""" The MIT License (MIT) Copyright (c) 2015-2021 Rapptz Copyright (c) 2021-present Pycord Development Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. """ from __future__ import annotations import asyncio import datetime import inspect import sys import traceback from collections.abc import Sequence from typing import Any, Awaitable, Callable, Generic, TypeVar, cast import aiohttp import discord from discord.backoff import ExponentialBackoff from discord.utils import MISSING __all__ = ("loop",) T = TypeVar("T") _func = Callable[..., Awaitable[Any]] LF = TypeVar("LF", bound=_func) FT = TypeVar("FT", bound=_func) ET = TypeVar("ET", bound=Callable[[Any, BaseException], Awaitable[Any]]) class SleepHandle: __slots__ = ("future", "loop", "handle") def __init__( self, dt: datetime.datetime, *, loop: asyncio.AbstractEventLoop ) -> None: self.loop = loop self.future = future = loop.create_future() relative_delta = discord.utils.compute_timedelta(dt) self.handle = loop.call_later(relative_delta, future.set_result, True) def recalculate(self, dt: datetime.datetime) -> None: self.handle.cancel() relative_delta = discord.utils.compute_timedelta(dt) self.handle = self.loop.call_later(relative_delta, self.future.set_result, True) def wait(self) -> asyncio.Future[Any]: return self.future def done(self) -> bool: return self.future.done() def cancel(self) -> None: self.handle.cancel() self.future.cancel() class Loop(Generic[LF]): """A background task helper that abstracts the loop and reconnection logic for you. The main interface to create this is through :func:`loop`. """ def __init__( self, coro: LF, seconds: float, hours: float, minutes: float, time: datetime.time | Sequence[datetime.time], count: int | None, reconnect: bool, loop: asyncio.AbstractEventLoop, ) -> None: self.coro: LF = coro self.reconnect: bool = reconnect self.loop: asyncio.AbstractEventLoop = loop self.count: int | None = count self._current_loop = 0 self._handle: SleepHandle = MISSING self._task: asyncio.Task[None] = MISSING self._injected = None self._valid_exception = ( OSError, discord.GatewayNotFound, discord.ConnectionClosed, aiohttp.ClientError, asyncio.TimeoutError, ) self._before_loop = None self._after_loop = None self._before_loop_running = False self._after_loop_running = False self._is_being_cancelled = False self._has_failed = False self._stop_next_iteration = False if self.count is not None and self.count <= 0: raise ValueError("count must be greater than 0 or None.") self.change_interval(seconds=seconds, minutes=minutes, hours=hours, time=time) self._last_iteration_failed = False self._last_iteration: datetime.datetime = MISSING self._next_iteration = None if not inspect.iscoroutinefunction(self.coro): raise TypeError( f"Expected coroutine function, not {type(self.coro).__name__!r}." ) async def _call_loop_function(self, name: str, *args: Any, **kwargs: Any) -> None: coro = getattr(self, f"_{name}") if coro is None: return if name.endswith("_loop"): setattr(self, f"_{name}_running", True) if self._injected is not None: await coro(self._injected, *args, **kwargs) else: await coro(*args, **kwargs) if name.endswith("_loop"): setattr(self, f"_{name}_running", False) def _try_sleep_until(self, dt: datetime.datetime): self._handle = SleepHandle(dt=dt, loop=self.loop) return self._handle.wait() async def _loop(self, *args: Any, **kwargs: Any) -> None: backoff = ExponentialBackoff() await self._call_loop_function("before_loop") self._last_iteration_failed = False if self._time is not MISSING: # the time index should be prepared every time the internal loop is started self._prepare_time_index() self._next_iteration = self._get_next_sleep_time() else: self._next_iteration = datetime.datetime.now(datetime.timezone.utc) try: await self._try_sleep_until(self._next_iteration) while True: if not self._last_iteration_failed: self._last_iteration = self._next_iteration self._next_iteration = self._get_next_sleep_time() try: await self.coro(*args, **kwargs) self._last_iteration_failed = False except self._valid_exception: self._last_iteration_failed = True if not self.reconnect: raise await asyncio.sleep(backoff.delay()) else: await self._try_sleep_until(self._next_iteration) if self._stop_next_iteration: return now = datetime.datetime.now(datetime.timezone.utc) if now > self._next_iteration: self._next_iteration = now if self._time is not MISSING: self._prepare_time_index(now) self._current_loop += 1 if self._current_loop == self.count: break except asyncio.CancelledError: self._is_being_cancelled = True raise except Exception as exc: self._has_failed = True await self._call_loop_function("error", exc) raise exc finally: await self._call_loop_function("after_loop") self._handle.cancel() self._is_being_cancelled = False self._current_loop = 0 self._stop_next_iteration = False self._has_failed = False def __get__(self, obj: T, objtype: type[T]) -> Loop[LF]: if obj is None: return self copy: Loop[LF] = Loop( self.coro, seconds=self._seconds, hours=self._hours, minutes=self._minutes, time=self._time, count=self.count, reconnect=self.reconnect, loop=self.loop, ) copy._injected = obj copy._before_loop = self._before_loop copy._after_loop = self._after_loop copy._error = self._error setattr(obj, self.coro.__name__, copy) return copy @property def seconds(self) -> float | None: """Read-only value for the number of seconds between each iteration. ``None`` if an explicit ``time`` value was passed instead. .. versionadded:: 2.0 """ if self._seconds is not MISSING: return self._seconds @property def minutes(self) -> float | None: """Read-only value for the number of minutes between each iteration. ``None`` if an explicit ``time`` value was passed instead. .. versionadded:: 2.0 """ if self._minutes is not MISSING: return self._minutes @property def hours(self) -> float | None: """Read-only value for the number of hours between each iteration. ``None`` if an explicit ``time`` value was passed instead. .. versionadded:: 2.0 """ if self._hours is not MISSING: return self._hours @property def time(self) -> list[datetime.time] | None: """Read-only list for the exact times this loop runs at. ``None`` if relative times were passed instead. .. versionadded:: 2.0 """ if self._time is not MISSING: return self._time.copy() @property def current_loop(self) -> int: """The current iteration of the loop.""" return self._current_loop @property def next_iteration(self) -> datetime.datetime | None: """When the next iteration of the loop will occur. .. versionadded:: 1.3 """ if self._task is MISSING: return None elif self._task and self._task.done() or self._stop_next_iteration: return None return self._next_iteration async def __call__(self, *args: Any, **kwargs: Any) -> Any: r"""|coro| Calls the internal callback that the task holds. .. versionadded:: 1.6 Parameters ------------ \*args The arguments to use. \*\*kwargs The keyword arguments to use. """ if self._injected is not None: args = (self._injected, *args) return await self.coro(*args, **kwargs) def start(self, *args: Any, **kwargs: Any) -> asyncio.Task[None]: r"""Starts the internal task in the event loop. Parameters ------------ \*args The arguments to use. \*\*kwargs The keyword arguments to use. Raises -------- RuntimeError A task has already been launched and is running. Returns --------- :class:`asyncio.Task` The task that has been created. """ if self._task is not MISSING and not self._task.done(): raise RuntimeError("Task is already launched and is not completed.") if self._injected is not None: args = (self._injected, *args) if self.loop is MISSING: self.loop = asyncio.get_event_loop() self._task = self.loop.create_task(self._loop(*args, **kwargs)) return self._task def stop(self) -> None: r"""Gracefully stops the task from running. Unlike :meth:`cancel`\, this allows the task to finish its current iteration before gracefully exiting. .. note:: If the internal function raises an error that can be handled before finishing then it will retry until it succeeds. If this is undesirable, either remove the error handling before stopping via :meth:`clear_exception_types` or use :meth:`cancel` instead. .. versionadded:: 1.2 """ if self._task is not MISSING and not self._task.done(): self._stop_next_iteration = True def _can_be_cancelled(self) -> bool: return bool( not self._is_being_cancelled and self._task and not self._task.done() ) def cancel(self) -> None: """Cancels the internal task, if it is running.""" if self._can_be_cancelled(): self._task.cancel() def restart(self, *args: Any, **kwargs: Any) -> None: r"""A convenience method to restart the internal task. .. note:: Due to the way this function works, the task is not returned like :meth:`start`. Parameters ------------ \*args The arguments to use. \*\*kwargs The keyword arguments to use. """ def restart_when_over( fut: Any, *, args: Any = args, kwargs: Any = kwargs ) -> None: self._task.remove_done_callback(restart_when_over) self.start(*args, **kwargs) if self._can_be_cancelled(): self._task.add_done_callback(restart_when_over) self._task.cancel() def add_exception_type(self, *exceptions: type[BaseException]) -> None: r"""Adds exception types to be handled during the reconnect logic. By default, the exception types handled are those handled by :meth:`discord.Client.connect`\, which includes a lot of internet disconnection errors. This function is useful if you're interacting with a 3rd party library that raises its own set of exceptions. Parameters ------------ \*exceptions: Type[:class:`BaseException`] An argument list of exception classes to handle. Raises -------- TypeError An exception passed is either not a class or not inherited from :class:`BaseException`. """ for exc in exceptions: if not inspect.isclass(exc): raise TypeError(f"{exc!r} must be a class.") if not issubclass(exc, BaseException): raise TypeError(f"{exc!r} must inherit from BaseException.") self._valid_exception = (*self._valid_exception, *exceptions) def clear_exception_types(self) -> None: """Removes all exception types that are handled. .. note:: This operation obviously cannot be undone! """ self._valid_exception = () def remove_exception_type(self, *exceptions: type[BaseException]) -> bool: r"""Removes exception types from being handled during the reconnect logic. Parameters ------------ \*exceptions: Type[:class:`BaseException`] An argument list of exception classes to handle. Returns --------- :class:`bool` Whether all exceptions were successfully removed. """ old_length = len(self._valid_exception) self._valid_exception = tuple( x for x in self._valid_exception if x not in exceptions ) return len(self._valid_exception) == old_length - len(exceptions) def get_task(self) -> asyncio.Task[None] | None: """Fetches the internal task or ``None`` if there isn't one running.""" return self._task if self._task is not MISSING else None def is_being_cancelled(self) -> bool: """Whether the task is being cancelled.""" return self._is_being_cancelled def failed(self) -> bool: """Whether the internal task has failed. .. versionadded:: 1.2 """ return self._has_failed def is_running(self) -> bool: """Check if the task is currently running. .. versionadded:: 1.4 """ return not bool(self._task.done()) if self._task is not MISSING else False async def _error(self, *args: Any) -> None: exception: Exception = args[-1] print( f"Unhandled exception in internal background task {self.coro.__name__!r}.", file=sys.stderr, ) traceback.print_exception( type(exception), exception, exception.__traceback__, file=sys.stderr ) def before_loop(self, coro: FT) -> FT: """A decorator that registers a coroutine to be called before the loop starts running. This is useful if you want to wait for some bot state before the loop starts, such as :meth:`discord.Client.wait_until_ready`. The coroutine must take no arguments (except ``self`` in a class context). Parameters ---------- coro: :ref:`coroutine ` The coroutine to register before the loop runs. Raises ------ TypeError The function was not a coroutine. """ if not inspect.iscoroutinefunction(coro): raise TypeError( f"Expected coroutine function, received {coro.__class__.__name__!r}." ) self._before_loop = coro return coro def after_loop(self, coro: FT) -> FT: """A decorator that register a coroutine to be called after the loop finished running. The coroutine must take no arguments (except ``self`` in a class context). .. note:: This coroutine is called even during cancellation. If it is desirable to tell apart whether something was cancelled or not, check to see whether :meth:`is_being_cancelled` is ``True`` or not. Parameters ---------- coro: :ref:`coroutine ` The coroutine to register after the loop finishes. Raises ------ TypeError The function was not a coroutine. """ if not inspect.iscoroutinefunction(coro): raise TypeError( f"Expected coroutine function, received {coro.__class__.__name__!r}." ) self._after_loop = coro return coro def error(self, coro: ET) -> ET: """A decorator that registers a coroutine to be called if the task encounters an unhandled exception. The coroutine must take only one argument the exception raised (except ``self`` in a class context). By default, this prints to :data:`sys.stderr` however it could be overridden to have a different implementation. .. versionadded:: 1.4 Parameters ---------- coro: :ref:`coroutine ` The coroutine to register in the event of an unhandled exception. Raises ------ TypeError The function was not a coroutine. """ if not inspect.iscoroutinefunction(coro): raise TypeError( f"Expected coroutine function, received {coro.__class__.__name__!r}." ) self._error = coro # type: ignore return coro def _get_next_sleep_time(self) -> datetime.datetime: if self._sleep is not MISSING: return self._last_iteration + datetime.timedelta(seconds=self._sleep) if self._time_index >= len(self._time): self._time_index = 0 if self._current_loop == 0: # if we're at the last index on the first iteration, we need to sleep until tomorrow return datetime.datetime.combine( datetime.datetime.now(self._time[0].tzinfo or datetime.timezone.utc) + datetime.timedelta(days=1), self._time[0], ) next_time = self._time[self._time_index] if self._current_loop == 0: self._time_index += 1 if ( next_time > datetime.datetime.now( next_time.tzinfo or datetime.timezone.utc ).timetz() ): return datetime.datetime.combine( datetime.datetime.now(next_time.tzinfo or datetime.timezone.utc), next_time, ) else: return datetime.datetime.combine( datetime.datetime.now(next_time.tzinfo or datetime.timezone.utc) + datetime.timedelta(days=1), next_time, ) next_date = cast( datetime.datetime, self._last_iteration.astimezone(next_time.tzinfo) ) if next_time < next_date.timetz(): next_date += datetime.timedelta(days=1) self._time_index += 1 return datetime.datetime.combine(next_date, next_time) def _prepare_time_index(self, now: datetime.datetime = MISSING) -> None: # now kwarg should be a datetime.datetime representing the time "now" # to calculate the next time index from # pre-condition: self._time is set time_now = ( now if now is not MISSING else datetime.datetime.now(datetime.timezone.utc).replace(microsecond=0) ) for idx, time in enumerate(self._time): if time >= time_now.astimezone(time.tzinfo).timetz(): self._time_index = idx break else: self._time_index = 0 def _get_time_parameter( self, time: datetime.time | Sequence[datetime.time], *, dt: type[datetime.time] = datetime.time, utc: datetime.timezone = datetime.timezone.utc, ) -> list[datetime.time]: if isinstance(time, dt): inner = time if time.tzinfo is not None else time.replace(tzinfo=utc) return [inner] if not isinstance(time, Sequence): raise TypeError( "Expected datetime.time or a sequence of datetime.time for ``time``," f" received {type(time)!r} instead." ) if not time: raise ValueError("time parameter must not be an empty sequence.") ret: list[datetime.time] = [] for index, t in enumerate(time): if not isinstance(t, dt): raise TypeError( f"Expected a sequence of {dt!r} for ``time``, received" f" {type(t).__name__!r} at index {index} instead." ) ret.append(t if t.tzinfo is not None else t.replace(tzinfo=utc)) return sorted(set(ret)) # de-dupe and sort times def change_interval( self, *, seconds: float = 0, minutes: float = 0, hours: float = 0, time: datetime.time | Sequence[datetime.time] = MISSING, ) -> None: """Changes the interval for the sleep time. .. versionadded:: 1.2 Parameters ---------- seconds: :class:`float` The number of seconds between every iteration. minutes: :class:`float` The number of minutes between every iteration. hours: :class:`float` The number of hours between every iteration. time: Union[:class:`datetime.time`, Sequence[:class:`datetime.time`]] The exact times to run this loop at. Either a non-empty list or a single value of :class:`datetime.time` should be passed. This cannot be used in conjunction with the relative time parameters. .. versionadded:: 2.0 .. note:: Duplicate times will be ignored, and only run once. Raises ------ ValueError An invalid value was given. TypeError An invalid value for the ``time`` parameter was passed, or the ``time`` parameter was passed in conjunction with relative time parameters. """ if time is MISSING: seconds = seconds or 0 minutes = minutes or 0 hours = hours or 0 sleep = seconds + (minutes * 60.0) + (hours * 3600.0) if sleep < 0: raise ValueError("Total number of seconds cannot be less than zero.") self._sleep = sleep self._seconds = float(seconds) self._hours = float(hours) self._minutes = float(minutes) self._time: list[datetime.time] = MISSING else: if any((seconds, minutes, hours)): raise TypeError("Cannot mix explicit time with relative time") self._time = self._get_time_parameter(time) self._sleep = self._seconds = self._minutes = self._hours = MISSING if self.is_running() and not ( self._before_loop_running or self._after_loop_running ): if self._time is not MISSING: # prepare the next time index starting from after the last iteration self._prepare_time_index(now=self._last_iteration) self._next_iteration = self._get_next_sleep_time() if not self._handle.done(): # the loop is sleeping, recalculate based on new interval self._handle.recalculate(self._next_iteration) def loop( *, seconds: float = MISSING, minutes: float = MISSING, hours: float = MISSING, time: datetime.time | Sequence[datetime.time] = MISSING, count: int | None = None, reconnect: bool = True, loop: asyncio.AbstractEventLoop = MISSING, ) -> Callable[[LF], Loop[LF]]: """A decorator that schedules a task in the background for you with optional reconnect logic. The decorator returns a :class:`Loop`. Parameters ---------- seconds: :class:`float` The number of seconds between every iteration. minutes: :class:`float` The number of minutes between every iteration. hours: :class:`float` The number of hours between every iteration. time: Union[:class:`datetime.time`, Sequence[:class:`datetime.time`]] The exact times to run this loop at. Either a non-empty list or a single value of :class:`datetime.time` should be passed. Timezones are supported. If no timezone is given for the times, it is assumed to represent UTC time. This cannot be used in conjunction with the relative time parameters. .. note:: Duplicate times will be ignored, and only run once. .. versionadded:: 2.0 count: Optional[:class:`int`] The number of loops to do, ``None`` if it should be an infinite loop. reconnect: :class:`bool` Whether to handle errors and restart the task using an exponential back-off algorithm similar to the one used in :meth:`discord.Client.connect`. loop: :class:`asyncio.AbstractEventLoop` The loop to use to register the task, if not given defaults to :func:`asyncio.get_event_loop`. Raises ------ ValueError An invalid value was given. TypeError The function was not a coroutine, an invalid value for the ``time`` parameter was passed, or ``time`` parameter was passed in conjunction with relative time parameters. """ def decorator(func: LF) -> Loop[LF]: return Loop[LF]( func, seconds=seconds, minutes=minutes, hours=hours, count=count, time=time, reconnect=reconnect, loop=loop, ) return decorator