41ed958ee6
Do nothing if the transport is already closed. Before it was not possible to close the transport twice.
958 lines
32 KiB
Python
958 lines
32 KiB
Python
"""Selector event loop for Unix with signal handling."""
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import errno
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import os
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import signal
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import socket
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import stat
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import subprocess
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import sys
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import threading
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from . import base_events
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from . import base_subprocess
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from . import constants
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from . import coroutines
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from . import events
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from . import selector_events
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from . import selectors
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from . import transports
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from .coroutines import coroutine
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from .log import logger
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__all__ = ['SelectorEventLoop',
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'AbstractChildWatcher', 'SafeChildWatcher',
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'FastChildWatcher', 'DefaultEventLoopPolicy',
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]
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if sys.platform == 'win32': # pragma: no cover
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raise ImportError('Signals are not really supported on Windows')
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def _sighandler_noop(signum, frame):
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"""Dummy signal handler."""
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pass
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class _UnixSelectorEventLoop(selector_events.BaseSelectorEventLoop):
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"""Unix event loop.
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Adds signal handling and UNIX Domain Socket support to SelectorEventLoop.
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"""
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def __init__(self, selector=None):
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super().__init__(selector)
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self._signal_handlers = {}
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def _socketpair(self):
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return socket.socketpair()
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def close(self):
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super().close()
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for sig in list(self._signal_handlers):
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self.remove_signal_handler(sig)
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def _process_self_data(self, data):
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for signum in data:
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if not signum:
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# ignore null bytes written by _write_to_self()
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continue
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self._handle_signal(signum)
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def add_signal_handler(self, sig, callback, *args):
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"""Add a handler for a signal. UNIX only.
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Raise ValueError if the signal number is invalid or uncatchable.
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Raise RuntimeError if there is a problem setting up the handler.
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"""
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if (coroutines.iscoroutine(callback)
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or coroutines.iscoroutinefunction(callback)):
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raise TypeError("coroutines cannot be used "
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"with add_signal_handler()")
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self._check_signal(sig)
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self._check_closed()
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try:
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# set_wakeup_fd() raises ValueError if this is not the
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# main thread. By calling it early we ensure that an
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# event loop running in another thread cannot add a signal
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# handler.
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signal.set_wakeup_fd(self._csock.fileno())
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except (ValueError, OSError) as exc:
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raise RuntimeError(str(exc))
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handle = events.Handle(callback, args, self)
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self._signal_handlers[sig] = handle
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try:
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# Register a dummy signal handler to ask Python to write the signal
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# number in the wakup file descriptor. _process_self_data() will
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# read signal numbers from this file descriptor to handle signals.
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signal.signal(sig, _sighandler_noop)
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# Set SA_RESTART to limit EINTR occurrences.
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signal.siginterrupt(sig, False)
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except OSError as exc:
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del self._signal_handlers[sig]
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if not self._signal_handlers:
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try:
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signal.set_wakeup_fd(-1)
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except (ValueError, OSError) as nexc:
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logger.info('set_wakeup_fd(-1) failed: %s', nexc)
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if exc.errno == errno.EINVAL:
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raise RuntimeError('sig {} cannot be caught'.format(sig))
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else:
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raise
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def _handle_signal(self, sig):
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"""Internal helper that is the actual signal handler."""
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handle = self._signal_handlers.get(sig)
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if handle is None:
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return # Assume it's some race condition.
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if handle._cancelled:
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self.remove_signal_handler(sig) # Remove it properly.
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else:
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self._add_callback_signalsafe(handle)
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def remove_signal_handler(self, sig):
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"""Remove a handler for a signal. UNIX only.
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Return True if a signal handler was removed, False if not.
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"""
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self._check_signal(sig)
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try:
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del self._signal_handlers[sig]
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except KeyError:
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return False
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if sig == signal.SIGINT:
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handler = signal.default_int_handler
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else:
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handler = signal.SIG_DFL
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try:
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signal.signal(sig, handler)
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except OSError as exc:
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if exc.errno == errno.EINVAL:
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raise RuntimeError('sig {} cannot be caught'.format(sig))
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else:
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raise
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if not self._signal_handlers:
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try:
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signal.set_wakeup_fd(-1)
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except (ValueError, OSError) as exc:
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logger.info('set_wakeup_fd(-1) failed: %s', exc)
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return True
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def _check_signal(self, sig):
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"""Internal helper to validate a signal.
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Raise ValueError if the signal number is invalid or uncatchable.
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Raise RuntimeError if there is a problem setting up the handler.
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"""
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if not isinstance(sig, int):
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raise TypeError('sig must be an int, not {!r}'.format(sig))
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if not (1 <= sig < signal.NSIG):
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raise ValueError(
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'sig {} out of range(1, {})'.format(sig, signal.NSIG))
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def _make_read_pipe_transport(self, pipe, protocol, waiter=None,
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extra=None):
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return _UnixReadPipeTransport(self, pipe, protocol, waiter, extra)
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def _make_write_pipe_transport(self, pipe, protocol, waiter=None,
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extra=None):
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return _UnixWritePipeTransport(self, pipe, protocol, waiter, extra)
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@coroutine
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def _make_subprocess_transport(self, protocol, args, shell,
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stdin, stdout, stderr, bufsize,
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extra=None, **kwargs):
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with events.get_child_watcher() as watcher:
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transp = _UnixSubprocessTransport(self, protocol, args, shell,
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stdin, stdout, stderr, bufsize,
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extra=extra, **kwargs)
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yield from transp._post_init()
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watcher.add_child_handler(transp.get_pid(),
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self._child_watcher_callback, transp)
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return transp
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def _child_watcher_callback(self, pid, returncode, transp):
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self.call_soon_threadsafe(transp._process_exited, returncode)
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@coroutine
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def create_unix_connection(self, protocol_factory, path, *,
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ssl=None, sock=None,
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server_hostname=None):
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assert server_hostname is None or isinstance(server_hostname, str)
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if ssl:
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if server_hostname is None:
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raise ValueError(
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'you have to pass server_hostname when using ssl')
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else:
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if server_hostname is not None:
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raise ValueError('server_hostname is only meaningful with ssl')
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if path is not None:
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if sock is not None:
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raise ValueError(
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'path and sock can not be specified at the same time')
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sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM, 0)
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try:
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sock.setblocking(False)
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yield from self.sock_connect(sock, path)
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except:
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sock.close()
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raise
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else:
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if sock is None:
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raise ValueError('no path and sock were specified')
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sock.setblocking(False)
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transport, protocol = yield from self._create_connection_transport(
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sock, protocol_factory, ssl, server_hostname)
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return transport, protocol
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@coroutine
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def create_unix_server(self, protocol_factory, path=None, *,
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sock=None, backlog=100, ssl=None):
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if isinstance(ssl, bool):
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raise TypeError('ssl argument must be an SSLContext or None')
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if path is not None:
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if sock is not None:
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raise ValueError(
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'path and sock can not be specified at the same time')
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sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
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try:
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sock.bind(path)
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except OSError as exc:
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sock.close()
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if exc.errno == errno.EADDRINUSE:
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# Let's improve the error message by adding
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# with what exact address it occurs.
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msg = 'Address {!r} is already in use'.format(path)
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raise OSError(errno.EADDRINUSE, msg) from None
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else:
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raise
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except:
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sock.close()
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raise
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else:
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if sock is None:
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raise ValueError(
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'path was not specified, and no sock specified')
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if sock.family != socket.AF_UNIX:
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raise ValueError(
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'A UNIX Domain Socket was expected, got {!r}'.format(sock))
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server = base_events.Server(self, [sock])
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sock.listen(backlog)
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sock.setblocking(False)
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self._start_serving(protocol_factory, sock, ssl, server)
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return server
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if hasattr(os, 'set_blocking'):
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def _set_nonblocking(fd):
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os.set_blocking(fd, False)
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else:
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import fcntl
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def _set_nonblocking(fd):
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flags = fcntl.fcntl(fd, fcntl.F_GETFL)
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flags = flags | os.O_NONBLOCK
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fcntl.fcntl(fd, fcntl.F_SETFL, flags)
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class _UnixReadPipeTransport(transports.ReadTransport):
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max_size = 256 * 1024 # max bytes we read in one event loop iteration
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def __init__(self, loop, pipe, protocol, waiter=None, extra=None):
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super().__init__(extra)
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self._extra['pipe'] = pipe
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self._loop = loop
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self._pipe = pipe
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self._fileno = pipe.fileno()
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mode = os.fstat(self._fileno).st_mode
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if not (stat.S_ISFIFO(mode) or
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stat.S_ISSOCK(mode) or
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stat.S_ISCHR(mode)):
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raise ValueError("Pipe transport is for pipes/sockets only.")
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_set_nonblocking(self._fileno)
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self._protocol = protocol
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self._closing = False
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self._loop.add_reader(self._fileno, self._read_ready)
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self._loop.call_soon(self._protocol.connection_made, self)
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if waiter is not None:
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# wait until protocol.connection_made() has been called
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self._loop.call_soon(waiter._set_result_unless_cancelled, None)
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def __repr__(self):
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info = [self.__class__.__name__]
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if self._pipe is None:
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info.append('closed')
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elif self._closing:
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info.append('closing')
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info.append('fd=%s' % self._fileno)
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if self._pipe is not None:
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polling = selector_events._test_selector_event(
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self._loop._selector,
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self._fileno, selectors.EVENT_READ)
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if polling:
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info.append('polling')
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else:
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info.append('idle')
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else:
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info.append('closed')
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return '<%s>' % ' '.join(info)
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def _read_ready(self):
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try:
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data = os.read(self._fileno, self.max_size)
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except (BlockingIOError, InterruptedError):
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pass
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except OSError as exc:
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self._fatal_error(exc, 'Fatal read error on pipe transport')
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else:
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if data:
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self._protocol.data_received(data)
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else:
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if self._loop.get_debug():
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logger.info("%r was closed by peer", self)
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self._closing = True
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self._loop.remove_reader(self._fileno)
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self._loop.call_soon(self._protocol.eof_received)
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self._loop.call_soon(self._call_connection_lost, None)
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def pause_reading(self):
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self._loop.remove_reader(self._fileno)
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def resume_reading(self):
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self._loop.add_reader(self._fileno, self._read_ready)
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def close(self):
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if not self._closing:
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self._close(None)
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def _fatal_error(self, exc, message='Fatal error on pipe transport'):
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# should be called by exception handler only
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if (isinstance(exc, OSError) and exc.errno == errno.EIO):
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if self._loop.get_debug():
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logger.debug("%r: %s", self, message, exc_info=True)
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else:
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self._loop.call_exception_handler({
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'message': message,
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'exception': exc,
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'transport': self,
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'protocol': self._protocol,
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})
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self._close(exc)
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def _close(self, exc):
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self._closing = True
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self._loop.remove_reader(self._fileno)
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self._loop.call_soon(self._call_connection_lost, exc)
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def _call_connection_lost(self, exc):
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try:
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self._protocol.connection_lost(exc)
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finally:
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self._pipe.close()
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self._pipe = None
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self._protocol = None
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self._loop = None
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class _UnixWritePipeTransport(transports._FlowControlMixin,
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transports.WriteTransport):
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def __init__(self, loop, pipe, protocol, waiter=None, extra=None):
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super().__init__(extra, loop)
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self._extra['pipe'] = pipe
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self._pipe = pipe
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self._fileno = pipe.fileno()
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mode = os.fstat(self._fileno).st_mode
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is_socket = stat.S_ISSOCK(mode)
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if not (is_socket or
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stat.S_ISFIFO(mode) or
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stat.S_ISCHR(mode)):
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raise ValueError("Pipe transport is only for "
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"pipes, sockets and character devices")
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_set_nonblocking(self._fileno)
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self._protocol = protocol
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self._buffer = []
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self._conn_lost = 0
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self._closing = False # Set when close() or write_eof() called.
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# On AIX, the reader trick only works for sockets.
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# On other platforms it works for pipes and sockets.
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# (Exception: OS X 10.4? Issue #19294.)
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if is_socket or not sys.platform.startswith("aix"):
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self._loop.add_reader(self._fileno, self._read_ready)
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self._loop.call_soon(self._protocol.connection_made, self)
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if waiter is not None:
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# wait until protocol.connection_made() has been called
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self._loop.call_soon(waiter._set_result_unless_cancelled, None)
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def __repr__(self):
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info = [self.__class__.__name__]
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if self._pipe is None:
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info.append('closed')
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elif self._closing:
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info.append('closing')
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info.append('fd=%s' % self._fileno)
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if self._pipe is not None:
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polling = selector_events._test_selector_event(
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self._loop._selector,
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self._fileno, selectors.EVENT_WRITE)
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if polling:
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info.append('polling')
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else:
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info.append('idle')
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bufsize = self.get_write_buffer_size()
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info.append('bufsize=%s' % bufsize)
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else:
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info.append('closed')
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return '<%s>' % ' '.join(info)
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def get_write_buffer_size(self):
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return sum(len(data) for data in self._buffer)
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def _read_ready(self):
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# Pipe was closed by peer.
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if self._loop.get_debug():
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logger.info("%r was closed by peer", self)
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if self._buffer:
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self._close(BrokenPipeError())
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else:
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self._close()
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def write(self, data):
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assert isinstance(data, (bytes, bytearray, memoryview)), repr(data)
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if isinstance(data, bytearray):
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data = memoryview(data)
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if not data:
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return
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if self._conn_lost or self._closing:
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if self._conn_lost >= constants.LOG_THRESHOLD_FOR_CONNLOST_WRITES:
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logger.warning('pipe closed by peer or '
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'os.write(pipe, data) raised exception.')
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self._conn_lost += 1
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return
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if not self._buffer:
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# Attempt to send it right away first.
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try:
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n = os.write(self._fileno, data)
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except (BlockingIOError, InterruptedError):
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n = 0
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except Exception as exc:
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self._conn_lost += 1
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self._fatal_error(exc, 'Fatal write error on pipe transport')
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return
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if n == len(data):
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return
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elif n > 0:
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data = data[n:]
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self._loop.add_writer(self._fileno, self._write_ready)
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self._buffer.append(data)
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self._maybe_pause_protocol()
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def _write_ready(self):
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data = b''.join(self._buffer)
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assert data, 'Data should not be empty'
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self._buffer.clear()
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try:
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n = os.write(self._fileno, data)
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except (BlockingIOError, InterruptedError):
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self._buffer.append(data)
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except Exception as exc:
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self._conn_lost += 1
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# Remove writer here, _fatal_error() doesn't it
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# because _buffer is empty.
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self._loop.remove_writer(self._fileno)
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self._fatal_error(exc, 'Fatal write error on pipe transport')
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else:
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if n == len(data):
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self._loop.remove_writer(self._fileno)
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self._maybe_resume_protocol() # May append to buffer.
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if not self._buffer and self._closing:
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self._loop.remove_reader(self._fileno)
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self._call_connection_lost(None)
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return
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elif n > 0:
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data = data[n:]
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self._buffer.append(data) # Try again later.
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def can_write_eof(self):
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return True
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def write_eof(self):
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if self._closing:
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return
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assert self._pipe
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self._closing = True
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if not self._buffer:
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self._loop.remove_reader(self._fileno)
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self._loop.call_soon(self._call_connection_lost, None)
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def close(self):
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if self._pipe is not None and not self._closing:
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# write_eof is all what we needed to close the write pipe
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self.write_eof()
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def abort(self):
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self._close(None)
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def _fatal_error(self, exc, message='Fatal error on pipe transport'):
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# should be called by exception handler only
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if isinstance(exc, (BrokenPipeError, ConnectionResetError)):
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if self._loop.get_debug():
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logger.debug("%r: %s", self, message, exc_info=True)
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|
else:
|
|
self._loop.call_exception_handler({
|
|
'message': message,
|
|
'exception': exc,
|
|
'transport': self,
|
|
'protocol': self._protocol,
|
|
})
|
|
self._close(exc)
|
|
|
|
def _close(self, exc=None):
|
|
self._closing = True
|
|
if self._buffer:
|
|
self._loop.remove_writer(self._fileno)
|
|
self._buffer.clear()
|
|
self._loop.remove_reader(self._fileno)
|
|
self._loop.call_soon(self._call_connection_lost, exc)
|
|
|
|
def _call_connection_lost(self, exc):
|
|
try:
|
|
self._protocol.connection_lost(exc)
|
|
finally:
|
|
self._pipe.close()
|
|
self._pipe = None
|
|
self._protocol = None
|
|
self._loop = None
|
|
|
|
|
|
if hasattr(os, 'set_inheritable'):
|
|
# Python 3.4 and newer
|
|
_set_inheritable = os.set_inheritable
|
|
else:
|
|
import fcntl
|
|
|
|
def _set_inheritable(fd, inheritable):
|
|
cloexec_flag = getattr(fcntl, 'FD_CLOEXEC', 1)
|
|
|
|
old = fcntl.fcntl(fd, fcntl.F_GETFD)
|
|
if not inheritable:
|
|
fcntl.fcntl(fd, fcntl.F_SETFD, old | cloexec_flag)
|
|
else:
|
|
fcntl.fcntl(fd, fcntl.F_SETFD, old & ~cloexec_flag)
|
|
|
|
|
|
class _UnixSubprocessTransport(base_subprocess.BaseSubprocessTransport):
|
|
|
|
def _start(self, args, shell, stdin, stdout, stderr, bufsize, **kwargs):
|
|
stdin_w = None
|
|
if stdin == subprocess.PIPE:
|
|
# Use a socket pair for stdin, since not all platforms
|
|
# support selecting read events on the write end of a
|
|
# socket (which we use in order to detect closing of the
|
|
# other end). Notably this is needed on AIX, and works
|
|
# just fine on other platforms.
|
|
stdin, stdin_w = self._loop._socketpair()
|
|
|
|
# Mark the write end of the stdin pipe as non-inheritable,
|
|
# needed by close_fds=False on Python 3.3 and older
|
|
# (Python 3.4 implements the PEP 446, socketpair returns
|
|
# non-inheritable sockets)
|
|
_set_inheritable(stdin_w.fileno(), False)
|
|
self._proc = subprocess.Popen(
|
|
args, shell=shell, stdin=stdin, stdout=stdout, stderr=stderr,
|
|
universal_newlines=False, bufsize=bufsize, **kwargs)
|
|
if stdin_w is not None:
|
|
stdin.close()
|
|
self._proc.stdin = open(stdin_w.detach(), 'wb', buffering=bufsize)
|
|
|
|
|
|
class AbstractChildWatcher:
|
|
"""Abstract base class for monitoring child processes.
|
|
|
|
Objects derived from this class monitor a collection of subprocesses and
|
|
report their termination or interruption by a signal.
|
|
|
|
New callbacks are registered with .add_child_handler(). Starting a new
|
|
process must be done within a 'with' block to allow the watcher to suspend
|
|
its activity until the new process if fully registered (this is needed to
|
|
prevent a race condition in some implementations).
|
|
|
|
Example:
|
|
with watcher:
|
|
proc = subprocess.Popen("sleep 1")
|
|
watcher.add_child_handler(proc.pid, callback)
|
|
|
|
Notes:
|
|
Implementations of this class must be thread-safe.
|
|
|
|
Since child watcher objects may catch the SIGCHLD signal and call
|
|
waitpid(-1), there should be only one active object per process.
|
|
"""
|
|
|
|
def add_child_handler(self, pid, callback, *args):
|
|
"""Register a new child handler.
|
|
|
|
Arrange for callback(pid, returncode, *args) to be called when
|
|
process 'pid' terminates. Specifying another callback for the same
|
|
process replaces the previous handler.
|
|
|
|
Note: callback() must be thread-safe.
|
|
"""
|
|
raise NotImplementedError()
|
|
|
|
def remove_child_handler(self, pid):
|
|
"""Removes the handler for process 'pid'.
|
|
|
|
The function returns True if the handler was successfully removed,
|
|
False if there was nothing to remove."""
|
|
|
|
raise NotImplementedError()
|
|
|
|
def attach_loop(self, loop):
|
|
"""Attach the watcher to an event loop.
|
|
|
|
If the watcher was previously attached to an event loop, then it is
|
|
first detached before attaching to the new loop.
|
|
|
|
Note: loop may be None.
|
|
"""
|
|
raise NotImplementedError()
|
|
|
|
def close(self):
|
|
"""Close the watcher.
|
|
|
|
This must be called to make sure that any underlying resource is freed.
|
|
"""
|
|
raise NotImplementedError()
|
|
|
|
def __enter__(self):
|
|
"""Enter the watcher's context and allow starting new processes
|
|
|
|
This function must return self"""
|
|
raise NotImplementedError()
|
|
|
|
def __exit__(self, a, b, c):
|
|
"""Exit the watcher's context"""
|
|
raise NotImplementedError()
|
|
|
|
|
|
class BaseChildWatcher(AbstractChildWatcher):
|
|
|
|
def __init__(self):
|
|
self._loop = None
|
|
|
|
def close(self):
|
|
self.attach_loop(None)
|
|
|
|
def _do_waitpid(self, expected_pid):
|
|
raise NotImplementedError()
|
|
|
|
def _do_waitpid_all(self):
|
|
raise NotImplementedError()
|
|
|
|
def attach_loop(self, loop):
|
|
assert loop is None or isinstance(loop, events.AbstractEventLoop)
|
|
|
|
if self._loop is not None:
|
|
self._loop.remove_signal_handler(signal.SIGCHLD)
|
|
|
|
self._loop = loop
|
|
if loop is not None:
|
|
loop.add_signal_handler(signal.SIGCHLD, self._sig_chld)
|
|
|
|
# Prevent a race condition in case a child terminated
|
|
# during the switch.
|
|
self._do_waitpid_all()
|
|
|
|
def _sig_chld(self):
|
|
try:
|
|
self._do_waitpid_all()
|
|
except Exception as exc:
|
|
# self._loop should always be available here
|
|
# as '_sig_chld' is added as a signal handler
|
|
# in 'attach_loop'
|
|
self._loop.call_exception_handler({
|
|
'message': 'Unknown exception in SIGCHLD handler',
|
|
'exception': exc,
|
|
})
|
|
|
|
def _compute_returncode(self, status):
|
|
if os.WIFSIGNALED(status):
|
|
# The child process died because of a signal.
|
|
return -os.WTERMSIG(status)
|
|
elif os.WIFEXITED(status):
|
|
# The child process exited (e.g sys.exit()).
|
|
return os.WEXITSTATUS(status)
|
|
else:
|
|
# The child exited, but we don't understand its status.
|
|
# This shouldn't happen, but if it does, let's just
|
|
# return that status; perhaps that helps debug it.
|
|
return status
|
|
|
|
|
|
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__()
|
|
self._callbacks = {}
|
|
|
|
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 = self._compute_returncode(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._callbacks = {}
|
|
self._lock = threading.Lock()
|
|
self._zombies = {}
|
|
self._forks = 0
|
|
|
|
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 = self._compute_returncode(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 _UnixDefaultEventLoopPolicy(events.BaseDefaultEventLoopPolicy):
|
|
"""UNIX event loop policy with a watcher for child processes."""
|
|
_loop_factory = _UnixSelectorEventLoop
|
|
|
|
def __init__(self):
|
|
super().__init__()
|
|
self._watcher = None
|
|
|
|
def _init_watcher(self):
|
|
with events._lock:
|
|
if self._watcher is None: # pragma: no branch
|
|
self._watcher = SafeChildWatcher()
|
|
if isinstance(threading.current_thread(),
|
|
threading._MainThread):
|
|
self._watcher.attach_loop(self._local._loop)
|
|
|
|
def set_event_loop(self, loop):
|
|
"""Set the event loop.
|
|
|
|
As a side effect, if a child watcher was set before, then calling
|
|
.set_event_loop() from the main thread will call .attach_loop(loop) on
|
|
the child watcher.
|
|
"""
|
|
|
|
super().set_event_loop(loop)
|
|
|
|
if self._watcher is not None and \
|
|
isinstance(threading.current_thread(), threading._MainThread):
|
|
self._watcher.attach_loop(loop)
|
|
|
|
def get_child_watcher(self):
|
|
"""Get the watcher for child processes.
|
|
|
|
If not yet set, a SafeChildWatcher object is automatically created.
|
|
"""
|
|
if self._watcher is None:
|
|
self._init_watcher()
|
|
|
|
return self._watcher
|
|
|
|
def set_child_watcher(self, watcher):
|
|
"""Set the watcher for child processes."""
|
|
|
|
assert watcher is None or isinstance(watcher, AbstractChildWatcher)
|
|
|
|
if self._watcher is not None:
|
|
self._watcher.close()
|
|
|
|
self._watcher = watcher
|
|
|
|
SelectorEventLoop = _UnixSelectorEventLoop
|
|
DefaultEventLoopPolicy = _UnixDefaultEventLoopPolicy
|