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mitogen/mitogen/master.py

666 lines
21 KiB
Python

# Copyright 2017, 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.
import dis
import imp
import inspect
import itertools
import logging
import os
import pkgutil
import re
import sys
import threading
import types
import zlib
try:
import Queue
except ImportError:
import queue as Queue
if not hasattr(pkgutil, 'find_loader'):
# find_loader() was new in >=2.5, but the modern pkgutil.py syntax has
# been kept intentionally 2.3 compatible so we can reuse it.
from mitogen.compat import pkgutil
import mitogen.core
import mitogen.parent
from mitogen.core import LOG
RLOG = logging.getLogger('mitogen.ctx')
def get_child_modules(path, fullname):
it = pkgutil.iter_modules([os.path.dirname(path)])
return ['%s.%s' % (fullname, name) for _, name, _ in it]
def scan_code_imports(co, LOAD_CONST=dis.opname.index('LOAD_CONST'),
IMPORT_NAME=dis.opname.index('IMPORT_NAME')):
"""Given a code object `co`, scan its bytecode yielding any
``IMPORT_NAME`` and associated prior ``LOAD_CONST`` instructions
representing an `Import` statement or `ImportFrom` statement.
:return:
Generator producing `(level, modname, namelist)` tuples, where:
* `level`: -1 for normal import, 0, for absolute import, and >0 for
relative import.
* `modname`: Name of module to import, or from where `namelist` names
are imported.
* `namelist`: for `ImportFrom`, the list of names to be imported from
`modname`.
"""
# Yield `(op, oparg)` tuples from the code object `co`.
ordit = itertools.imap(ord, co.co_code)
nextb = ordit.next
opit = ((c, (None
if c < dis.HAVE_ARGUMENT else
(nextb() | (nextb() << 8))))
for c in ordit)
opit, opit2, opit3 = itertools.tee(opit, 3)
try:
next(opit2)
next(opit3)
next(opit3)
except StopIteration:
return
for oparg1, oparg2, (op3, arg3) in itertools.izip(opit, opit2, opit3):
if op3 == IMPORT_NAME:
op2, arg2 = oparg2
op1, arg1 = oparg1
if op1 == op2 == LOAD_CONST:
yield (co.co_consts[arg1],
co.co_names[arg3],
co.co_consts[arg2] or ())
def join_thread_async(target_thread, on_join):
"""Start a thread that waits for another thread to shutdown, before
invoking `on_join()`. In CPython it seems possible to use this method to
ensure a non-main thread is signalled when the main thread has exitted,
using yet another thread as a proxy."""
def _watch():
target_thread.join()
on_join()
thread = threading.Thread(target=_watch)
thread.start()
class SelectError(mitogen.core.Error):
pass
class Select(object):
notify = None
def __init__(self, receivers=(), oneshot=True):
self._receivers = []
self._oneshot = oneshot
self._queue = Queue.Queue()
for recv in receivers:
self.add(recv)
def _put(self, value):
self._queue.put(value)
if self.notify:
self.notify(self)
def __bool__(self):
return bool(self._receivers)
def __enter__(self):
return self
def __exit__(self, e_type, e_val, e_tb):
self.close()
def __iter__(self):
while self._receivers:
recv, msg = self.get()
yield recv, msg
loop_msg = 'Adding this Select instance would create a Select cycle'
def _check_no_loop(self, recv):
if recv is self:
raise SelectError(self.loop_msg)
for recv_ in self._receivers:
if recv_ == recv:
raise SelectError(self.loop_msg)
if isinstance(recv_, Select):
recv_._check_no_loop(recv)
owned_msg = 'Cannot add: Receiver is already owned by another Select'
def add(self, recv):
if isinstance(recv, Select):
recv._check_no_loop(self)
self._receivers.append(recv)
if recv.notify is not None:
raise SelectError(self.owned_msg)
recv.notify = self._put
# Avoid race by polling once after installation.
if not recv.empty():
self._put(recv)
not_present_msg = 'Instance is not a member of this Select'
def remove(self, recv):
try:
if recv.notify != self._put:
raise ValueError
self._receivers.remove(recv)
recv.notify = None
except (IndexError, ValueError):
raise SelectError(self.not_present_msg)
def close(self):
for recv in self._receivers[:]:
self.remove(recv)
def empty(self):
return self._queue.empty()
empty_msg = 'Cannot get(), Select instance is empty'
def get(self, timeout=None):
if not self._receivers:
raise SelectError(self.empty_msg)
while True:
recv = mitogen.core._queue_interruptible_get(self._queue, timeout)
try:
msg = recv.get(block=False)
if self._oneshot:
self.remove(recv)
return recv, msg
except mitogen.core.TimeoutError:
# A receiver may have been queued with no result if another
# thread drained it before we woke up, or because another
# thread drained it between add() calling recv.empty() and
# self._put(). In this case just sleep again.
continue
class LogForwarder(object):
def __init__(self, router):
self._router = router
self._cache = {}
router.add_handler(self._on_forward_log, mitogen.core.FORWARD_LOG)
def _on_forward_log(self, msg):
if msg == mitogen.core._DEAD:
return
logger = self._cache.get(msg.src_id)
if logger is None:
context = self._router.context_by_id(msg.src_id)
if context is None:
LOG.error('FORWARD_LOG received from src_id %d', msg.src_id)
return
name = '%s.%s' % (RLOG.name, context.name)
self._cache[msg.src_id] = logger = logging.getLogger(name)
name, level_s, s = msg.data.split('\x00', 2)
logger.log(int(level_s), '%s: %s', name, s)
def __repr__(self):
return 'LogForwarder(%r)' % (self._router,)
class ModuleFinder(object):
STDLIB_DIRS = [
# virtualenv on OS X does some weird half-ass job of symlinking the
# stdlib into the virtualenv directory. So pick two modules at random
# that represent both places the stdlib seems to come from.
os.path.dirname(os.path.dirname(logging.__file__)),
os.path.dirname(os.path.dirname(os.__file__)),
]
def __init__(self):
#: Import machinery is expensive, keep :py:meth`:get_module_source`
#: results around.
self._found_cache = {}
#: Avoid repeated dependency scanning, which is expensive.
self._related_cache = {}
def __repr__(self):
return 'ModuleFinder()'
def is_stdlib_name(self, modname):
"""Return ``True`` if `modname` appears to come from the standard
library."""
if imp.is_builtin(modname) != 0:
return True
module = sys.modules.get(modname)
if module is None:
return False
# six installs crap with no __file__
modpath = getattr(module, '__file__', '')
if 'site-packages' in modpath:
return False
for dirname in self.STDLIB_DIRS:
if os.path.commonprefix((dirname, modpath)) == dirname:
return True
return False
def _py_filename(self, path):
path = path.rstrip('co')
if path.endswith('.py'):
return path
def _get_module_via_pkgutil(self, fullname):
"""Attempt to fetch source code via pkgutil. In an ideal world, this
would be the only required implementation of get_module()."""
loader = pkgutil.find_loader(fullname)
LOG.debug('pkgutil._get_module_via_pkgutil(%r) -> %r', fullname, loader)
if not loader:
return
try:
path = self._py_filename(loader.get_filename(fullname))
source = loader.get_source(fullname)
if path is not None and source is not None:
return path, source, loader.is_package(fullname)
except AttributeError:
return
def _get_module_via_sys_modules(self, fullname):
"""Attempt to fetch source code via sys.modules. This is specifically
to support __main__, but it may catch a few more cases."""
module = sys.modules.get(fullname)
if not isinstance(module, types.ModuleType):
LOG.debug('sys.modules[%r] absent or not a regular module',
fullname)
return
modpath = self._py_filename(getattr(module, '__file__', ''))
if not modpath:
return
is_pkg = hasattr(module, '__path__')
try:
source = inspect.getsource(module)
except IOError:
# Work around inspect.getsourcelines() bug.
if not is_pkg:
raise
source = '\n'
return (module.__file__.rstrip('co'),
source,
hasattr(module, '__path__'))
get_module_methods = [_get_module_via_pkgutil,
_get_module_via_sys_modules]
def get_module_source(self, fullname):
"""Given the name of a loaded module `fullname`, attempt to find its
source code.
:returns:
Tuple of `(module path, source text, is package?)`, or ``None`` if
the source cannot be found.
"""
tup = self._found_cache.get(fullname)
if tup:
return tup
for method in self.get_module_methods:
tup = method(self, fullname)
if tup:
return tup
return None, None, None
def resolve_relpath(self, fullname, level):
"""Given an ImportFrom AST node, guess the prefix that should be tacked
on to an alias name to produce a canonical name. `fullname` is the name
of the module in which the ImportFrom appears."""
mod = sys.modules.get(fullname, None)
if hasattr(mod, '__path__'):
fullname += '.__init__'
if level == 0 or not fullname:
return ''
bits = fullname.split('.')
if len(bits) <= level:
# This would be an ImportError in real code.
return ''
return '.'.join(bits[:-level])
def generate_parent_names(self, fullname):
while '.' in fullname:
fullname, _, _ = fullname.rpartition('.')
yield fullname
def find_related_imports(self, fullname):
"""
Given the `fullname` of a currently loaded module, and a copy of its
source code, examine :py:data:`sys.modules` to determine which of the
``import`` statements from the source code caused a corresponding
module to be loaded that is not part of the standard library.
"""
related = self._related_cache.get(fullname)
if related is not None:
return related
modpath, src, _ = self.get_module_source(fullname)
if src is None:
LOG.warning('%r: cannot find source for %r', self, fullname)
return []
maybe_names = list(self.generate_parent_names(fullname))
co = compile(src, modpath, 'exec')
for level, modname, namelist in scan_code_imports(co):
if level == -1:
modnames = [modname, '%s.%s' % (fullname, modname)]
else:
modnames = [self.resolve_relpath(fullname, level) + modname]
maybe_names.extend(modnames)
maybe_names.extend(
'%s.%s' % (mname, name)
for mname in modnames
for name in namelist
)
return self._related_cache.setdefault(fullname, sorted(
set(
name
for name in maybe_names
if sys.modules.get(name) is not None
and not self.is_stdlib_name(name)
and 'six.moves' not in name # TODO: crap
)
))
def find_related(self, fullname):
stack = [fullname]
found = set()
while stack:
fullname = stack.pop(0)
fullnames = self.find_related_imports(fullname)
stack.extend(set(fullnames).difference(found, stack, [fullname]))
found.update(fullnames)
return sorted(found)
class ModuleResponder(object):
def __init__(self, router):
self._router = router
self._finder = ModuleFinder()
self._cache = {} # fullname -> pickled
router.add_handler(self._on_get_module, mitogen.core.GET_MODULE)
def __repr__(self):
return 'ModuleResponder(%r)' % (self._router,)
MAIN_RE = re.compile(r'^if\s+__name__\s*==\s*.__main__.\s*:', re.M)
def neutralize_main(self, src):
"""Given the source for the __main__ module, try to find where it
begins conditional execution based on a "if __name__ == '__main__'"
guard, and remove any code after that point."""
match = self.MAIN_RE.search(src)
if match:
return src[:match.start()]
return src
def _build_tuple(self, fullname):
if fullname in self._cache:
return self._cache[fullname]
path, source, is_pkg = self._finder.get_module_source(fullname)
if source is None:
LOG.error('_build_tuple(%r): could not locate source', fullname)
tup = fullname, None, None, None, None
self._cache[fullname] = tup
return tup
if source is None:
raise ImportError('could not find %r' % (fullname,))
if is_pkg:
pkg_present = get_child_modules(path, fullname)
LOG.debug('_build_tuple(%r, %r) -> %r',
path, fullname, pkg_present)
else:
pkg_present = None
if fullname == '__main__':
source = self.neutralize_main(source)
compressed = zlib.compress(source)
related = list(self._finder.find_related(fullname))
# 0:fullname 1:pkg_present 2:path 3:compressed 4:related
tup = fullname, pkg_present, path, compressed, related
self._cache[fullname] = tup
return tup
def _send_load_module(self, stream, msg, fullname):
LOG.debug('_send_load_module(%r, %r)', stream, fullname)
self._router.route(
mitogen.core.Message.pickled(
self._build_tuple(fullname),
dst_id=msg.src_id,
handle=mitogen.core.LOAD_MODULE,
)
)
stream.sent_modules.add(fullname)
def _on_get_module(self, msg):
LOG.debug('%r.get_module(%r)', self, msg)
if msg == mitogen.core._DEAD:
return
stream = self._router.stream_by_id(msg.src_id)
fullname = msg.data
try:
tup = self._build_tuple(fullname)
for name in tup[4] or (): # related
if name == fullname:
# Must be sent last
continue
parent_pkg, _, _ = name.partition('.')
if parent_pkg != fullname and parent_pkg not in stream.sent_packages:
# Parent hasn't been required, so don't load this guy yet.
continue
if name in stream.sent_modules:
# Submodule has been sent already, skip.
continue
self._send_load_module(stream, msg, name)
self._send_load_module(stream, msg, fullname)
if tup[1] is not None:
# It's a package, record the fact it was sent.
stream.sent_packages.add(fullname)
except Exception:
LOG.debug('While importing %r', fullname, exc_info=True)
self._router.route(
mitogen.core.Message.pickled(
(fullname, None, None, None, []),
dst_id=msg.src_id,
handle=msg.reply_to,
)
)
class Broker(mitogen.core.Broker):
shutdown_timeout = 5.0
def __init__(self, install_watcher=True):
if install_watcher:
join_thread_async(threading.currentThread(), self.shutdown)
super(Broker, self).__init__()
class Context(mitogen.core.Context):
via = None
def on_disconnect(self, broker):
"""
Override base behaviour of triggering Broker shutdown on parent stream
disconnection.
"""
mitogen.core.fire(self, 'disconnect')
def call_async(self, fn, *args, **kwargs):
LOG.debug('%r.call_async(%r, *%r, **%r)',
self, fn, args, kwargs)
if isinstance(fn, types.MethodType) and \
isinstance(fn.im_self, (type, types.ClassType)):
klass = fn.im_self.__name__
else:
klass = None
recv = self.send_async(
mitogen.core.Message.pickled(
(fn.__module__, klass, fn.__name__, args, kwargs),
handle=mitogen.core.CALL_FUNCTION,
)
)
recv.raise_channelerror = False
return recv
def call(self, fn, *args, **kwargs):
return self.call_async(fn, *args, **kwargs).get_data()
class Router(mitogen.parent.Router):
context_class = Context
broker_class = Broker
debug = False
profiling = False
def __init__(self, broker=None):
if broker is None:
broker = self.broker_class()
super(Router, self).__init__(broker)
self.id_allocator = IdAllocator(self)
self.responder = ModuleResponder(self)
self.log_forwarder = LogForwarder(self)
def enable_debug(self):
mitogen.core.enable_debug_logging()
self.debug = True
def __enter__(self):
return self
def __exit__(self, e_type, e_val, tb):
self.broker.shutdown()
self.broker.join()
def local(self, **kwargs):
return self.connect('local', **kwargs)
def sudo(self, **kwargs):
return self.connect('sudo', **kwargs)
def ssh(self, **kwargs):
return self.connect('ssh', **kwargs)
def propagate_route(self, target, via):
self.add_route(target.context_id, via.context_id)
child = via
parent = via.via
while parent is not None:
LOG.debug('Adding route to %r for %r via %r', parent, target, child)
parent.send(
mitogen.core.Message(
data='%s\x00%s' % (target.context_id, child.context_id),
handle=mitogen.core.ADD_ROUTE,
)
)
child = parent
parent = parent.via
class IdAllocator(object):
def __init__(self, router):
self.router = router
self.next_id = 1
self.lock = threading.Lock()
router.add_handler(self.on_allocate_id, mitogen.core.ALLOCATE_ID)
def __repr__(self):
return 'IdAllocator(%r)' % (self.router,)
def allocate(self):
self.lock.acquire()
try:
id_ = self.next_id
self.next_id += 1
return id_
finally:
self.lock.release()
def on_allocate_id(self, msg):
id_ = self.allocate()
requestee = self.router.context_by_id(msg.src_id)
allocated = self.router.context_by_id(id_, msg.src_id)
LOG.debug('%r: allocating %r to %r', self, allocated, requestee)
self.router.route(
mitogen.core.Message.pickled(
id_,
dst_id=msg.src_id,
handle=msg.reply_to,
)
)
LOG.debug('%r: publishing route to %r via %r', self,
allocated, requestee)
self.router.propagate_route(allocated, requestee)