from __future__ import absolute_import, division
import copy
import time
[docs]class Heartbeat(object):
DEFAULT_CONFIG = {
'group_id': None,
'heartbeat_interval_ms': 3000,
'session_timeout_ms': 10000,
'max_poll_interval_ms': 300000,
'retry_backoff_ms': 100,
}
def __init__(self, **configs):
self.config = copy.copy(self.DEFAULT_CONFIG)
for key in self.config:
if key in configs:
self.config[key] = configs[key]
if self.config['group_id'] is not None:
assert (self.config['heartbeat_interval_ms']
<= self.config['session_timeout_ms']), (
'Heartbeat interval must be lower than the session timeout')
self.last_send = -1 * float('inf')
self.last_receive = -1 * float('inf')
self.last_poll = -1 * float('inf')
self.last_reset = time.time()
self.heartbeat_failed = None
[docs] def poll(self):
self.last_poll = time.time()
[docs] def sent_heartbeat(self):
self.last_send = time.time()
self.heartbeat_failed = False
[docs] def fail_heartbeat(self):
self.heartbeat_failed = True
[docs] def received_heartbeat(self):
self.last_receive = time.time()
[docs] def time_to_next_heartbeat(self):
"""Returns seconds (float) remaining before next heartbeat should be sent"""
time_since_last_heartbeat = time.time() - max(self.last_send, self.last_reset)
if self.heartbeat_failed:
delay_to_next_heartbeat = self.config['retry_backoff_ms'] / 1000
else:
delay_to_next_heartbeat = self.config['heartbeat_interval_ms'] / 1000
return max(0, delay_to_next_heartbeat - time_since_last_heartbeat)
[docs] def should_heartbeat(self):
return self.time_to_next_heartbeat() == 0
[docs] def session_timeout_expired(self):
last_recv = max(self.last_receive, self.last_reset)
return (time.time() - last_recv) > (self.config['session_timeout_ms'] / 1000)
[docs] def reset_timeouts(self):
self.last_reset = time.time()
self.last_poll = time.time()
self.heartbeat_failed = False
[docs] def poll_timeout_expired(self):
return (time.time() - self.last_poll) > (self.config['max_poll_interval_ms'] / 1000)