Mini Shell
"""Base implementation of event loop.
The event loop can be broken up into a multiplexer (the part
responsible for notifying us of I/O events) and the event loop proper,
which wraps a multiplexer with functionality for scheduling callbacks,
immediately or at a given time in the future.
Whenever a public API takes a callback, subsequent positional
arguments will be passed to the callback if/when it is called. This
avoids the proliferation of trivial lambdas implementing closures.
Keyword arguments for the callback are not supported; this is a
conscious design decision, leaving the door open for keyword arguments
to modify the meaning of the API call itself.
"""
import collections
import concurrent.futures
import heapq
import inspect
import itertools
import logging
import os
import socket
import subprocess
import threading
import time
import traceback
import sys
import warnings
import weakref
from . import compat
from . import coroutines
from . import events
from . import futures
from . import tasks
from .coroutines import coroutine
from .log import logger
__all__ = ['BaseEventLoop']
# Minimum number of _scheduled timer handles before cleanup of
# cancelled handles is performed.
_MIN_SCHEDULED_TIMER_HANDLES = 100
# Minimum fraction of _scheduled timer handles that are cancelled
# before cleanup of cancelled handles is performed.
_MIN_CANCELLED_TIMER_HANDLES_FRACTION = 0.5
# Exceptions which must not call the exception handler in fatal error
# methods (_fatal_error())
_FATAL_ERROR_IGNORE = (BrokenPipeError,
ConnectionResetError, ConnectionAbortedError)
_HAS_IPv6 = hasattr(socket, 'AF_INET6')
# Maximum timeout passed to select to avoid OS limitations
MAXIMUM_SELECT_TIMEOUT = 24 * 3600
def _format_handle(handle):
cb = handle._callback
if isinstance(getattr(cb, '__self__', None), tasks.Task):
# format the task
return repr(cb.__self__)
else:
return str(handle)
def _format_pipe(fd):
if fd == subprocess.PIPE:
return '<pipe>'
elif fd == subprocess.STDOUT:
return '<stdout>'
else:
return repr(fd)
def _set_reuseport(sock):
if not hasattr(socket, 'SO_REUSEPORT'):
raise ValueError('reuse_port not supported by socket module')
else:
try:
sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEPORT, 1)
except OSError:
raise ValueError('reuse_port not supported by socket module, '
'SO_REUSEPORT defined but not implemented.')
def _is_stream_socket(sock_type):
if hasattr(socket, 'SOCK_NONBLOCK'):
# Linux's socket.type is a bitmask that can include extra info
# about socket (like SOCK_NONBLOCK bit), therefore we can't do simple
# `sock_type == socket.SOCK_STREAM`, see
# https://github.com/torvalds/linux/blob/v4.13/include/linux/net.h#L77
# for more details.
return (sock_type & 0xF) == socket.SOCK_STREAM
else:
return sock_type == socket.SOCK_STREAM
def _is_dgram_socket(sock_type):
if hasattr(socket, 'SOCK_NONBLOCK'):
# See the comment in `_is_stream_socket`.
return (sock_type & 0xF) == socket.SOCK_DGRAM
else:
return sock_type == socket.SOCK_DGRAM
def _ipaddr_info(host, port, family, type, proto):
# Try to skip getaddrinfo if "host" is already an IP. Users might have
# handled name resolution in their own code and pass in resolved IPs.
if not hasattr(socket, 'inet_pton'):
return
if proto not in {0, socket.IPPROTO_TCP, socket.IPPROTO_UDP} or \
host is None:
return None
if _is_stream_socket(type):
proto = socket.IPPROTO_TCP
elif _is_dgram_socket(type):
proto = socket.IPPROTO_UDP
else:
return None
if port is None:
port = 0
elif isinstance(port, bytes) and port == b'':
port = 0
elif isinstance(port, str) and port == '':
port = 0
else:
# If port's a service name like "http", don't skip getaddrinfo.
try:
port = int(port)
except (TypeError, ValueError):
return None
if family == socket.AF_UNSPEC:
afs = [socket.AF_INET]
if _HAS_IPv6:
afs.append(socket.AF_INET6)
else:
afs = [family]
if isinstance(host, bytes):
host = host.decode('idna')
if '%' in host:
# Linux's inet_pton doesn't accept an IPv6 zone index after host,
# like '::1%lo0'.
return None
for af in afs:
try:
socket.inet_pton(af, host)
# The host has already been resolved.
if _HAS_IPv6 and af == socket.AF_INET6:
return af, type, proto, '', (host, port, 0, 0)
else:
return af, type, proto, '', (host, port)
except OSError:
pass
# "host" is not an IP address.
return None
def _ensure_resolved(address, *, family=0, type=socket.SOCK_STREAM, proto=0,
flags=0, loop):
host, port = address[:2]
info = _ipaddr_info(host, port, family, type, proto)
if info is not None:
# "host" is already a resolved IP.
fut = loop.create_future()
fut.set_result([info])
return fut
else:
return loop.getaddrinfo(host, port, family=family, type=type,
proto=proto, flags=flags)
if hasattr(socket, 'TCP_NODELAY'):
def _set_nodelay(sock):
if (sock.family in {socket.AF_INET, socket.AF_INET6} and
_is_stream_socket(sock.type) and
sock.proto == socket.IPPROTO_TCP):
sock.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, 1)
else:
def _set_nodelay(sock):
pass
def _run_until_complete_cb(fut):
exc = fut._exception
if (isinstance(exc, BaseException)
and not isinstance(exc, Exception)):
# Issue #22429: run_forever() already finished, no need to
# stop it.
return
fut._loop.stop()
class Server(events.AbstractServer):
def __init__(self, loop, sockets):
self._loop = loop
self.sockets = sockets
self._active_count = 0
self._waiters = []
def __repr__(self):
return '<%s sockets=%r>' % (self.__class__.__name__, self.sockets)
def _attach(self):
assert self.sockets is not None
self._active_count += 1
def _detach(self):
assert self._active_count > 0
self._active_count -= 1
if self._active_count == 0 and self.sockets is None:
self._wakeup()
def close(self):
sockets = self.sockets
if sockets is None:
return
self.sockets = None
for sock in sockets:
self._loop._stop_serving(sock)
if self._active_count == 0:
self._wakeup()
def _wakeup(self):
waiters = self._waiters
self._waiters = None
for waiter in waiters:
if not waiter.done():
waiter.set_result(waiter)
@coroutine
def wait_closed(self):
if self.sockets is None or self._waiters is None:
return
waiter = self._loop.create_future()
self._waiters.append(waiter)
yield from waiter
class BaseEventLoop(events.AbstractEventLoop):
def __init__(self):
self._timer_cancelled_count = 0
self._closed = False
self._stopping = False
self._ready = collections.deque()
self._scheduled = []
self._default_executor = None
self._internal_fds = 0
# Identifier of the thread running the event loop, or None if the
# event loop is not running
self._thread_id = None
self._clock_resolution = time.get_clock_info('monotonic').resolution
self._exception_handler = None
self.set_debug((not sys.flags.ignore_environment
and bool(os.environ.get('PYTHONASYNCIODEBUG'))))
# In debug mode, if the execution of a callback or a step of a task
# exceed this duration in seconds, the slow callback/task is logged.
self.slow_callback_duration = 0.1
self._current_handle = None
self._task_factory = None
self._coroutine_wrapper_set = False
if hasattr(sys, 'get_asyncgen_hooks'):
# Python >= 3.6
# A weak set of all asynchronous generators that are
# being iterated by the loop.
self._asyncgens = weakref.WeakSet()
else:
self._asyncgens = None
# Set to True when `loop.shutdown_asyncgens` is called.
self._asyncgens_shutdown_called = False
def __repr__(self):
return ('<%s running=%s closed=%s debug=%s>'
% (self.__class__.__name__, self.is_running(),
self.is_closed(), self.get_debug()))
def create_future(self):
"""Create a Future object attached to the loop."""
return futures.Future(loop=self)
def create_task(self, coro):
"""Schedule a coroutine object.
Return a task object.
"""
self._check_closed()
if self._task_factory is None:
task = tasks.Task(coro, loop=self)
if task._source_traceback:
del task._source_traceback[-1]
else:
task = self._task_factory(self, coro)
return task
def set_task_factory(self, factory):
"""Set a task factory that will be used by loop.create_task().
If factory is None the default task factory will be set.
If factory is a callable, it should have a signature matching
'(loop, coro)', where 'loop' will be a reference to the active
event loop, 'coro' will be a coroutine object. The callable
must return a Future.
"""
if factory is not None and not callable(factory):
raise TypeError('task factory must be a callable or None')
self._task_factory = factory
def get_task_factory(self):
"""Return a task factory, or None if the default one is in use."""
return self._task_factory
def _make_socket_transport(self, sock, protocol, waiter=None, *,
extra=None, server=None):
"""Create socket transport."""
raise NotImplementedError
def _make_ssl_transport(self, rawsock, protocol, sslcontext, waiter=None,
*, server_side=False, server_hostname=None,
extra=None, server=None):
"""Create SSL transport."""
raise NotImplementedError
def _make_datagram_transport(self, sock, protocol,
address=None, waiter=None, extra=None):
"""Create datagram transport."""
raise NotImplementedError
def _make_read_pipe_transport(self, pipe, protocol, waiter=None,
extra=None):
"""Create read pipe transport."""
raise NotImplementedError
def _make_write_pipe_transport(self, pipe, protocol, waiter=None,
extra=None):
"""Create write pipe transport."""
raise NotImplementedError
@coroutine
def _make_subprocess_transport(self, protocol, args, shell,
stdin, stdout, stderr, bufsize,
extra=None, **kwargs):
"""Create subprocess transport."""
raise NotImplementedError
def _write_to_self(self):
"""Write a byte to self-pipe, to wake up the event loop.
This may be called from a different thread.
The subclass is responsible for implementing the self-pipe.
"""
raise NotImplementedError
def _process_events(self, event_list):
"""Process selector events."""
raise NotImplementedError
def _check_closed(self):
if self._closed:
raise RuntimeError('Event loop is closed')
def _asyncgen_finalizer_hook(self, agen):
self._asyncgens.discard(agen)
if not self.is_closed():
self.call_soon_threadsafe(self.create_task, agen.aclose())
def _asyncgen_firstiter_hook(self, agen):
if self._asyncgens_shutdown_called:
warnings.warn(
"asynchronous generator {!r} was scheduled after "
"loop.shutdown_asyncgens() call".format(agen),
ResourceWarning, source=self)
self._asyncgens.add(agen)
@coroutine
def shutdown_asyncgens(self):
"""Shutdown all active asynchronous generators."""
self._asyncgens_shutdown_called = True
if self._asyncgens is None or not len(self._asyncgens):
# If Python version is <3.6 or we don't have any asynchronous
# generators alive.
return
closing_agens = list(self._asyncgens)
self._asyncgens.clear()
shutdown_coro = tasks.gather(
*[ag.aclose() for ag in closing_agens],
return_exceptions=True,
loop=self)
results = yield from shutdown_coro
for result, agen in zip(results, closing_agens):
if isinstance(result, Exception):
self.call_exception_handler({
'message': 'an error occurred during closing of '
'asynchronous generator {!r}'.format(agen),
'exception': result,
'asyncgen': agen
})
def run_forever(self):
"""Run until stop() is called."""
self._check_closed()
if self.is_running():
raise RuntimeError('This event loop is already running')
if events._get_running_loop() is not None:
raise RuntimeError(
'Cannot run the event loop while another loop is running')
self._set_coroutine_wrapper(self._debug)
self._thread_id = threading.get_ident()
if self._asyncgens is not None:
old_agen_hooks = sys.get_asyncgen_hooks()
sys.set_asyncgen_hooks(firstiter=self._asyncgen_firstiter_hook,
finalizer=self._asyncgen_finalizer_hook)
try:
events._set_running_loop(self)
while True:
self._run_once()
if self._stopping:
break
finally:
self._stopping = False
self._thread_id = None
events._set_running_loop(None)
self._set_coroutine_wrapper(False)
if self._asyncgens is not None:
sys.set_asyncgen_hooks(*old_agen_hooks)
def run_until_complete(self, future):
"""Run until the Future is done.
If the argument is a coroutine, it is wrapped in a Task.
WARNING: It would be disastrous to call run_until_complete()
with the same coroutine twice -- it would wrap it in two
different Tasks and that can't be good.
Return the Future's result, or raise its exception.
"""
self._check_closed()
new_task = not futures.isfuture(future)
future = tasks.ensure_future(future, loop=self)
if new_task:
# An exception is raised if the future didn't complete, so there
# is no need to log the "destroy pending task" message
future._log_destroy_pending = False
future.add_done_callback(_run_until_complete_cb)
try:
self.run_forever()
except:
if new_task and future.done() and not future.cancelled():
# The coroutine raised a BaseException. Consume the exception
# to not log a warning, the caller doesn't have access to the
# local task.
future.exception()
raise
finally:
future.remove_done_callback(_run_until_complete_cb)
if not future.done():
raise RuntimeError('Event loop stopped before Future completed.')
return future.result()
def stop(self):
"""Stop running the event loop.
Every callback already scheduled will still run. This simply informs
run_forever to stop looping after a complete iteration.
"""
self._stopping = True
def close(self):
"""Close the event loop.
This clears the queues and shuts down the executor,
but does not wait for the executor to finish.
The event loop must not be running.
"""
if self.is_running():
raise RuntimeError("Cannot close a running event loop")
if self._closed:
return
if self._debug:
logger.debug("Close %r", self)
self._closed = True
self._ready.clear()
self._scheduled.clear()
executor = self._default_executor
if executor is not None:
self._default_executor = None
executor.shutdown(wait=False)
def is_closed(self):
"""Returns True if the event loop was closed."""
return self._closed
# On Python 3.3 and older, objects with a destructor part of a reference
# cycle are never destroyed. It's not more the case on Python 3.4 thanks
# to the PEP 442.
if compat.PY34:
def __del__(self):
if not self.is_closed():
warnings.warn("unclosed event loop %r" % self, ResourceWarning,
source=self)
if not self.is_running():
self.close()
def is_running(self):
"""Returns True if the event loop is running."""
return (self._thread_id is not None)
def time(self):
"""Return the time according to the event loop's clock.
This is a float expressed in seconds since an epoch, but the
epoch, precision, accuracy and drift are unspecified and may
differ per event loop.
"""
return time.monotonic()
def call_later(self, delay, callback, *args):
"""Arrange for a callback to be called at a given time.
Return a Handle: an opaque object with a cancel() method that
can be used to cancel the call.
The delay can be an int or float, expressed in seconds. It is
always relative to the current time.
Each callback will be called exactly once. If two callbacks
are scheduled for exactly the same time, it undefined which
will be called first.
Any positional arguments after the callback will be passed to
the callback when it is called.
"""
timer = self.call_at(self.time() + delay, callback, *args)
if timer._source_traceback:
del timer._source_traceback[-1]
return timer
def call_at(self, when, callback, *args):
"""Like call_later(), but uses an absolute time.
Absolute time corresponds to the event loop's time() method.
"""
self._check_closed()
if self._debug:
self._check_thread()
self._check_callback(callback, 'call_at')
timer = events.TimerHandle(when, callback, args, self)
if timer._source_traceback:
del timer._source_traceback[-1]
heapq.heappush(self._scheduled, timer)
timer._scheduled = True
return timer
def call_soon(self, callback, *args):
"""Arrange for a callback to be called as soon as possible.
This operates as a FIFO queue: callbacks are called in the
order in which they are registered. Each callback will be
called exactly once.
Any positional arguments after the callback will be passed to
the callback when it is called.
"""
self._check_closed()
if self._debug:
self._check_thread()
self._check_callback(callback, 'call_soon')
handle = self._call_soon(callback, args)
if handle._source_traceback:
del handle._source_traceback[-1]
return handle
def _check_callback(self, callback, method):
if (coroutines.iscoroutine(callback) or
coroutines.iscoroutinefunction(callback)):
raise TypeError(
"coroutines cannot be used with {}()".format(method))
if not callable(callback):
raise TypeError(
'a callable object was expected by {}(), got {!r}'.format(
method, callback))
def _call_soon(self, callback, args):
handle = events.Handle(callback, args, self)
if handle._source_traceback:
del handle._source_traceback[-1]
self._ready.append(handle)
return handle
def _check_thread(self):
"""Check that the current thread is the thread running the event loop.
Non-thread-safe methods of this class make this assumption and will
likely behave incorrectly when the assumption is violated.
Should only be called when (self._debug == True). The caller is
responsible for checking this condition for performance reasons.
"""
if self._thread_id is None:
return
thread_id = threading.get_ident()
if thread_id != self._thread_id:
raise RuntimeError(
"Non-thread-safe operation invoked on an event loop other "
"than the current one")
def call_soon_threadsafe(self, callback, *args):
"""Like call_soon(), but thread-safe."""
self._check_closed()
if self._debug:
self._check_callback(callback, 'call_soon_threadsafe')
handle = self._call_soon(callback, args)
if handle._source_traceback:
del handle._source_traceback[-1]
self._write_to_self()
return handle
def run_in_executor(self, executor, func, *args):
self._check_closed()
if self._debug:
self._check_callback(func, 'run_in_executor')
if executor is None:
executor = self._default_executor
if executor is None:
executor = concurrent.futures.ThreadPoolExecutor()
self._default_executor = executor
return futures.wrap_future(executor.submit(func, *args), loop=self)
def set_default_executor(self, executor):
self._default_executor = executor
def _getaddrinfo_debug(self, host, port, family, type, proto, flags):
msg = ["%s:%r" % (host, port)]
if family:
msg.append('family=%r' % family)
if type:
msg.append('type=%r' % type)
if proto:
msg.append('proto=%r' % proto)
if flags:
msg.append('flags=%r' % flags)
msg = ', '.join(msg)
logger.debug('Get address info %s', msg)
t0 = self.time()
addrinfo = socket.getaddrinfo(host, port, family, type, proto, flags)
dt = self.time() - t0
msg = ('Getting address info %s took %.3f ms: %r'
% (msg, dt * 1e3, addrinfo))
if dt >= self.slow_callback_duration:
logger.info(msg)
else:
logger.debug(msg)
return addrinfo
def getaddrinfo(self, host, port, *,
family=0, type=0, proto=0, flags=0):
if self._debug:
return self.run_in_executor(None, self._getaddrinfo_debug,
host, port, family, type, proto, flags)
else:
return self.run_in_executor(None, socket.getaddrinfo,
host, port, family, type, proto, flags)
def getnameinfo(self, sockaddr, flags=0):
return self.run_in_executor(None, socket.getnameinfo, sockaddr, flags)
@coroutine
def create_connection(self, protocol_factory, host=None, port=None, *,
ssl=None, family=0, proto=0, flags=0, sock=None,
local_addr=None, server_hostname=None):
"""Connect to a TCP server.
Create a streaming transport connection to a given Internet host and
port: socket family AF_INET or socket.AF_INET6 depending on host (or
family if specified), socket type SOCK_STREAM. protocol_factory must be
a callable returning a protocol instance.
This method is a coroutine which will try to establish the connection
in the background. When successful, the coroutine returns a
(transport, protocol) pair.
"""
if server_hostname is not None and not ssl:
raise ValueError('server_hostname is only meaningful with ssl')
if server_hostname is None and ssl:
# Use host as default for server_hostname. It is an error
# if host is empty or not set, e.g. when an
# already-connected socket was passed or when only a port
# is given. To avoid this error, you can pass
# server_hostname='' -- this will bypass the hostname
# check. (This also means that if host is a numeric
# IP/IPv6 address, we will attempt to verify that exact
# address; this will probably fail, but it is possible to
# create a certificate for a specific IP address, so we
# don't judge it here.)
if not host:
raise ValueError('You must set server_hostname '
'when using ssl without a host')
server_hostname = host
if host is not None or port is not None:
if sock is not None:
raise ValueError(
'host/port and sock can not be specified at the same time')
f1 = _ensure_resolved((host, port), family=family,
type=socket.SOCK_STREAM, proto=proto,
flags=flags, loop=self)
fs = [f1]
if local_addr is not None:
f2 = _ensure_resolved(local_addr, family=family,
type=socket.SOCK_STREAM, proto=proto,
flags=flags, loop=self)
fs.append(f2)
else:
f2 = None
yield from tasks.wait(fs, loop=self)
infos = f1.result()
if not infos:
raise OSError('getaddrinfo() returned empty list')
if f2 is not None:
laddr_infos = f2.result()
if not laddr_infos:
raise OSError('getaddrinfo() returned empty list')
exceptions = []
for family, type, proto, cname, address in infos:
try:
sock = socket.socket(family=family, type=type, proto=proto)
sock.setblocking(False)
if f2 is not None:
for _, _, _, _, laddr in laddr_infos:
try:
sock.bind(laddr)
break
except OSError as exc:
exc = OSError(
exc.errno, 'error while '
'attempting to bind on address '
'{!r}: {}'.format(
laddr, exc.strerror.lower()))
exceptions.append(exc)
else:
sock.close()
sock = None
continue
if self._debug:
logger.debug("connect %r to %r", sock, address)
yield from self.sock_connect(sock, address)
except OSError as exc:
if sock is not None:
sock.close()
exceptions.append(exc)
except:
if sock is not None:
sock.close()
raise
else:
break
else:
if len(exceptions) == 1:
raise exceptions[0]
else:
# If they all have the same str(), raise one.
model = str(exceptions[0])
if all(str(exc) == model for exc in exceptions):
raise exceptions[0]
# Raise a combined exception so the user can see all
# the various error messages.
raise OSError('Multiple exceptions: {}'.format(
', '.join(str(exc) for exc in exceptions)))
else:
if sock is None:
raise ValueError(
'host and port was not specified and no sock specified')
if not _is_stream_socket(sock.type):
# We allow AF_INET, AF_INET6, AF_UNIX as long as they
# are SOCK_STREAM.
# We support passing AF_UNIX sockets even though we have
# a dedicated API for that: create_unix_connection.
# Disallowing AF_UNIX in this method, breaks backwards
# compatibility.
raise ValueError(
'A Stream Socket was expected, got {!r}'.format(sock))
transport, protocol = yield from self._create_connection_transport(
sock, protocol_factory, ssl, server_hostname)
if self._debug:
# Get the socket from the transport because SSL transport closes
# the old socket and creates a new SSL socket
sock = transport.get_extra_info('socket')
logger.debug("%r connected to %s:%r: (%r, %r)",
sock, host, port, transport, protocol)
return transport, protocol
@coroutine
def _create_connection_transport(self, sock, protocol_factory, ssl,
server_hostname, server_side=False):
sock.setblocking(False)
protocol = protocol_factory()
waiter = self.create_future()
if ssl:
sslcontext = None if isinstance(ssl, bool) else ssl
transport = self._make_ssl_transport(
sock, protocol, sslcontext, waiter,
server_side=server_side, server_hostname=server_hostname)
else:
transport = self._make_socket_transport(sock, protocol, waiter)
try:
yield from waiter
except:
transport.close()
raise
return transport, protocol
@coroutine
def create_datagram_endpoint(self, protocol_factory,
local_addr=None, remote_addr=None, *,
family=0, proto=0, flags=0,
reuse_address=None, reuse_port=None,
allow_broadcast=None, sock=None):
"""Create datagram connection."""
if sock is not None:
if not _is_dgram_socket(sock.type):
raise ValueError(
'A UDP Socket was expected, got {!r}'.format(sock))
if (local_addr or remote_addr or
family or proto or flags or
reuse_address or reuse_port or allow_broadcast):
# show the problematic kwargs in exception msg
opts = dict(local_addr=local_addr, remote_addr=remote_addr,
family=family, proto=proto, flags=flags,
reuse_address=reuse_address, reuse_port=reuse_port,
allow_broadcast=allow_broadcast)
problems = ', '.join(
'{}={}'.format(k, v) for k, v in opts.items() if v)
raise ValueError(
'socket modifier keyword arguments can not be used '
'when sock is specified. ({})'.format(problems))
sock.setblocking(False)
r_addr = None
else:
if not (local_addr or remote_addr):
if family == 0:
raise ValueError('unexpected address family')
addr_pairs_info = (((family, proto), (None, None)),)
else:
# join address by (family, protocol)
addr_infos = collections.OrderedDict()
for idx, addr in ((0, local_addr), (1, remote_addr)):
if addr is not None:
assert isinstance(addr, tuple) and len(addr) == 2, (
'2-tuple is expected')
infos = yield from _ensure_resolved(
addr, family=family, type=socket.SOCK_DGRAM,
proto=proto, flags=flags, loop=self)
if not infos:
raise OSError('getaddrinfo() returned empty list')
for fam, _, pro, _, address in infos:
key = (fam, pro)
if key not in addr_infos:
addr_infos[key] = [None, None]
addr_infos[key][idx] = address
# each addr has to have info for each (family, proto) pair
addr_pairs_info = [
(key, addr_pair) for key, addr_pair in addr_infos.items()
if not ((local_addr and addr_pair[0] is None) or
(remote_addr and addr_pair[1] is None))]
if not addr_pairs_info:
raise ValueError('can not get address information')
exceptions = []
if reuse_address is None:
reuse_address = os.name == 'posix' and sys.platform != 'cygwin'
for ((family, proto),
(local_address, remote_address)) in addr_pairs_info:
sock = None
r_addr = None
try:
sock = socket.socket(
family=family, type=socket.SOCK_DGRAM, proto=proto)
if reuse_address:
sock.setsockopt(
socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
if reuse_port:
_set_reuseport(sock)
if allow_broadcast:
sock.setsockopt(
socket.SOL_SOCKET, socket.SO_BROADCAST, 1)
sock.setblocking(False)
if local_addr:
sock.bind(local_address)
if remote_addr:
yield from self.sock_connect(sock, remote_address)
r_addr = remote_address
except OSError as exc:
if sock is not None:
sock.close()
exceptions.append(exc)
except:
if sock is not None:
sock.close()
raise
else:
break
else:
raise exceptions[0]
protocol = protocol_factory()
waiter = self.create_future()
transport = self._make_datagram_transport(
sock, protocol, r_addr, waiter)
if self._debug:
if local_addr:
logger.info("Datagram endpoint local_addr=%r remote_addr=%r "
"created: (%r, %r)",
local_addr, remote_addr, transport, protocol)
else:
logger.debug("Datagram endpoint remote_addr=%r created: "
"(%r, %r)",
remote_addr, transport, protocol)
try:
yield from waiter
except:
transport.close()
raise
return transport, protocol
@coroutine
def _create_server_getaddrinfo(self, host, port, family, flags):
infos = yield from _ensure_resolved((host, port), family=family,
type=socket.SOCK_STREAM,
flags=flags, loop=self)
if not infos:
raise OSError('getaddrinfo({!r}) returned empty list'.format(host))
return infos
@coroutine
def create_server(self, protocol_factory, host=None, port=None,
*,
family=socket.AF_UNSPEC,
flags=socket.AI_PASSIVE,
sock=None,
backlog=100,
ssl=None,
reuse_address=None,
reuse_port=None):
"""Create a TCP server.
The host parameter can be a string, in that case the TCP server is bound
to host and port.
The host parameter can also be a sequence of strings and in that case
the TCP server is bound to all hosts of the sequence. If a host
appears multiple times (possibly indirectly e.g. when hostnames
resolve to the same IP address), the server is only bound once to that
host.
Return a Server object which can be used to stop the service.
This method is a coroutine.
"""
if isinstance(ssl, bool):
raise TypeError('ssl argument must be an SSLContext or None')
if host is not None or port is not None:
if sock is not None:
raise ValueError(
'host/port and sock can not be specified at the same time')
if reuse_address is None:
reuse_address = os.name == 'posix' and sys.platform != 'cygwin'
sockets = []
if host == '':
hosts = [None]
elif (isinstance(host, str) or
not isinstance(host, collections.Iterable)):
hosts = [host]
else:
hosts = host
fs = [self._create_server_getaddrinfo(host, port, family=family,
flags=flags)
for host in hosts]
infos = yield from tasks.gather(*fs, loop=self)
infos = set(itertools.chain.from_iterable(infos))
completed = False
try:
for res in infos:
af, socktype, proto, canonname, sa = res
try:
sock = socket.socket(af, socktype, proto)
except socket.error:
# Assume it's a bad family/type/protocol combination.
if self._debug:
logger.warning('create_server() failed to create '
'socket.socket(%r, %r, %r)',
af, socktype, proto, exc_info=True)
continue
sockets.append(sock)
if reuse_address:
sock.setsockopt(
socket.SOL_SOCKET, socket.SO_REUSEADDR, True)
if reuse_port:
_set_reuseport(sock)
# Disable IPv4/IPv6 dual stack support (enabled by
# default on Linux) which makes a single socket
# listen on both address families.
if (_HAS_IPv6 and
af == socket.AF_INET6 and
hasattr(socket, 'IPPROTO_IPV6')):
sock.setsockopt(socket.IPPROTO_IPV6,
socket.IPV6_V6ONLY,
True)
try:
sock.bind(sa)
except OSError as err:
raise OSError(err.errno, 'error while attempting '
'to bind on address %r: %s'
% (sa, err.strerror.lower()))
completed = True
finally:
if not completed:
for sock in sockets:
sock.close()
else:
if sock is None:
raise ValueError('Neither host/port nor sock were specified')
if not _is_stream_socket(sock.type):
raise ValueError(
'A Stream Socket was expected, got {!r}'.format(sock))
sockets = [sock]
server = Server(self, sockets)
for sock in sockets:
sock.listen(backlog)
sock.setblocking(False)
self._start_serving(protocol_factory, sock, ssl, server, backlog)
if self._debug:
logger.info("%r is serving", server)
return server
@coroutine
def connect_accepted_socket(self, protocol_factory, sock, *, ssl=None):
"""Handle an accepted connection.
This is used by servers that accept connections outside of
asyncio but that use asyncio to handle connections.
This method is a coroutine. When completed, the coroutine
returns a (transport, protocol) pair.
"""
if not _is_stream_socket(sock.type):
raise ValueError(
'A Stream Socket was expected, got {!r}'.format(sock))
transport, protocol = yield from self._create_connection_transport(
sock, protocol_factory, ssl, '', server_side=True)
if self._debug:
# Get the socket from the transport because SSL transport closes
# the old socket and creates a new SSL socket
sock = transport.get_extra_info('socket')
logger.debug("%r handled: (%r, %r)", sock, transport, protocol)
return transport, protocol
@coroutine
def connect_read_pipe(self, protocol_factory, pipe):
protocol = protocol_factory()
waiter = self.create_future()
transport = self._make_read_pipe_transport(pipe, protocol, waiter)
try:
yield from waiter
except:
transport.close()
raise
if self._debug:
logger.debug('Read pipe %r connected: (%r, %r)',
pipe.fileno(), transport, protocol)
return transport, protocol
@coroutine
def connect_write_pipe(self, protocol_factory, pipe):
protocol = protocol_factory()
waiter = self.create_future()
transport = self._make_write_pipe_transport(pipe, protocol, waiter)
try:
yield from waiter
except:
transport.close()
raise
if self._debug:
logger.debug('Write pipe %r connected: (%r, %r)',
pipe.fileno(), transport, protocol)
return transport, protocol
def _log_subprocess(self, msg, stdin, stdout, stderr):
info = [msg]
if stdin is not None:
info.append('stdin=%s' % _format_pipe(stdin))
if stdout is not None and stderr == subprocess.STDOUT:
info.append('stdout=stderr=%s' % _format_pipe(stdout))
else:
if stdout is not None:
info.append('stdout=%s' % _format_pipe(stdout))
if stderr is not None:
info.append('stderr=%s' % _format_pipe(stderr))
logger.debug(' '.join(info))
@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):
if not isinstance(cmd, (bytes, str)):
raise ValueError("cmd must be a string")
if universal_newlines:
raise ValueError("universal_newlines must be False")
if not shell:
raise ValueError("shell must be True")
if bufsize != 0:
raise ValueError("bufsize must be 0")
protocol = protocol_factory()
debug_log = None
if self._debug:
# don't log parameters: they may contain sensitive information
# (password) and may be too long
debug_log = 'run shell command %r' % cmd
self._log_subprocess(debug_log, stdin, stdout, stderr)
transport = yield from self._make_subprocess_transport(
protocol, cmd, True, stdin, stdout, stderr, bufsize, **kwargs)
if self._debug and debug_log is not None:
logger.info('%s: %r', debug_log, transport)
return transport, protocol
@coroutine
def subprocess_exec(self, protocol_factory, program, *args,
stdin=subprocess.PIPE, stdout=subprocess.PIPE,
stderr=subprocess.PIPE, universal_newlines=False,
shell=False, bufsize=0, **kwargs):
if universal_newlines:
raise ValueError("universal_newlines must be False")
if shell:
raise ValueError("shell must be False")
if bufsize != 0:
raise ValueError("bufsize must be 0")
popen_args = (program,) + args
for arg in popen_args:
if not isinstance(arg, (str, bytes)):
raise TypeError("program arguments must be "
"a bytes or text string, not %s"
% type(arg).__name__)
protocol = protocol_factory()
debug_log = None
if self._debug:
# don't log parameters: they may contain sensitive information
# (password) and may be too long
debug_log = 'execute program %r' % program
self._log_subprocess(debug_log, stdin, stdout, stderr)
transport = yield from self._make_subprocess_transport(
protocol, popen_args, False, stdin, stdout, stderr,
bufsize, **kwargs)
if self._debug and debug_log is not None:
logger.info('%s: %r', debug_log, transport)
return transport, protocol
def get_exception_handler(self):
"""Return an exception handler, or None if the default one is in use.
"""
return self._exception_handler
def set_exception_handler(self, handler):
"""Set handler as the new event loop exception handler.
If handler is None, the default exception handler will
be set.
If handler is a callable object, it should have a
signature matching '(loop, context)', where 'loop'
will be a reference to the active event loop, 'context'
will be a dict object (see `call_exception_handler()`
documentation for details about context).
"""
if handler is not None and not callable(handler):
raise TypeError('A callable object or None is expected, '
'got {!r}'.format(handler))
self._exception_handler = handler
def default_exception_handler(self, context):
"""Default exception handler.
This is called when an exception occurs and no exception
handler is set, and can be called by a custom exception
handler that wants to defer to the default behavior.
This default handler logs the error message and other
context-dependent information. In debug mode, a truncated
stack trace is also appended showing where the given object
(e.g. a handle or future or task) was created, if any.
The context parameter has the same meaning as in
`call_exception_handler()`.
"""
message = context.get('message')
if not message:
message = 'Unhandled exception in event loop'
exception = context.get('exception')
if exception is not None:
exc_info = (type(exception), exception, exception.__traceback__)
else:
exc_info = False
if ('source_traceback' not in context
and self._current_handle is not None
and self._current_handle._source_traceback):
context['handle_traceback'] = self._current_handle._source_traceback
log_lines = [message]
for key in sorted(context):
if key in {'message', 'exception'}:
continue
value = context[key]
if key == 'source_traceback':
tb = ''.join(traceback.format_list(value))
value = 'Object created at (most recent call last):\n'
value += tb.rstrip()
elif key == 'handle_traceback':
tb = ''.join(traceback.format_list(value))
value = 'Handle created at (most recent call last):\n'
value += tb.rstrip()
else:
value = repr(value)
log_lines.append('{}: {}'.format(key, value))
logger.error('\n'.join(log_lines), exc_info=exc_info)
def call_exception_handler(self, context):
"""Call the current event loop's exception handler.
The context argument is a dict containing the following keys:
- 'message': Error message;
- 'exception' (optional): Exception object;
- 'future' (optional): Future instance;
- 'handle' (optional): Handle instance;
- 'protocol' (optional): Protocol instance;
- 'transport' (optional): Transport instance;
- 'socket' (optional): Socket instance;
- 'asyncgen' (optional): Asynchronous generator that caused
the exception.
New keys maybe introduced in the future.
Note: do not overload this method in an event loop subclass.
For custom exception handling, use the
`set_exception_handler()` method.
"""
if self._exception_handler is None:
try:
self.default_exception_handler(context)
except Exception:
# Second protection layer for unexpected errors
# in the default implementation, as well as for subclassed
# event loops with overloaded "default_exception_handler".
logger.error('Exception in default exception handler',
exc_info=True)
else:
try:
self._exception_handler(self, context)
except Exception as exc:
# Exception in the user set custom exception handler.
try:
# Let's try default handler.
self.default_exception_handler({
'message': 'Unhandled error in exception handler',
'exception': exc,
'context': context,
})
except Exception:
# Guard 'default_exception_handler' in case it is
# overloaded.
logger.error('Exception in default exception handler '
'while handling an unexpected error '
'in custom exception handler',
exc_info=True)
def _add_callback(self, handle):
"""Add a Handle to _scheduled (TimerHandle) or _ready."""
assert isinstance(handle, events.Handle), 'A Handle is required here'
if handle._cancelled:
return
assert not isinstance(handle, events.TimerHandle)
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 _timer_handle_cancelled(self, handle):
"""Notification that a TimerHandle has been cancelled."""
if handle._scheduled:
self._timer_cancelled_count += 1
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.
"""
sched_count = len(self._scheduled)
if (sched_count > _MIN_SCHEDULED_TIMER_HANDLES and
self._timer_cancelled_count / sched_count >
_MIN_CANCELLED_TIMER_HANDLES_FRACTION):
# Remove delayed calls that were cancelled if their number
# is too high
new_scheduled = []
for handle in self._scheduled:
if handle._cancelled:
handle._scheduled = False
else:
new_scheduled.append(handle)
heapq.heapify(new_scheduled)
self._scheduled = new_scheduled
self._timer_cancelled_count = 0
else:
# Remove delayed calls that were cancelled from head of queue.
while self._scheduled and self._scheduled[0]._cancelled:
self._timer_cancelled_count -= 1
handle = heapq.heappop(self._scheduled)
handle._scheduled = False
timeout = None
if self._ready or self._stopping:
timeout = 0
elif self._scheduled:
# Compute the desired timeout.
when = self._scheduled[0]._when
timeout = min(max(0, when - self.time()), MAXIMUM_SELECT_TIMEOUT)
if self._debug and timeout != 0:
t0 = self.time()
event_list = self._selector.select(timeout)
dt = self.time() - t0
if dt >= 1.0:
level = logging.INFO
else:
level = logging.DEBUG
nevent = len(event_list)
if timeout is None:
logger.log(level, 'poll took %.3f ms: %s events',
dt * 1e3, nevent)
elif nevent:
logger.log(level,
'poll %.3f ms took %.3f ms: %s events',
timeout * 1e3, dt * 1e3, nevent)
elif dt >= 1.0:
logger.log(level,
'poll %.3f ms took %.3f ms: timeout',
timeout * 1e3, dt * 1e3)
else:
event_list = self._selector.select(timeout)
self._process_events(event_list)
# Handle 'later' callbacks that are ready.
end_time = self.time() + self._clock_resolution
while self._scheduled:
handle = self._scheduled[0]
if handle._when >= end_time:
break
handle = heapq.heappop(self._scheduled)
handle._scheduled = False
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 thread-safe without using locks.
ntodo = len(self._ready)
for i in range(ntodo):
handle = self._ready.popleft()
if handle._cancelled:
continue
if self._debug:
try:
self._current_handle = handle
t0 = self.time()
handle._run()
dt = self.time() - t0
if dt >= self.slow_callback_duration:
logger.warning('Executing %s took %.3f seconds',
_format_handle(handle), dt)
finally:
self._current_handle = None
else:
handle._run()
handle = None # Needed to break cycles when an exception occurs.
def _set_coroutine_wrapper(self, enabled):
try:
set_wrapper = sys.set_coroutine_wrapper
get_wrapper = sys.get_coroutine_wrapper
except AttributeError:
return
enabled = bool(enabled)
if self._coroutine_wrapper_set == enabled:
return
wrapper = coroutines.debug_wrapper
current_wrapper = get_wrapper()
if enabled:
if current_wrapper not in (None, wrapper):
warnings.warn(
"loop.set_debug(True): cannot set debug coroutine "
"wrapper; another wrapper is already set %r" %
current_wrapper, RuntimeWarning)
else:
set_wrapper(wrapper)
self._coroutine_wrapper_set = True
else:
if current_wrapper not in (None, wrapper):
warnings.warn(
"loop.set_debug(False): cannot unset debug coroutine "
"wrapper; another wrapper was set %r" %
current_wrapper, RuntimeWarning)
else:
set_wrapper(None)
self._coroutine_wrapper_set = False
def get_debug(self):
return self._debug
def set_debug(self, enabled):
self._debug = enabled
if self.is_running():
self._set_coroutine_wrapper(enabled)
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