-
Notifications
You must be signed in to change notification settings - Fork 12
/
single_subscriber.py
54 lines (42 loc) · 1.67 KB
/
single_subscriber.py
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
# 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 abc import abstractmethod, ABCMeta
from typing import AsyncContextManager, Callable, Set, Optional
from google.cloud.pubsub_v1.subscriber.message import Message
from google.cloud.pubsublite.types import (
SubscriptionPath,
FlowControlSettings,
Partition,
)
class AsyncSingleSubscriber(AsyncContextManager, metaclass=ABCMeta):
"""
A Cloud Pub/Sub asynchronous subscriber.
Must be used in an `async with` block or have __aenter__() awaited before use.
"""
@abstractmethod
async def read(self) -> Message:
"""
Read the next message off of the stream.
Returns:
The next message. ack() or nack() must eventually be called exactly once.
Pub/Sub Lite does not support nack() by default- if you do call nack(), it will immediately fail the client
unless you have a NackHandler installed.
Raises:
GoogleAPICallError: On a permanent error.
"""
raise NotImplementedError()
AsyncSubscriberFactory = Callable[
[SubscriptionPath, Optional[Set[Partition]], FlowControlSettings],
AsyncSingleSubscriber,
]