This document describes the current stable version of Celery (5.3). For development docs, go here.

Source code for celery.concurrency.thread

"""Thread execution pool."""
from __future__ import annotations

from concurrent.futures import Future, ThreadPoolExecutor, wait
from typing import TYPE_CHECKING, Any, Callable

from .base import BasePool, apply_target

__all__ = ('TaskPool',)

if TYPE_CHECKING:
    import sys

    if sys.version_info >= (3, 8):
        from typing import TypedDict
    else:
        from typing_extensions import TypedDict

    PoolInfo = TypedDict('PoolInfo', {'max-concurrency': int, 'threads': int})

    # `TargetFunction` should be a Protocol that represents fast_trace_task and
    # trace_task_ret.
    TargetFunction = Callable[..., Any]


class ApplyResult:
    def __init__(self, future: Future) -> None:
        self.f = future
        self.get = self.f.result

    def wait(self, timeout: float | None = None) -> None:
        wait([self.f], timeout)


[docs]class TaskPool(BasePool): """Thread Task Pool.""" limit: int body_can_be_buffer = True signal_safe = False def __init__(self, *args: Any, **kwargs: Any) -> None: super().__init__(*args, **kwargs) self.executor = ThreadPoolExecutor(max_workers=self.limit)
[docs] def on_stop(self) -> None: self.executor.shutdown() super().on_stop()
[docs] def on_apply( self, target: TargetFunction, args: tuple[Any, ...] | None = None, kwargs: dict[str, Any] | None = None, callback: Callable[..., Any] | None = None, accept_callback: Callable[..., Any] | None = None, **_: Any ) -> ApplyResult: f = self.executor.submit(apply_target, target, args, kwargs, callback, accept_callback) return ApplyResult(f)
def _get_info(self) -> PoolInfo: info = super()._get_info() info.update({ 'max-concurrency': self.limit, 'threads': len(self.executor._threads) }) return info