forked from googleapis/python-pubsub
/
heartbeater.py
71 lines (58 loc) · 2.33 KB
/
heartbeater.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
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
# Copyright 2018, 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
#
# https://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 __future__ import absolute_import
import logging
import threading
_LOGGER = logging.getLogger(__name__)
_HEARTBEAT_WORKER_NAME = "Thread-Heartbeater"
# How often to send heartbeats in seconds. Determined as half the period of
# time where the Pub/Sub server will close the stream as inactive, which is
# 60 seconds.
_DEFAULT_PERIOD = 30
class Heartbeater(object):
def __init__(self, manager, period=_DEFAULT_PERIOD):
self._thread = None
self._operational_lock = threading.Lock()
self._manager = manager
self._stop_event = threading.Event()
self._period = period
def heartbeat(self):
"""Periodically send streaming pull heartbeats.
"""
while not self._stop_event.is_set():
if self._manager.heartbeat():
_LOGGER.debug("Sent heartbeat.")
self._stop_event.wait(timeout=self._period)
_LOGGER.info("%s exiting.", _HEARTBEAT_WORKER_NAME)
def start(self):
with self._operational_lock:
if self._thread is not None:
raise ValueError("Heartbeater is already running.")
# Create and start the helper thread.
self._stop_event.clear()
thread = threading.Thread(
name=_HEARTBEAT_WORKER_NAME, target=self.heartbeat
)
thread.daemon = True
thread.start()
_LOGGER.debug("Started helper thread %s", thread.name)
self._thread = thread
def stop(self):
with self._operational_lock:
self._stop_event.set()
if self._thread is not None:
# The thread should automatically exit when the consumer is
# inactive.
self._thread.join()
self._thread = None