206 lines
6.5 KiB
Python
206 lines
6.5 KiB
Python
# This file is part of Pebble.
|
|
# Copyright (c) 2013-2022, Matteo Cafasso
|
|
|
|
# Pebble is free software: you can redistribute it and/or modify
|
|
# it under the terms of the GNU Lesser General Public License
|
|
# as published by the Free Software Foundation,
|
|
# either version 3 of the License, or (at your option) any later version.
|
|
|
|
# Pebble is distributed in the hope that it will be useful,
|
|
# but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
# GNU Lesser General Public License for more details.
|
|
|
|
# You should have received a copy of the GNU Lesser General Public License
|
|
# along with Pebble. If not, see <http://www.gnu.org/licenses/>.
|
|
|
|
|
|
import time
|
|
import multiprocessing
|
|
|
|
from itertools import count
|
|
from typing import Callable
|
|
from concurrent.futures import Future
|
|
|
|
from pebble.common import execute, launch_thread
|
|
from pebble.pool.base_pool import MapFuture, map_results
|
|
from pebble.pool.base_pool import iter_chunks, run_initializer
|
|
from pebble.pool.base_pool import CREATED, ERROR, RUNNING, SLEEP_UNIT
|
|
from pebble.pool.base_pool import PoolContext, BasePool, Task, TaskPayload
|
|
|
|
|
|
class ThreadPool(BasePool):
|
|
"""Allows to schedule jobs within a Pool of Threads.
|
|
|
|
max_workers is an integer representing the amount of desired process workers
|
|
managed by the pool.
|
|
If max_tasks is a number greater than zero,
|
|
each worker will be restarted after performing an equal amount of tasks.
|
|
|
|
initializer must be callable, if passed, it will be called
|
|
every time a worker is started, receiving initargs as arguments.
|
|
|
|
"""
|
|
def __init__(self, max_workers: int = multiprocessing.cpu_count(),
|
|
max_tasks: int = 0,
|
|
initializer: Callable = None,
|
|
initargs: list = ()):
|
|
super().__init__(max_workers, max_tasks, initializer, initargs)
|
|
self._pool_manager = PoolManager(self._context)
|
|
self._pool_manager_loop = None
|
|
|
|
def _start_pool(self):
|
|
with self._context.state_mutex:
|
|
if self._context.state == CREATED:
|
|
self._pool_manager.start()
|
|
self._pool_manager_loop = launch_thread(
|
|
None, pool_manager_loop, True, self._pool_manager)
|
|
|
|
self._context.state = RUNNING
|
|
|
|
def _stop_pool(self):
|
|
if self._pool_manager_loop is not None:
|
|
self._pool_manager_loop.join()
|
|
self._pool_manager.stop()
|
|
|
|
def schedule(self, function, args=(), kwargs={}) -> Future:
|
|
"""Schedules *function* to be run the Pool.
|
|
|
|
*args* and *kwargs* will be forwareded to the scheduled function
|
|
respectively as arguments and keyword arguments.
|
|
|
|
A *concurrent.futures.Future* object is returned.
|
|
|
|
"""
|
|
self._check_pool_state()
|
|
|
|
future = Future()
|
|
payload = TaskPayload(function, args, kwargs)
|
|
task = Task(next(self._task_counter), future, None, payload)
|
|
|
|
self._context.task_queue.put(task)
|
|
|
|
return future
|
|
|
|
def submit(self, function: Callable, *args, **kwargs) -> Future:
|
|
"""This function is provided for compatibility with
|
|
`asyncio.loop.run_in_executor`.
|
|
|
|
For scheduling jobs within the pool use `schedule` instead.
|
|
|
|
"""
|
|
return self.schedule(function, args=args, kwargs=kwargs)
|
|
|
|
def map(self, function: Callable, *iterables, **kwargs) -> MapFuture:
|
|
"""Returns an iterator equivalent to map(function, iterables).
|
|
|
|
*chunksize* controls the size of the chunks the iterable will
|
|
be broken into before being passed to the function. If None
|
|
the size will be controlled by the Pool.
|
|
|
|
"""
|
|
self._check_pool_state()
|
|
|
|
timeout = kwargs.get('timeout')
|
|
chunksize = kwargs.get('chunksize', 1)
|
|
|
|
if chunksize < 1:
|
|
raise ValueError("chunksize must be >= 1")
|
|
|
|
futures = [self.schedule(process_chunk, args=(function, chunk))
|
|
for chunk in iter_chunks(chunksize, *iterables)]
|
|
|
|
return map_results(MapFuture(futures), timeout)
|
|
|
|
|
|
def pool_manager_loop(pool_manager: 'PoolManager'):
|
|
context = pool_manager.context
|
|
|
|
while context.alive:
|
|
pool_manager.update_status()
|
|
time.sleep(SLEEP_UNIT)
|
|
|
|
|
|
class PoolManager:
|
|
def __init__(self, context: PoolContext):
|
|
self.workers = []
|
|
self.context = context
|
|
|
|
def start(self):
|
|
self.create_workers()
|
|
|
|
def stop(self):
|
|
for worker in self.workers:
|
|
self.context.task_queue.put(None)
|
|
for worker in tuple(self.workers):
|
|
self.join_worker(worker)
|
|
|
|
def update_status(self):
|
|
expired = self.inspect_workers()
|
|
|
|
for worker in expired:
|
|
self.join_worker(worker)
|
|
|
|
self.create_workers()
|
|
|
|
def inspect_workers(self) -> tuple:
|
|
return tuple(w for w in self.workers if not w.is_alive())
|
|
|
|
def create_workers(self):
|
|
for _ in range(self.context.workers - len(self.workers)):
|
|
worker = launch_thread(None, worker_thread, True, self.context)
|
|
|
|
self.workers.append(worker)
|
|
|
|
def join_worker(self, worker):
|
|
worker.join()
|
|
self.workers.remove(worker)
|
|
|
|
|
|
def worker_thread(context: PoolContext):
|
|
"""The worker thread routines."""
|
|
queue = context.task_queue
|
|
parameters = context.worker_parameters
|
|
|
|
if parameters.initializer is not None:
|
|
if not run_initializer(parameters.initializer, parameters.initargs):
|
|
context.state = ERROR
|
|
return
|
|
|
|
for task in get_next_task(context, parameters.max_tasks):
|
|
execute_next_task(task)
|
|
queue.task_done()
|
|
|
|
|
|
def get_next_task(context: PoolContext, max_tasks: int):
|
|
counter = count()
|
|
queue = context.task_queue
|
|
|
|
while context.alive and (max_tasks == 0 or next(counter) < max_tasks):
|
|
task = queue.get()
|
|
|
|
if task is not None:
|
|
if task.future.cancelled():
|
|
task.set_running_or_notify_cancel()
|
|
queue.task_done()
|
|
else:
|
|
yield task
|
|
|
|
|
|
def execute_next_task(task: Task):
|
|
payload = task.payload
|
|
task.timestamp = time.time()
|
|
task.set_running_or_notify_cancel()
|
|
|
|
result = execute(payload.function, *payload.args, **payload.kwargs)
|
|
|
|
if isinstance(result, BaseException):
|
|
task.future.set_exception(result)
|
|
else:
|
|
task.future.set_result(result)
|
|
|
|
|
|
def process_chunk(function: Callable, chunk: list) -> list:
|
|
"""Processes a chunk of the iterable passed to map dealing with errors."""
|
|
return [execute(function, *args) for args in chunk]
|