diff options
Diffstat (limited to 'Lib/asyncio/unix_events.py')
| -rw-r--r-- | Lib/asyncio/unix_events.py | 325 |
1 files changed, 3 insertions, 322 deletions
diff --git a/Lib/asyncio/unix_events.py b/Lib/asyncio/unix_events.py index 41ccf1b78fb..9a2e300259e 100644 --- a/Lib/asyncio/unix_events.py +++ b/Lib/asyncio/unix_events.py @@ -28,9 +28,9 @@ from .log import logger __all__ = ( 'SelectorEventLoop', - 'AbstractChildWatcher', 'SafeChildWatcher', - 'FastChildWatcher', 'PidfdChildWatcher', - 'MultiLoopChildWatcher', 'ThreadedChildWatcher', + 'AbstractChildWatcher', + 'PidfdChildWatcher', + 'ThreadedChildWatcher', 'DefaultEventLoopPolicy', 'EventLoop', ) @@ -1062,325 +1062,6 @@ class BaseChildWatcher(AbstractChildWatcher): }) -class SafeChildWatcher(BaseChildWatcher): - """'Safe' child watcher implementation. - - This implementation avoids disrupting other code spawning processes by - polling explicitly each process in the SIGCHLD handler instead of calling - os.waitpid(-1). - - This is a safe solution but it has a significant overhead when handling a - big number of children (O(n) each time SIGCHLD is raised) - """ - - def __init__(self): - super().__init__() - warnings._deprecated("SafeChildWatcher", - "{name!r} is deprecated as of Python 3.12 and will be " - "removed in Python {remove}.", - remove=(3, 14)) - - def close(self): - self._callbacks.clear() - super().close() - - def __enter__(self): - return self - - def __exit__(self, a, b, c): - pass - - def add_child_handler(self, pid, callback, *args): - self._callbacks[pid] = (callback, args) - - # Prevent a race condition in case the child is already terminated. - self._do_waitpid(pid) - - def remove_child_handler(self, pid): - try: - del self._callbacks[pid] - return True - except KeyError: - return False - - def _do_waitpid_all(self): - - for pid in list(self._callbacks): - self._do_waitpid(pid) - - def _do_waitpid(self, expected_pid): - assert expected_pid > 0 - - try: - pid, status = os.waitpid(expected_pid, os.WNOHANG) - except ChildProcessError: - # The child process is already reaped - # (may happen if waitpid() is called elsewhere). - pid = expected_pid - returncode = 255 - logger.warning( - "Unknown child process pid %d, will report returncode 255", - pid) - else: - if pid == 0: - # The child process is still alive. - return - - returncode = waitstatus_to_exitcode(status) - if self._loop.get_debug(): - logger.debug('process %s exited with returncode %s', - expected_pid, returncode) - - try: - callback, args = self._callbacks.pop(pid) - except KeyError: # pragma: no cover - # May happen if .remove_child_handler() is called - # after os.waitpid() returns. - if self._loop.get_debug(): - logger.warning("Child watcher got an unexpected pid: %r", - pid, exc_info=True) - else: - callback(pid, returncode, *args) - - -class FastChildWatcher(BaseChildWatcher): - """'Fast' child watcher implementation. - - This implementation reaps every terminated processes by calling - os.waitpid(-1) directly, possibly breaking other code spawning processes - and waiting for their termination. - - There is no noticeable overhead when handling a big number of children - (O(1) each time a child terminates). - """ - def __init__(self): - super().__init__() - self._lock = threading.Lock() - self._zombies = {} - self._forks = 0 - warnings._deprecated("FastChildWatcher", - "{name!r} is deprecated as of Python 3.12 and will be " - "removed in Python {remove}.", - remove=(3, 14)) - - def close(self): - self._callbacks.clear() - self._zombies.clear() - super().close() - - def __enter__(self): - with self._lock: - self._forks += 1 - - return self - - def __exit__(self, a, b, c): - with self._lock: - self._forks -= 1 - - if self._forks or not self._zombies: - return - - collateral_victims = str(self._zombies) - self._zombies.clear() - - logger.warning( - "Caught subprocesses termination from unknown pids: %s", - collateral_victims) - - def add_child_handler(self, pid, callback, *args): - assert self._forks, "Must use the context manager" - - with self._lock: - try: - returncode = self._zombies.pop(pid) - except KeyError: - # The child is running. - self._callbacks[pid] = callback, args - return - - # The child is dead already. We can fire the callback. - callback(pid, returncode, *args) - - def remove_child_handler(self, pid): - try: - del self._callbacks[pid] - return True - except KeyError: - return False - - def _do_waitpid_all(self): - # Because of signal coalescing, we must keep calling waitpid() as - # long as we're able to reap a child. - while True: - try: - pid, status = os.waitpid(-1, os.WNOHANG) - except ChildProcessError: - # No more child processes exist. - return - else: - if pid == 0: - # A child process is still alive. - return - - returncode = waitstatus_to_exitcode(status) - - with self._lock: - try: - callback, args = self._callbacks.pop(pid) - except KeyError: - # unknown child - if self._forks: - # It may not be registered yet. - self._zombies[pid] = returncode - if self._loop.get_debug(): - logger.debug('unknown process %s exited ' - 'with returncode %s', - pid, returncode) - continue - callback = None - else: - if self._loop.get_debug(): - logger.debug('process %s exited with returncode %s', - pid, returncode) - - if callback is None: - logger.warning( - "Caught subprocess termination from unknown pid: " - "%d -> %d", pid, returncode) - else: - callback(pid, returncode, *args) - - -class MultiLoopChildWatcher(AbstractChildWatcher): - """A watcher that doesn't require running loop in the main thread. - - This implementation registers a SIGCHLD signal handler on - instantiation (which may conflict with other code that - install own handler for this signal). - - The solution is safe but it has a significant overhead when - handling a big number of processes (*O(n)* each time a - SIGCHLD is received). - """ - - # Implementation note: - # The class keeps compatibility with AbstractChildWatcher ABC - # To achieve this it has empty attach_loop() method - # and doesn't accept explicit loop argument - # for add_child_handler()/remove_child_handler() - # but retrieves the current loop by get_running_loop() - - def __init__(self): - self._callbacks = {} - self._saved_sighandler = None - warnings._deprecated("MultiLoopChildWatcher", - "{name!r} is deprecated as of Python 3.12 and will be " - "removed in Python {remove}.", - remove=(3, 14)) - - def is_active(self): - return self._saved_sighandler is not None - - def close(self): - self._callbacks.clear() - if self._saved_sighandler is None: - return - - handler = signal.getsignal(signal.SIGCHLD) - if handler != self._sig_chld: - logger.warning("SIGCHLD handler was changed by outside code") - else: - signal.signal(signal.SIGCHLD, self._saved_sighandler) - self._saved_sighandler = None - - def __enter__(self): - return self - - def __exit__(self, exc_type, exc_val, exc_tb): - pass - - def add_child_handler(self, pid, callback, *args): - loop = events.get_running_loop() - self._callbacks[pid] = (loop, callback, args) - - # Prevent a race condition in case the child is already terminated. - self._do_waitpid(pid) - - def remove_child_handler(self, pid): - try: - del self._callbacks[pid] - return True - except KeyError: - return False - - def attach_loop(self, loop): - # Don't save the loop but initialize itself if called first time - # The reason to do it here is that attach_loop() is called from - # unix policy only for the main thread. - # Main thread is required for subscription on SIGCHLD signal - if self._saved_sighandler is not None: - return - - self._saved_sighandler = signal.signal(signal.SIGCHLD, self._sig_chld) - if self._saved_sighandler is None: - logger.warning("Previous SIGCHLD handler was set by non-Python code, " - "restore to default handler on watcher close.") - self._saved_sighandler = signal.SIG_DFL - - # Set SA_RESTART to limit EINTR occurrences. - signal.siginterrupt(signal.SIGCHLD, False) - - def _do_waitpid_all(self): - for pid in list(self._callbacks): - self._do_waitpid(pid) - - def _do_waitpid(self, expected_pid): - assert expected_pid > 0 - - try: - pid, status = os.waitpid(expected_pid, os.WNOHANG) - except ChildProcessError: - # The child process is already reaped - # (may happen if waitpid() is called elsewhere). - pid = expected_pid - returncode = 255 - logger.warning( - "Unknown child process pid %d, will report returncode 255", - pid) - debug_log = False - else: - if pid == 0: - # The child process is still alive. - return - - returncode = waitstatus_to_exitcode(status) - debug_log = True - try: - loop, callback, args = self._callbacks.pop(pid) - except KeyError: # pragma: no cover - # May happen if .remove_child_handler() is called - # after os.waitpid() returns. - logger.warning("Child watcher got an unexpected pid: %r", - pid, exc_info=True) - else: - if loop.is_closed(): - logger.warning("Loop %r that handles pid %r is closed", loop, pid) - else: - if debug_log and loop.get_debug(): - logger.debug('process %s exited with returncode %s', - expected_pid, returncode) - loop.call_soon_threadsafe(callback, pid, returncode, *args) - - def _sig_chld(self, signum, frame): - try: - self._do_waitpid_all() - except (SystemExit, KeyboardInterrupt): - raise - except BaseException: - logger.warning('Unknown exception in SIGCHLD handler', exc_info=True) - - class ThreadedChildWatcher(AbstractChildWatcher): """Threaded child watcher implementation. |