| Server IP : 74.208.127.88 / Your IP : 3.148.185.226 Web Server : Apache/2.4.41 (Ubuntu) System : Linux ubuntu 5.4.0-163-generic #180-Ubuntu SMP Tue Sep 5 13:21:23 UTC 2023 x86_64 User : www-data ( 33) PHP Version : 7.4.3-4ubuntu2.29 Disable Function : pcntl_alarm,pcntl_fork,pcntl_waitpid,pcntl_wait,pcntl_wifexited,pcntl_wifstopped,pcntl_wifsignaled,pcntl_wifcontinued,pcntl_wexitstatus,pcntl_wtermsig,pcntl_wstopsig,pcntl_signal,pcntl_signal_get_handler,pcntl_signal_dispatch,pcntl_get_last_error,pcntl_strerror,pcntl_sigprocmask,pcntl_sigwaitinfo,pcntl_sigtimedwait,pcntl_exec,pcntl_getpriority,pcntl_setpriority,pcntl_async_signals,pcntl_unshare, MySQL : OFF | cURL : ON | WGET : ON | Perl : ON | Python : OFF | Sudo : ON | Pkexec : ON Directory : /proc/self/root/lib/python3/dist-packages/landscape/lib/ |
Upload File : |
import random
class ExponentialBackoff:
"""
Keeps track of a backoff delay that staggers down and staggers up
exponentially.
"""
def __init__(self, start_delay, max_delay):
self._error_count = 0 # A tally of server errors
self._start_delay = start_delay
self._max_delay = max_delay
def decrease(self):
"""Decreases error count with zero being the lowest"""
self._error_count -= 1
self._error_count = max(self._error_count, 0)
def increase(self):
"""Increases error count but not higher than gives the max delay"""
if self.get_delay() < self._max_delay:
self._error_count += 1
def get_delay(self):
"""
Calculates the delay using formula that gives this chart. In this
specific example start is 5 seconds and max is 60 seconds
Count Delay
0 0
1 5
2 10
3 20
4 40
5 60 (max)
"""
if self._error_count:
delay = (2 ** (self._error_count - 1)) * self._start_delay
else:
delay = 0
return min(int(delay), self._max_delay)
def get_random_delay(self, stagger_fraction=0.25):
"""
Adds randomness to the specified stagger of the delay. For example
for a delay of 12 and 25% stagger, it works out to 9 + rand(0,3)
"""
delay = self.get_delay()
non_random_part = delay * (1-stagger_fraction)
random_part = delay * stagger_fraction * random.random()
return int(non_random_part + random_part)