import logging from asyncio import gather from asyncio.coroutines import iscoroutinefunction from asyncio.exceptions import CancelledError from asyncio.locks import Event from asyncio.tasks import Task, create_task from math import inf from typing import Any, Awaitable, Callable, Dict, Iterable, Iterator, List, Optional, Tuple from . import exceptions from .types import ArgsT, KwArgsT, CoroutineFunc, FinalCallbackT, CancelCallbackT log = logging.getLogger(__name__) class BaseTaskPool: _pools: List['BaseTaskPool'] = [] @classmethod def _add_pool(cls, pool: 'BaseTaskPool') -> int: cls._pools.append(pool) return len(cls._pools) - 1 # TODO: Make use of `max_running` def __init__(self, max_running: int = inf, name: str = None) -> None: self._max_running: int = max_running self._open: bool = True self._counter: int = 0 self._running: Dict[int, Task] = {} self._cancelled: Dict[int, Task] = {} self._ended: Dict[int, Task] = {} self._idx: int = self._add_pool(self) self._name: str = name self._all_tasks_known_flag: Event = Event() self._all_tasks_known_flag.set() self._more_allowed_flag: Event = Event() self._check_more_allowed() log.debug("%s initialized", str(self)) def __str__(self) -> str: return f'{self.__class__.__name__}-{self._name or self._idx}' @property def max_running(self) -> int: return self._max_running @property def is_open(self) -> bool: return self._open @property def num_running(self) -> int: return len(self._running) @property def num_cancelled(self) -> int: return len(self._cancelled) @property def num_ended(self) -> int: return len(self._ended) @property def num_finished(self) -> int: return self.num_ended - self.num_cancelled @property def is_full(self) -> bool: return not self._more_allowed_flag.is_set() def _check_more_allowed(self) -> None: if self.is_full and self.num_running < self.max_running: self._more_allowed_flag.set() elif not self.is_full and self.num_running >= self.max_running: self._more_allowed_flag.clear() def _task_name(self, task_id: int) -> str: return f'{self}_Task-{task_id}' async def _cancel_task(self, task_id: int, custom_callback: CancelCallbackT = None) -> None: log.debug("Cancelling %s ...", self._task_name(task_id)) task = self._running.pop(task_id) assert task is not None self._cancelled[task_id] = task await _execute_function(custom_callback, args=(task_id, )) log.debug("Cancelled %s", self._task_name(task_id)) async def _end_task(self, task_id: int, custom_callback: FinalCallbackT = None) -> None: task = self._running.pop(task_id, None) if task is None: task = self._cancelled[task_id] self._ended[task_id] = task await _execute_function(custom_callback, args=(task_id, )) self._check_more_allowed() log.info("Ended %s", self._task_name(task_id)) async def _task_wrapper(self, awaitable: Awaitable, task_id: int, final_callback: FinalCallbackT = None, cancel_callback: CancelCallbackT = None) -> Any: log.info("Started %s", self._task_name(task_id)) try: return await awaitable except CancelledError: await self._cancel_task(task_id, custom_callback=cancel_callback) finally: await self._end_task(task_id, custom_callback=final_callback) def _start_task(self, awaitable: Awaitable, ignore_closed: bool = False, final_callback: FinalCallbackT = None, cancel_callback: CancelCallbackT = None) -> int: if not (self._open or ignore_closed): raise exceptions.PoolIsClosed("Cannot start new tasks") task_id = self._counter self._counter += 1 self._running[task_id] = create_task( self._task_wrapper(awaitable, task_id, final_callback, cancel_callback), name=self._task_name(task_id) ) self._check_more_allowed() return task_id def _cancel_one(self, task_id: int, msg: str = None) -> None: try: task = self._running[task_id] except KeyError: if self._cancelled.get(task_id): raise exceptions.AlreadyCancelled(f"{self._task_name(task_id)} has already been cancelled") if self._ended.get(task_id): raise exceptions.AlreadyFinished(f"{self._task_name(task_id)} has finished running") raise exceptions.InvalidTaskID(f"No task with ID {task_id} found in {self}") task.cancel(msg=msg) def cancel(self, *task_ids: int, msg: str = None) -> None: for task_id in task_ids: self._cancel_one(task_id, msg=msg) def cancel_all(self, msg: str = None) -> None: for task in self._running.values(): task.cancel(msg=msg) def close(self) -> None: self._open = False log.info("%s is closed!", str(self)) async def gather(self, return_exceptions: bool = False): if self._open: raise exceptions.PoolStillOpen("Pool must be closed, before tasks can be gathered") await self._all_tasks_known_flag.wait() results = await gather(*self._running.values(), *self._ended.values(), return_exceptions=return_exceptions) self._running = self._cancelled = self._ended = {} return results class TaskPool(BaseTaskPool): def _apply_one(self, func: CoroutineFunc, args: ArgsT = (), kwargs: KwArgsT = None, final_callback: FinalCallbackT = None, cancel_callback: CancelCallbackT = None) -> int: if kwargs is None: kwargs = {} return self._start_task(func(*args, **kwargs), final_callback=final_callback, cancel_callback=cancel_callback) def apply(self, func: CoroutineFunc, args: ArgsT = (), kwargs: KwArgsT = None, num: int = 1, final_callback: FinalCallbackT = None, cancel_callback: CancelCallbackT = None) -> Tuple[int]: return tuple(self._apply_one(func, args, kwargs, final_callback, cancel_callback) for _ in range(num)) @staticmethod def _get_next_coroutine(func: CoroutineFunc, args_iter: Iterator[Any], arg_stars: int = 0) -> Optional[Awaitable]: try: arg = next(args_iter) except StopIteration: return if arg_stars == 0: return func(arg) if arg_stars == 1: return func(*arg) if arg_stars == 2: return func(**arg) raise ValueError def _map(self, func: CoroutineFunc, args_iter: ArgsT, arg_stars: int = 0, num_tasks: int = 1, final_callback: FinalCallbackT = None, cancel_callback: CancelCallbackT = None) -> None: if self._all_tasks_known_flag.is_set(): self._all_tasks_known_flag.clear() args_iter = iter(args_iter) def _start_next_coroutine() -> bool: cor = self._get_next_coroutine(func, args_iter, arg_stars) if cor is None: self._all_tasks_known_flag.set() return True self._start_task(cor, ignore_closed=True, final_callback=_start_next, cancel_callback=cancel_callback) return False async def _start_next(task_id: int) -> None: await _execute_function(final_callback, args=(task_id, )) _start_next_coroutine() for _ in range(num_tasks): reached_end = _start_next_coroutine() if reached_end: break def map(self, func: CoroutineFunc, args_iter: ArgsT, num_tasks: int = 1, final_callback: FinalCallbackT = None, cancel_callback: CancelCallbackT = None) -> None: self._map(func, args_iter, arg_stars=0, num_tasks=num_tasks, final_callback=final_callback, cancel_callback=cancel_callback) def starmap(self, func: CoroutineFunc, args_iter: Iterable[ArgsT], num_tasks: int = 1, final_callback: FinalCallbackT = None, cancel_callback: CancelCallbackT = None) -> None: self._map(func, args_iter, arg_stars=1, num_tasks=num_tasks, final_callback=final_callback, cancel_callback=cancel_callback) def doublestarmap(self, func: CoroutineFunc, kwargs_iter: Iterable[KwArgsT], num_tasks: int = 1, final_callback: FinalCallbackT = None, cancel_callback: CancelCallbackT = None) -> None: self._map(func, kwargs_iter, arg_stars=2, num_tasks=num_tasks, final_callback=final_callback, cancel_callback=cancel_callback) class SimpleTaskPool(BaseTaskPool): def __init__(self, func: CoroutineFunc, args: ArgsT = (), kwargs: KwArgsT = None, final_callback: FinalCallbackT = None, cancel_callback: CancelCallbackT = None, name: str = None) -> None: self._func: CoroutineFunc = func self._args: ArgsT = args self._kwargs: KwArgsT = kwargs if kwargs is not None else {} self._final_callback: FinalCallbackT = final_callback self._cancel_callback: CancelCallbackT = cancel_callback super().__init__(name=name) @property def func_name(self) -> str: return self._func.__name__ @property def size(self) -> int: return self.num_running def _start_one(self) -> int: return self._start_task(self._func(*self._args, **self._kwargs), final_callback=self._final_callback, cancel_callback=self._cancel_callback) def start(self, num: int = 1) -> List[int]: return [self._start_one() for _ in range(num)] def stop(self, num: int = 1) -> List[int]: num = min(num, self.size) ids = [] for i, task_id in enumerate(reversed(self._running)): if i >= num: break ids.append(task_id) self.cancel(*ids) return ids def stop_all(self) -> List[int]: return self.stop(self.size) async def _execute_function(func: Callable, args: ArgsT = (), kwargs: KwArgsT = None) -> None: if kwargs is None: kwargs = {} if callable(func): if iscoroutinefunction(func): await func(*args, **kwargs) else: func(*args, **kwargs)