/
multiplexed_async_subscriber_client.py
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/
multiplexed_async_subscriber_client.py
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# Copyright 2020 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from typing import (
Union,
AsyncIterator,
Awaitable,
Callable,
Optional,
Set,
)
from google.cloud.pubsub_v1.subscriber.message import Message
from google.cloud.pubsublite.cloudpubsub.internal.single_subscriber import (
AsyncSubscriberFactory,
AsyncSingleSubscriber,
)
from google.cloud.pubsublite.cloudpubsub.subscriber_client_interface import (
AsyncSubscriberClientInterface,
)
from google.cloud.pubsublite.types import (
SubscriptionPath,
FlowControlSettings,
Partition,
)
from overrides import overrides
async def _iterate_subscriber(
subscriber: AsyncSingleSubscriber, on_failure: Callable[[], Awaitable[None]]
) -> AsyncIterator[Message]:
try:
while True:
batch = await subscriber.read()
for message in batch:
yield message
except: # noqa: E722
await on_failure()
raise
class MultiplexedAsyncSubscriberClient(AsyncSubscriberClientInterface):
_underlying_factory: AsyncSubscriberFactory
_live_clients: Set[AsyncSingleSubscriber]
def __init__(self, underlying_factory: AsyncSubscriberFactory):
self._underlying_factory = underlying_factory
self._live_clients = set()
@overrides
async def subscribe(
self,
subscription: Union[SubscriptionPath, str],
per_partition_flow_control_settings: FlowControlSettings,
fixed_partitions: Optional[Set[Partition]] = None,
) -> AsyncIterator[Message]:
if isinstance(subscription, str):
subscription = SubscriptionPath.parse(subscription)
subscriber = self._underlying_factory(
subscription, fixed_partitions, per_partition_flow_control_settings
)
await subscriber.__aenter__()
self._live_clients.add(subscriber)
return _iterate_subscriber(
subscriber, lambda: self._try_remove_client(subscriber)
)
@overrides
async def __aenter__(self):
return self
async def _try_remove_client(self, client: AsyncSingleSubscriber):
if client in self._live_clients:
self._live_clients.remove(client)
await client.__aexit__(None, None, None)
@overrides
async def __aexit__(self, exc_type, exc_value, traceback):
live_clients = self._live_clients
self._live_clients = set()
for client in live_clients:
await client.__aexit__(None, None, None)