Preview: subprocess.py
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/lib64/python3.9/asyncio/subprocess.py
__all__ = 'create_subprocess_exec', 'create_subprocess_shell'
import subprocess
import warnings
from . import events
from . import protocols
from . import streams
from . import tasks
from .log import logger
PIPE = subprocess.PIPE
STDOUT = subprocess.STDOUT
DEVNULL = subprocess.DEVNULL
class SubprocessStreamProtocol(streams.FlowControlMixin,
protocols.SubprocessProtocol):
"""Like StreamReaderProtocol, but for a subprocess."""
def __init__(self, limit, loop):
super().__init__(loop=loop)
self._limit = limit
self.stdin = self.stdout = self.stderr = None
self._transport = None
self._process_exited = False
self._pipe_fds = []
self._stdin_closed = self._loop.create_future()
def __repr__(self):
info = [self.__class__.__name__]
if self.stdin is not None:
info.append(f'stdin={self.stdin!r}')
if self.stdout is not None:
info.append(f'stdout={self.stdout!r}')
if self.stderr is not None:
info.append(f'stderr={self.stderr!r}')
return '<{}>'.format(' '.join(info))
def connection_made(self, transport):
self._transport = transport
stdout_transport = transport.get_pipe_transport(1)
if stdout_transport is not None:
self.stdout = streams.StreamReader(limit=self._limit,
loop=self._loop)
self.stdout.set_transport(stdout_transport)
self._pipe_fds.append(1)
stderr_transport = transport.get_pipe_transport(2)
if stderr_transport is not None:
self.stderr = streams.StreamReader(limit=self._limit,
loop=self._loop)
self.stderr.set_transport(stderr_transport)
self._pipe_fds.append(2)
stdin_transport = transport.get_pipe_transport(0)
if stdin_transport is not None:
self.stdin = streams.StreamWriter(stdin_transport,
protocol=self,
reader=None,
loop=self._loop)
def pipe_data_received(self, fd, data):
if fd == 1:
reader = self.stdout
elif fd == 2:
reader = self.stderr
else:
reader = None
if reader is not None:
reader.feed_data(data)
def pipe_connection_lost(self, fd, exc):
if fd == 0:
pipe = self.stdin
if pipe is not None:
pipe.close()
self.connection_lost(exc)
if exc is None:
self._stdin_closed.set_result(None)
else:
self._stdin_closed.set_exception(exc)
return
if fd == 1:
reader = self.stdout
elif fd == 2:
reader = self.stderr
else:
reader = None
if reader is not None:
if exc is None:
reader.feed_eof()
else:
reader.set_exception(exc)
if fd in self._pipe_fds:
self._pipe_fds.remove(fd)
self._maybe_close_transport()
def process_exited(self):
self._process_exited = True
self._maybe_close_transport()
def _maybe_close_transport(self):
if len(self._pipe_fds) == 0 and self._process_exited:
self._transport.close()
self._transport = None
def _get_close_waiter(self, stream):
if stream is self.stdin:
return self._stdin_closed
class Process:
def __init__(self, transport, protocol, loop):
self._transport = transport
self._protocol = protocol
self._loop = loop
self.stdin = protocol.stdin
self.stdout = protocol.stdout
self.stderr = protocol.stderr
self.pid = transport.get_pid()
def __repr__(self):
return f'<{self.__class__.__name__} {self.pid}>'
@property
def returncode(self):
return self._transport.get_returncode()
async def wait(self):
"""Wait until the process exit and return the process return code."""
return await self._transport._wait()
def send_signal(self, signal):
self._transport.send_signal(signal)
def terminate(self):
self._transport.terminate()
def kill(self):
self._transport.kill()
async def _feed_stdin(self, input):
debug = self._loop.get_debug()
self.stdin.write(input)
if debug:
logger.debug(
'%r communicate: feed stdin (%s bytes)', self, len(input))
try:
await self.stdin.drain()
except (BrokenPipeError, ConnectionResetError) as exc:
# communicate() ignores BrokenPipeError and ConnectionResetError
if debug:
logger.debug('%r communicate: stdin got %r', self, exc)
if debug:
logger.debug('%r communicate: close stdin', self)
self.stdin.close()
async def _noop(self):
return None
async def _read_stream(self, fd):
transport = self._transport.get_pipe_transport(fd)
if fd == 2:
stream = self.stderr
else:
assert fd == 1
stream = self.stdout
if self._loop.get_debug():
name = 'stdout' if fd == 1 else 'stderr'
logger.debug('%r communicate: read %s', self, name)
output = await stream.read()
if self._loop.get_debug():
name = 'stdout' if fd == 1 else 'stderr'
logger.debug('%r communicate: close %s', self, name)
transport.close()
return output
async def communicate(self, input=None):
if input is not None:
stdin = self._feed_stdin(input)
else:
stdin = self._noop()
if self.stdout is not None:
stdout = self._read_stream(1)
else:
stdout = self._noop()
if self.stderr is not None:
stderr = self._read_stream(2)
else:
stderr = self._noop()
stdin, stdout, stderr = await tasks._gather(stdin, stdout, stderr,
loop=self._loop)
await self.wait()
return (stdout, stderr)
async def create_subprocess_shell(cmd, stdin=None, stdout=None, stderr=None,
loop=None, limit=streams._DEFAULT_LIMIT,
**kwds):
if loop is None:
loop = events.get_event_loop()
else:
warnings.warn("The loop argument is deprecated since Python 3.8 "
"and scheduled for removal in Python 3.10.",
DeprecationWarning,
stacklevel=2
)
protocol_factory = lambda: SubprocessStreamProtocol(limit=limit,
loop=loop)
transport, protocol = await loop.subprocess_shell(
protocol_factory,
cmd, stdin=stdin, stdout=stdout,
stderr=stderr, **kwds)
return Process(transport, protocol, loop)
async def create_subprocess_exec(program, *args, stdin=None, stdout=None,
stderr=None, loop=None,
limit=streams._DEFAULT_LIMIT, **kwds):
if loop is None:
loop = events.get_event_loop()
else:
warnings.warn("The loop argument is deprecated since Python 3.8 "
"and scheduled for removal in Python 3.10.",
DeprecationWarning,
stacklevel=2
)
protocol_factory = lambda: SubprocessStreamProtocol(limit=limit,
loop=loop)
transport, protocol = await loop.subprocess_exec(
protocol_factory,
program, *args,
stdin=stdin, stdout=stdout,
stderr=stderr, **kwds)
return Process(transport, protocol, loop)
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