Python tornado.iostream.PipeIOStream() Examples

The following are 21 code examples of tornado.iostream.PipeIOStream(). You can vote up the ones you like or vote down the ones you don't like, and go to the original project or source file by following the links above each example. You may also want to check out all available functions/classes of the module tornado.iostream , or try the search function .
Example #1
Source File: iostream_test.py    From tornado-zh with MIT License 6 votes vote down vote up 
def test_pipe_iostream(self):
        r, w = os.pipe()

        rs = PipeIOStream(r, io_loop=self.io_loop)
        ws = PipeIOStream(w, io_loop=self.io_loop)

        ws.write(b"hel")
        ws.write(b"lo world")

        rs.read_until(b' ', callback=self.stop)
        data = self.wait()
        self.assertEqual(data, b"hello ")

        rs.read_bytes(3, self.stop)
        data = self.wait()
        self.assertEqual(data, b"wor")

        ws.close()

        rs.read_until_close(self.stop)
        data = self.wait()
        self.assertEqual(data, b"ld")

        rs.close()
Example #2
Source File: iostream_test.py    From tornado-zh with MIT License 6 votes vote down vote up 
def test_pipe_iostream_big_write(self):
        r, w = os.pipe()

        rs = PipeIOStream(r, io_loop=self.io_loop)
        ws = PipeIOStream(w, io_loop=self.io_loop)

        NUM_BYTES = 1048576

        # Write 1MB of data, which should fill the buffer
        ws.write(b"1" * NUM_BYTES)

        rs.read_bytes(NUM_BYTES, self.stop)
        data = self.wait()
        self.assertEqual(data, b"1" * NUM_BYTES)

        ws.close()
        rs.close()
Example #3
Source File: iostream_test.py    From tornado-zh with MIT License 6 votes vote down vote up 
def test_pipe_iostream(self):
        r, w = os.pipe()

        rs = PipeIOStream(r, io_loop=self.io_loop)
        ws = PipeIOStream(w, io_loop=self.io_loop)

        ws.write(b"hel")
        ws.write(b"lo world")

        rs.read_until(b' ', callback=self.stop)
        data = self.wait()
        self.assertEqual(data, b"hello ")

        rs.read_bytes(3, self.stop)
        data = self.wait()
        self.assertEqual(data, b"wor")

        ws.close()

        rs.read_until_close(self.stop)
        data = self.wait()
        self.assertEqual(data, b"ld")

        rs.close()
Example #4
Source File: iostream_test.py    From EventGhost with GNU General Public License v2.0 6 votes vote down vote up 
def test_pipe_iostream_big_write(self):
        r, w = os.pipe()

        rs = PipeIOStream(r, io_loop=self.io_loop)
        ws = PipeIOStream(w, io_loop=self.io_loop)

        NUM_BYTES = 1048576

        # Write 1MB of data, which should fill the buffer
        ws.write(b"1" * NUM_BYTES)

        rs.read_bytes(NUM_BYTES, self.stop)
        data = self.wait()
        self.assertEqual(data, b"1" * NUM_BYTES)

        ws.close()
        rs.close()
Example #5
Source File: iostream_test.py    From EventGhost with GNU General Public License v2.0 6 votes vote down vote up 
def test_pipe_iostream(self):
        r, w = os.pipe()

        rs = PipeIOStream(r, io_loop=self.io_loop)
        ws = PipeIOStream(w, io_loop=self.io_loop)

        ws.write(b"hel")
        ws.write(b"lo world")

        rs.read_until(b' ', callback=self.stop)
        data = self.wait()
        self.assertEqual(data, b"hello ")

        rs.read_bytes(3, self.stop)
        data = self.wait()
        self.assertEqual(data, b"wor")

        ws.close()

        rs.read_until_close(self.stop)
        data = self.wait()
        self.assertEqual(data, b"ld")

        rs.close()
Example #6
Source File: iostream_test.py    From viewfinder with Apache License 2.0 6 votes vote down vote up 
def test_pipe_iostream(self):
        r, w = os.pipe()

        rs = PipeIOStream(r, io_loop=self.io_loop)
        ws = PipeIOStream(w, io_loop=self.io_loop)

        ws.write(b"hel")
        ws.write(b"lo world")

        rs.read_until(b' ', callback=self.stop)
        data = self.wait()
        self.assertEqual(data, b"hello ")

        rs.read_bytes(3, self.stop)
        data = self.wait()
        self.assertEqual(data, b"wor")

        ws.close()

        rs.read_until_close(self.stop)
        data = self.wait()
        self.assertEqual(data, b"ld")

        rs.close()
Example #7
Source File: iostream_test.py    From viewfinder with Apache License 2.0 6 votes vote down vote up 
def test_pipe_iostream(self):
        r, w = os.pipe()

        rs = PipeIOStream(r, io_loop=self.io_loop)
        ws = PipeIOStream(w, io_loop=self.io_loop)

        ws.write(b"hel")
        ws.write(b"lo world")

        rs.read_until(b' ', callback=self.stop)
        data = self.wait()
        self.assertEqual(data, b"hello ")

        rs.read_bytes(3, self.stop)
        data = self.wait()
        self.assertEqual(data, b"wor")

        ws.close()

        rs.read_until_close(self.stop)
        data = self.wait()
        self.assertEqual(data, b"ld")

        rs.close()
Example #8
Source File: process.py    From V1EngineeringInc-Docs with Creative Commons Attribution Share Alike 4.0 International 5 votes vote down vote up 
def __init__(self, *args: Any, **kwargs: Any) -> None:
        self.io_loop = ioloop.IOLoop.current()
        # All FDs we create should be closed on error; those in to_close
        # should be closed in the parent process on success.
        pipe_fds = []  # type: List[int]
        to_close = []  # type: List[int]
        if kwargs.get("stdin") is Subprocess.STREAM:
            in_r, in_w = _pipe_cloexec()
            kwargs["stdin"] = in_r
            pipe_fds.extend((in_r, in_w))
            to_close.append(in_r)
            self.stdin = PipeIOStream(in_w)
        if kwargs.get("stdout") is Subprocess.STREAM:
            out_r, out_w = _pipe_cloexec()
            kwargs["stdout"] = out_w
            pipe_fds.extend((out_r, out_w))
            to_close.append(out_w)
            self.stdout = PipeIOStream(out_r)
        if kwargs.get("stderr") is Subprocess.STREAM:
            err_r, err_w = _pipe_cloexec()
            kwargs["stderr"] = err_w
            pipe_fds.extend((err_r, err_w))
            to_close.append(err_w)
            self.stderr = PipeIOStream(err_r)
        try:
            self.proc = subprocess.Popen(*args, **kwargs)
        except:
            for fd in pipe_fds:
                os.close(fd)
            raise
        for fd in to_close:
            os.close(fd)
        self.pid = self.proc.pid
        for attr in ["stdin", "stdout", "stderr"]:
            if not hasattr(self, attr):  # don't clobber streams set above
                setattr(self, attr, getattr(self.proc, attr))
        self._exit_callback = None  # type: Optional[Callable[[int], None]]
        self.returncode = None  # type: Optional[int]
Example #9
Source File: process.py    From tornado-zh with MIT License 5 votes vote down vote up 
def __init__(self, *args, **kwargs):
        self.io_loop = kwargs.pop('io_loop', None) or ioloop.IOLoop.current()
        # All FDs we create should be closed on error; those in to_close
        # should be closed in the parent process on success.
        pipe_fds = []
        to_close = []
        if kwargs.get('stdin') is Subprocess.STREAM:
            in_r, in_w = _pipe_cloexec()
            kwargs['stdin'] = in_r
            pipe_fds.extend((in_r, in_w))
            to_close.append(in_r)
            self.stdin = PipeIOStream(in_w, io_loop=self.io_loop)
        if kwargs.get('stdout') is Subprocess.STREAM:
            out_r, out_w = _pipe_cloexec()
            kwargs['stdout'] = out_w
            pipe_fds.extend((out_r, out_w))
            to_close.append(out_w)
            self.stdout = PipeIOStream(out_r, io_loop=self.io_loop)
        if kwargs.get('stderr') is Subprocess.STREAM:
            err_r, err_w = _pipe_cloexec()
            kwargs['stderr'] = err_w
            pipe_fds.extend((err_r, err_w))
            to_close.append(err_w)
            self.stderr = PipeIOStream(err_r, io_loop=self.io_loop)
        try:
            self.proc = subprocess.Popen(*args, **kwargs)
        except:
            for fd in pipe_fds:
                os.close(fd)
            raise
        for fd in to_close:
            os.close(fd)
        for attr in ['stdin', 'stdout', 'stderr', 'pid']:
            if not hasattr(self, attr):  # don't clobber streams set above
                setattr(self, attr, getattr(self.proc, attr))
        self._exit_callback = None
        self.returncode = None
Example #10
Source File: process.py    From EventGhost with GNU General Public License v2.0 5 votes vote down vote up 
def __init__(self, *args, **kwargs):
        self.io_loop = kwargs.pop('io_loop', None) or ioloop.IOLoop.current()
        # All FDs we create should be closed on error; those in to_close
        # should be closed in the parent process on success.
        pipe_fds = []
        to_close = []
        if kwargs.get('stdin') is Subprocess.STREAM:
            in_r, in_w = _pipe_cloexec()
            kwargs['stdin'] = in_r
            pipe_fds.extend((in_r, in_w))
            to_close.append(in_r)
            self.stdin = PipeIOStream(in_w, io_loop=self.io_loop)
        if kwargs.get('stdout') is Subprocess.STREAM:
            out_r, out_w = _pipe_cloexec()
            kwargs['stdout'] = out_w
            pipe_fds.extend((out_r, out_w))
            to_close.append(out_w)
            self.stdout = PipeIOStream(out_r, io_loop=self.io_loop)
        if kwargs.get('stderr') is Subprocess.STREAM:
            err_r, err_w = _pipe_cloexec()
            kwargs['stderr'] = err_w
            pipe_fds.extend((err_r, err_w))
            to_close.append(err_w)
            self.stderr = PipeIOStream(err_r, io_loop=self.io_loop)
        try:
            self.proc = subprocess.Popen(*args, **kwargs)
        except:
            for fd in pipe_fds:
                os.close(fd)
            raise
        for fd in to_close:
            os.close(fd)
        for attr in ['stdin', 'stdout', 'stderr', 'pid']:
            if not hasattr(self, attr):  # don't clobber streams set above
                setattr(self, attr, getattr(self.proc, attr))
        self._exit_callback = None
        self.returncode = None
Example #11
Source File: stream.py    From tchannel-python with MIT License 5 votes vote down vote up 
def __init__(self, rpipe, wpipe=None, auto_close=False):
        """Pipe-based stream

        NOTE: reading from or writing to files, use os.open to get the file
        descriptor instead of python's open. Socket file descriptors and
        others are fine.

        when you use os.pipe to generate one write pipe and one read pipe, you
        need to pass both of them into init method.

        :param rpipe: an integer file descriptor which supports read ops
        :param wpipe: an integer file descriptor which supports write ops
        :param auto: flag to indicate to close the stream automatically or not
        """
        assert rpipe is not None
        self._rpipe = rpipe
        self._wpipe = wpipe

        self._rs = (PipeIOStream(self._rpipe) if
                    self._rpipe is not None else None)
        self._ws = (PipeIOStream(self._wpipe) if
                    self._wpipe is not None else None)
        self.auto_close = auto_close
        self.state = StreamState.init

        self.exception = None
Example #12
Source File: iostream_test.py    From pySINDy with MIT License 5 votes vote down vote up 
def make_iostream_pair(self, **kwargs):
        r, w = os.pipe()

        return PipeIOStream(r, **kwargs), PipeIOStream(w, **kwargs)
Example #13
Source File: process.py    From pySINDy with MIT License 5 votes vote down vote up 
def __init__(self, *args, **kwargs):
        self.io_loop = ioloop.IOLoop.current()
        # All FDs we create should be closed on error; those in to_close
        # should be closed in the parent process on success.
        pipe_fds = []
        to_close = []
        if kwargs.get('stdin') is Subprocess.STREAM:
            in_r, in_w = _pipe_cloexec()
            kwargs['stdin'] = in_r
            pipe_fds.extend((in_r, in_w))
            to_close.append(in_r)
            self.stdin = PipeIOStream(in_w)
        if kwargs.get('stdout') is Subprocess.STREAM:
            out_r, out_w = _pipe_cloexec()
            kwargs['stdout'] = out_w
            pipe_fds.extend((out_r, out_w))
            to_close.append(out_w)
            self.stdout = PipeIOStream(out_r)
        if kwargs.get('stderr') is Subprocess.STREAM:
            err_r, err_w = _pipe_cloexec()
            kwargs['stderr'] = err_w
            pipe_fds.extend((err_r, err_w))
            to_close.append(err_w)
            self.stderr = PipeIOStream(err_r)
        try:
            self.proc = subprocess.Popen(*args, **kwargs)
        except:
            for fd in pipe_fds:
                os.close(fd)
            raise
        for fd in to_close:
            os.close(fd)
        for attr in ['stdin', 'stdout', 'stderr', 'pid']:
            if not hasattr(self, attr):  # don't clobber streams set above
                setattr(self, attr, getattr(self.proc, attr))
        self._exit_callback = None
        self.returncode = None
Example #14
Source File: process.py    From teleport with Apache License 2.0 5 votes vote down vote up 
def __init__(self, *args: Any, **kwargs: Any) -> None:
        self.io_loop = ioloop.IOLoop.current()
        # All FDs we create should be closed on error; those in to_close
        # should be closed in the parent process on success.
        pipe_fds = []  # type: List[int]
        to_close = []  # type: List[int]
        if kwargs.get("stdin") is Subprocess.STREAM:
            in_r, in_w = _pipe_cloexec()
            kwargs["stdin"] = in_r
            pipe_fds.extend((in_r, in_w))
            to_close.append(in_r)
            self.stdin = PipeIOStream(in_w)
        if kwargs.get("stdout") is Subprocess.STREAM:
            out_r, out_w = _pipe_cloexec()
            kwargs["stdout"] = out_w
            pipe_fds.extend((out_r, out_w))
            to_close.append(out_w)
            self.stdout = PipeIOStream(out_r)
        if kwargs.get("stderr") is Subprocess.STREAM:
            err_r, err_w = _pipe_cloexec()
            kwargs["stderr"] = err_w
            pipe_fds.extend((err_r, err_w))
            to_close.append(err_w)
            self.stderr = PipeIOStream(err_r)
        try:
            self.proc = subprocess.Popen(*args, **kwargs)
        except:
            for fd in pipe_fds:
                os.close(fd)
            raise
        for fd in to_close:
            os.close(fd)
        self.pid = self.proc.pid
        for attr in ["stdin", "stdout", "stderr"]:
            if not hasattr(self, attr):  # don't clobber streams set above
                setattr(self, attr, getattr(self.proc, attr))
        self._exit_callback = None  # type: Optional[Callable[[int], None]]
        self.returncode = None  # type: Optional[int]
Example #15
Source File: process.py    From teleport with Apache License 2.0 5 votes vote down vote up 
def __init__(self, *args: Any, **kwargs: Any) -> None:
        self.io_loop = ioloop.IOLoop.current()
        # All FDs we create should be closed on error; those in to_close
        # should be closed in the parent process on success.
        pipe_fds = []  # type: List[int]
        to_close = []  # type: List[int]
        if kwargs.get("stdin") is Subprocess.STREAM:
            in_r, in_w = _pipe_cloexec()
            kwargs["stdin"] = in_r
            pipe_fds.extend((in_r, in_w))
            to_close.append(in_r)
            self.stdin = PipeIOStream(in_w)
        if kwargs.get("stdout") is Subprocess.STREAM:
            out_r, out_w = _pipe_cloexec()
            kwargs["stdout"] = out_w
            pipe_fds.extend((out_r, out_w))
            to_close.append(out_w)
            self.stdout = PipeIOStream(out_r)
        if kwargs.get("stderr") is Subprocess.STREAM:
            err_r, err_w = _pipe_cloexec()
            kwargs["stderr"] = err_w
            pipe_fds.extend((err_r, err_w))
            to_close.append(err_w)
            self.stderr = PipeIOStream(err_r)
        try:
            self.proc = subprocess.Popen(*args, **kwargs)
        except:
            for fd in pipe_fds:
                os.close(fd)
            raise
        for fd in to_close:
            os.close(fd)
        self.pid = self.proc.pid
        for attr in ["stdin", "stdout", "stderr"]:
            if not hasattr(self, attr):  # don't clobber streams set above
                setattr(self, attr, getattr(self.proc, attr))
        self._exit_callback = None  # type: Optional[Callable[[int], None]]
        self.returncode = None  # type: Optional[int]
Example #16
Source File: iostream_test.py    From teleport with Apache License 2.0 5 votes vote down vote up 
def make_iostream_pair(self, **kwargs):
        r, w = os.pipe()

        return PipeIOStream(r, **kwargs), PipeIOStream(w, **kwargs)
Example #17
Source File: process.py    From teleport with Apache License 2.0 5 votes vote down vote up 
def __init__(self, *args, **kwargs):
        self.io_loop = ioloop.IOLoop.current()
        # All FDs we create should be closed on error; those in to_close
        # should be closed in the parent process on success.
        pipe_fds = []
        to_close = []
        if kwargs.get('stdin') is Subprocess.STREAM:
            in_r, in_w = _pipe_cloexec()
            kwargs['stdin'] = in_r
            pipe_fds.extend((in_r, in_w))
            to_close.append(in_r)
            self.stdin = PipeIOStream(in_w)
        if kwargs.get('stdout') is Subprocess.STREAM:
            out_r, out_w = _pipe_cloexec()
            kwargs['stdout'] = out_w
            pipe_fds.extend((out_r, out_w))
            to_close.append(out_w)
            self.stdout = PipeIOStream(out_r)
        if kwargs.get('stderr') is Subprocess.STREAM:
            err_r, err_w = _pipe_cloexec()
            kwargs['stderr'] = err_w
            pipe_fds.extend((err_r, err_w))
            to_close.append(err_w)
            self.stderr = PipeIOStream(err_r)
        try:
            self.proc = subprocess.Popen(*args, **kwargs)
        except:
            for fd in pipe_fds:
                os.close(fd)
            raise
        for fd in to_close:
            os.close(fd)
        for attr in ['stdin', 'stdout', 'stderr', 'pid']:
            if not hasattr(self, attr):  # don't clobber streams set above
                setattr(self, attr, getattr(self.proc, attr))
        self._exit_callback = None
        self.returncode = None
Example #18
Source File: process.py    From viewfinder with Apache License 2.0 5 votes vote down vote up 
def __init__(self, *args, **kwargs):
        self.io_loop = kwargs.pop('io_loop', None) or ioloop.IOLoop.current()
        # All FDs we create should be closed on error; those in to_close
        # should be closed in the parent process on success.
        pipe_fds = []
        to_close = []
        if kwargs.get('stdin') is Subprocess.STREAM:
            in_r, in_w = _pipe_cloexec()
            kwargs['stdin'] = in_r
            pipe_fds.extend((in_r, in_w))
            to_close.append(in_r)
            self.stdin = PipeIOStream(in_w, io_loop=self.io_loop)
        if kwargs.get('stdout') is Subprocess.STREAM:
            out_r, out_w = _pipe_cloexec()
            kwargs['stdout'] = out_w
            pipe_fds.extend((out_r, out_w))
            to_close.append(out_w)
            self.stdout = PipeIOStream(out_r, io_loop=self.io_loop)
        if kwargs.get('stderr') is Subprocess.STREAM:
            err_r, err_w = _pipe_cloexec()
            kwargs['stderr'] = err_w
            pipe_fds.extend((err_r, err_w))
            to_close.append(err_w)
            self.stderr = PipeIOStream(err_r, io_loop=self.io_loop)
        try:
            self.proc = subprocess.Popen(*args, **kwargs)
        except:
            for fd in pipe_fds:
                os.close(fd)
            raise
        for fd in to_close:
            os.close(fd)
        for attr in ['stdin', 'stdout', 'stderr', 'pid']:
            if not hasattr(self, attr):  # don't clobber streams set above
                setattr(self, attr, getattr(self.proc, attr))
        self._exit_callback = None
        self.returncode = None
Example #19
Source File: process.py    From viewfinder with Apache License 2.0 5 votes vote down vote up 
def __init__(self, *args, **kwargs):
        self.io_loop = kwargs.pop('io_loop', None) or ioloop.IOLoop.current()
        # All FDs we create should be closed on error; those in to_close
        # should be closed in the parent process on success.
        pipe_fds = []
        to_close = []
        if kwargs.get('stdin') is Subprocess.STREAM:
            in_r, in_w = _pipe_cloexec()
            kwargs['stdin'] = in_r
            pipe_fds.extend((in_r, in_w))
            to_close.append(in_r)
            self.stdin = PipeIOStream(in_w, io_loop=self.io_loop)
        if kwargs.get('stdout') is Subprocess.STREAM:
            out_r, out_w = _pipe_cloexec()
            kwargs['stdout'] = out_w
            pipe_fds.extend((out_r, out_w))
            to_close.append(out_w)
            self.stdout = PipeIOStream(out_r, io_loop=self.io_loop)
        if kwargs.get('stderr') is Subprocess.STREAM:
            err_r, err_w = _pipe_cloexec()
            kwargs['stderr'] = err_w
            pipe_fds.extend((err_r, err_w))
            to_close.append(err_w)
            self.stderr = PipeIOStream(err_r, io_loop=self.io_loop)
        try:
            self.proc = subprocess.Popen(*args, **kwargs)
        except:
            for fd in pipe_fds:
                os.close(fd)
            raise
        for fd in to_close:
            os.close(fd)
        for attr in ['stdin', 'stdout', 'stderr', 'pid']:
            if not hasattr(self, attr):  # don't clobber streams set above
                setattr(self, attr, getattr(self.proc, attr))
        self._exit_callback = None
        self.returncode = None
Example #20
Source File: process.py    From opendevops with GNU General Public License v3.0 5 votes vote down vote up 
def __init__(self, *args: Any, **kwargs: Any) -> None:
        self.io_loop = ioloop.IOLoop.current()
        # All FDs we create should be closed on error; those in to_close
        # should be closed in the parent process on success.
        pipe_fds = []  # type: List[int]
        to_close = []  # type: List[int]
        if kwargs.get("stdin") is Subprocess.STREAM:
            in_r, in_w = _pipe_cloexec()
            kwargs["stdin"] = in_r
            pipe_fds.extend((in_r, in_w))
            to_close.append(in_r)
            self.stdin = PipeIOStream(in_w)
        if kwargs.get("stdout") is Subprocess.STREAM:
            out_r, out_w = _pipe_cloexec()
            kwargs["stdout"] = out_w
            pipe_fds.extend((out_r, out_w))
            to_close.append(out_w)
            self.stdout = PipeIOStream(out_r)
        if kwargs.get("stderr") is Subprocess.STREAM:
            err_r, err_w = _pipe_cloexec()
            kwargs["stderr"] = err_w
            pipe_fds.extend((err_r, err_w))
            to_close.append(err_w)
            self.stderr = PipeIOStream(err_r)
        try:
            self.proc = subprocess.Popen(*args, **kwargs)
        except:
            for fd in pipe_fds:
                os.close(fd)
            raise
        for fd in to_close:
            os.close(fd)
        self.pid = self.proc.pid
        for attr in ["stdin", "stdout", "stderr"]:
            if not hasattr(self, attr):  # don't clobber streams set above
                setattr(self, attr, getattr(self.proc, attr))
        self._exit_callback = None  # type: Optional[Callable[[int], None]]
        self.returncode = None  # type: Optional[int]
Example #21
Source File: process.py    From tornado-zh with MIT License 5 votes vote down vote up 
def __init__(self, *args, **kwargs):
        self.io_loop = kwargs.pop('io_loop', None) or ioloop.IOLoop.current()
        # All FDs we create should be closed on error; those in to_close
        # should be closed in the parent process on success.
        pipe_fds = []
        to_close = []
        if kwargs.get('stdin') is Subprocess.STREAM:
            in_r, in_w = _pipe_cloexec()
            kwargs['stdin'] = in_r
            pipe_fds.extend((in_r, in_w))
            to_close.append(in_r)
            self.stdin = PipeIOStream(in_w, io_loop=self.io_loop)
        if kwargs.get('stdout') is Subprocess.STREAM:
            out_r, out_w = _pipe_cloexec()
            kwargs['stdout'] = out_w
            pipe_fds.extend((out_r, out_w))
            to_close.append(out_w)
            self.stdout = PipeIOStream(out_r, io_loop=self.io_loop)
        if kwargs.get('stderr') is Subprocess.STREAM:
            err_r, err_w = _pipe_cloexec()
            kwargs['stderr'] = err_w
            pipe_fds.extend((err_r, err_w))
            to_close.append(err_w)
            self.stderr = PipeIOStream(err_r, io_loop=self.io_loop)
        try:
            self.proc = subprocess.Popen(*args, **kwargs)
        except:
            for fd in pipe_fds:
                os.close(fd)
            raise
        for fd in to_close:
            os.close(fd)
        for attr in ['stdin', 'stdout', 'stderr', 'pid']:
            if not hasattr(self, attr):  # don't clobber streams set above
                setattr(self, attr, getattr(self.proc, attr))
        self._exit_callback = None
        self.returncode = None