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deploy-base/mitogen-0.2.7/mitogen/parent.py

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add mitogen - requires ansible 2.7
2019-06-14 01:17:02 +00:00
# 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 codecs
import errno
import fcntl
import getpass
import inspect
import logging
import os
import signal
import socket
import struct
import subprocess
import sys
import termios
import textwrap
import threading
import time
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 LOG
from mitogen.core import IOLOG
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
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_')
)
def get_log_level():
return (LOG.level or logging.getLogger().level 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'
_core_source_lock = threading.Lock()
_core_source_partial = None
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.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: https://github.com/freebsd/freebsd/blob/master/lib/libc/gen/termios.c#L162
# Linux: https://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 close_nonstandard_fds():
for fd in xrange(3, SC_OPEN_MAX):
try:
os.close(fd)
except OSError:
pass
def create_socketpair(size=None):
"""
Create a :func:`socket.socketpair` to use for use as a child process's UNIX
stdio channels. As socket pairs are bidirectional, they are economical on
file descriptor usage as the same descriptor can be used for ``stdin`` and
``stdout``. As they are sockets their buffers are tunable, allowing large
buffers to be configured in order to improve throughput for file transfers
and reduce :class:`mitogen.core.Broker` IO loop iterations.
"""
parentfp, childfp = socket.socketpair()
parentfp.setsockopt(socket.SOL_SOCKET,
socket.SO_SNDBUF,
size or mitogen.core.CHUNK_SIZE)
childfp.setsockopt(socket.SOL_SOCKET,
socket.SO_RCVBUF,
size or mitogen.core.CHUNK_SIZE)
return parentfp, childfp
def detach_popen(**kwargs):
"""
Use :class:`subprocess.Popen` to construct a child process, then hack the
Popen so that it forgets the child it created, allowing it to survive a
call to Popen.__del__.
If the child process is not detached, there is a race between it exitting
and __del__ being called. If it exits before __del__ runs, then __del__'s
call to :func:`os.waitpid` will capture the one and only exit event
delivered to this process, causing later 'legitimate' calls to fail with
ECHILD.
:param list close_on_error:
Array of integer file descriptors to close on exception.
:returns:
Process ID of the new child.
"""
# This allows Popen() to be used for e.g. graceful post-fork error
# handling, without tying the surrounding code into managing a Popen
# object, which isn't possible for at least :mod:`mitogen.fork`. This
# should be replaced by a swappable helper class in a future version.
real_preexec_fn = kwargs.pop('preexec_fn', None)
def preexec_fn():
if _preexec_hook:
_preexec_hook()
if real_preexec_fn:
real_preexec_fn()
proc = subprocess.Popen(preexec_fn=preexec_fn, **kwargs)
proc._child_created = False
return proc.pid
def create_child(args, merge_stdio=False, stderr_pipe=False, preexec_fn=None):
"""
Create a child process whose stdin/stdout is connected to a socket.
:param args:
Argument vector for execv() call.
: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 not 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 outpu as the session progresses,
without interfering with `stdout`.
:returns:
`(pid, socket_obj, :data:`None` or pipe_fd)`
"""
parentfp, childfp = create_socketpair()
# When running under a monkey patches-enabled gevent, the socket module
# yields file descriptors who already have O_NONBLOCK, which is
# persisted across fork, totally breaking Python. Therefore, drop
# O_NONBLOCK from Python's future stdin fd.
mitogen.core.set_block(childfp.fileno())
stderr_r = None
extra = {}
if merge_stdio:
extra = {'stderr': childfp}
elif stderr_pipe:
stderr_r, stderr_w = os.pipe()
mitogen.core.set_cloexec(stderr_r)
mitogen.core.set_cloexec(stderr_w)
extra = {'stderr': stderr_w}
try:
pid = detach_popen(
args=args,
stdin=childfp,
stdout=childfp,
close_fds=True,
preexec_fn=preexec_fn,
**extra
)
except Exception:
childfp.close()
parentfp.close()
if stderr_pipe:
os.close(stderr_r)
os.close(stderr_w)
raise
if stderr_pipe:
os.close(stderr_w)
childfp.close()
# Decouple the socket from the lifetime of the Python socket object.
fd = os.dup(parentfp.fileno())
parentfp.close()
LOG.debug('create_child() child %d fd %d, parent %d, cmd: %s',
pid, fd, os.getpid(), Argv(args))
return pid, fd, 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:
See :func`os.openpty`.
"""
try:
return os.openpty()
except OSError:
e = sys.exc_info()[1]
if IS_LINUX and e.args[0] == errno.EPERM:
return _linux_broken_devpts_openpty()
raise mitogen.core.StreamError(OPENPTY_MSG, e)
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:
:py:func:`os.execl` argument list.
:returns:
`(pid, tty_fd, None)`
"""
master_fd, slave_fd = openpty()
try:
mitogen.core.set_block(slave_fd)
disable_echo(master_fd)
disable_echo(slave_fd)
pid = detach_popen(
args=args,
stdin=slave_fd,
stdout=slave_fd,
stderr=slave_fd,
preexec_fn=_acquire_controlling_tty,
close_fds=True,
)
except Exception:
os.close(master_fd)
os.close(slave_fd)
raise
os.close(slave_fd)
LOG.debug('tty_create_child() child %d fd %d, parent %d, cmd: %s',
pid, master_fd, os.getpid(), Argv(args))
return pid, master_fd, None
def hybrid_tty_create_child(args):
"""
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.
:param list args:
:py:func:`os.execl` argument list.
:returns:
`(pid, socketpair_fd, tty_fd)`
"""
master_fd, slave_fd = openpty()
try:
disable_echo(master_fd)
disable_echo(slave_fd)
mitogen.core.set_block(slave_fd)
parentfp, childfp = create_socketpair()
try:
mitogen.core.set_block(childfp)
pid = detach_popen(
args=args,
stdin=childfp,
stdout=childfp,
stderr=slave_fd,
preexec_fn=_acquire_controlling_tty,
close_fds=True,
)
except Exception:
parentfp.close()
childfp.close()
raise
except Exception:
os.close(master_fd)
os.close(slave_fd)
raise
os.close(slave_fd)
childfp.close()
# Decouple the socket from the lifetime of the Python socket object.
stdio_fd = os.dup(parentfp.fileno())
parentfp.close()
LOG.debug('hybrid_tty_create_child() pid=%d stdio=%d, tty=%d, cmd: %s',
pid, stdio_fd, master_fd, Argv(args))
return pid, stdio_fd, master_fd
def write_all(fd, s, deadline=None):
"""Arrange for all of bytestring `s` to be written to the file descriptor
`fd`.
:param int fd:
File descriptor to write to.
:param bytes s:
Bytestring to write to file descriptor.
:param float deadline:
If not :data:`None`, absolute UNIX timestamp after which timeout should
occur.
:raises mitogen.core.TimeoutError:
Bytestring could not be written entirely before deadline was exceeded.
:raises mitogen.parent.EofError:
Stream indicated EOF, suggesting the child process has exitted.
:raises mitogen.core.StreamError:
File descriptor was disconnected before write could complete.
"""
timeout = None
written = 0
poller = PREFERRED_POLLER()
poller.start_transmit(fd)
try:
while written < len(s):
if deadline is not None:
timeout = max(0, deadline - time.time())
if timeout == 0:
raise mitogen.core.TimeoutError('write timed out')
if mitogen.core.PY3:
window = memoryview(s)[written:]
else:
window = buffer(s, written)
for fd in poller.poll(timeout):
n, disconnected = mitogen.core.io_op(os.write, fd, window)
if disconnected:
raise EofError('EOF on stream during write')
written += n
finally:
poller.close()
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()
class IteratingRead(object):
def __init__(self, fds, deadline=None):
self.deadline = deadline
self.timeout = None
self.poller = PREFERRED_POLLER()
for fd in fds:
self.poller.start_receive(fd)
self.bits = []
self.timeout = None
def close(self):
self.poller.close()
def __iter__(self):
return self
def next(self):
while self.poller.readers:
if self.deadline is not None:
self.timeout = max(0, self.deadline - time.time())
if self.timeout == 0:
break
for fd in self.poller.poll(self.timeout):
s, disconnected = mitogen.core.io_op(os.read, fd, 4096)
if disconnected or not s:
LOG.debug('iter_read(%r) -> disconnected: %s',
fd, disconnected)
self.poller.stop_receive(fd)
else:
IOLOG.debug('iter_read(%r) -> %r', fd, s)
self.bits.append(s)
return s
if not self.poller.readers:
raise EofError(u'EOF on stream; last 300 bytes received: %r' %
(b('').join(self.bits)[-300:].decode('latin1'),))
raise mitogen.core.TimeoutError('read timed out')
__next__ = next
def iter_read(fds, deadline=None):
"""Return a generator that arranges for up to 4096-byte chunks to be read
at a time from the file descriptor `fd` until the generator is destroyed.
:param int fd:
File descriptor to read from.
:param float deadline:
If not :data:`None`, an absolute UNIX timestamp after which timeout
should occur.
:raises mitogen.core.TimeoutError:
Attempt to read beyond deadline.
:raises mitogen.parent.EofError:
All streams indicated EOF, suggesting the child process has exitted.
:raises mitogen.core.StreamError:
Attempt to read past end of file.
"""
return IteratingRead(fds=fds, deadline=deadline)
def discard_until(fd, s, deadline):
"""Read chunks from `fd` until one is encountered that ends with `s`. This
is used to skip output produced by ``/etc/profile``, ``/etc/motd`` and
mandatory SSH banners while waiting for :attr:`Stream.EC0_MARKER` to
appear, indicating the first stage is ready to receive the compressed
:mod:`mitogen.core` source.
:param int fd:
File descriptor to read from.
:param bytes s:
Marker string to discard until encountered.
:param float deadline:
Absolute UNIX timestamp after which timeout should occur.
:raises mitogen.core.TimeoutError:
Attempt to read beyond deadline.
:raises mitogen.parent.EofError:
All streams indicated EOF, suggesting the child process has exitted.
:raises mitogen.core.StreamError:
Attempt to read past end of file.
"""
it = iter_read([fd], deadline)
try:
for buf in it:
if IOLOG.level == logging.DEBUG:
for line in buf.splitlines():
IOLOG.debug('discard_until: discarding %r', line)
if buf.endswith(s):
return
finally:
it.close() # ensure Poller.close() is called.
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->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)
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
root.setLevel(old_level)
LOG.debug('replaced %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 stream_by_method_name(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.Stream
@mitogen.core.takes_econtext
def _proxy_connect(name, method_name, kwargs, econtext):
"""
Implements the target portion of Router._proxy_connect() by upgrading the
local context 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=stream_by_method_name(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 wstatus_to_str(status):
"""
Parse and format a :func:`os.waitpid` exit status.
"""
if os.WIFEXITED(status):
return 'exited with return code %d' % (os.WEXITSTATUS(status),)
if os.WIFSIGNALED(status):
n = os.WTERMSIG(status)
return 'exited due to signal %d (%s)' % (n, SIGNAL_BY_NUM.get(n))
if os.WIFSTOPPED(status):
n = os.WSTOPSIG(status)
return 'stopped due to signal %d (%s)' % (n, SIGNAL_BY_NUM.get(n))
return 'unknown wait status (%d)' % (status,)
class EofError(mitogen.core.StreamError):
"""
Raised by :func:`iter_read` and :func:`write_all` when EOF is detected by
the child process.
"""
# inherits from StreamError to maintain compatibility.
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 poll(2) interface. Not available on some versions
of OS X, otherwise it is the preferred poller for small FD counts.
"""
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 kqueue(2) 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 epoll(2) 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 apps that start threads dynamically, it's possible Latch will also get
# very high-numbered wait fds when there are many connections, 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 DiagLogStream(mitogen.core.BasicStream):
"""
For "hybrid TTY/socketpair" mode, after a connection has been setup, a
spare TTY file descriptor will exist 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 will send a
termination signal to any processes whose controlling TTY is the TTY that
has been closed.
DiagLogStream takes over this descriptor and creates corresponding log
messages for anything written to it.
"""
def __init__(self, fd, stream):
self.receive_side = mitogen.core.Side(self, fd)
self.transmit_side = self.receive_side
self.stream = stream
self.buf = ''
def __repr__(self):
return "mitogen.parent.DiagLogStream(fd=%r, '%s')" % (
self.receive_side.fd,
self.stream.name,
)
def on_receive(self, broker):
"""
This handler is only called after the stream is registered with the IO
loop, the descriptor is manually read/written by _connect_bootstrap()
prior to that.
"""
buf = self.receive_side.read()
if not buf:
return self.on_disconnect(broker)
self.buf += buf.decode('utf-8', 'replace')
while u'\n' in self.buf:
lines = self.buf.split('\n')
self.buf = lines[-1]
for line in lines[:-1]:
LOG.debug('%s: %s', self.stream.name, line.rstrip())
class Stream(mitogen.core.Stream):
"""
Base for streams capable of starting new slaves.
"""
#: The path to the remote Python interpreter.
python_path = get_sys_executable()
#: Maximum time to wait for a connection attempt.
connect_timeout = 30.0
#: Derived from :py:attr:`connect_timeout`; absolute floating point
#: UNIX timestamp after which the connection attempt should be abandoned.
connect_deadline = None
#: 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
#: Set to the child's PID by connect().
pid = None
#: Passed via Router wrapper methods, must eventually be passed to
#: ExternalContext.main().
max_message_size = None
#: If :attr:`create_child` supplied a diag_fd, references the corresponding
#: :class:`DiagLogStream`, allowing it to be disconnected when this stream
#: is disconnected. Set to :data:`None` if no `diag_fd` was present.
diag_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'
_reaped = False
def __init__(self, *args, **kwargs):
super(Stream, self).__init__(*args, **kwargs)
self.sent_modules = set(['mitogen', 'mitogen.core'])
def construct(self, max_message_size, remote_name=None, python_path=None,
debug=False, connect_timeout=None, profiling=False,
unidirectional=False, old_router=None, **kwargs):
"""Get the named context running on the local machine, creating it if
it does not exist."""
super(Stream, self).construct(**kwargs)
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')
self.remote_name = remote_name
self.debug = debug
self.profiling = profiling
self.unidirectional = unidirectional
self.max_message_size = max_message_size
self.connect_deadline = time.time() + self.connect_timeout
def on_shutdown(self, broker):
"""Request the slave gracefully shut itself down."""
LOG.debug('%r closing CALL_FUNCTION channel', self)
self._send(
mitogen.core.Message(
src_id=mitogen.context_id,
dst_id=self.remote_id,
handle=mitogen.core.SHUTDOWN,
)
)
def _reap_child(self):
"""
Reap the child process during disconnection.
"""
if self.detached and self.child_is_immediate_subprocess:
LOG.debug('%r: immediate child is detached, won\'t reap it', self)
return
if self.profiling:
LOG.info('%r: wont kill child because profiling=True', self)
return
if self._reaped:
# on_disconnect() may be invoked more than once, for example, if
# there is still a pending message to be sent after the first
# on_disconnect() call.
return
try:
pid, status = os.waitpid(self.pid, os.WNOHANG)
except OSError:
e = sys.exc_info()[1]
if e.args[0] == errno.ECHILD:
LOG.warn('%r: waitpid(%r) produced ECHILD', self, self.pid)
return
raise
self._reaped = True
if pid:
LOG.debug('%r: PID %d %s', self, pid, wstatus_to_str(status))
return
if not self._router.profiling:
# For processes like sudo we cannot actually send sudo a signal,
# because it is setuid, so this is best-effort only.
LOG.debug('%r: child process still alive, sending SIGTERM', self)
try:
os.kill(self.pid, signal.SIGTERM)
except OSError:
e = sys.exc_info()[1]
if e.args[0] != errno.EPERM:
raise
def on_disconnect(self, broker):
super(Stream, self).on_disconnect(broker)
if self.diag_stream is not None:
self.diag_stream.on_disconnect(broker)
self._reap_child()
# 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.
# * '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.
# * For Darwin, OS X installs a craptacular argv0-introspecting Python
# version switcher as /usr/bin/python. Override attempts to call it
# with an explicit call to python2.7
#
# 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 sys.platform == 'darwin' and sys.executable == '/usr/bin/python':
sys.executable += sys.version[:3]
os.environ['ARGV0']=sys.executable
os.execl(sys.executable,sys.executable+'(mitogen:CONTEXT_NAME)')
os.write(1,'MITO000\n'.encode())
C=_(os.fdopen(0,'rb').read(PREAMBLE_COMPRESSED_LEN),'zip')
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.python_path, list):
return self.python_path
return [self.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(' ', '\t')
source = source.replace('CONTEXT_NAME', self.remote_name)
preamble_compressed = self.get_preamble()
source = source.replace('PREAMBLE_COMPRESSED_LEN',
str(len(preamble_compressed)))
compressed = zlib.compress(source.encode(), 9)
encoded = codecs.encode(compressed, 'base64').replace(b('\n'), b(''))
# We can't use bytes.decode() in 3.x since it was restricted to always
# return unicode, so codecs.decode() is used instead. In 3.x
# codecs.decode() requires a bytes object. Since we must be compatible
# with 2.4 (no bytes literal), an extra .encode() either returns the
# same str (2.x) or an equivalent bytes (3.x).
return self.get_python_argv() + [
'-c',
'import codecs,os,sys;_=codecs.decode;'
'exec(_(_("%s".encode(),"base64"),"zip"))' % (encoded.decode(),)
]
def get_econtext_config(self):
assert self.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.remote_id,
'debug': self.debug,
'profiling': self.profiling,
'unidirectional': self.unidirectional,
'log_level': get_log_level(),
'whitelist': self._router.get_module_whitelist(),
'blacklist': self._router.get_module_blacklist(),
'max_message_size': self.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 start_child(self):
args = self.get_boot_command()
try:
return self.create_child(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)
eof_error_hint = None
def _adorn_eof_error(self, e):
"""
Used by subclasses to 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 _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.pid)
def connect(self):
LOG.debug('%r.connect()', self)
self.pid, fd, diag_fd = self.start_child()
self.name = self._get_name()
self.receive_side = mitogen.core.Side(self, fd)
self.transmit_side = mitogen.core.Side(self, os.dup(fd))
if diag_fd is not None:
self.diag_stream = DiagLogStream(diag_fd, self)
else:
self.diag_stream = None
LOG.debug('%r.connect(): pid:%r stdin:%r, stdout:%r, diag:%r',
self, self.pid, self.receive_side.fd, self.transmit_side.fd,
self.diag_stream and self.diag_stream.receive_side.fd)
try:
self._connect_bootstrap()
except EofError:
self.on_disconnect(self._router.broker)
e = sys.exc_info()[1]
self._adorn_eof_error(e)
raise
except Exception:
self.on_disconnect(self._router.broker)
self._reap_child()
raise
#: 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 = mitogen.core.b('MITO000\n')
EC1_MARKER = mitogen.core.b('MITO001\n')
def _ec0_received(self):
LOG.debug('%r._ec0_received()', self)
write_all(self.transmit_side.fd, self.get_preamble())
discard_until(self.receive_side.fd, self.EC1_MARKER,
self.connect_deadline)
if self.diag_stream:
self._router.broker.start_receive(self.diag_stream)
def _connect_bootstrap(self):
discard_until(self.receive_side.fd, self.EC0_MARKER,
self.connect_deadline)
self._ec0_received()
class ChildIdAllocator(object):
def __init__(self, router):
self.router = router
self.lock = threading.Lock()
self.it = iter(xrange(0))
def allocate(self):
self.lock.acquire()
try:
for id_ in self.it:
return id_
master = mitogen.core.Context(self.router, 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 * time.time()),
)
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('%r.call_no_reply(): %r', self, 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('%r.call_async(): %r', self, 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 Router router:
Router to install handlers on.
:param 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
#: 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.send(
mitogen.core.Message(
handle=handle,
data=data.encode('utf-8'),
dst_id=stream.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.egress_ids and (
(self.parent is None) or
(self.parent.context_id != stream.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 DEL_ROUTE upstream
if/when that child disconnects.
"""
self._routes_by_stream[stream] = set([stream.remote_id])
self._propagate_up(mitogen.core.ADD_ROUTE, stream.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
LOG.debug('%r: %r is gone; propagating DEL_ROUTE for %r',
self, stream, 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.auth_id)
current = self.router.stream_by_id(target_id)
if current and current.remote_id != mitogen.parent_id:
LOG.error('Cannot add duplicate route to %r via %r, '
'already have existing route via %r',
target_id, stream, current)
return
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.auth_id)
if registered_stream != stream:
LOG.error('%r: received DEL_ROUTE for %d from %r, expected %r',
self, target_id, stream, registered_stream)
return
context = self.router.context_by_id(target_id, create=False)
if context:
LOG.debug('%r: firing local disconnect for %r', self, context)
mitogen.core.fire(context, 'disconnect')
LOG.debug('%r: deleting route to %d via %r', self, target_id, stream)
routes = self._routes_by_stream.get(stream)
if routes:
routes.discard(target_id)
self.router.del_route(target_id)
if stream.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('%r.upgrade()', 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.remote_id != msg.src_id or stream.detached:
LOG.warning('bad DETACHING received on %r: %r', stream, msg)
return
LOG.debug('%r: marking as detached', stream)
stream.detached = True
msg.reply(None)
def get_streams(self):
"""
Return a snapshot of all streams in existence at time of call.
"""
self._write_lock.acquire()
try:
return itervalues(self._stream_by_id)
finally:
self._write_lock.release()
def add_route(self, target_id, stream):
"""
Arrange for messages whose `dst_id` is `target_id` to be forwarded on
the directly connected stream for `via_id`. This method is called
automatically 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.
"""
LOG.debug('%r.add_route(%r, %r)', self, target_id, stream)
assert isinstance(target_id, int)
assert isinstance(stream, Stream)
self._write_lock.acquire()
try:
self._stream_by_id[target_id] = stream
finally:
self._write_lock.release()
def del_route(self, target_id):
LOG.debug('%r.del_route(%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, name=None, **kwargs):
context_id = self.allocate_id()
context = self.context_class(self, context_id)
kwargs['old_router'] = self
kwargs['max_message_size'] = self.max_message_size
stream = klass(self, context_id, **kwargs)
if name is not None:
stream.name = name
try:
stream.connect()
except mitogen.core.TimeoutError:
raise mitogen.core.StreamError(self.connection_timeout_msg)
context.name = stream.name
self.route_monitor.notice_stream(stream)
self.register(context, stream)
return context
def connect(self, method_name, name=None, **kwargs):
klass = stream_by_method_name(method_name)
kwargs.setdefault(u'debug', self.debug)
kwargs.setdefault(u'profiling', self.profiling)
kwargs.setdefault(u'unidirectional', self.unidirectional)
via = kwargs.pop(u'via', None)
if via is not None:
return self.proxy_connect(via, method_name, name=name,
**mitogen.core.Kwargs(kwargs))
return self._connect(klass, name=name,
**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 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)
class ProcessMonitor(object):
"""
Install a :data:`signal.SIGCHLD` handler that generates callbacks when a
specific child process has exitted. This class is obsolete, do not use.
"""
def __init__(self):
# pid -> callback()
self.callback_by_pid = {}
signal.signal(signal.SIGCHLD, self._on_sigchld)
def _on_sigchld(self, _signum, _frame):
for pid, callback in self.callback_by_pid.items():
pid, status = os.waitpid(pid, os.WNOHANG)
if pid:
callback(status)
del self.callback_by_pid[pid]
def add(self, pid, callback):
"""
Add a callback function to be notified of the exit status of a process.
:param int pid:
Process ID to be notified of.
:param callback:
Function invoked as `callback(status)`, where `status` is the raw
exit status of the child process.
"""
self.callback_by_pid[pid] = callback
_instance = None
@classmethod
def instance(cls):
if cls._instance is None:
cls._instance = cls()
return cls._instance
class ModuleForwarder(object):
"""
Respond to GET_MODULE requests in a slave 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(%r)' % (self.router,)
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.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.sent_modules:
return
LOG.debug('%r._on_forward_module() sending %r to %r via %r',
self, fullname, context_id, stream.remote_id)
self._send_module_and_related(stream, fullname)
if stream.remote_id != context_id:
stream._send(
mitogen.core.Message(
data=msg.data,
handle=mitogen.core.FORWARD_MODULE,
dst_id=stream.remote_id,
)
)
def _on_get_module(self, msg):
LOG.debug('%r._on_get_module(%r)', self, msg)
if msg.is_dead:
return
fullname = msg.data.decode('utf-8')
callback = lambda: self._on_cache_callback(msg, fullname)
self.importer._request_module(fullname, callback)
def _on_cache_callback(self, msg, fullname):
LOG.debug('%r._on_get_module(): sending %r', self, fullname)
stream = self.router.stream_by_id(msg.src_id)
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._send_module_and_related(%r): absent: %r',
self, fullname, related)
self._send_one_module(stream, tup)
def _send_one_module(self, stream, tup):
if tup[0] not in stream.sent_modules:
stream.sent_modules.add(tup[0])
self.router._async_route(
mitogen.core.Message.pickled(
tup,
dst_id=stream.remote_id,
handle=mitogen.core.LOAD_MODULE,
)
)
Reference in a new issue Copy permalink