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|
# Copyright 2018 Gentoo Foundation
# Distributed under the terms of the GNU General Public License v2
__all__ = (
'AbstractChildWatcher',
'DefaultEventLoopPolicy',
)
try:
import asyncio as _real_asyncio
from asyncio.base_subprocess import BaseSubprocessTransport as _BaseSubprocessTransport
from asyncio.unix_events import AbstractChildWatcher as _AbstractChildWatcher
from asyncio.transports import (
ReadTransport as _ReadTransport,
WriteTransport as _WriteTransport,
)
except ImportError:
_real_asyncio = None
_AbstractChildWatcher = object
_BaseSubprocessTransport = object
_ReadTransport = object
_WriteTransport = object
import errno
import fcntl
import functools
import logging
import os
import socket
import stat
import subprocess
import sys
from portage.util._eventloop.global_event_loop import (
_asyncio_enabled,
global_event_loop as _global_event_loop,
)
from portage.util.futures import (
asyncio,
events,
)
from portage.util.futures.transports import _FlowControlMixin
class _PortageEventLoop(events.AbstractEventLoop):
"""
Implementation of asyncio.AbstractEventLoop which wraps portage's
internal event loop.
"""
def __init__(self, loop):
"""
@type loop: EventLoop
@param loop: an instance of portage's internal event loop
"""
self._loop = loop
self.run_until_complete = loop.run_until_complete
self.call_soon = loop.call_soon
self.call_soon_threadsafe = loop.call_soon_threadsafe
self.call_later = loop.call_later
self.call_at = loop.call_at
self.is_running = loop.is_running
self.is_closed = loop.is_closed
self.close = loop.close
self.create_future = loop.create_future
self.add_reader = loop.add_reader
self.remove_reader = loop.remove_reader
self.add_writer = loop.add_writer
self.remove_writer = loop.remove_writer
self.run_in_executor = loop.run_in_executor
self.time = loop.time
self.default_exception_handler = loop.default_exception_handler
self.call_exception_handler = loop.call_exception_handler
self.set_debug = loop.set_debug
self.get_debug = loop.get_debug
@property
def _asyncio_child_watcher(self):
"""
In order to avoid accessing the internal _loop attribute, portage
internals should use this property when possible.
@rtype: asyncio.AbstractChildWatcher
@return: the internal event loop's AbstractChildWatcher interface
"""
return self._loop._asyncio_child_watcher
@property
def _asyncio_wrapper(self):
"""
In order to avoid accessing the internal _loop attribute, portage
internals should use this property when possible.
@rtype: asyncio.AbstractEventLoop
@return: the internal event loop's AbstractEventLoop interface
"""
return self
def create_task(self, coro):
"""
Schedule a coroutine object.
@type coro: coroutine
@param coro: a coroutine to schedule
@rtype: asyncio.Task
@return: a task object
"""
return asyncio.Task(coro, loop=self)
def connect_read_pipe(self, protocol_factory, pipe):
"""
Register read pipe in event loop. Set the pipe to non-blocking mode.
@type protocol_factory: callable
@param protocol_factory: must instantiate object with Protocol interface
@type pipe: file
@param pipe: a pipe to read from
@rtype: asyncio.Future
@return: Return pair (transport, protocol), where transport supports the
ReadTransport interface.
"""
protocol = protocol_factory()
result = self.create_future()
waiter = self.create_future()
transport = self._make_read_pipe_transport(pipe, protocol, waiter=waiter)
def waiter_callback(waiter):
try:
waiter.result()
except Exception as e:
transport.close()
result.set_exception(e)
else:
result.set_result((transport, protocol))
waiter.add_done_callback(waiter_callback)
return result
def connect_write_pipe(self, protocol_factory, pipe):
"""
Register write pipe in event loop. Set the pipe to non-blocking mode.
@type protocol_factory: callable
@param protocol_factory: must instantiate object with Protocol interface
@type pipe: file
@param pipe: a pipe to write to
@rtype: asyncio.Future
@return: Return pair (transport, protocol), where transport supports the
WriteTransport interface.
"""
protocol = protocol_factory()
result = self.create_future()
waiter = self.create_future()
transport = self._make_write_pipe_transport(pipe, protocol, waiter)
def waiter_callback(waiter):
try:
waiter.result()
except Exception as e:
transport.close()
result.set_exception(e)
else:
result.set_result((transport, protocol))
waiter.add_done_callback(waiter_callback)
return result
def subprocess_exec(self, protocol_factory, program, *args, **kwargs):
"""
Run subprocesses asynchronously using the subprocess module.
@type protocol_factory: callable
@param protocol_factory: must instantiate a subclass of the
asyncio.SubprocessProtocol class
@type program: str or bytes
@param program: the program to execute
@type args: str or bytes
@param args: program's arguments
@type kwargs: varies
@param kwargs: subprocess.Popen parameters
@rtype: asyncio.Future
@return: Returns a pair of (transport, protocol), where transport
is an instance of BaseSubprocessTransport
"""
# python2.7 does not allow arguments with defaults after *args
stdin = kwargs.pop('stdin', subprocess.PIPE)
stdout = kwargs.pop('stdout', subprocess.PIPE)
stderr = kwargs.pop('stderr', subprocess.PIPE)
universal_newlines = kwargs.pop('universal_newlines', False)
shell = kwargs.pop('shell', False)
bufsize = kwargs.pop('bufsize', 0)
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__)
result = self.create_future()
self._make_subprocess_transport(
result, protocol_factory(), popen_args, False, stdin, stdout, stderr,
bufsize, **kwargs)
return result
def _make_read_pipe_transport(self, pipe, protocol, waiter=None,
extra=None):
return _UnixReadPipeTransport(self, pipe, protocol, waiter, extra)
def _make_write_pipe_transport(self, pipe, protocol, waiter=None,
extra=None):
return _UnixWritePipeTransport(self, pipe, protocol, waiter, extra)
def _make_subprocess_transport(self, result, protocol, args, shell,
stdin, stdout, stderr, bufsize, extra=None, **kwargs):
waiter = self.create_future()
transp = _UnixSubprocessTransport(self,
protocol, args, shell, stdin, stdout, stderr, bufsize,
waiter=waiter, extra=extra,
**kwargs)
self._loop._asyncio_child_watcher.add_child_handler(
transp.get_pid(), self._child_watcher_callback, transp)
waiter.add_done_callback(functools.partial(
self._subprocess_transport_callback, transp, protocol, result))
def _subprocess_transport_callback(self, transp, protocol, result, waiter):
if waiter.exception() is None:
result.set_result((transp, protocol))
else:
transp.close()
wait_transp = asyncio.ensure_future(transp._wait(), loop=self)
wait_transp.add_done_callback(
functools.partial(self._subprocess_transport_failure,
result, waiter.exception()))
def _child_watcher_callback(self, pid, returncode, transp):
self.call_soon_threadsafe(transp._process_exited, returncode)
def _subprocess_transport_failure(self, result, exception, wait_transp):
result.set_exception(wait_transp.exception() or exception)
if hasattr(os, 'set_blocking'):
def _set_nonblocking(fd):
os.set_blocking(fd, False)
else:
def _set_nonblocking(fd):
flags = fcntl.fcntl(fd, fcntl.F_GETFL)
flags = flags | os.O_NONBLOCK
fcntl.fcntl(fd, fcntl.F_SETFL, flags)
class _UnixReadPipeTransport(_ReadTransport):
"""
This is identical to the standard library's private
asyncio.unix_events._UnixReadPipeTransport class, except that it
only calls public AbstractEventLoop methods.
"""
max_size = 256 * 1024 # max bytes we read in one event loop iteration
def __init__(self, loop, pipe, protocol, waiter=None, extra=None):
super().__init__(extra)
self._extra['pipe'] = pipe
self._loop = loop
self._pipe = pipe
self._fileno = pipe.fileno()
self._protocol = protocol
self._closing = False
mode = os.fstat(self._fileno).st_mode
if not (stat.S_ISFIFO(mode) or
stat.S_ISSOCK(mode) or
stat.S_ISCHR(mode)):
self._pipe = None
self._fileno = None
self._protocol = None
raise ValueError("Pipe transport is for pipes/sockets only.")
_set_nonblocking(self._fileno)
self._loop.call_soon(self._protocol.connection_made, self)
# only start reading when connection_made() has been called
self._loop.call_soon(self._loop.add_reader,
self._fileno, self._read_ready)
if waiter is not None:
# only wake up the waiter when connection_made() has been called
self._loop.call_soon(
lambda: None if waiter.cancelled() else waiter.set_result(None))
def _read_ready(self):
try:
data = os.read(self._fileno, self.max_size)
except (BlockingIOError, InterruptedError):
pass
except OSError as exc:
self._fatal_error(exc, 'Fatal read error on pipe transport')
else:
if data:
self._protocol.data_received(data)
else:
self._closing = True
self._loop.remove_reader(self._fileno)
self._loop.call_soon(self._protocol.eof_received)
self._loop.call_soon(self._call_connection_lost, None)
def pause_reading(self):
self._loop.remove_reader(self._fileno)
def resume_reading(self):
self._loop.add_reader(self._fileno, self._read_ready)
def set_protocol(self, protocol):
self._protocol = protocol
def get_protocol(self):
return self._protocol
def is_closing(self):
return self._closing
def close(self):
if not self._closing:
self._close(None)
def _fatal_error(self, exc, message='Fatal error on pipe transport'):
# should be called by exception handler only
if (isinstance(exc, OSError) and exc.errno == errno.EIO):
if self._loop.get_debug():
logging.debug("%r: %s", self, message, exc_info=True)
else:
self._loop.call_exception_handler({
'message': message,
'exception': exc,
'transport': self,
'protocol': self._protocol,
})
self._close(exc)
def _close(self, exc):
self._closing = True
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
class _UnixWritePipeTransport(_FlowControlMixin, _WriteTransport):
"""
This is identical to the standard library's private
asyncio.unix_events._UnixWritePipeTransport class, except that it
only calls public AbstractEventLoop methods.
"""
def __init__(self, loop, pipe, protocol, waiter=None, extra=None):
super().__init__(extra, loop)
self._extra['pipe'] = pipe
self._pipe = pipe
self._fileno = pipe.fileno()
self._protocol = protocol
self._buffer = bytearray()
self._conn_lost = 0
self._closing = False # Set when close() or write_eof() called.
mode = os.fstat(self._fileno).st_mode
is_char = stat.S_ISCHR(mode)
is_fifo = stat.S_ISFIFO(mode)
is_socket = stat.S_ISSOCK(mode)
if not (is_char or is_fifo or is_socket):
self._pipe = None
self._fileno = None
self._protocol = None
raise ValueError("Pipe transport is only for "
"pipes, sockets and character devices")
_set_nonblocking(self._fileno)
self._loop.call_soon(self._protocol.connection_made, self)
# On AIX, the reader trick (to be notified when the read end of the
# socket is closed) only works for sockets. On other platforms it
# works for pipes and sockets. (Exception: OS X 10.4? Issue #19294.)
if is_socket or (is_fifo and not sys.platform.startswith("aix")):
# only start reading when connection_made() has been called
self._loop.call_soon(self._loop.add_reader,
self._fileno, self._read_ready)
if waiter is not None:
# only wake up the waiter when connection_made() has been called
self._loop.call_soon(
lambda: None if waiter.cancelled() else waiter.set_result(None))
def get_write_buffer_size(self):
return len(self._buffer)
def _read_ready(self):
# Pipe was closed by peer.
if self._loop.get_debug():
logging.info("%r was closed by peer", self)
if self._buffer:
self._close(BrokenPipeError())
else:
self._close()
def write(self, data):
assert isinstance(data, (bytes, bytearray, memoryview)), repr(data)
if isinstance(data, bytearray):
data = memoryview(data)
if not data:
return
if self._conn_lost or self._closing:
self._conn_lost += 1
return
if not self._buffer:
# Attempt to send it right away first.
try:
n = os.write(self._fileno, data)
except (BlockingIOError, InterruptedError):
n = 0
except Exception as exc:
self._conn_lost += 1
self._fatal_error(exc, 'Fatal write error on pipe transport')
return
if n == len(data):
return
elif n > 0:
data = memoryview(data)[n:]
self._loop.add_writer(self._fileno, self._write_ready)
self._buffer += data
self._maybe_pause_protocol()
def _write_ready(self):
assert self._buffer, 'Data should not be empty'
try:
n = os.write(self._fileno, self._buffer)
except (BlockingIOError, InterruptedError):
pass
except Exception as exc:
self._buffer.clear()
self._conn_lost += 1
# Remove writer here, _fatal_error() doesn't it
# because _buffer is empty.
self._loop.remove_writer(self._fileno)
self._fatal_error(exc, 'Fatal write error on pipe transport')
else:
if n == len(self._buffer):
self._buffer.clear()
self._loop.remove_writer(self._fileno)
self._maybe_resume_protocol() # May append to buffer.
if self._closing:
self._loop.remove_reader(self._fileno)
self._call_connection_lost(None)
return
elif n > 0:
del self._buffer[:n]
def can_write_eof(self):
return True
def write_eof(self):
if self._closing:
return
assert self._pipe
self._closing = True
if not self._buffer:
self._loop.remove_reader(self._fileno)
self._loop.call_soon(self._call_connection_lost, None)
def set_protocol(self, protocol):
self._protocol = protocol
def get_protocol(self):
return self._protocol
def is_closing(self):
return self._closing
def close(self):
if self._pipe is not None and not self._closing:
# write_eof is all what we needed to close the write pipe
self.write_eof()
def abort(self):
self._close(None)
def _fatal_error(self, exc, message='Fatal error on pipe transport'):
# should be called by exception handler only
if isinstance(exc,
(BrokenPipeError, ConnectionResetError, ConnectionAbortedError)):
if self._loop.get_debug():
logging.debug("%r: %s", self, message, exc_info=True)
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:
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(_BaseSubprocessTransport):
"""
This is identical to the standard library's private
asyncio.unix_events._UnixSubprocessTransport class, except that it
only calls public AbstractEventLoop methods.
"""
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 = socket.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 = os.fdopen(stdin_w.detach(), 'wb', bufsize)
class AbstractChildWatcher(_AbstractChildWatcher):
def add_child_handler(self, pid, callback, *args):
raise NotImplementedError()
def remove_child_handler(self, pid):
raise NotImplementedError()
def attach_loop(self, loop):
raise NotImplementedError()
def close(self):
raise NotImplementedError()
def __enter__(self):
raise NotImplementedError()
def __exit__(self, a, b, c):
raise NotImplementedError()
class _PortageChildWatcher(_AbstractChildWatcher):
def __init__(self, loop):
"""
@type loop: EventLoop
@param loop: an instance of portage's internal event loop
"""
self._loop = loop
self._callbacks = {}
def close(self):
pass
def __enter__(self):
return self
def __exit__(self, a, b, c):
pass
def _child_exit(self, pid, status, data):
self._callbacks.pop(pid)
callback, args = data
callback(pid, self._compute_returncode(status), *args)
def _compute_returncode(self, status):
if os.WIFSIGNALED(status):
return -os.WTERMSIG(status)
elif os.WIFEXITED(status):
return os.WEXITSTATUS(status)
else:
return status
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.
"""
source_id = self._callbacks.get(pid)
if source_id is not None:
self._loop.source_remove(source_id)
self._callbacks[pid] = self._loop.child_watch_add(
pid, self._child_exit, data=(callback, args))
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.
"""
source_id = self._callbacks.pop(pid, None)
if source_id is not None:
return self._loop.source_remove(source_id)
return False
class _PortageEventLoopPolicy(events.AbstractEventLoopPolicy):
"""
Implementation of asyncio.AbstractEventLoopPolicy based on portage's
internal event loop. This supports running event loops in forks,
which is not supported by the default asyncio event loop policy,
see https://bugs.python.org/issue22087.
"""
def get_event_loop(self):
"""
Get the event loop for the current context.
Returns an event loop object implementing the AbstractEventLoop
interface.
@rtype: asyncio.AbstractEventLoop (or compatible)
@return: the current event loop policy
"""
return _global_event_loop()._asyncio_wrapper
def get_child_watcher(self):
"""Get the watcher for child processes."""
return _global_event_loop()._asyncio_child_watcher
class _AsyncioEventLoopPolicy(_PortageEventLoopPolicy):
"""
A subclass of _PortageEventLoopPolicy which raises
NotImplementedError if it is set as the real asyncio event loop
policy, since this class is intended to *wrap* the real asyncio
event loop policy.
"""
def _check_recursion(self):
if _real_asyncio.get_event_loop_policy() is self:
raise NotImplementedError('this class is only a wrapper')
def get_event_loop(self):
self._check_recursion()
return super(_AsyncioEventLoopPolicy, self).get_event_loop()
def get_child_watcher(self):
self._check_recursion()
return super(_AsyncioEventLoopPolicy, self).get_child_watcher()
DefaultEventLoopPolicy = (_AsyncioEventLoopPolicy if _asyncio_enabled
else _PortageEventLoopPolicy)
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