mirror of
https://github.com/python/cpython.git
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4a2dbeb0d3
logger.log() is now responsible to format the timeout. It might be faster if the log is disabled for DEBUG level, but it's also more readable and fix an issue with Python 2.6 in the Trollius project.
650 lines
24 KiB
Python
650 lines
24 KiB
Python
"""Base implementation of event loop.
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The event loop can be broken up into a multiplexer (the part
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responsible for notifying us of IO events) and the event loop proper,
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which wraps a multiplexer with functionality for scheduling callbacks,
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immediately or at a given time in the future.
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Whenever a public API takes a callback, subsequent positional
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arguments will be passed to the callback if/when it is called. This
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avoids the proliferation of trivial lambdas implementing closures.
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Keyword arguments for the callback are not supported; this is a
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conscious design decision, leaving the door open for keyword arguments
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to modify the meaning of the API call itself.
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"""
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import collections
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import concurrent.futures
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import heapq
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import logging
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import socket
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import subprocess
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import time
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import os
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import sys
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from . import events
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from . import futures
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from . import tasks
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from .log import logger
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__all__ = ['BaseEventLoop', 'Server']
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# Argument for default thread pool executor creation.
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_MAX_WORKERS = 5
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class _StopError(BaseException):
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"""Raised to stop the event loop."""
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def _raise_stop_error(*args):
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raise _StopError
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class Server(events.AbstractServer):
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def __init__(self, loop, sockets):
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self.loop = loop
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self.sockets = sockets
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self.active_count = 0
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self.waiters = []
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def attach(self, transport):
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assert self.sockets is not None
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self.active_count += 1
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def detach(self, transport):
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assert self.active_count > 0
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self.active_count -= 1
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if self.active_count == 0 and self.sockets is None:
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self._wakeup()
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def close(self):
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sockets = self.sockets
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if sockets is not None:
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self.sockets = None
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for sock in sockets:
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self.loop._stop_serving(sock)
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if self.active_count == 0:
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self._wakeup()
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def _wakeup(self):
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waiters = self.waiters
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self.waiters = None
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for waiter in waiters:
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if not waiter.done():
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waiter.set_result(waiter)
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@tasks.coroutine
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def wait_closed(self):
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if self.sockets is None or self.waiters is None:
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return
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waiter = futures.Future(loop=self.loop)
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self.waiters.append(waiter)
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yield from waiter
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class BaseEventLoop(events.AbstractEventLoop):
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def __init__(self):
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self._ready = collections.deque()
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self._scheduled = []
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self._default_executor = None
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self._internal_fds = 0
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self._running = False
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def _make_socket_transport(self, sock, protocol, waiter=None, *,
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extra=None, server=None):
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"""Create socket transport."""
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raise NotImplementedError
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def _make_ssl_transport(self, rawsock, protocol, sslcontext, waiter, *,
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server_side=False, server_hostname=None,
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extra=None, server=None):
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"""Create SSL transport."""
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raise NotImplementedError
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def _make_datagram_transport(self, sock, protocol,
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address=None, extra=None):
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"""Create datagram transport."""
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raise NotImplementedError
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def _make_read_pipe_transport(self, pipe, protocol, waiter=None,
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extra=None):
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"""Create read pipe transport."""
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raise NotImplementedError
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def _make_write_pipe_transport(self, pipe, protocol, waiter=None,
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extra=None):
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"""Create write pipe transport."""
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raise NotImplementedError
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@tasks.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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"""Create subprocess transport."""
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raise NotImplementedError
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def _read_from_self(self):
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"""XXX"""
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raise NotImplementedError
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def _write_to_self(self):
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"""XXX"""
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raise NotImplementedError
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def _process_events(self, event_list):
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"""Process selector events."""
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raise NotImplementedError
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def run_forever(self):
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"""Run until stop() is called."""
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if self._running:
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raise RuntimeError('Event loop is running.')
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self._running = True
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try:
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while True:
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try:
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self._run_once()
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except _StopError:
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break
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finally:
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self._running = False
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def run_until_complete(self, future):
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"""Run until the Future is done.
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If the argument is a coroutine, it is wrapped in a Task.
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XXX TBD: It would be disastrous to call run_until_complete()
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with the same coroutine twice -- it would wrap it in two
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different Tasks and that can't be good.
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Return the Future's result, or raise its exception.
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"""
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future = tasks.async(future, loop=self)
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future.add_done_callback(_raise_stop_error)
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self.run_forever()
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future.remove_done_callback(_raise_stop_error)
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if not future.done():
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raise RuntimeError('Event loop stopped before Future completed.')
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return future.result()
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def stop(self):
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"""Stop running the event loop.
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Every callback scheduled before stop() is called will run.
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Callback scheduled after stop() is called won't. However,
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those callbacks will run if run() is called again later.
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"""
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self.call_soon(_raise_stop_error)
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def close(self):
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"""Close the event loop.
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This clears the queues and shuts down the executor,
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but does not wait for the executor to finish.
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"""
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self._ready.clear()
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self._scheduled.clear()
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executor = self._default_executor
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if executor is not None:
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self._default_executor = None
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executor.shutdown(wait=False)
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def is_running(self):
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"""Returns running status of event loop."""
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return self._running
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def time(self):
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"""Return the time according to the event loop's clock."""
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return time.monotonic()
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def call_later(self, delay, callback, *args):
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"""Arrange for a callback to be called at a given time.
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Return a Handle: an opaque object with a cancel() method that
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can be used to cancel the call.
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The delay can be an int or float, expressed in seconds. It is
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always a relative time.
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Each callback will be called exactly once. If two callbacks
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are scheduled for exactly the same time, it undefined which
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will be called first.
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Any positional arguments after the callback will be passed to
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the callback when it is called.
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"""
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return self.call_at(self.time() + delay, callback, *args)
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def call_at(self, when, callback, *args):
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"""Like call_later(), but uses an absolute time."""
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timer = events.TimerHandle(when, callback, args)
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heapq.heappush(self._scheduled, timer)
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return timer
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def call_soon(self, callback, *args):
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"""Arrange for a callback to be called as soon as possible.
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This operates as a FIFO queue, callbacks are called in the
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order in which they are registered. Each callback will be
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called exactly once.
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Any positional arguments after the callback will be passed to
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the callback when it is called.
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"""
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handle = events.make_handle(callback, args)
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self._ready.append(handle)
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return handle
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def call_soon_threadsafe(self, callback, *args):
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"""XXX"""
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handle = self.call_soon(callback, *args)
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self._write_to_self()
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return handle
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def run_in_executor(self, executor, callback, *args):
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if isinstance(callback, events.Handle):
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assert not args
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assert not isinstance(callback, events.TimerHandle)
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if callback._cancelled:
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f = futures.Future(loop=self)
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f.set_result(None)
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return f
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callback, args = callback._callback, callback._args
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if executor is None:
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executor = self._default_executor
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if executor is None:
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executor = concurrent.futures.ThreadPoolExecutor(_MAX_WORKERS)
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self._default_executor = executor
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return futures.wrap_future(executor.submit(callback, *args), loop=self)
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def set_default_executor(self, executor):
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self._default_executor = executor
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def getaddrinfo(self, host, port, *,
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family=0, type=0, proto=0, flags=0):
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return self.run_in_executor(None, socket.getaddrinfo,
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host, port, family, type, proto, flags)
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def getnameinfo(self, sockaddr, flags=0):
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return self.run_in_executor(None, socket.getnameinfo, sockaddr, flags)
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@tasks.coroutine
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def create_connection(self, protocol_factory, host=None, port=None, *,
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ssl=None, family=0, proto=0, flags=0, sock=None,
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local_addr=None, server_hostname=None):
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"""XXX"""
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if server_hostname is not None and not ssl:
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raise ValueError('server_hostname is only meaningful with ssl')
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if server_hostname is None and ssl:
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# Use host as default for server_hostname. It is an error
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# if host is empty or not set, e.g. when an
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# already-connected socket was passed or when only a port
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# is given. To avoid this error, you can pass
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# server_hostname='' -- this will bypass the hostname
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# check. (This also means that if host is a numeric
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# IP/IPv6 address, we will attempt to verify that exact
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# address; this will probably fail, but it is possible to
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# create a certificate for a specific IP address, so we
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# don't judge it here.)
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if not host:
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raise ValueError('You must set server_hostname '
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'when using ssl without a host')
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server_hostname = host
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if host is not None or port is not None:
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if sock is not None:
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raise ValueError(
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'host/port and sock can not be specified at the same time')
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f1 = self.getaddrinfo(
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host, port, family=family,
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type=socket.SOCK_STREAM, proto=proto, flags=flags)
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fs = [f1]
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if local_addr is not None:
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f2 = self.getaddrinfo(
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*local_addr, family=family,
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type=socket.SOCK_STREAM, proto=proto, flags=flags)
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fs.append(f2)
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else:
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f2 = None
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yield from tasks.wait(fs, loop=self)
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infos = f1.result()
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if not infos:
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raise OSError('getaddrinfo() returned empty list')
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if f2 is not None:
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laddr_infos = f2.result()
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if not laddr_infos:
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raise OSError('getaddrinfo() returned empty list')
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exceptions = []
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for family, type, proto, cname, address in infos:
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try:
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sock = socket.socket(family=family, type=type, proto=proto)
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sock.setblocking(False)
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if f2 is not None:
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for _, _, _, _, laddr in laddr_infos:
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try:
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sock.bind(laddr)
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break
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except OSError as exc:
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exc = OSError(
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exc.errno, 'error while '
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'attempting to bind on address '
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'{!r}: {}'.format(
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laddr, exc.strerror.lower()))
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exceptions.append(exc)
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else:
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sock.close()
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sock = None
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continue
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yield from self.sock_connect(sock, address)
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except OSError as exc:
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if sock is not None:
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sock.close()
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exceptions.append(exc)
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else:
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break
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else:
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if len(exceptions) == 1:
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raise exceptions[0]
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else:
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# If they all have the same str(), raise one.
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model = str(exceptions[0])
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if all(str(exc) == model for exc in exceptions):
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raise exceptions[0]
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# Raise a combined exception so the user can see all
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# the various error messages.
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raise OSError('Multiple exceptions: {}'.format(
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', '.join(str(exc) for exc in exceptions)))
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elif sock is None:
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raise ValueError(
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'host and port was not specified and no sock specified')
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sock.setblocking(False)
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protocol = protocol_factory()
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waiter = futures.Future(loop=self)
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if ssl:
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sslcontext = None if isinstance(ssl, bool) else ssl
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transport = self._make_ssl_transport(
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sock, protocol, sslcontext, waiter,
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server_side=False, server_hostname=server_hostname)
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else:
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transport = self._make_socket_transport(sock, protocol, waiter)
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yield from waiter
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return transport, protocol
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@tasks.coroutine
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def create_datagram_endpoint(self, protocol_factory,
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local_addr=None, remote_addr=None, *,
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family=0, proto=0, flags=0):
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"""Create datagram connection."""
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if not (local_addr or remote_addr):
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if family == 0:
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raise ValueError('unexpected address family')
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addr_pairs_info = (((family, proto), (None, None)),)
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else:
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# join addresss by (family, protocol)
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addr_infos = collections.OrderedDict()
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for idx, addr in ((0, local_addr), (1, remote_addr)):
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if addr is not None:
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assert isinstance(addr, tuple) and len(addr) == 2, (
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'2-tuple is expected')
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infos = yield from self.getaddrinfo(
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*addr, family=family, type=socket.SOCK_DGRAM,
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proto=proto, flags=flags)
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if not infos:
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raise OSError('getaddrinfo() returned empty list')
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for fam, _, pro, _, address in infos:
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key = (fam, pro)
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if key not in addr_infos:
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addr_infos[key] = [None, None]
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addr_infos[key][idx] = address
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# each addr has to have info for each (family, proto) pair
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addr_pairs_info = [
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(key, addr_pair) for key, addr_pair in addr_infos.items()
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if not ((local_addr and addr_pair[0] is None) or
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(remote_addr and addr_pair[1] is None))]
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if not addr_pairs_info:
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raise ValueError('can not get address information')
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exceptions = []
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for ((family, proto),
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(local_address, remote_address)) in addr_pairs_info:
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sock = None
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r_addr = None
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try:
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sock = socket.socket(
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family=family, type=socket.SOCK_DGRAM, proto=proto)
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sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
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sock.setblocking(False)
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if local_addr:
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sock.bind(local_address)
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if remote_addr:
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yield from self.sock_connect(sock, remote_address)
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r_addr = remote_address
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except OSError as exc:
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if sock is not None:
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sock.close()
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exceptions.append(exc)
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else:
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break
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else:
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raise exceptions[0]
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protocol = protocol_factory()
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transport = self._make_datagram_transport(sock, protocol, r_addr)
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return transport, protocol
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@tasks.coroutine
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def create_server(self, protocol_factory, host=None, port=None,
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*,
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family=socket.AF_UNSPEC,
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flags=socket.AI_PASSIVE,
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sock=None,
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backlog=100,
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ssl=None,
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reuse_address=None):
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"""XXX"""
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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 host is not None or port is not None:
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if sock is not None:
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raise ValueError(
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'host/port and sock can not be specified at the same time')
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AF_INET6 = getattr(socket, 'AF_INET6', 0)
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if reuse_address is None:
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reuse_address = os.name == 'posix' and sys.platform != 'cygwin'
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sockets = []
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if host == '':
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host = None
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infos = yield from self.getaddrinfo(
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host, port, family=family,
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type=socket.SOCK_STREAM, proto=0, flags=flags)
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if not infos:
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raise OSError('getaddrinfo() returned empty list')
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completed = False
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try:
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for res in infos:
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af, socktype, proto, canonname, sa = res
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try:
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sock = socket.socket(af, socktype, proto)
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except socket.error:
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# Assume it's a bad family/type/protocol combination.
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continue
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sockets.append(sock)
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if reuse_address:
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sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR,
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True)
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# Disable IPv4/IPv6 dual stack support (enabled by
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# default on Linux) which makes a single socket
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# listen on both address families.
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if af == AF_INET6 and hasattr(socket, 'IPPROTO_IPV6'):
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sock.setsockopt(socket.IPPROTO_IPV6,
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socket.IPV6_V6ONLY,
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True)
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try:
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sock.bind(sa)
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except OSError as err:
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raise OSError(err.errno, 'error while attempting '
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'to bind on address %r: %s'
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% (sa, err.strerror.lower()))
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completed = True
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finally:
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if not completed:
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for sock in sockets:
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sock.close()
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else:
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if sock is None:
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raise ValueError(
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'host and port was not specified and no sock specified')
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sockets = [sock]
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server = Server(self, sockets)
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for sock in sockets:
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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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@tasks.coroutine
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def connect_read_pipe(self, protocol_factory, pipe):
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protocol = protocol_factory()
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waiter = futures.Future(loop=self)
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transport = self._make_read_pipe_transport(pipe, protocol, waiter)
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yield from waiter
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return transport, protocol
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@tasks.coroutine
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|
def connect_write_pipe(self, protocol_factory, pipe):
|
|
protocol = protocol_factory()
|
|
waiter = futures.Future(loop=self)
|
|
transport = self._make_write_pipe_transport(pipe, protocol, waiter)
|
|
yield from waiter
|
|
return transport, protocol
|
|
|
|
@tasks.coroutine
|
|
def subprocess_shell(self, protocol_factory, cmd, *, stdin=subprocess.PIPE,
|
|
stdout=subprocess.PIPE, stderr=subprocess.PIPE,
|
|
universal_newlines=False, shell=True, bufsize=0,
|
|
**kwargs):
|
|
assert not universal_newlines, "universal_newlines must be False"
|
|
assert shell, "shell must be True"
|
|
assert isinstance(cmd, str), cmd
|
|
protocol = protocol_factory()
|
|
transport = yield from self._make_subprocess_transport(
|
|
protocol, cmd, True, stdin, stdout, stderr, bufsize, **kwargs)
|
|
return transport, protocol
|
|
|
|
@tasks.coroutine
|
|
def subprocess_exec(self, protocol_factory, *args, stdin=subprocess.PIPE,
|
|
stdout=subprocess.PIPE, stderr=subprocess.PIPE,
|
|
universal_newlines=False, shell=False, bufsize=0,
|
|
**kwargs):
|
|
assert not universal_newlines, "universal_newlines must be False"
|
|
assert not shell, "shell must be False"
|
|
protocol = protocol_factory()
|
|
transport = yield from self._make_subprocess_transport(
|
|
protocol, args, False, stdin, stdout, stderr, bufsize, **kwargs)
|
|
return transport, protocol
|
|
|
|
def _add_callback(self, handle):
|
|
"""Add a Handle to ready or scheduled."""
|
|
assert isinstance(handle, events.Handle), 'A Handle is required here'
|
|
if handle._cancelled:
|
|
return
|
|
if isinstance(handle, events.TimerHandle):
|
|
heapq.heappush(self._scheduled, handle)
|
|
else:
|
|
self._ready.append(handle)
|
|
|
|
def _add_callback_signalsafe(self, handle):
|
|
"""Like _add_callback() but called from a signal handler."""
|
|
self._add_callback(handle)
|
|
self._write_to_self()
|
|
|
|
def _run_once(self):
|
|
"""Run one full iteration of the event loop.
|
|
|
|
This calls all currently ready callbacks, polls for I/O,
|
|
schedules the resulting callbacks, and finally schedules
|
|
'call_later' callbacks.
|
|
"""
|
|
# Remove delayed calls that were cancelled from head of queue.
|
|
while self._scheduled and self._scheduled[0]._cancelled:
|
|
heapq.heappop(self._scheduled)
|
|
|
|
timeout = None
|
|
if self._ready:
|
|
timeout = 0
|
|
elif self._scheduled:
|
|
# Compute the desired timeout.
|
|
when = self._scheduled[0]._when
|
|
deadline = max(0, when - self.time())
|
|
if timeout is None:
|
|
timeout = deadline
|
|
else:
|
|
timeout = min(timeout, deadline)
|
|
|
|
# TODO: Instrumentation only in debug mode?
|
|
if logger.isEnabledFor(logging.INFO):
|
|
t0 = self.time()
|
|
event_list = self._selector.select(timeout)
|
|
t1 = self.time()
|
|
if t1-t0 >= 1:
|
|
level = logging.INFO
|
|
else:
|
|
level = logging.DEBUG
|
|
if timeout is not None:
|
|
logger.log(level, 'poll %.3f took %.3f seconds',
|
|
timeout, t1-t0)
|
|
else:
|
|
logger.log(level, 'poll took %.3f seconds', t1-t0)
|
|
else:
|
|
event_list = self._selector.select(timeout)
|
|
self._process_events(event_list)
|
|
|
|
# Handle 'later' callbacks that are ready.
|
|
now = self.time()
|
|
while self._scheduled:
|
|
handle = self._scheduled[0]
|
|
if handle._when > now:
|
|
break
|
|
handle = heapq.heappop(self._scheduled)
|
|
self._ready.append(handle)
|
|
|
|
# This is the only place where callbacks are actually *called*.
|
|
# All other places just add them to ready.
|
|
# Note: We run all currently scheduled callbacks, but not any
|
|
# callbacks scheduled by callbacks run this time around --
|
|
# they will be run the next time (after another I/O poll).
|
|
# Use an idiom that is threadsafe without using locks.
|
|
ntodo = len(self._ready)
|
|
for i in range(ntodo):
|
|
handle = self._ready.popleft()
|
|
if not handle._cancelled:
|
|
handle._run()
|
|
handle = None # Needed to break cycles when an exception occurs.
|