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mitogen/mitogen/parent.py

2785 lines
96 KiB
Python

# Copyright 2019, David Wilson
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
# 1. Redistributions of source code must retain the above copyright notice,
# this list of conditions and the following disclaimer.
#
# 2. Redistributions in binary form must reproduce the above copyright notice,
# this list of conditions and the following disclaimer in the documentation
# and/or other materials provided with the distribution.
#
# 3. Neither the name of the copyright holder nor the names of its contributors
# may be used to endorse or promote products derived from this software without
# specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGE.
# !mitogen: minify_safe
"""
This module defines functionality common to master and parent processes. It is
sent to any child context that is due to become a parent, due to recursive
connection.
"""
import binascii
import errno
import fcntl
import getpass
import heapq
import inspect
import logging
import os
import re
import signal
import socket
import struct
import subprocess
import sys
import termios
import textwrap
import threading
import zlib
# Absolute imports for <2.5.
select = __import__('select')
try:
import thread
except ImportError:
import threading as thread
import mitogen.core
from mitogen.core import b
from mitogen.core import bytes_partition
from mitogen.core import IOLOG
LOG = logging.getLogger(__name__)
# #410: we must avoid the use of socketpairs if SELinux is enabled.
try:
fp = open('/sys/fs/selinux/enforce', 'rb')
try:
SELINUX_ENABLED = bool(int(fp.read()))
finally:
fp.close()
except IOError:
SELINUX_ENABLED = False
try:
next
except NameError:
# Python 2.4/2.5
from mitogen.core import next
itervalues = getattr(dict, 'itervalues', dict.values)
if mitogen.core.PY3:
xrange = range
closure_attr = '__closure__'
IM_SELF_ATTR = '__self__'
else:
closure_attr = 'func_closure'
IM_SELF_ATTR = 'im_self'
try:
SC_OPEN_MAX = os.sysconf('SC_OPEN_MAX')
except ValueError:
SC_OPEN_MAX = 1024
BROKER_SHUTDOWN_MSG = (
'Connection cancelled because the associated Broker began to shut down.'
)
OPENPTY_MSG = (
"Failed to create a PTY: %s. It is likely the maximum number of PTYs has "
"been reached. Consider increasing the 'kern.tty.ptmx_max' sysctl on OS "
"X, the 'kernel.pty.max' sysctl on Linux, or modifying your configuration "
"to avoid PTY use."
)
SYS_EXECUTABLE_MSG = (
"The Python sys.executable variable is unset, indicating Python was "
"unable to determine its original program name. Unless explicitly "
"configured otherwise, child contexts will be started using "
"'/usr/bin/python'"
)
_sys_executable_warning_logged = False
def _ioctl_cast(n):
"""
Linux ioctl() request parameter is unsigned, whereas on BSD/Darwin it is
signed. Until 2.5 Python exclusively implemented the BSD behaviour,
preventing use of large unsigned int requests like the TTY layer uses
below. So on 2.4, we cast our unsigned to look like signed for Python.
"""
if sys.version_info < (2, 5):
n, = struct.unpack('i', struct.pack('I', n))
return n
# If not :data:`None`, called prior to exec() of any new child process. Used by
# :func:`mitogen.utils.reset_affinity` to allow the child to be freely
# scheduled.
_preexec_hook = None
# Get PTY number; asm-generic/ioctls.h
LINUX_TIOCGPTN = _ioctl_cast(2147767344)
# Lock/unlock PTY; asm-generic/ioctls.h
LINUX_TIOCSPTLCK = _ioctl_cast(1074025521)
IS_LINUX = os.uname()[0] == 'Linux'
SIGNAL_BY_NUM = dict(
(getattr(signal, name), name)
for name in sorted(vars(signal), reverse=True)
if name.startswith('SIG') and not name.startswith('SIG_')
)
_core_source_lock = threading.Lock()
_core_source_partial = None
def get_log_level():
return (LOG.getEffectiveLevel() or logging.INFO)
def get_sys_executable():
"""
Return :data:`sys.executable` if it is set, otherwise return
``"/usr/bin/python"`` and log a warning.
"""
if sys.executable:
return sys.executable
global _sys_executable_warning_logged
if not _sys_executable_warning_logged:
LOG.warn(SYS_EXECUTABLE_MSG)
_sys_executable_warning_logged = True
return '/usr/bin/python'
def _get_core_source():
"""
In non-masters, simply fetch the cached mitogen.core source code via the
import mechanism. In masters, this function is replaced with a version that
performs minification directly.
"""
return inspect.getsource(mitogen.core)
def get_core_source_partial():
"""
_get_core_source() is expensive, even with @lru_cache in minify.py, threads
can enter it simultaneously causing severe slowdowns.
"""
global _core_source_partial
if _core_source_partial is None:
_core_source_lock.acquire()
try:
if _core_source_partial is None:
_core_source_partial = PartialZlib(
_get_core_source().encode('utf-8')
)
finally:
_core_source_lock.release()
return _core_source_partial
def get_default_remote_name():
"""
Return the default name appearing in argv[0] of remote machines.
"""
s = u'%s@%s:%d'
s %= (getpass.getuser(), socket.gethostname(), os.getpid())
# In mixed UNIX/Windows environments, the username may contain slashes.
return s.translate({
ord(u'\\'): ord(u'_'),
ord(u'/'): ord(u'_')
})
def is_immediate_child(msg, stream):
"""
Handler policy that requires messages to arrive only from immediately
connected children.
"""
return msg.src_id == stream.protocol.remote_id
def flags(names):
"""
Return the result of ORing a set of (space separated) :py:mod:`termios`
module constants together.
"""
return sum(getattr(termios, name, 0)
for name in names.split())
def cfmakeraw(tflags):
"""
Given a list returned by :py:func:`termios.tcgetattr`, return a list
modified in a manner similar to the `cfmakeraw()` C library function, but
additionally disabling local echo.
"""
# BSD: github.com/freebsd/freebsd/blob/master/lib/libc/gen/termios.c#L162
# Linux: github.com/lattera/glibc/blob/master/termios/cfmakeraw.c#L20
iflag, oflag, cflag, lflag, ispeed, ospeed, cc = tflags
iflag &= ~flags('IMAXBEL IXOFF INPCK BRKINT PARMRK '
'ISTRIP INLCR ICRNL IXON IGNPAR')
iflag &= ~flags('IGNBRK BRKINT PARMRK')
oflag &= ~flags('OPOST')
lflag &= ~flags('ECHO ECHOE ECHOK ECHONL ICANON ISIG '
'IEXTEN NOFLSH TOSTOP PENDIN')
cflag &= ~flags('CSIZE PARENB')
cflag |= flags('CS8 CREAD')
return [iflag, oflag, cflag, lflag, ispeed, ospeed, cc]
def disable_echo(fd):
old = termios.tcgetattr(fd)
new = cfmakeraw(old)
flags = getattr(termios, 'TCSASOFT', 0)
if not mitogen.core.IS_WSL:
# issue #319: Windows Subsystem for Linux as of July 2018 throws EINVAL
# if TCSAFLUSH is specified.
flags |= termios.TCSAFLUSH
termios.tcsetattr(fd, flags, new)
def create_socketpair(size=None):
"""
Create a :func:`socket.socketpair` for use as a child's UNIX stdio
channels. As socketpairs are bidirectional, they are economical on file
descriptor usage as one descriptor can be used for ``stdin`` and
``stdout``. As they are sockets their buffers are tunable, allowing large
buffers to improve file transfer throughput and reduce IO loop iterations.
"""
if size is None:
size = mitogen.core.CHUNK_SIZE
parentfp, childfp = socket.socketpair()
for fp in parentfp, childfp:
fp.setsockopt(socket.SOL_SOCKET, socket.SO_SNDBUF, size)
return parentfp, childfp
def create_best_pipe(escalates_privilege=False):
"""
By default we prefer to communicate with children over a UNIX socket, as a
single file descriptor can represent bidirectional communication, and a
cross-platform API exists to align buffer sizes with the needs of the
library.
SELinux prevents us setting up a privileged process to inherit an AF_UNIX
socket, a facility explicitly designed as a better replacement for pipes,
because at some point in the mid 90s it might have been commonly possible
for AF_INET sockets to end up undesirably connected to a privileged
process, so let's make up arbitrary rules breaking all sockets instead.
If SELinux is detected, fall back to using pipes.
:param bool escalates_privilege:
If :data:`True`, the target program may escalate privileges, causing
SELinux to disconnect AF_UNIX sockets, so avoid those.
:returns:
`(parent_rfp, child_wfp, child_rfp, parent_wfp)`
"""
if (not escalates_privilege) or (not SELINUX_ENABLED):
parentfp, childfp = create_socketpair()
return parentfp, childfp, childfp, parentfp
parent_rfp, child_wfp = mitogen.core.pipe()
try:
child_rfp, parent_wfp = mitogen.core.pipe()
return parent_rfp, child_wfp, child_rfp, parent_wfp
except:
parent_rfp.close()
child_wfp.close()
raise
def popen(**kwargs):
"""
Wrap :class:`subprocess.Popen` to ensure any global :data:`_preexec_hook`
is invoked in the child.
"""
real_preexec_fn = kwargs.pop('preexec_fn', None)
def preexec_fn():
if _preexec_hook:
_preexec_hook()
if real_preexec_fn:
real_preexec_fn()
return subprocess.Popen(preexec_fn=preexec_fn, **kwargs)
def create_child(args, merge_stdio=False, stderr_pipe=False,
escalates_privilege=False, preexec_fn=None):
"""
Create a child process whose stdin/stdout is connected to a socket.
:param list args:
Program argument vector.
:param bool merge_stdio:
If :data:`True`, arrange for `stderr` to be connected to the `stdout`
socketpair, rather than inherited from the parent process. This may be
necessary to ensure that no TTY is connected to any stdio handle, for
instance when using LXC.
:param bool stderr_pipe:
If :data:`True` and `merge_stdio` is :data:`False`, arrange for
`stderr` to be connected to a separate pipe, to allow any ongoing debug
logs generated by e.g. SSH to be output as the session progresses,
without interfering with `stdout`.
:param bool escalates_privilege:
If :data:`True`, the target program may escalate privileges, causing
SELinux to disconnect AF_UNIX sockets, so avoid those.
:param function preexec_fn:
If not :data:`None`, a function to run within the post-fork child
before executing the target program.
:returns:
:class:`Process` instance.
"""
parent_rfp, child_wfp, child_rfp, parent_wfp = create_best_pipe(
escalates_privilege=escalates_privilege
)
stderr = None
stderr_r = None
if merge_stdio:
stderr = child_wfp
elif stderr_pipe:
stderr_r, stderr = mitogen.core.pipe()
mitogen.core.set_cloexec(stderr_r.fileno())
try:
proc = popen(
args=args,
stdin=child_rfp,
stdout=child_wfp,
stderr=stderr,
close_fds=True,
preexec_fn=preexec_fn,
)
except:
child_rfp.close()
child_wfp.close()
parent_rfp.close()
parent_wfp.close()
if stderr_pipe:
stderr.close()
stderr_r.close()
raise
child_rfp.close()
child_wfp.close()
if stderr_pipe:
stderr.close()
return PopenProcess(
proc=proc,
stdin=parent_wfp,
stdout=parent_rfp,
stderr=stderr_r,
)
def _acquire_controlling_tty():
os.setsid()
if sys.platform in ('linux', 'linux2'):
# On Linux, the controlling tty becomes the first tty opened by a
# process lacking any prior tty.
os.close(os.open(os.ttyname(2), os.O_RDWR))
if hasattr(termios, 'TIOCSCTTY') and not mitogen.core.IS_WSL:
# #550: prehistoric WSL does not like TIOCSCTTY.
# On BSD an explicit ioctl is required. For some inexplicable reason,
# Python 2.6 on Travis also requires it.
fcntl.ioctl(2, termios.TIOCSCTTY)
def _linux_broken_devpts_openpty():
"""
#462: On broken Linux hosts with mismatched configuration (e.g. old
/etc/fstab template installed), /dev/pts may be mounted without the gid=
mount option, causing new slave devices to be created with the group ID of
the calling process. This upsets glibc, whose openpty() is required by
specification to produce a slave owned by a special group ID (which is
always the 'tty' group).
Glibc attempts to use "pt_chown" to fix ownership. If that fails, it
chown()s the PTY directly, which fails due to non-root, causing openpty()
to fail with EPERM ("Operation not permitted"). Since we don't need the
magical TTY group to run sudo and su, open the PTY ourselves in this case.
"""
master_fd = None
try:
# Opening /dev/ptmx causes a PTY pair to be allocated, and the
# corresponding slave /dev/pts/* device to be created, owned by UID/GID
# matching this process.
master_fd = os.open('/dev/ptmx', os.O_RDWR)
# Clear the lock bit from the PTY. This a prehistoric feature from a
# time when slave device files were persistent.
fcntl.ioctl(master_fd, LINUX_TIOCSPTLCK, struct.pack('i', 0))
# Since v4.13 TIOCGPTPEER exists to open the slave in one step, but we
# must support older kernels. Ask for the PTY number.
pty_num_s = fcntl.ioctl(master_fd, LINUX_TIOCGPTN,
struct.pack('i', 0))
pty_num, = struct.unpack('i', pty_num_s)
pty_name = '/dev/pts/%d' % (pty_num,)
# Now open it with O_NOCTTY to ensure it doesn't change our controlling
# TTY. Otherwise when we close the FD we get killed by the kernel, and
# the child we spawn that should really attach to it will get EPERM
# during _acquire_controlling_tty().
slave_fd = os.open(pty_name, os.O_RDWR|os.O_NOCTTY)
return master_fd, slave_fd
except OSError:
if master_fd is not None:
os.close(master_fd)
e = sys.exc_info()[1]
raise mitogen.core.StreamError(OPENPTY_MSG, e)
def openpty():
"""
Call :func:`os.openpty`, raising a descriptive error if the call fails.
:raises mitogen.core.StreamError:
Creating a PTY failed.
:returns:
`(master_fp, slave_fp)` file-like objects.
"""
try:
master_fd, slave_fd = os.openpty()
except OSError:
e = sys.exc_info()[1]
if not (IS_LINUX and e.args[0] == errno.EPERM):
raise mitogen.core.StreamError(OPENPTY_MSG, e)
master_fd, slave_fd = _linux_broken_devpts_openpty()
master_fp = os.fdopen(master_fd, 'r+b', 0)
slave_fp = os.fdopen(slave_fd, 'r+b', 0)
disable_echo(master_fd)
disable_echo(slave_fd)
mitogen.core.set_block(slave_fd)
return master_fp, slave_fp
def tty_create_child(args):
"""
Return a file descriptor connected to the master end of a pseudo-terminal,
whose slave end is connected to stdin/stdout/stderr of a new child process.
The child is created such that the pseudo-terminal becomes its controlling
TTY, ensuring access to /dev/tty returns a new file descriptor open on the
slave end.
:param list args:
Program argument vector.
:returns:
:class:`Process` instance.
"""
master_fp, slave_fp = openpty()
try:
proc = popen(
args=args,
stdin=slave_fp,
stdout=slave_fp,
stderr=slave_fp,
preexec_fn=_acquire_controlling_tty,
close_fds=True,
)
except:
master_fp.close()
slave_fp.close()
raise
slave_fp.close()
return PopenProcess(
proc=proc,
stdin=master_fp,
stdout=master_fp,
)
def hybrid_tty_create_child(args, escalates_privilege=False):
"""
Like :func:`tty_create_child`, except attach stdin/stdout to a socketpair
like :func:`create_child`, but leave stderr and the controlling TTY
attached to a TTY.
This permits high throughput communication with programs that are reached
via some program that requires a TTY for password input, like many
configurations of sudo. The UNIX TTY layer tends to have tiny (no more than
14KiB) buffers, forcing many IO loop iterations when transferring bulk
data, causing significant performance loss.
:param bool escalates_privilege:
If :data:`True`, the target program may escalate privileges, causing
SELinux to disconnect AF_UNIX sockets, so avoid those.
:param list args:
Program argument vector.
:returns:
:class:`Process` instance.
"""
master_fp, slave_fp = openpty()
try:
parent_rfp, child_wfp, child_rfp, parent_wfp = create_best_pipe(
escalates_privilege=escalates_privilege,
)
try:
mitogen.core.set_block(child_rfp)
mitogen.core.set_block(child_wfp)
proc = popen(
args=args,
stdin=child_rfp,
stdout=child_wfp,
stderr=slave_fp,
preexec_fn=_acquire_controlling_tty,
close_fds=True,
)
except:
parent_rfp.close()
child_wfp.close()
parent_wfp.close()
child_rfp.close()
raise
except:
master_fp.close()
slave_fp.close()
raise
slave_fp.close()
child_rfp.close()
child_wfp.close()
return PopenProcess(
proc=proc,
stdin=parent_wfp,
stdout=parent_rfp,
stderr=master_fp,
)
class Timer(object):
"""
Represents a future event.
"""
#: Set to :data:`False` if :meth:`cancel` has been called, or immediately
#: prior to being executed by :meth:`TimerList.expire`.
active = True
def __init__(self, when, func):
self.when = when
self.func = func
def __repr__(self):
return 'Timer(%r, %r)' % (self.when, self.func)
def __eq__(self, other):
return self.when == other.when
def __lt__(self, other):
return self.when < other.when
def __le__(self, other):
return self.when <= other.when
def cancel(self):
"""
Cancel this event. If it has not yet executed, it will not execute
during any subsequent :meth:`TimerList.expire` call.
"""
self.active = False
class TimerList(object):
"""
Efficiently manage a list of cancellable future events relative to wall
clock time. An instance of this class is installed as
:attr:`mitogen.master.Broker.timers` by default, and as
:attr:`mitogen.core.Broker.timers` in children after a call to
:func:`mitogen.parent.upgrade_router`.
You can use :class:`TimerList` to cause the broker to wake at arbitrary
future moments, useful for implementing timeouts and polling in an
asynchronous context.
:class:`TimerList` methods can only be called from asynchronous context,
for example via :meth:`mitogen.core.Broker.defer`.
The broker automatically adjusts its sleep delay according to the installed
timer list, and arranges for timers to expire via automatic calls to
:meth:`expire`. The main user interface to :class:`TimerList` is
:meth:`schedule`.
"""
_now = mitogen.core.now
def __init__(self):
self._lst = []
def get_timeout(self):
"""
Return the floating point seconds until the next event is due.
:returns:
Floating point delay, or 0.0, or :data:`None` if no events are
scheduled.
"""
while self._lst and not self._lst[0].active:
heapq.heappop(self._lst)
if self._lst:
return max(0, self._lst[0].when - self._now())
def schedule(self, when, func):
"""
Schedule a future event.
:param float when:
UNIX time in seconds when event should occur.
:param callable func:
Callable to invoke on expiry.
:returns:
A :class:`Timer` instance, exposing :meth:`Timer.cancel`, which may
be used to cancel the future invocation.
"""
timer = Timer(when, func)
heapq.heappush(self._lst, timer)
return timer
def expire(self):
"""
Invoke callbacks for any events in the past.
"""
now = self._now()
while self._lst and self._lst[0].when <= now:
timer = heapq.heappop(self._lst)
if timer.active:
timer.active = False
timer.func()
class PartialZlib(object):
"""
Because the mitogen.core source has a line appended to it during bootstrap,
it must be recompressed for each connection. This is not a problem for a
small number of connections, but it amounts to 30 seconds CPU time by the
time 500 targets are in use.
For that reason, build a compressor containing mitogen.core and flush as
much of it as possible into an initial buffer. Then to append the custom
line, clone the compressor and compress just that line.
A full compression costs ~6ms on a modern machine, this method costs ~35
usec.
"""
def __init__(self, s):
self.s = s
if sys.version_info > (2, 5):
self._compressor = zlib.compressobj(9)
self._out = self._compressor.compress(s)
self._out += self._compressor.flush(zlib.Z_SYNC_FLUSH)
else:
self._compressor = None
def append(self, s):
"""
Append the bytestring `s` to the compressor state and return the
final compressed output.
"""
if self._compressor is None:
return zlib.compress(self.s + s, 9)
else:
compressor = self._compressor.copy()
out = self._out
out += compressor.compress(s)
return out + compressor.flush()
def _upgrade_broker(broker):
"""
Extract the poller state from Broker and replace it with the industrial
strength poller for this OS. Must run on the Broker thread.
"""
# This function is deadly! The act of calling start_receive() generates log
# messages which must be silenced as the upgrade progresses, otherwise the
# poller state will change as it is copied, resulting in write fds that are
# lost. (Due to LogHandler->Router->Stream->Protocol->Broker->Poller, where
# Stream only calls start_transmit() when transitioning from empty to
# non-empty buffer. If the start_transmit() is lost, writes from the child
# hang permanently).
root = logging.getLogger()
old_level = root.level
root.setLevel(logging.CRITICAL)
try:
old = broker.poller
new = PREFERRED_POLLER()
for fd, data in old.readers:
new.start_receive(fd, data)
for fd, data in old.writers:
new.start_transmit(fd, data)
old.close()
broker.poller = new
finally:
root.setLevel(old_level)
broker.timers = TimerList()
LOG.debug('upgraded %r with %r (new: %d readers, %d writers; '
'old: %d readers, %d writers)', old, new,
len(new.readers), len(new.writers),
len(old.readers), len(old.writers))
@mitogen.core.takes_econtext
def upgrade_router(econtext):
if not isinstance(econtext.router, Router): # TODO
econtext.broker.defer(_upgrade_broker, econtext.broker)
econtext.router.__class__ = Router # TODO
econtext.router.upgrade(
importer=econtext.importer,
parent=econtext.parent,
)
def get_connection_class(name):
"""
Given the name of a Mitogen connection method, import its implementation
module and return its Stream subclass.
"""
if name == u'local':
name = u'parent'
module = mitogen.core.import_module(u'mitogen.' + name)
return module.Connection
@mitogen.core.takes_econtext
def _proxy_connect(name, method_name, kwargs, econtext):
"""
Implements the target portion of Router._proxy_connect() by upgrading the
local process to a parent if it was not already, then calling back into
Router._connect() using the arguments passed to the parent's
Router.connect().
:returns:
Dict containing:
* ``id``: :data:`None`, or integer new context ID.
* ``name``: :data:`None`, or string name attribute of new Context.
* ``msg``: :data:`None`, or StreamError exception text.
"""
upgrade_router(econtext)
try:
context = econtext.router._connect(
klass=get_connection_class(method_name),
name=name,
**kwargs
)
except mitogen.core.StreamError:
return {
u'id': None,
u'name': None,
u'msg': 'error occurred on host %s: %s' % (
socket.gethostname(),
sys.exc_info()[1],
),
}
return {
u'id': context.context_id,
u'name': context.name,
u'msg': None,
}
def returncode_to_str(n):
"""
Parse and format a :func:`os.waitpid` exit status.
"""
if n < 0:
return 'exited due to signal %d (%s)' % (-n, SIGNAL_BY_NUM.get(-n))
return 'exited with return code %d' % (n,)
class EofError(mitogen.core.StreamError):
"""
Raised by :class:`Connection` when an empty read is detected from the
remote process before bootstrap completes.
"""
# inherits from StreamError to maintain compatibility.
pass
class CancelledError(mitogen.core.StreamError):
"""
Raised by :class:`Connection` when :meth:`mitogen.core.Broker.shutdown` is
called before bootstrap completes.
"""
pass
class Argv(object):
"""
Wrapper to defer argv formatting when debug logging is disabled.
"""
def __init__(self, argv):
self.argv = argv
must_escape = frozenset('\\$"`!')
must_escape_or_space = must_escape | frozenset(' ')
def escape(self, x):
if not self.must_escape_or_space.intersection(x):
return x
s = '"'
for c in x:
if c in self.must_escape:
s += '\\'
s += c
s += '"'
return s
def __str__(self):
return ' '.join(map(self.escape, self.argv))
class CallSpec(object):
"""
Wrapper to defer call argument formatting when debug logging is disabled.
"""
def __init__(self, func, args, kwargs):
self.func = func
self.args = args
self.kwargs = kwargs
def _get_name(self):
bits = [self.func.__module__]
if inspect.ismethod(self.func):
im_self = getattr(self.func, IM_SELF_ATTR)
bits.append(getattr(im_self, '__name__', None) or
getattr(type(im_self), '__name__', None))
bits.append(self.func.__name__)
return u'.'.join(bits)
def _get_args(self):
return u', '.join(repr(a) for a in self.args)
def _get_kwargs(self):
s = u''
if self.kwargs:
s = u', '.join('%s=%r' % (k, v) for k, v in self.kwargs.items())
if self.args:
s = u', ' + s
return s
def __repr__(self):
return '%s(%s%s)' % (
self._get_name(),
self._get_args(),
self._get_kwargs(),
)
class PollPoller(mitogen.core.Poller):
"""
Poller based on the POSIX :linux:man2:`poll` interface. Not available on
some versions of OS X, otherwise it is the preferred poller for small FD
counts, as there is no setup/teardown/configuration system call overhead.
"""
SUPPORTED = hasattr(select, 'poll')
_repr = 'PollPoller()'
def __init__(self):
super(PollPoller, self).__init__()
self._pollobj = select.poll()
# TODO: no proof we dont need writemask too
_readmask = (
getattr(select, 'POLLIN', 0) |
getattr(select, 'POLLHUP', 0)
)
def _update(self, fd):
mask = (((fd in self._rfds) and self._readmask) |
((fd in self._wfds) and select.POLLOUT))
if mask:
self._pollobj.register(fd, mask)
else:
try:
self._pollobj.unregister(fd)
except KeyError:
pass
def _poll(self, timeout):
if timeout:
timeout *= 1000
events, _ = mitogen.core.io_op(self._pollobj.poll, timeout)
for fd, event in events:
if event & self._readmask:
IOLOG.debug('%r: POLLIN|POLLHUP for %r', self, fd)
data, gen = self._rfds.get(fd, (None, None))
if gen and gen < self._generation:
yield data
if event & select.POLLOUT:
IOLOG.debug('%r: POLLOUT for %r', self, fd)
data, gen = self._wfds.get(fd, (None, None))
if gen and gen < self._generation:
yield data
class KqueuePoller(mitogen.core.Poller):
"""
Poller based on the FreeBSD/Darwin :freebsd:man2:`kqueue` interface.
"""
SUPPORTED = hasattr(select, 'kqueue')
_repr = 'KqueuePoller()'
def __init__(self):
super(KqueuePoller, self).__init__()
self._kqueue = select.kqueue()
self._changelist = []
def close(self):
super(KqueuePoller, self).close()
self._kqueue.close()
def _control(self, fd, filters, flags):
mitogen.core._vv and IOLOG.debug(
'%r._control(%r, %r, %r)', self, fd, filters, flags)
# TODO: at shutdown it is currently possible for KQ_EV_ADD/KQ_EV_DEL
# pairs to be pending after the associated file descriptor has already
# been closed. Fixing this requires maintaining extra state, or perhaps
# making fd closure the poller's responsibility. In the meantime,
# simply apply changes immediately.
# self._changelist.append(select.kevent(fd, filters, flags))
changelist = [select.kevent(fd, filters, flags)]
events, _ = mitogen.core.io_op(self._kqueue.control, changelist, 0, 0)
assert not events
def start_receive(self, fd, data=None):
mitogen.core._vv and IOLOG.debug('%r.start_receive(%r, %r)',
self, fd, data)
if fd not in self._rfds:
self._control(fd, select.KQ_FILTER_READ, select.KQ_EV_ADD)
self._rfds[fd] = (data or fd, self._generation)
def stop_receive(self, fd):
mitogen.core._vv and IOLOG.debug('%r.stop_receive(%r)', self, fd)
if fd in self._rfds:
self._control(fd, select.KQ_FILTER_READ, select.KQ_EV_DELETE)
del self._rfds[fd]
def start_transmit(self, fd, data=None):
mitogen.core._vv and IOLOG.debug('%r.start_transmit(%r, %r)',
self, fd, data)
if fd not in self._wfds:
self._control(fd, select.KQ_FILTER_WRITE, select.KQ_EV_ADD)
self._wfds[fd] = (data or fd, self._generation)
def stop_transmit(self, fd):
mitogen.core._vv and IOLOG.debug('%r.stop_transmit(%r)', self, fd)
if fd in self._wfds:
self._control(fd, select.KQ_FILTER_WRITE, select.KQ_EV_DELETE)
del self._wfds[fd]
def _poll(self, timeout):
changelist = self._changelist
self._changelist = []
events, _ = mitogen.core.io_op(self._kqueue.control,
changelist, 32, timeout)
for event in events:
fd = event.ident
if event.flags & select.KQ_EV_ERROR:
LOG.debug('ignoring stale event for fd %r: errno=%d: %s',
fd, event.data, errno.errorcode.get(event.data))
elif event.filter == select.KQ_FILTER_READ:
data, gen = self._rfds.get(fd, (None, None))
# Events can still be read for an already-discarded fd.
if gen and gen < self._generation:
mitogen.core._vv and IOLOG.debug('%r: POLLIN: %r', self, fd)
yield data
elif event.filter == select.KQ_FILTER_WRITE and fd in self._wfds:
data, gen = self._wfds.get(fd, (None, None))
if gen and gen < self._generation:
mitogen.core._vv and IOLOG.debug('%r: POLLOUT: %r', self, fd)
yield data
class EpollPoller(mitogen.core.Poller):
"""
Poller based on the Linux :linux:man7:`epoll` interface.
"""
SUPPORTED = hasattr(select, 'epoll')
_repr = 'EpollPoller()'
def __init__(self):
super(EpollPoller, self).__init__()
self._epoll = select.epoll(32)
self._registered_fds = set()
def close(self):
super(EpollPoller, self).close()
self._epoll.close()
def _control(self, fd):
mitogen.core._vv and IOLOG.debug('%r._control(%r)', self, fd)
mask = (((fd in self._rfds) and select.EPOLLIN) |
((fd in self._wfds) and select.EPOLLOUT))
if mask:
if fd in self._registered_fds:
self._epoll.modify(fd, mask)
else:
self._epoll.register(fd, mask)
self._registered_fds.add(fd)
elif fd in self._registered_fds:
self._epoll.unregister(fd)
self._registered_fds.remove(fd)
def start_receive(self, fd, data=None):
mitogen.core._vv and IOLOG.debug('%r.start_receive(%r, %r)',
self, fd, data)
self._rfds[fd] = (data or fd, self._generation)
self._control(fd)
def stop_receive(self, fd):
mitogen.core._vv and IOLOG.debug('%r.stop_receive(%r)', self, fd)
self._rfds.pop(fd, None)
self._control(fd)
def start_transmit(self, fd, data=None):
mitogen.core._vv and IOLOG.debug('%r.start_transmit(%r, %r)',
self, fd, data)
self._wfds[fd] = (data or fd, self._generation)
self._control(fd)
def stop_transmit(self, fd):
mitogen.core._vv and IOLOG.debug('%r.stop_transmit(%r)', self, fd)
self._wfds.pop(fd, None)
self._control(fd)
_inmask = (getattr(select, 'EPOLLIN', 0) |
getattr(select, 'EPOLLHUP', 0))
def _poll(self, timeout):
the_timeout = -1
if timeout is not None:
the_timeout = timeout
events, _ = mitogen.core.io_op(self._epoll.poll, the_timeout, 32)
for fd, event in events:
if event & self._inmask:
data, gen = self._rfds.get(fd, (None, None))
if gen and gen < self._generation:
# Events can still be read for an already-discarded fd.
mitogen.core._vv and IOLOG.debug('%r: POLLIN: %r', self, fd)
yield data
if event & select.EPOLLOUT:
data, gen = self._wfds.get(fd, (None, None))
if gen and gen < self._generation:
mitogen.core._vv and IOLOG.debug('%r: POLLOUT: %r', self, fd)
yield data
# 2.4 and 2.5 only had select.select() and select.poll().
for _klass in mitogen.core.Poller, PollPoller, KqueuePoller, EpollPoller:
if _klass.SUPPORTED:
PREFERRED_POLLER = _klass
# For processes that start many threads or connections, it's possible Latch
# will also get high-numbered FDs, and so select() becomes useless there too.
# So swap in our favourite poller.
if PollPoller.SUPPORTED:
mitogen.core.Latch.poller_class = PollPoller
else:
mitogen.core.Latch.poller_class = PREFERRED_POLLER
class LineLoggingProtocolMixin(object):
def __init__(self, **kwargs):
super(LineLoggingProtocolMixin, self).__init__(**kwargs)
self.logged_lines = []
self.logged_partial = None
def on_line_received(self, line):
self.logged_partial = None
self.logged_lines.append((mitogen.core.now(), line))
self.logged_lines[:] = self.logged_lines[-100:]
return super(LineLoggingProtocolMixin, self).on_line_received(line)
def on_partial_line_received(self, line):
self.logged_partial = line
return super(LineLoggingProtocolMixin, self).on_partial_line_received(line)
def on_disconnect(self, broker):
if self.logged_partial:
self.logged_lines.append((mitogen.core.now(), self.logged_partial))
self.logged_partial = None
super(LineLoggingProtocolMixin, self).on_disconnect(broker)
def get_history(streams):
history = []
for stream in streams:
if stream:
history.extend(getattr(stream.protocol, 'logged_lines', []))
history.sort()
s = b('\n').join(h[1] for h in history)
return mitogen.core.to_text(s)
class RegexProtocol(LineLoggingProtocolMixin, mitogen.core.DelimitedProtocol):
"""
Implement a delimited protocol where messages matching a set of regular
expressions are dispatched to individual handler methods. Input is
dispatches using :attr:`PATTERNS` and :attr:`PARTIAL_PATTERNS`, before
falling back to :meth:`on_unrecognized_line_received` and
:meth:`on_unrecognized_partial_line_received`.
"""
#: A sequence of 2-tuples of the form `(compiled pattern, method)` for
#: patterns that should be matched against complete (delimited) messages,
#: i.e. full lines.
PATTERNS = []
#: Like :attr:`PATTERNS`, but patterns that are matched against incomplete
#: lines.
PARTIAL_PATTERNS = []
def on_line_received(self, line):
super(RegexProtocol, self).on_line_received(line)
for pattern, func in self.PATTERNS:
match = pattern.search(line)
if match is not None:
return func(self, line, match)
return self.on_unrecognized_line_received(line)
def on_unrecognized_line_received(self, line):
LOG.debug('%s: (unrecognized): %s',
self.stream.name, line.decode('utf-8', 'replace'))
def on_partial_line_received(self, line):
super(RegexProtocol, self).on_partial_line_received(line)
LOG.debug('%s: (partial): %s',
self.stream.name, line.decode('utf-8', 'replace'))
for pattern, func in self.PARTIAL_PATTERNS:
match = pattern.search(line)
if match is not None:
return func(self, line, match)
return self.on_unrecognized_partial_line_received(line)
def on_unrecognized_partial_line_received(self, line):
LOG.debug('%s: (unrecognized partial): %s',
self.stream.name, line.decode('utf-8', 'replace'))
class BootstrapProtocol(RegexProtocol):
"""
Respond to stdout of a child during bootstrap. Wait for :attr:`EC0_MARKER`
to be written by the first stage to indicate it can receive the bootstrap,
then await :attr:`EC1_MARKER` to indicate success, and
:class:`MitogenProtocol` can be enabled.
"""
#: Sentinel value emitted by the first stage to indicate it is ready to
#: receive the compressed bootstrap. For :mod:`mitogen.ssh` this must have
#: length of at least `max(len('password'), len('debug1:'))`
EC0_MARKER = b('MITO000')
EC1_MARKER = b('MITO001')
EC2_MARKER = b('MITO002')
def __init__(self, broker):
super(BootstrapProtocol, self).__init__()
self._writer = mitogen.core.BufferedWriter(broker, self)
def on_transmit(self, broker):
self._writer.on_transmit(broker)
def _on_ec0_received(self, line, match):
LOG.debug('%r: first stage started succcessfully', self)
self._writer.write(self.stream.conn.get_preamble())
def _on_ec1_received(self, line, match):
LOG.debug('%r: first stage received mitogen.core source', self)
def _on_ec2_received(self, line, match):
LOG.debug('%r: new child booted successfully', self)
self.stream.conn._complete_connection()
return False
def on_unrecognized_line_received(self, line):
LOG.debug('%s: stdout: %s', self.stream.name,
line.decode('utf-8', 'replace'))
PATTERNS = [
(re.compile(EC0_MARKER), _on_ec0_received),
(re.compile(EC1_MARKER), _on_ec1_received),
(re.compile(EC2_MARKER), _on_ec2_received),
]
class LogProtocol(LineLoggingProtocolMixin, mitogen.core.DelimitedProtocol):
"""
For "hybrid TTY/socketpair" mode, after connection setup a spare TTY master
FD exists that cannot be closed, and to which SSH or sudo may continue
writing log messages.
The descriptor cannot be closed since the UNIX TTY layer sends SIGHUP to
processes whose controlling TTY is the slave whose master side was closed.
LogProtocol takes over this FD and creates log messages for anything
written to it.
"""
def on_line_received(self, line):
"""
Read a line, decode it as UTF-8, and log it.
"""
super(LogProtocol, self).on_line_received(line)
LOG.info(u'%s: %s', self.stream.name, line.decode('utf-8', 'replace'))
class MitogenProtocol(mitogen.core.MitogenProtocol):
"""
Extend core.MitogenProtocol to cause SHUTDOWN to be sent to the child
during graceful shutdown.
"""
def on_shutdown(self, broker):
"""
Respond to the broker's request for the stream to shut down by sending
SHUTDOWN to the child.
"""
LOG.debug('%r: requesting child shutdown', self)
self._send(
mitogen.core.Message(
src_id=mitogen.context_id,
dst_id=self.remote_id,
handle=mitogen.core.SHUTDOWN,
)
)
class Options(object):
name = None
#: The path to the remote Python interpreter.
python_path = get_sys_executable()
#: Maximum time to wait for a connection attempt.
connect_timeout = 30.0
#: True to cause context to write verbose /tmp/mitogen.<pid>.log.
debug = False
#: True to cause context to write /tmp/mitogen.stats.<pid>.<thread>.log.
profiling = False
#: True if unidirectional routing is enabled in the new child.
unidirectional = False
#: Passed via Router wrapper methods, must eventually be passed to
#: ExternalContext.main().
max_message_size = None
#: Remote name.
remote_name = None
#: Derived from :py:attr:`connect_timeout`; absolute floating point
#: UNIX timestamp after which the connection attempt should be abandoned.
connect_deadline = None
def __init__(self, max_message_size, name=None, remote_name=None,
python_path=None, debug=False, connect_timeout=None,
profiling=False, unidirectional=False, old_router=None):
self.name = name
self.max_message_size = max_message_size
if python_path:
self.python_path = python_path
if connect_timeout:
self.connect_timeout = connect_timeout
if remote_name is None:
remote_name = get_default_remote_name()
if '/' in remote_name or '\\' in remote_name:
raise ValueError('remote_name= cannot contain slashes')
if remote_name:
self.remote_name = mitogen.core.to_text(remote_name)
self.debug = debug
self.profiling = profiling
self.unidirectional = unidirectional
self.max_message_size = max_message_size
self.connect_deadline = mitogen.core.now() + self.connect_timeout
class Connection(object):
"""
Manage the lifetime of a set of :class:`Streams <Stream>` connecting to a
remote Python interpreter, including bootstrap, disconnection, and external
tool integration.
Base for streams capable of starting children.
"""
options_class = Options
#: The protocol attached to stdio of the child.
stream_protocol_class = BootstrapProtocol
#: The protocol attached to stderr of the child.
diag_protocol_class = LogProtocol
#: :class:`Process`
proc = None
#: :class:`mitogen.core.Stream` with sides connected to stdin/stdout.
stdio_stream = None
#: If `proc.stderr` is set, referencing either a plain pipe or the
#: controlling TTY, this references the corresponding
#: :class:`LogProtocol`'s stream, allowing it to be disconnected when this
#: stream is disconnected.
stderr_stream = None
#: Function with the semantics of :func:`create_child` used to create the
#: child process.
create_child = staticmethod(create_child)
#: Dictionary of extra kwargs passed to :attr:`create_child`.
create_child_args = {}
#: :data:`True` if the remote has indicated that it intends to detach, and
#: should not be killed on disconnect.
detached = False
#: If :data:`True`, indicates the child should not be killed during
#: graceful detachment, as it the actual process implementing the child
#: context. In all other cases, the subprocess is SSH, sudo, or a similar
#: tool that should be reminded to quit during disconnection.
child_is_immediate_subprocess = True
#: Prefix given to default names generated by :meth:`connect`.
name_prefix = u'local'
#: :class:`Timer` that runs :meth:`_on_timer_expired` when connection
#: timeout occurs.
_timer = None
#: When disconnection completes, instance of :class:`Reaper` used to wait
#: on the exit status of the subprocess.
_reaper = None
#: On failure, the exception object that should be propagated back to the
#: user.
exception = None
#: Extra text appended to :class:`EofError` if that exception is raised on
#: a failed connection attempt. May be used in subclasses to hint at common
#: problems with a particular connection method.
eof_error_hint = None
def __init__(self, options, router):
#: :class:`Options`
self.options = options
self._router = router
def __repr__(self):
return 'Connection(%r)' % (self.stdio_stream,)
# Minimised, gzipped, base64'd and passed to 'python -c'. It forks, dups
# file descriptor 0 as 100, creates a pipe, then execs a new interpreter
# with a custom argv.
# * Optimized for minimum byte count after minification & compression.
# The script preamble_size.py measures this.
# * 'CONTEXT_NAME' and 'PREAMBLE_COMPRESSED_LEN' are substituted with
# their respective values.
# * CONTEXT_NAME must be prefixed with the name of the Python binary in
# order to allow virtualenvs to detect their install prefix.
#
# macOS tweaks for Python 2.7 must be kept in sync with the the Ansible
# module test_echo_module, used by the integration tests.
# * macOS <= 10.14 (Darwin <= 18) install an unreliable Python version
# switcher as /usr/bin/python, which introspects argv0. To workaround
# it we redirect attempts to call /usr/bin/python with an explicit
# call to /usr/bin/python2.7. macOS 10.15 (Darwin 19) removed it.
# * macOS 11.x (Darwin 20, Big Sur) and macOS 12.x (Darwin 21, Montery)
# do something slightly different. The Python executable is patched to
# perform an extra execvp(). I don't fully understand the details, but
# setting PYTHON_LAUNCHED_FROM_WRAPPER=1 avoids it.
# * macOS 12.3+ (Darwin 21.4+, Monterey) doesn't ship Python.
# https://developer.apple.com/documentation/macos-release-notes/macos-12_3-release-notes#Python
#
# Locals:
# R: read side of interpreter stdin.
# W: write side of interpreter stdin.
# r: read side of core_src FD.
# w: write side of core_src FD.
# C: the decompressed core source.
# Final os.close(2) to avoid --py-debug build from corrupting stream with
# "[1234 refs]" during exit.
@staticmethod
def _first_stage():
R,W=os.pipe()
r,w=os.pipe()
if os.fork():
os.dup2(0,100)
os.dup2(R,0)
os.dup2(r,101)
os.close(R)
os.close(r)
os.close(W)
os.close(w)
if os.uname()[0]=='Darwin'and os.uname()[2][:2]<'19'and sys.executable=='/usr/bin/python':sys.executable='/usr/bin/python2.7'
if os.uname()[0]=='Darwin'and os.uname()[2][:2]in'2021'and sys.version[:3]=='2.7':os.environ['PYTHON_LAUNCHED_FROM_WRAPPER']='1'
os.environ['ARGV0']=sys.executable
os.execl(sys.executable,sys.executable+'(mitogen:CONTEXT_NAME)')
os.write(1,'MITO000\n'.encode())
C=zlib.decompress(os.fdopen(0,'rb').read(PREAMBLE_COMPRESSED_LEN))
fp=os.fdopen(W,'wb',0)
fp.write(C)
fp.close()
fp=os.fdopen(w,'wb',0)
fp.write(C)
fp.close()
os.write(1,'MITO001\n'.encode())
os.close(2)
def get_python_argv(self):
"""
Return the initial argument vector elements necessary to invoke Python,
by returning a 1-element list containing :attr:`python_path` if it is a
string, or simply returning it if it is already a list.
This allows emulation of existing tools where the Python invocation may
be set to e.g. `['/usr/bin/env', 'python']`.
"""
if isinstance(self.options.python_path, list):
return self.options.python_path
return [self.options.python_path]
def get_boot_command(self):
source = inspect.getsource(self._first_stage)
source = textwrap.dedent('\n'.join(source.strip().split('\n')[2:]))
source = source.replace(' ', ' ')
source = source.replace('CONTEXT_NAME', self.options.remote_name)
preamble_compressed = self.get_preamble()
source = source.replace('PREAMBLE_COMPRESSED_LEN',
str(len(preamble_compressed)))
compressed = zlib.compress(source.encode(), 9)
encoded = binascii.b2a_base64(compressed).replace(b('\n'), b(''))
# Just enough to decode, decompress, and exec the first stage.
# Priorities: wider compatibility, faster startup, shorter length.
# `import os` here, instead of stage 1, to save a few bytes.
# `sys.path=...` for https://github.com/python/cpython/issues/115911.
return self.get_python_argv() + [
'-c',
'import sys;sys.path=[p for p in sys.path if p];import binascii,os,zlib;'
'exec(zlib.decompress(binascii.a2b_base64("%s")))' % (encoded.decode(),),
]
def get_econtext_config(self):
assert self.options.max_message_size is not None
parent_ids = mitogen.parent_ids[:]
parent_ids.insert(0, mitogen.context_id)
return {
'parent_ids': parent_ids,
'context_id': self.context.context_id,
'debug': self.options.debug,
'profiling': self.options.profiling,
'unidirectional': self.options.unidirectional,
'log_level': get_log_level(),
'whitelist': self._router.get_module_whitelist(),
'blacklist': self._router.get_module_blacklist(),
'max_message_size': self.options.max_message_size,
'version': mitogen.__version__,
}
def get_preamble(self):
suffix = (
'\nExternalContext(%r).main()\n' %
(self.get_econtext_config(),)
)
partial = get_core_source_partial()
return partial.append(suffix.encode('utf-8'))
def _get_name(self):
"""
Called by :meth:`connect` after :attr:`pid` is known. Subclasses can
override it to specify a default stream name, or set
:attr:`name_prefix` to generate a default format.
"""
return u'%s.%s' % (self.name_prefix, self.proc.pid)
def start_child(self):
args = self.get_boot_command()
LOG.debug('command line for %r: %s', self, Argv(args))
try:
return self.create_child(args=args, **self.create_child_args)
except OSError:
e = sys.exc_info()[1]
msg = 'Child start failed: %s. Command was: %s' % (e, Argv(args))
raise mitogen.core.StreamError(msg)
def _adorn_eof_error(self, e):
"""
Subclasses may provide additional information in the case of a failed
connection.
"""
if self.eof_error_hint:
e.args = ('%s\n\n%s' % (e.args[0], self.eof_error_hint),)
def _complete_connection(self):
self._timer.cancel()
if not self.exception:
mitogen.core.unlisten(self._router.broker, 'shutdown',
self._on_broker_shutdown)
self._router.register(self.context, self.stdio_stream)
self.stdio_stream.set_protocol(
MitogenProtocol(
router=self._router,
remote_id=self.context.context_id,
)
)
self._router.route_monitor.notice_stream(self.stdio_stream)
self.latch.put()
def _fail_connection(self, exc):
"""
Fail the connection attempt.
"""
LOG.debug('failing connection %s due to %r',
self.stdio_stream and self.stdio_stream.name, exc)
if self.exception is None:
self._adorn_eof_error(exc)
self.exception = exc
mitogen.core.unlisten(self._router.broker, 'shutdown',
self._on_broker_shutdown)
for stream in self.stdio_stream, self.stderr_stream:
if stream and not stream.receive_side.closed:
stream.on_disconnect(self._router.broker)
self._complete_connection()
eof_error_msg = 'EOF on stream; last 100 lines received:\n'
def on_stdio_disconnect(self):
"""
Handle stdio stream disconnection by failing the Connection if the
stderr stream has already been closed. Otherwise, wait for it to close
(or timeout), to allow buffered diagnostic logs to be consumed.
It is normal that when a subprocess aborts, stdio has nothing buffered
when it is closed, thus signalling readability, causing an empty read
(interpreted as indicating disconnection) on the next loop iteration,
even if its stderr pipe has lots of diagnostic logs still buffered in
the kernel. Therefore we must wait for both pipes to indicate they are
empty before triggering connection failure.
"""
stderr = self.stderr_stream
if stderr is None or stderr.receive_side.closed:
self._on_streams_disconnected()
def on_stderr_disconnect(self):
"""
Inverse of :func:`on_stdio_disconnect`.
"""
if self.stdio_stream.receive_side.closed:
self._on_streams_disconnected()
def _on_streams_disconnected(self):
"""
When disconnection has been detected for both streams, cancel the
connection timer, mark the connection failed, and reap the child
process. Do nothing if the timer has already been cancelled, indicating
some existing failure has already been noticed.
"""
if self._timer.active:
self._timer.cancel()
self._fail_connection(EofError(
self.eof_error_msg + get_history(
[self.stdio_stream, self.stderr_stream]
)
))
if self._reaper:
return
self._reaper = Reaper(
broker=self._router.broker,
proc=self.proc,
kill=not (
(self.detached and self.child_is_immediate_subprocess) or
# Avoid killing so child has chance to write cProfile data
self._router.profiling
),
# Don't delay shutdown waiting for a detached child, since the
# detached child may expect to live indefinitely after its parent
# exited.
wait_on_shutdown=(not self.detached),
)
self._reaper.reap()
def _on_broker_shutdown(self):
"""
Respond to broker.shutdown() being called by failing the connection
attempt.
"""
self._fail_connection(CancelledError(BROKER_SHUTDOWN_MSG))
def stream_factory(self):
return self.stream_protocol_class.build_stream(
broker=self._router.broker,
)
def stderr_stream_factory(self):
return self.diag_protocol_class.build_stream()
def _setup_stdio_stream(self):
stream = self.stream_factory()
stream.conn = self
stream.name = self.options.name or self._get_name()
stream.accept(self.proc.stdout, self.proc.stdin)
mitogen.core.listen(stream, 'disconnect', self.on_stdio_disconnect)
self._router.broker.start_receive(stream)
return stream
def _setup_stderr_stream(self):
stream = self.stderr_stream_factory()
stream.conn = self
stream.name = self.options.name or self._get_name()
stream.accept(self.proc.stderr, self.proc.stderr)
mitogen.core.listen(stream, 'disconnect', self.on_stderr_disconnect)
self._router.broker.start_receive(stream)
return stream
def _on_timer_expired(self):
self._fail_connection(
mitogen.core.TimeoutError(
'Failed to setup connection after %.2f seconds',
self.options.connect_timeout,
)
)
def _async_connect(self):
LOG.debug('creating connection to context %d using %s',
self.context.context_id, self.__class__.__module__)
mitogen.core.listen(self._router.broker, 'shutdown',
self._on_broker_shutdown)
self._timer = self._router.broker.timers.schedule(
when=self.options.connect_deadline,
func=self._on_timer_expired,
)
try:
self.proc = self.start_child()
except Exception:
LOG.debug('failed to start child', exc_info=True)
self._fail_connection(sys.exc_info()[1])
return
LOG.debug('child for %r started: pid:%r stdin:%r stdout:%r stderr:%r',
self, self.proc.pid,
self.proc.stdin.fileno(),
self.proc.stdout.fileno(),
self.proc.stderr and self.proc.stderr.fileno())
self.stdio_stream = self._setup_stdio_stream()
if self.context.name is None:
self.context.name = self.stdio_stream.name
self.proc.name = self.stdio_stream.name
if self.proc.stderr:
self.stderr_stream = self._setup_stderr_stream()
def connect(self, context):
self.context = context
self.latch = mitogen.core.Latch()
self._router.broker.defer(self._async_connect)
self.latch.get()
if self.exception:
raise self.exception
class ChildIdAllocator(object):
"""
Allocate new context IDs from a block of unique context IDs allocated by
the master process.
"""
def __init__(self, router):
self.router = router
self.lock = threading.Lock()
self.it = iter(xrange(0))
def allocate(self):
"""
Allocate an ID, requesting a fresh block from the master if the
existing block is exhausted.
:returns:
The new context ID.
.. warning::
This method is not safe to call from the :class:`Broker` thread, as
it may block on IO of its own.
"""
self.lock.acquire()
try:
for id_ in self.it:
return id_
master = self.router.context_by_id(0)
start, end = master.send_await(
mitogen.core.Message(dst_id=0, handle=mitogen.core.ALLOCATE_ID)
)
self.it = iter(xrange(start, end))
finally:
self.lock.release()
return self.allocate()
class CallChain(object):
"""
Deliver :data:`mitogen.core.CALL_FUNCTION` messages to a target context,
optionally threading related calls so an exception in an earlier call
cancels subsequent calls.
:param mitogen.core.Context context:
Target context.
:param bool pipelined:
Enable pipelining.
:meth:`call`, :meth:`call_no_reply` and :meth:`call_async`
normally issue calls and produce responses with no memory of prior
exceptions. If a call made with :meth:`call_no_reply` fails, the exception
is logged to the target context's logging framework.
**Pipelining**
When pipelining is enabled, if an exception occurs during a call,
subsequent calls made by the same :class:`CallChain` fail with the same
exception, including those already in-flight on the network, and no further
calls execute until :meth:`reset` is invoked.
No exception is logged for calls made with :meth:`call_no_reply`, instead
the exception is saved and reported as the result of subsequent
:meth:`call` or :meth:`call_async` calls.
Sequences of asynchronous calls can be made without wasting network
round-trips to discover if prior calls succeed, and chains originating from
multiple unrelated source contexts may overlap concurrently at a target
context without interference.
In this example, 4 calls complete in one round-trip::
chain = mitogen.parent.CallChain(context, pipelined=True)
chain.call_no_reply(os.mkdir, '/tmp/foo')
# If previous mkdir() failed, this never runs:
chain.call_no_reply(os.mkdir, '/tmp/foo/bar')
# If either mkdir() failed, this never runs, and the exception is
# asynchronously delivered to the receiver.
recv = chain.call_async(subprocess.check_output, '/tmp/foo')
# If anything so far failed, this never runs, and raises the exception.
chain.call(do_something)
# If this code was executed, the exception would also be raised.
if recv.get().unpickle() == 'baz':
pass
When pipelining is enabled, :meth:`reset` must be invoked to ensure any
exception is discarded, otherwise unbounded memory usage is possible in
long-running programs. The context manager protocol is supported to ensure
:meth:`reset` is always invoked::
with mitogen.parent.CallChain(context, pipelined=True) as chain:
chain.call_no_reply(...)
chain.call_no_reply(...)
chain.call_no_reply(...)
chain.call(...)
# chain.reset() automatically invoked.
"""
def __init__(self, context, pipelined=False):
self.context = context
if pipelined:
self.chain_id = self.make_chain_id()
else:
self.chain_id = None
@classmethod
def make_chain_id(cls):
return '%s-%s-%x-%x' % (
socket.gethostname(),
os.getpid(),
thread.get_ident(),
int(1e6 * mitogen.core.now()),
)
def __repr__(self):
return '%s(%s)' % (self.__class__.__name__, self.context)
def __enter__(self):
return self
def __exit__(self, _1, _2, _3):
self.reset()
def reset(self):
"""
Instruct the target to forget any related exception.
"""
if not self.chain_id:
return
saved, self.chain_id = self.chain_id, None
try:
self.call_no_reply(mitogen.core.Dispatcher.forget_chain, saved)
finally:
self.chain_id = saved
closures_msg = (
'Mitogen cannot invoke closures, as doing so would require '
'serializing arbitrary program state, and no universal '
'method exists to recover a reference to them.'
)
lambda_msg = (
'Mitogen cannot invoke anonymous functions, as no universal method '
'exists to recover a reference to an anonymous function.'
)
method_msg = (
'Mitogen cannot invoke instance methods, as doing so would require '
'serializing arbitrary program state.'
)
def make_msg(self, fn, *args, **kwargs):
if getattr(fn, closure_attr, None) is not None:
raise TypeError(self.closures_msg)
if fn.__name__ == '<lambda>':
raise TypeError(self.lambda_msg)
if inspect.ismethod(fn):
im_self = getattr(fn, IM_SELF_ATTR)
if not inspect.isclass(im_self):
raise TypeError(self.method_msg)
klass = mitogen.core.to_text(im_self.__name__)
else:
klass = None
tup = (
self.chain_id,
mitogen.core.to_text(fn.__module__),
klass,
mitogen.core.to_text(fn.__name__),
args,
mitogen.core.Kwargs(kwargs)
)
return mitogen.core.Message.pickled(tup,
handle=mitogen.core.CALL_FUNCTION)
def call_no_reply(self, fn, *args, **kwargs):
"""
Like :meth:`call_async`, but do not wait for a return value, and inform
the target context no reply is expected. If the call fails and
pipelining is disabled, the exception will be logged to the target
context's logging framework.
"""
LOG.debug('starting no-reply function call to %r: %r',
self.context.name or self.context.context_id,
CallSpec(fn, args, kwargs))
self.context.send(self.make_msg(fn, *args, **kwargs))
def call_async(self, fn, *args, **kwargs):
"""
Arrange for `fn(*args, **kwargs)` to be invoked on the context's main
thread.
:param fn:
A free function in module scope or a class method of a class
directly reachable from module scope:
.. code-block:: python
# mymodule.py
def my_func():
'''A free function reachable as mymodule.my_func'''
class MyClass:
@classmethod
def my_classmethod(cls):
'''Reachable as mymodule.MyClass.my_classmethod'''
def my_instancemethod(self):
'''Unreachable: requires a class instance!'''
class MyEmbeddedClass:
@classmethod
def my_classmethod(cls):
'''Not directly reachable from module scope!'''
:param tuple args:
Function arguments, if any. See :ref:`serialization-rules` for
permitted types.
:param dict kwargs:
Function keyword arguments, if any. See :ref:`serialization-rules`
for permitted types.
:returns:
:class:`mitogen.core.Receiver` configured to receive the result of
the invocation:
.. code-block:: python
recv = context.call_async(os.check_output, 'ls /tmp/')
try:
# Prints output once it is received.
msg = recv.get()
print(msg.unpickle())
except mitogen.core.CallError, e:
print('Call failed:', str(e))
Asynchronous calls may be dispatched in parallel to multiple
contexts and consumed as they complete using
:class:`mitogen.select.Select`.
"""
LOG.debug('starting function call to %s: %r',
self.context.name or self.context.context_id,
CallSpec(fn, args, kwargs))
return self.context.send_async(self.make_msg(fn, *args, **kwargs))
def call(self, fn, *args, **kwargs):
"""
Like :meth:`call_async`, but block until the return value is available.
Equivalent to::
call_async(fn, *args, **kwargs).get().unpickle()
:returns:
The function's return value.
:raises mitogen.core.CallError:
An exception was raised in the remote context during execution.
"""
receiver = self.call_async(fn, *args, **kwargs)
return receiver.get().unpickle(throw_dead=False)
class Context(mitogen.core.Context):
"""
Extend :class:`mitogen.core.Context` with functionality useful to masters,
and child contexts who later become parents. Currently when this class is
required, the target context's router is upgraded at runtime.
"""
#: A :class:`CallChain` instance constructed by default, with pipelining
#: disabled. :meth:`call`, :meth:`call_async` and :meth:`call_no_reply` use
#: this instance.
call_chain_class = CallChain
via = None
def __init__(self, *args, **kwargs):
super(Context, self).__init__(*args, **kwargs)
self.default_call_chain = self.call_chain_class(self)
def __ne__(self, other):
return not (self == other)
def __eq__(self, other):
return (
isinstance(other, mitogen.core.Context) and
(other.context_id == self.context_id) and
(other.router == self.router)
)
def __hash__(self):
return hash((self.router, self.context_id))
def call_async(self, fn, *args, **kwargs):
"""
See :meth:`CallChain.call_async`.
"""
return self.default_call_chain.call_async(fn, *args, **kwargs)
def call(self, fn, *args, **kwargs):
"""
See :meth:`CallChain.call`.
"""
return self.default_call_chain.call(fn, *args, **kwargs)
def call_no_reply(self, fn, *args, **kwargs):
"""
See :meth:`CallChain.call_no_reply`.
"""
self.default_call_chain.call_no_reply(fn, *args, **kwargs)
def shutdown(self, wait=False):
"""
Arrange for the context to receive a ``SHUTDOWN`` message, triggering
graceful shutdown.
Due to a lack of support for timers, no attempt is made yet to force
terminate a hung context using this method. This will be fixed shortly.
:param bool wait:
If :data:`True`, block the calling thread until the context has
completely terminated.
:returns:
If `wait` is :data:`False`, returns a :class:`mitogen.core.Latch`
whose :meth:`get() <mitogen.core.Latch.get>` method returns
:data:`None` when shutdown completes. The `timeout` parameter may
be used to implement graceful timeouts.
"""
LOG.debug('%r.shutdown() sending SHUTDOWN', self)
latch = mitogen.core.Latch()
mitogen.core.listen(self, 'disconnect', lambda: latch.put(None))
self.send(
mitogen.core.Message(
handle=mitogen.core.SHUTDOWN,
)
)
if wait:
latch.get()
else:
return latch
class RouteMonitor(object):
"""
Generate and respond to :data:`mitogen.core.ADD_ROUTE` and
:data:`mitogen.core.DEL_ROUTE` messages sent to the local context by
maintaining a table of available routes, and propagating messages towards
parents and siblings as appropriate.
:class:`RouteMonitor` is responsible for generating routing messages for
directly attached children. It learns of new children via
:meth:`notice_stream` called by :class:`Router`, and subscribes to their
``disconnect`` event to learn when they disappear.
In children, constructing this class overwrites the stub
:data:`mitogen.core.DEL_ROUTE` handler installed by
:class:`mitogen.core.ExternalContext`, which is expected behaviour when a
child is beging upgraded in preparation to become a parent of children of
its own.
By virtue of only being active while responding to messages from a handler,
RouteMonitor lives entirely on the broker thread, so its data requires no
locking.
:param mitogen.master.Router router:
Router to install handlers on.
:param mitogen.core.Context parent:
:data:`None` in the master process, or reference to the parent context
we should propagate route updates towards.
"""
def __init__(self, router, parent=None):
self.router = router
self.parent = parent
self._log = logging.getLogger('mitogen.route_monitor')
#: Mapping of Stream instance to integer context IDs reachable via the
#: stream; used to cleanup routes during disconnection.
self._routes_by_stream = {}
self.router.add_handler(
fn=self._on_add_route,
handle=mitogen.core.ADD_ROUTE,
persist=True,
policy=is_immediate_child,
overwrite=True,
)
self.router.add_handler(
fn=self._on_del_route,
handle=mitogen.core.DEL_ROUTE,
persist=True,
policy=is_immediate_child,
overwrite=True,
)
def __repr__(self):
return 'RouteMonitor()'
def _send_one(self, stream, handle, target_id, name):
"""
Compose and send an update message on a stream.
:param mitogen.core.Stream stream:
Stream to send it on.
:param int handle:
:data:`mitogen.core.ADD_ROUTE` or :data:`mitogen.core.DEL_ROUTE`
:param int target_id:
ID of the connecting or disconnecting context.
:param str name:
Context name or :data:`None`.
"""
if not stream:
# We may not have a stream during shutdown.
return
data = str(target_id)
if name:
data = '%s:%s' % (target_id, name)
stream.protocol.send(
mitogen.core.Message(
handle=handle,
data=data.encode('utf-8'),
dst_id=stream.protocol.remote_id,
)
)
def _propagate_up(self, handle, target_id, name=None):
"""
In a non-master context, propagate an update towards the master.
:param int handle:
:data:`mitogen.core.ADD_ROUTE` or :data:`mitogen.core.DEL_ROUTE`
:param int target_id:
ID of the connecting or disconnecting context.
:param str name:
For :data:`mitogen.core.ADD_ROUTE`, the name of the new context
assigned by its parent. This is used by parents to assign the
:attr:`mitogen.core.Context.name` attribute.
"""
if self.parent:
stream = self.router.stream_by_id(self.parent.context_id)
self._send_one(stream, handle, target_id, name)
def _propagate_down(self, handle, target_id):
"""
For DEL_ROUTE, we additionally want to broadcast the message to any
stream that has ever communicated with the disconnecting ID, so
core.py's :meth:`mitogen.core.Router._on_del_route` can turn the
message into a disconnect event.
:param int handle:
:data:`mitogen.core.ADD_ROUTE` or :data:`mitogen.core.DEL_ROUTE`
:param int target_id:
ID of the connecting or disconnecting context.
"""
for stream in self.router.get_streams():
if target_id in stream.protocol.egress_ids and (
(self.parent is None) or
(self.parent.context_id != stream.protocol.remote_id)
):
self._send_one(stream, mitogen.core.DEL_ROUTE, target_id, None)
def notice_stream(self, stream):
"""
When this parent is responsible for a new directly connected child
stream, we're also responsible for broadcasting
:data:`mitogen.core.DEL_ROUTE` upstream when that child disconnects.
"""
self._routes_by_stream[stream] = set([stream.protocol.remote_id])
self._propagate_up(mitogen.core.ADD_ROUTE, stream.protocol.remote_id,
stream.name)
mitogen.core.listen(
obj=stream,
name='disconnect',
func=lambda: self._on_stream_disconnect(stream),
)
def get_routes(self, stream):
"""
Return the set of context IDs reachable on a stream.
:param mitogen.core.Stream stream:
:returns: set([int])
"""
return self._routes_by_stream.get(stream) or set()
def _on_stream_disconnect(self, stream):
"""
Respond to disconnection of a local stream by propagating DEL_ROUTE for
any contexts we know were attached to it.
"""
# During a stream crash it is possible for disconnect signal to fire
# twice, in which case ignore the second instance.
routes = self._routes_by_stream.pop(stream, None)
if routes is None:
return
self._log.debug('stream %s is gone; propagating DEL_ROUTE for %r',
stream.name, routes)
for target_id in routes:
self.router.del_route(target_id)
self._propagate_up(mitogen.core.DEL_ROUTE, target_id)
self._propagate_down(mitogen.core.DEL_ROUTE, target_id)
context = self.router.context_by_id(target_id, create=False)
if context:
mitogen.core.fire(context, 'disconnect')
def _on_add_route(self, msg):
"""
Respond to :data:`mitogen.core.ADD_ROUTE` by validating the source of
the message, updating the local table, and propagating the message
upwards.
"""
if msg.is_dead:
return
target_id_s, _, target_name = bytes_partition(msg.data, b(':'))
target_name = target_name.decode()
target_id = int(target_id_s)
self.router.context_by_id(target_id).name = target_name
stream = self.router.stream_by_id(msg.src_id)
current = self.router.stream_by_id(target_id)
if current and current.protocol.remote_id != mitogen.parent_id:
self._log.error('Cannot add duplicate route to %r via %r, '
'already have existing route via %r',
target_id, stream, current)
return
self._log.debug('Adding route to %d via %r', target_id, stream)
self._routes_by_stream[stream].add(target_id)
self.router.add_route(target_id, stream)
self._propagate_up(mitogen.core.ADD_ROUTE, target_id, target_name)
def _on_del_route(self, msg):
"""
Respond to :data:`mitogen.core.DEL_ROUTE` by validating the source of
the message, updating the local table, propagating the message
upwards, and downwards towards any stream that every had a message
forwarded from it towards the disconnecting context.
"""
if msg.is_dead:
return
target_id = int(msg.data)
registered_stream = self.router.stream_by_id(target_id)
if registered_stream is None:
return
stream = self.router.stream_by_id(msg.src_id)
if registered_stream != stream:
self._log.error('received DEL_ROUTE for %d from %r, expected %r',
target_id, stream, registered_stream)
return
context = self.router.context_by_id(target_id, create=False)
if context:
self._log.debug('firing local disconnect signal for %r', context)
mitogen.core.fire(context, 'disconnect')
self._log.debug('deleting route to %d via %r', target_id, stream)
routes = self._routes_by_stream.get(stream)
if routes:
routes.discard(target_id)
self.router.del_route(target_id)
if stream.protocol.remote_id != mitogen.parent_id:
self._propagate_up(mitogen.core.DEL_ROUTE, target_id)
self._propagate_down(mitogen.core.DEL_ROUTE, target_id)
class Router(mitogen.core.Router):
context_class = Context
debug = False
profiling = False
id_allocator = None
responder = None
log_forwarder = None
route_monitor = None
def upgrade(self, importer, parent):
LOG.debug('upgrading %r with capabilities to start new children', self)
self.id_allocator = ChildIdAllocator(router=self)
self.responder = ModuleForwarder(
router=self,
parent_context=parent,
importer=importer,
)
self.route_monitor = RouteMonitor(self, parent)
self.add_handler(
fn=self._on_detaching,
handle=mitogen.core.DETACHING,
persist=True,
)
def _on_detaching(self, msg):
if msg.is_dead:
return
stream = self.stream_by_id(msg.src_id)
if stream.protocol.remote_id != msg.src_id or stream.conn.detached:
LOG.warning('bad DETACHING received on %r: %r', stream, msg)
return
LOG.debug('%r: marking as detached', stream)
stream.conn.detached = True
msg.reply(None)
def get_streams(self):
"""
Return an atomic snapshot of all streams in existence at time of call.
This is safe to call from any thread.
"""
self._write_lock.acquire()
try:
return itervalues(self._stream_by_id)
finally:
self._write_lock.release()
def disconnect(self, context):
"""
Disconnect a context and forget its stream, assuming the context is
directly connected.
"""
stream = self.stream_by_id(context)
if stream is None or stream.protocol.remote_id != context.context_id:
return
l = mitogen.core.Latch()
mitogen.core.listen(stream, 'disconnect', l.put)
def disconnect():
LOG.debug('Starting disconnect of %r', stream)
stream.on_disconnect(self.broker)
self.broker.defer(disconnect)
l.get()
def add_route(self, target_id, stream):
"""
Arrange for messages whose `dst_id` is `target_id` to be forwarded on a
directly connected :class:`Stream`. Safe to call from any thread.
This is called automatically by :class:`RouteMonitor` in response to
:data:`mitogen.core.ADD_ROUTE` messages, but remains public while the
design has not yet settled, and situations may arise where routing is
not fully automatic.
:param int target_id:
Target context ID to add a route for.
:param mitogen.core.Stream stream:
Stream over which messages to the target should be routed.
"""
LOG.debug('%r: adding route to context %r via %r',
self, target_id, stream)
assert isinstance(target_id, int)
assert isinstance(stream, mitogen.core.Stream)
self._write_lock.acquire()
try:
self._stream_by_id[target_id] = stream
finally:
self._write_lock.release()
def del_route(self, target_id):
"""
Delete any route that exists for `target_id`. It is not an error to
delete a route that does not currently exist. Safe to call from any
thread.
This is called automatically by :class:`RouteMonitor` in response to
:data:`mitogen.core.DEL_ROUTE` messages, but remains public while the
design has not yet settled, and situations may arise where routing is
not fully automatic.
:param int target_id:
Target context ID to delete route for.
"""
LOG.debug('%r: deleting route to %r', self, target_id)
# DEL_ROUTE may be sent by a parent if it knows this context sent
# messages to a peer that has now disconnected, to let us raise
# 'disconnect' event on the appropriate Context instance. In that case,
# we won't a matching _stream_by_id entry for the disappearing route,
# so don't raise an error for a missing key here.
self._write_lock.acquire()
try:
self._stream_by_id.pop(target_id, None)
finally:
self._write_lock.release()
def get_module_blacklist(self):
if mitogen.context_id == 0:
return self.responder.blacklist
return self.importer.master_blacklist
def get_module_whitelist(self):
if mitogen.context_id == 0:
return self.responder.whitelist
return self.importer.master_whitelist
def allocate_id(self):
return self.id_allocator.allocate()
connection_timeout_msg = u"Connection timed out."
def _connect(self, klass, **kwargs):
context_id = self.allocate_id()
context = self.context_class(self, context_id)
context.name = kwargs.get('name')
kwargs['old_router'] = self
kwargs['max_message_size'] = self.max_message_size
conn = klass(klass.options_class(**kwargs), self)
try:
conn.connect(context=context)
except mitogen.core.TimeoutError:
raise mitogen.core.StreamError(self.connection_timeout_msg)
return context
def connect(self, method_name, name=None, **kwargs):
if name:
name = mitogen.core.to_text(name)
klass = get_connection_class(method_name)
kwargs.setdefault(u'debug', self.debug)
kwargs.setdefault(u'profiling', self.profiling)
kwargs.setdefault(u'unidirectional', self.unidirectional)
kwargs.setdefault(u'name', name)
via = kwargs.pop(u'via', None)
if via is not None:
return self.proxy_connect(via, method_name,
**mitogen.core.Kwargs(kwargs))
return self._connect(klass, **mitogen.core.Kwargs(kwargs))
def proxy_connect(self, via_context, method_name, name=None, **kwargs):
resp = via_context.call(_proxy_connect,
name=name,
method_name=method_name,
kwargs=mitogen.core.Kwargs(kwargs),
)
if resp['msg'] is not None:
raise mitogen.core.StreamError(resp['msg'])
name = u'%s.%s' % (via_context.name, resp['name'])
context = self.context_class(self, resp['id'], name=name)
context.via = via_context
self._write_lock.acquire()
try:
self._context_by_id[context.context_id] = context
finally:
self._write_lock.release()
return context
def buildah(self, **kwargs):
return self.connect(u'buildah', **kwargs)
def doas(self, **kwargs):
return self.connect(u'doas', **kwargs)
def docker(self, **kwargs):
return self.connect(u'docker', **kwargs)
def kubectl(self, **kwargs):
return self.connect(u'kubectl', **kwargs)
def fork(self, **kwargs):
return self.connect(u'fork', **kwargs)
def jail(self, **kwargs):
return self.connect(u'jail', **kwargs)
def local(self, **kwargs):
return self.connect(u'local', **kwargs)
def lxc(self, **kwargs):
return self.connect(u'lxc', **kwargs)
def lxd(self, **kwargs):
return self.connect(u'lxd', **kwargs)
def setns(self, **kwargs):
return self.connect(u'setns', **kwargs)
def su(self, **kwargs):
return self.connect(u'su', **kwargs)
def sudo(self, **kwargs):
return self.connect(u'sudo', **kwargs)
def ssh(self, **kwargs):
return self.connect(u'ssh', **kwargs)
def podman(self, **kwargs):
return self.connect(u'podman', **kwargs)
class Reaper(object):
"""
Asynchronous logic for reaping :class:`Process` objects. This is necessary
to prevent uncontrolled buildup of zombie processes in long-lived parents
that will eventually reach an OS limit, preventing creation of new threads
and processes, and to log the exit status of the child in the case of an
error.
To avoid modifying process-global state such as with
:func:`signal.set_wakeup_fd` or installing a :data:`signal.SIGCHLD` handler
that might interfere with the user's ability to use those facilities,
Reaper polls for exit with backoff using timers installed on an associated
:class:`Broker`.
:param mitogen.core.Broker broker:
The :class:`Broker` on which to install timers
:param mitogen.parent.Process proc:
The process to reap.
:param bool kill:
If :data:`True`, send ``SIGTERM`` and ``SIGKILL`` to the process.
:param bool wait_on_shutdown:
If :data:`True`, delay :class:`Broker` shutdown if child has not yet
exited. If :data:`False` simply forget the child.
"""
#: :class:`Timer` that invokes :meth:`reap` after some polling delay.
_timer = None
def __init__(self, broker, proc, kill, wait_on_shutdown):
self.broker = broker
self.proc = proc
self.kill = kill
self.wait_on_shutdown = wait_on_shutdown
self._tries = 0
def _signal_child(self, signum):
# For processes like sudo we cannot actually send sudo a signal,
# because it is setuid, so this is best-effort only.
LOG.debug('%r: sending %s', self.proc, SIGNAL_BY_NUM[signum])
try:
os.kill(self.proc.pid, signum)
except OSError:
e = sys.exc_info()[1]
if e.args[0] != errno.EPERM:
raise
def _calc_delay(self, count):
"""
Calculate a poll delay given `count` attempts have already been made.
These constants have no principle, they just produce rapid but still
relatively conservative retries.
"""
delay = 0.05
for _ in xrange(count):
delay *= 1.72
return delay
def _on_broker_shutdown(self):
"""
Respond to :class:`Broker` shutdown by cancelling the reap timer if
:attr:`Router.await_children_at_shutdown` is disabled. Otherwise
shutdown is delayed for up to :attr:`Broker.shutdown_timeout` for
subprocesses may have no intention of exiting any time soon.
"""
if not self.wait_on_shutdown:
self._timer.cancel()
def _install_timer(self, delay):
new = self._timer is None
self._timer = self.broker.timers.schedule(
when=mitogen.core.now() + delay,
func=self.reap,
)
if new:
mitogen.core.listen(self.broker, 'shutdown',
self._on_broker_shutdown)
def _remove_timer(self):
if self._timer and self._timer.active:
self._timer.cancel()
mitogen.core.unlisten(self.broker, 'shutdown',
self._on_broker_shutdown)
def reap(self):
"""
Reap the child process during disconnection.
"""
status = self.proc.poll()
if status is not None:
LOG.debug('%r: %s', self.proc, returncode_to_str(status))
mitogen.core.fire(self.proc, 'exit')
self._remove_timer()
return
self._tries += 1
if self._tries > 20:
LOG.warning('%r: child will not exit, giving up', self)
self._remove_timer()
return
delay = self._calc_delay(self._tries - 1)
LOG.debug('%r still running after IO disconnect, recheck in %.03fs',
self.proc, delay)
self._install_timer(delay)
if not self.kill:
pass
elif self._tries == 2:
self._signal_child(signal.SIGTERM)
elif self._tries == 6: # roughly 4 seconds
self._signal_child(signal.SIGKILL)
class Process(object):
"""
Process objects provide a uniform interface to the :mod:`subprocess` and
:mod:`mitogen.fork`. This class is extended by :class:`PopenProcess` and
:class:`mitogen.fork.Process`.
:param int pid:
The process ID.
:param file stdin:
File object attached to standard input.
:param file stdout:
File object attached to standard output.
:param file stderr:
File object attached to standard error, or :data:`None`.
"""
#: Name of the process used in logs. Set to the stream/context name by
#: :class:`Connection`.
name = None
def __init__(self, pid, stdin, stdout, stderr=None):
#: The process ID.
self.pid = pid
#: File object attached to standard input.
self.stdin = stdin
#: File object attached to standard output.
self.stdout = stdout
#: File object attached to standard error.
self.stderr = stderr
def __repr__(self):
return '%s %s pid %d' % (
type(self).__name__,
self.name,
self.pid,
)
def poll(self):
"""
Fetch the child process exit status, or :data:`None` if it is still
running. This should be overridden by subclasses.
:returns:
Exit status in the style of the :attr:`subprocess.Popen.returncode`
attribute, i.e. with signals represented by a negative integer.
"""
raise NotImplementedError()
class PopenProcess(Process):
"""
:class:`Process` subclass wrapping a :class:`subprocess.Popen` object.
:param subprocess.Popen proc:
The subprocess.
"""
def __init__(self, proc, stdin, stdout, stderr=None):
super(PopenProcess, self).__init__(proc.pid, stdin, stdout, stderr)
#: The subprocess.
self.proc = proc
def poll(self):
return self.proc.poll()
class ModuleForwarder(object):
"""
Respond to :data:`mitogen.core.GET_MODULE` requests in a child by
forwarding the request to our parent context, or satisfying the request
from our local Importer cache.
"""
def __init__(self, router, parent_context, importer):
self.router = router
self.parent_context = parent_context
self.importer = importer
router.add_handler(
fn=self._on_forward_module,
handle=mitogen.core.FORWARD_MODULE,
persist=True,
policy=mitogen.core.has_parent_authority,
)
router.add_handler(
fn=self._on_get_module,
handle=mitogen.core.GET_MODULE,
persist=True,
policy=is_immediate_child,
)
def __repr__(self):
return 'ModuleForwarder'
def _on_forward_module(self, msg):
if msg.is_dead:
return
context_id_s, _, fullname = bytes_partition(msg.data, b('\x00'))
fullname = mitogen.core.to_text(fullname)
context_id = int(context_id_s)
stream = self.router.stream_by_id(context_id)
if stream.protocol.remote_id == mitogen.parent_id:
LOG.error('%r: dropping FORWARD_MODULE(%d, %r): no route to child',
self, context_id, fullname)
return
if fullname in stream.protocol.sent_modules:
return
LOG.debug('%r._on_forward_module() sending %r to %r via %r',
self, fullname, context_id, stream.protocol.remote_id)
self._send_module_and_related(stream, fullname)
if stream.protocol.remote_id != context_id:
stream.protocol._send(
mitogen.core.Message(
data=msg.data,
handle=mitogen.core.FORWARD_MODULE,
dst_id=stream.protocol.remote_id,
)
)
def _on_get_module(self, msg):
if msg.is_dead:
return
fullname = msg.data.decode('utf-8')
LOG.debug('%r: %s requested by context %d', self, fullname, msg.src_id)
callback = lambda: self._on_cache_callback(msg, fullname)
self.importer._request_module(fullname, callback)
def _on_cache_callback(self, msg, fullname):
stream = self.router.stream_by_id(msg.src_id)
LOG.debug('%r: sending %s to %r', self, fullname, stream)
self._send_module_and_related(stream, fullname)
def _send_module_and_related(self, stream, fullname):
tup = self.importer._cache[fullname]
for related in tup[4]:
rtup = self.importer._cache.get(related)
if rtup:
self._send_one_module(stream, rtup)
else:
LOG.debug('%r: %s not in cache (for %s)',
self, related, fullname)
self._send_one_module(stream, tup)
def _send_one_module(self, stream, tup):
if tup[0] not in stream.protocol.sent_modules:
stream.protocol.sent_modules.add(tup[0])
self.router._async_route(
mitogen.core.Message.pickled(
tup,
dst_id=stream.protocol.remote_id,
handle=mitogen.core.LOAD_MODULE,
)
)