"""Gevent execution pool."""
from time import monotonic
from kombu.asynchronous import timer as _timer
from . import base
try:
from gevent import Timeout
except ImportError:
Timeout = None
__all__ = ('TaskPool',)
# pylint: disable=redefined-outer-name
# We cache globals and attribute lookups, so disable this warning.
def apply_timeout(target, args=(), kwargs=None, callback=None,
accept_callback=None, pid=None, timeout=None,
timeout_callback=None, Timeout=Timeout,
apply_target=base.apply_target, **rest):
kwargs = {} if not kwargs else kwargs
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().__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
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().__init__(*args, **kwargs)
[docs] def on_start(self):
self._pool = self.Pool(self.limit)
self._quick_put = self._pool.spawn
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)