import logging import os import sys import warnings from enum import IntEnum from pathlib import Path from typing import TYPE_CHECKING, AsyncGenerator, Callable, Generator, Optional, Set, Tuple, Union import anyio from ._rust_notify import RustNotify from .filters import DefaultFilter __all__ = 'watch', 'awatch', 'Change', 'FileChange' logger = logging.getLogger('watchfiles.main') class Change(IntEnum): """ Enum representing the type of change that occurred. """ added = 1 """A new file or directory was added.""" modified = 2 """A file or directory was modified, can be either a metadata or data change.""" deleted = 3 """A file or directory was deleted.""" def raw_str(self) -> str: return self.name FileChange = Tuple[Change, str] """ A tuple representing a file change, first element is a [`Change`][watchfiles.Change] member, second is the path of the file or directory that changed. """ if TYPE_CHECKING: import asyncio from typing import Protocol import trio AnyEvent = Union[anyio.Event, asyncio.Event, trio.Event] class AbstractEvent(Protocol): def is_set(self) -> bool: ... def watch( *paths: Union[Path, str], watch_filter: Optional[Callable[['Change', str], bool]] = DefaultFilter(), debounce: int = 1_600, step: int = 50, stop_event: Optional['AbstractEvent'] = None, rust_timeout: int = 5_000, yield_on_timeout: bool = False, debug: bool = False, raise_interrupt: bool = True, force_polling: Optional[bool] = None, poll_delay_ms: int = 300, recursive: bool = True, ignore_permission_denied: Optional[bool] = None, ) -> Generator[Set[FileChange], None, None]: """ Watch one or more paths and yield a set of changes whenever files change. The paths watched can be directories or files, directories are watched recursively - changes in subdirectories are also detected. #### Force polling Notify will fall back to file polling if it can't use file system notifications, but we also force notify to us polling if the `force_polling` argument is `True`; if `force_polling` is unset (or `None`), we enable force polling thus: * if the `WATCHFILES_FORCE_POLLING` environment variable exists and is not empty: * if the value is `false`, `disable` or `disabled`, force polling is disabled * otherwise, force polling is enabled * otherwise, we enable force polling only if we detect we're running on WSL (Windows Subsystem for Linux) Args: *paths: filesystem paths to watch. watch_filter: callable used to filter out changes which are not important, you can either use a raw callable or a [`BaseFilter`][watchfiles.BaseFilter] instance, defaults to an instance of [`DefaultFilter`][watchfiles.DefaultFilter]. To keep all changes, use `None`. debounce: maximum time in milliseconds to group changes over before yielding them. step: time to wait for new changes in milliseconds, if no changes are detected in this time, and at least one change has been detected, the changes are yielded. stop_event: event to stop watching, if this is set, the generator will stop iteration, this can be anything with an `is_set()` method which returns a bool, e.g. `threading.Event()`. rust_timeout: maximum time in milliseconds to wait in the rust code for changes, `0` means no timeout. yield_on_timeout: if `True`, the generator will yield upon timeout in rust even if no changes are detected. debug: whether to print information about all filesystem changes in rust to stdout. raise_interrupt: whether to re-raise `KeyboardInterrupt`s, or suppress the error and just stop iterating. force_polling: See [Force polling](#force-polling) above. poll_delay_ms: delay between polling for changes, only used if `force_polling=True`. recursive: if `True`, watch for changes in sub-directories recursively, otherwise watch only for changes in the top-level directory, default is `True`. ignore_permission_denied: if `True`, will ignore permission denied errors, otherwise will raise them by default. Setting the `WATCHFILES_IGNORE_PERMISSION_DENIED` environment variable will set this value too. Yields: The generator yields sets of [`FileChange`][watchfiles.main.FileChange]s. ```py title="Example of watch usage" from watchfiles import watch for changes in watch('./first/dir', './second/dir', raise_interrupt=False): print(changes) ``` """ force_polling = _default_force_polling(force_polling) ignore_permission_denied = _default_ignore_permission_denied(ignore_permission_denied) with RustNotify( [str(p) for p in paths], debug, force_polling, poll_delay_ms, recursive, ignore_permission_denied ) as watcher: while True: raw_changes = watcher.watch(debounce, step, rust_timeout, stop_event) if raw_changes == 'timeout': if yield_on_timeout: yield set() else: logger.debug('rust notify timeout, continuing') elif raw_changes == 'signal': if raise_interrupt: raise KeyboardInterrupt else: logger.warning('KeyboardInterrupt caught, stopping watch') return elif raw_changes == 'stop': return else: changes = _prep_changes(raw_changes, watch_filter) if changes: _log_changes(changes) yield changes else: logger.debug('all changes filtered out, raw_changes=%s', raw_changes) async def awatch( # noqa C901 *paths: Union[Path, str], watch_filter: Optional[Callable[[Change, str], bool]] = DefaultFilter(), debounce: int = 1_600, step: int = 50, stop_event: Optional['AnyEvent'] = None, rust_timeout: Optional[int] = None, yield_on_timeout: bool = False, debug: bool = False, raise_interrupt: Optional[bool] = None, force_polling: Optional[bool] = None, poll_delay_ms: int = 300, recursive: bool = True, ignore_permission_denied: Optional[bool] = None, ) -> AsyncGenerator[Set[FileChange], None]: """ Asynchronous equivalent of [`watch`][watchfiles.watch] using threads to wait for changes. Arguments match those of [`watch`][watchfiles.watch] except `stop_event`. All async methods use [anyio](https://anyio.readthedocs.io/en/latest/) to run the event loop. Unlike [`watch`][watchfiles.watch] `KeyboardInterrupt` cannot be suppressed by `awatch` so they need to be caught where `asyncio.run` or equivalent is called. Args: *paths: filesystem paths to watch. watch_filter: matches the same argument of [`watch`][watchfiles.watch]. debounce: matches the same argument of [`watch`][watchfiles.watch]. step: matches the same argument of [`watch`][watchfiles.watch]. stop_event: `anyio.Event` which can be used to stop iteration, see example below. rust_timeout: matches the same argument of [`watch`][watchfiles.watch], except that `None` means use `1_000` on Windows and `5_000` on other platforms thus helping with exiting on `Ctrl+C` on Windows, see [#110](https://github.com/samuelcolvin/watchfiles/issues/110). yield_on_timeout: matches the same argument of [`watch`][watchfiles.watch]. debug: matches the same argument of [`watch`][watchfiles.watch]. raise_interrupt: This is deprecated, `KeyboardInterrupt` will cause this coroutine to be cancelled and then be raised by the top level `asyncio.run` call or equivalent, and should be caught there. See [#136](https://github.com/samuelcolvin/watchfiles/issues/136) force_polling: if true, always use polling instead of file system notifications, default is `None` where `force_polling` is set to `True` if the `WATCHFILES_FORCE_POLLING` environment variable exists. poll_delay_ms: delay between polling for changes, only used if `force_polling=True`. recursive: if `True`, watch for changes in sub-directories recursively, otherwise watch only for changes in the top-level directory, default is `True`. ignore_permission_denied: if `True`, will ignore permission denied errors, otherwise will raise them by default. Setting the `WATCHFILES_IGNORE_PERMISSION_DENIED` environment variable will set this value too. Yields: The generator yields sets of [`FileChange`][watchfiles.main.FileChange]s. ```py title="Example of awatch usage" import asyncio from watchfiles import awatch async def main(): async for changes in awatch('./first/dir', './second/dir'): print(changes) if __name__ == '__main__': try: asyncio.run(main()) except KeyboardInterrupt: print('stopped via KeyboardInterrupt') ``` ```py title="Example of awatch usage with a stop event" import asyncio from watchfiles import awatch async def main(): stop_event = asyncio.Event() async def stop_soon(): await asyncio.sleep(3) stop_event.set() stop_soon_task = asyncio.create_task(stop_soon()) async for changes in awatch('/path/to/dir', stop_event=stop_event): print(changes) # cleanup by awaiting the (now complete) stop_soon_task await stop_soon_task asyncio.run(main()) ``` """ if raise_interrupt is not None: warnings.warn( 'raise_interrupt is deprecated, KeyboardInterrupt will cause this coroutine to be cancelled and then ' 'be raised by the top level asyncio.run call or equivalent, and should be caught there. See #136.', DeprecationWarning, ) if stop_event is None: stop_event_: 'AnyEvent' = anyio.Event() else: stop_event_ = stop_event force_polling = _default_force_polling(force_polling) ignore_permission_denied = _default_ignore_permission_denied(ignore_permission_denied) with RustNotify( [str(p) for p in paths], debug, force_polling, poll_delay_ms, recursive, ignore_permission_denied ) as watcher: timeout = _calc_async_timeout(rust_timeout) CancelledError = anyio.get_cancelled_exc_class() while True: async with anyio.create_task_group() as tg: try: raw_changes = await anyio.to_thread.run_sync(watcher.watch, debounce, step, timeout, stop_event_) except (CancelledError, KeyboardInterrupt): stop_event_.set() # suppressing KeyboardInterrupt wouldn't stop it getting raised by the top level asyncio.run call raise tg.cancel_scope.cancel() if raw_changes == 'timeout': if yield_on_timeout: yield set() else: logger.debug('rust notify timeout, continuing') elif raw_changes == 'stop': return elif raw_changes == 'signal': # in theory the watch thread should never get a signal raise RuntimeError('watch thread unexpectedly received a signal') else: changes = _prep_changes(raw_changes, watch_filter) if changes: _log_changes(changes) yield changes else: logger.debug('all changes filtered out, raw_changes=%s', raw_changes) def _prep_changes( raw_changes: Set[Tuple[int, str]], watch_filter: Optional[Callable[[Change, str], bool]] ) -> Set[FileChange]: # if we wanted to be really snazzy, we could move this into rust changes = {(Change(change), path) for change, path in raw_changes} if watch_filter: changes = {c for c in changes if watch_filter(c[0], c[1])} return changes def _log_changes(changes: Set[FileChange]) -> None: if logger.isEnabledFor(logging.INFO): # pragma: no branch count = len(changes) plural = '' if count == 1 else 's' if logger.isEnabledFor(logging.DEBUG): logger.debug('%d change%s detected: %s', count, plural, changes) else: logger.info('%d change%s detected', count, plural) def _calc_async_timeout(timeout: Optional[int]) -> int: """ see https://github.com/samuelcolvin/watchfiles/issues/110 """ if timeout is None: if sys.platform == 'win32': return 1_000 else: return 5_000 else: return timeout def _default_force_polling(force_polling: Optional[bool]) -> bool: """ See docstring for `watch` above for details. See samuelcolvin/watchfiles#167 and samuelcolvin/watchfiles#187 for discussion and rationale. """ if force_polling is not None: return force_polling env_var = os.getenv('WATCHFILES_FORCE_POLLING') if env_var: return env_var.lower() not in {'false', 'disable', 'disabled'} else: return _auto_force_polling() def _auto_force_polling() -> bool: """ Whether to auto-enable force polling, it should be enabled automatically only on WSL. See samuelcolvin/watchfiles#187 for discussion. """ import platform uname = platform.uname() return 'microsoft-standard' in uname.release.lower() and uname.system.lower() == 'linux' def _default_ignore_permission_denied(ignore_permission_denied: Optional[bool]) -> bool: if ignore_permission_denied is not None: return ignore_permission_denied env_var = os.getenv('WATCHFILES_IGNORE_PERMISSION_DENIED') return bool(env_var)