zulip/zerver/tornado/ioloop_logging.py

76 lines
2.8 KiB
Python

import logging
import select
import time
from typing import Any, Dict, List, Tuple
from django.conf import settings
from tornado.ioloop import IOLoop, PollIOLoop
# There isn't a good way to get at what the underlying poll implementation
# will be without actually constructing an IOLoop, so we just assume it will
# be epoll.
orig_poll_impl = select.epoll
# This is used for a somewhat hacky way of passing the port number
# into this early-initialized module.
logging_data: Dict[str, str] = {}
class InstrumentedPollIOLoop(PollIOLoop):
def initialize(self, **kwargs): # type: ignore[no-untyped-def] # TODO investigate likely buggy monkey patching here
super().initialize(impl=InstrumentedPoll(), **kwargs)
def instrument_tornado_ioloop() -> None:
IOLoop.configure(InstrumentedPollIOLoop)
# A hack to keep track of how much time we spend working, versus sleeping in
# the event loop.
#
# Creating a new event loop instance with a custom impl object fails (events
# don't get processed), so instead we modify the ioloop module variable holding
# the default poll implementation. We need to do this before any Tornado code
# runs that might instantiate the default event loop.
class InstrumentedPoll:
def __init__(self) -> None:
self._underlying = orig_poll_impl()
self._times: List[Tuple[float, float]] = []
self._last_print = 0.0
# Python won't let us subclass e.g. select.epoll, so instead
# we proxy every method. __getattr__ handles anything we
# don't define elsewhere.
def __getattr__(self, name: str) -> Any:
return getattr(self._underlying, name)
# Call the underlying poll method, and report timing data.
def poll(self, timeout: float) -> Any:
# Avoid accumulating a bunch of insignificant data points
# from short timeouts.
if timeout < 1e-3:
return self._underlying.poll(timeout)
# Record start and end times for the underlying poll
t0 = time.time()
result = self._underlying.poll(timeout)
t1 = time.time()
# Log this datapoint and restrict our log to the past minute
self._times.append((t0, t1))
while self._times and self._times[0][0] < t1 - 60:
self._times.pop(0)
# Report (at most once every 5s) the percentage of time spent
# outside poll
if self._times and t1 - self._last_print >= 5:
total = t1 - self._times[0][0]
in_poll = sum(b-a for a, b in self._times)
if total > 0:
percent_busy = 100 * (1 - in_poll / total)
if settings.PRODUCTION:
logging.info('Tornado %s %5.1f%% busy over the past %4.1f seconds'
% (logging_data.get('port', 'unknown'), percent_busy, total))
self._last_print = t1
return result