This document describes the current stable version of Celery (4.2). For development docs, go here.

Source code for celery.concurrency.gevent

# -*- coding: utf-8 -*-
"""Gevent execution pool."""
from __future__ import absolute_import, unicode_literals

from kombu.asynchronous import timer as _timer
from kombu.five import monotonic

from . import base

try:
    from gevent import Timeout
except ImportError:  # pragma: no cover
    Timeout = None  # noqa

__all__ = ('TaskPool',)

# pylint: disable=redefined-outer-name
# We cache globals and attribute lookups, so disable this warning.


def apply_timeout(target, args=(), kwargs={}, callback=None,
                  accept_callback=None, pid=None, timeout=None,
                  timeout_callback=None, Timeout=Timeout,
                  apply_target=base.apply_target, **rest):
    try:
        with Timeout(timeout):
            return apply_target(target, args, kwargs, callback,
                                accept_callback, pid,
                                propagate=(Timeout,), **rest)
    except Timeout:
        return timeout_callback(False, timeout)


class Timer(_timer.Timer):

    def __init__(self, *args, **kwargs):
        from gevent import Greenlet, GreenletExit

        class _Greenlet(Greenlet):
            cancel = Greenlet.kill

        self._Greenlet = _Greenlet
        self._GreenletExit = GreenletExit
        super(Timer, self).__init__(*args, **kwargs)
        self._queue = set()

    def _enter(self, eta, priority, entry, **kwargs):
        secs = max(eta - monotonic(), 0)
        g = self._Greenlet.spawn_later(secs, entry)
        self._queue.add(g)
        g.link(self._entry_exit)
        g.entry = entry
        g.eta = eta
        g.priority = priority
        g.canceled = False
        return g

    def _entry_exit(self, g):
        try:
            g.kill()
        finally:
            self._queue.discard(g)

    def clear(self):
        queue = self._queue
        while queue:
            try:
                queue.pop().kill()
            except KeyError:
                pass

    @property
    def queue(self):
        return self._queue


[docs]class TaskPool(base.BasePool): """GEvent Pool.""" Timer = Timer signal_safe = False is_green = True task_join_will_block = False _pool = None _quick_put = None def __init__(self, *args, **kwargs): from gevent import spawn_raw from gevent.pool import Pool self.Pool = Pool self.spawn_n = spawn_raw self.timeout = kwargs.get('timeout') super(TaskPool, self).__init__(*args, **kwargs)
[docs] def on_start(self): self._pool = self.Pool(self.limit)
self._quick_put = self._pool.spawn
[docs] def on_stop(self): if self._pool is not None:
self._pool.join()
[docs] def on_apply(self, target, args=None, kwargs=None, callback=None, accept_callback=None, timeout=None, timeout_callback=None, apply_target=base.apply_target, **_): timeout = self.timeout if timeout is None else timeout return self._quick_put(apply_timeout if timeout else apply_target, target, args, kwargs, callback, accept_callback, timeout=timeout,
timeout_callback=timeout_callback)
[docs] def grow(self, n=1): self._pool._semaphore.counter += n
self._pool.size += n
[docs] def shrink(self, n=1): self._pool._semaphore.counter -= n
self._pool.size -= n @property def num_processes(self):
return len(self._pool)