hs (HomeServer)
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config: The config returned by `parse_config`
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"""
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def __init__(self, hs, config):
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self.cache_directory = hs.config.media_store_path
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self.bucket = config["bucket"]
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self.storage_class = config["storage_class"]
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def store_file(self, path, file_info):
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"""See StorageProvider.store_file"""
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def _store_file():
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boto3.resource('s3').Bucket(self.bucket).upload_file(
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Filename=os.path.join(self.cache_directory, path),
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Key=path,
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ExtraArgs={"StorageClass": self.storage_class},
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)
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return make_deferred_yieldable(
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reactor.callInThread(_store_file)
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)
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def fetch(self, path, file_info):
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"""See StorageProvider.fetch"""
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d = defer.Deferred()
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_S3DownloadThread(self.bucket, path, d).start()
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return make_deferred_yieldable(d)
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@staticmethod
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def parse_config(config):
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"""Called on startup to parse config supplied. This should parse
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the config and raise if there is a problem.
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The returned value is passed into the constructor.
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In this case we return a dict with fields, `bucket` and `storage_class`
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"""
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bucket = config["bucket"]
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storage_class = config.get("storage_class", "STANDARD")
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assert isinstance(bucket, basestring)
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assert storage_class in _VALID_STORAGE_CLASSES
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return {
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"bucket": bucket,
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"storage_class": storage_class,
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}
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class _S3DownloadThread(threading.Thread):
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"""Attempts to download a file from S3.
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Args:
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bucket (str): The S3 bucket which may have the file
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key (str): The key of the file
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deferred (Deferred[_S3Responder|None]): If file exists
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resolved with an _S3Responder instance, if it doesn't
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exist then resolves with None.
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"""
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def __init__(self, bucket, key, deferred):
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super(_S3DownloadThread, self).__init__(name="s3-download")
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self.bucket = bucket
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self.key = key
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self.deferred = deferred
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def run(self):
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session = boto3.session.Session()
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s3 = session.client('s3')
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try:
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resp = s3.get_object(Bucket=self.bucket, Key=self.key)
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except botocore.exceptions.ClientError as e:
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if e.response['Error']['Code'] in ("404", "NoSuchKey",):
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reactor.callFromThread(self.deferred.callback, None)
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return
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reactor.callFromThread(self.deferred.errback, Failure())
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return
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producer = _S3Responder()
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reactor.callFromThread(self.deferred.callback, producer)
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_stream_to_producer(reactor, producer, resp["Body"], timeout=90.)
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def _stream_to_producer(reactor, producer, body, status=None, timeout=None):
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"""Streams a file like object to the producer.
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Correctly handles producer being paused/resumed/stopped.
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Args:
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reactor
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producer (_S3Responder): Producer object to stream results to
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body (file like): The object to read from
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status (_ProducerStatus|None): Used to track whether we're currently
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paused or not. Used for testing
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timeout (float|None): Timeout in seconds to wait for consume to resume
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after being paused
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"""
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# Set when we should be producing, cleared when we are paused
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wakeup_event = producer.wakeup_event
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# Set if we should stop producing forever
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stop_event = producer.stop_event
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if not status:
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status = _ProducerStatus()
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try:
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while not stop_event.is_set():
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# We wait for the producer to signal that the consumer wants
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# more data (or we should abort)
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if not wakeup_event.is_set():
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status.set_paused(True)
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ret = wakeup_event.wait(timeout)
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if not ret:
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raise Exception("Timed out waiting to resume")
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status.set_paused(False)
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# Check if we were woken up so that we abort the download
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if stop_event.is_set():
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return
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chunk = body.read(READ_CHUNK_SIZE)
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if not chunk:
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return
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reactor.callFromThread(producer._write, chunk)
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except Exception:
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reactor.callFromThread(producer._error, Failure())
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finally:
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reactor.callFromThread(producer._finish)
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if body:
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body.close()
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class _S3Responder(Responder):
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"""A Responder for S3. Created by _S3DownloadThread
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"""
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def __init__(self):
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# Triggered by responder when more data has been requested (or
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# stop_event has been triggered)
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self.wakeup_event = threading.Event()
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# Trigered by responder when we should abort the download.
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self.stop_event = threading.Event()
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# The consumer we're registered to
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self.consumer = None
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# The deferred returned by write_to_consumer, which should resolve when
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# all the data has been written (or there has been a fatal error).
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self.deferred = defer.Deferred()
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def write_to_consumer(self, consumer):
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"""See Responder.write_to_consumer
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"""
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self.consumer = consumer
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# We are a IPushProducer, so we start producing immediately until we
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# get a pauseProducing or stopProducing
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consumer.registerProducer(self, True)
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self.wakeup_event.set()
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return self.deferred
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def __exit__(self, exc_type, exc_val, exc_tb):
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self.stop_event.set()
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self.wakeup_event.set()
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def resumeProducing(self):
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"""See IPushProducer.resumeProducing
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"""
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# The consumer is asking for more data, signal _S3DownloadThread
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self.wakeup_event.set()
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def pauseProducing(self):
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"""See IPushProducer.stopProducing
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"""
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self.wakeup_event.clear()
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def stopProducing(self):
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"""See IPushProducer.stopProducing
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"""
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# The consumer wants no more data ever, signal _S3DownloadThread
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self.stop_event.set()
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self.wakeup_event.set()
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if not self.deferred.called:
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self.deferred.errback(Exception("Consumer ask to stop producing"))
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def _write(self, chunk):
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"""Writes the chunk of data to consumer. Called by _S3DownloadThread.
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"""
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if self.consumer and not self.stop_event.is_set():
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self.consumer.write(chunk)
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def _error(self, failure):
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"""Called when a fatal error occured while getting data. Called by
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_S3DownloadThread.
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"""
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if self.consumer:
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self.consumer.unregisterProducer()
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self.consumer = None
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if not self.deferred.called:
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self.deferred.errback(failure)
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def _finish(self):
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"""Called when there is no more data to write. Called by _S3DownloadThread.
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"""
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if self.consumer:
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self.consumer.unregisterProducer()
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self.consumer = None
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if not self.deferred.called:
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self.deferred.callback(None)
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class _ProducerStatus(object):
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"""Used to track whether the s3 download thread is currently paused
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waiting for consumer to resume. Used for testing.
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"""
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def __init__(self):
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self.is_paused = threading.Event()
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self.is_paused.clear()
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def wait_until_paused(self, timeout=None):
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is_paused = self.is_paused.wait(timeout)
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if not is_paused:
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raise Exception("Timed out waiting")
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def set_paused(self, paused):
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if paused:
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self.is_paused.set()
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else:
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self.is_paused.clear()
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