oslo.rootwrap/oslo_rootwrap/client.py
Victor Stinner 31cfdbd407 Fix Python 3 support for eventlet monkey-patching
Use eventlet.green.subprocess if eventlet is used and enable eventlet
tests on Python 3.

This change adds oslo_rootwrap.subprocess which is
eventlet.green.subprocess if eventlet monkey-patching is enabled or
if the TEST_EVENTLET environment variable is set, or subprocess of
the Python standard library otherwise.

When eventlet is used (with monkey-patching or not), it's more
reliable to use eventlet.green.subprocess instead of using directly
subprocess from the Python standard library.

On Python 2, it "works" to use directly subprocess: subprocess.Popen
calls os.pipe() and os.fdopen(fd) which are both monkey-patched. On
Python 3, it doesn't work because subprocess uses os.pipe() and
io.open(fd), and the io module is *not* monkey-patched at all.

Change-Id: Ib859bebe52612b35f0f1f53aedf76222683795e7
2015-10-13 21:51:47 +02:00

138 lines
5.3 KiB
Python

# Copyright (c) 2014 Mirantis Inc.
# All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
import logging
from multiprocessing import managers
from multiprocessing import util as mp_util
import threading
import weakref
import oslo_rootwrap
from oslo_rootwrap import daemon
from oslo_rootwrap import jsonrpc
from oslo_rootwrap import subprocess
if oslo_rootwrap._patched_socket:
# We have to use slow version of recvall with eventlet because of a bug in
# GreenSocket.recv_into:
# https://bitbucket.org/eventlet/eventlet/pull-request/41
# This check happens here instead of jsonrpc to avoid importing eventlet
# from daemon code that is run with root privileges.
jsonrpc.JsonConnection.recvall = jsonrpc.JsonConnection._recvall_slow
try:
finalize = weakref.finalize
except AttributeError:
def finalize(obj, func, *args, **kwargs):
return mp_util.Finalize(obj, func, args=args, kwargs=kwargs,
exitpriority=0)
ClientManager = daemon.get_manager_class()
LOG = logging.getLogger(__name__)
class Client(object):
def __init__(self, rootwrap_daemon_cmd):
self._start_command = rootwrap_daemon_cmd
self._initialized = False
self._mutex = threading.Lock()
self._manager = None
self._proxy = None
self._process = None
self._finalize = None
def _initialize(self):
if self._process is not None and self._process.poll() is not None:
LOG.warning("Leaving behind already spawned process with pid %d, "
"root should kill it if it's still there (I can't)",
self._process.pid)
process_obj = subprocess.Popen(self._start_command,
stdin=subprocess.PIPE,
stdout=subprocess.PIPE,
stderr=subprocess.PIPE)
LOG.debug("Popen for %s command has been instantiated",
self._start_command)
self._process = process_obj
socket_path = process_obj.stdout.readline()[:-1]
# For Python 3 we need to convert bytes to str here
if not isinstance(socket_path, str):
socket_path = socket_path.decode('utf-8')
authkey = process_obj.stdout.read(32)
if process_obj.poll() is not None:
stderr = process_obj.stderr.read()
# NOTE(yorik-sar): don't expose stdout here
raise Exception("Failed to spawn rootwrap process.\nstderr:\n%s" %
(stderr,))
LOG.info("Spawned new rootwrap daemon process with pid=%d",
process_obj.pid)
self._manager = ClientManager(socket_path, authkey)
self._manager.connect()
self._proxy = self._manager.rootwrap()
self._finalize = finalize(self, self._shutdown, self._process,
self._manager)
self._initialized = True
@staticmethod
def _shutdown(process, manager, JsonClient=jsonrpc.JsonClient):
# Storing JsonClient in arguments because globals are set to None
# before executing atexit routines in Python 2.x
if process.poll() is None:
LOG.info('Stopping rootwrap daemon process with pid=%s',
process.pid)
try:
manager.rootwrap().shutdown()
except (EOFError, IOError):
pass # assume it is dead already
# We might want to wait for process to exit or kill it, but we
# can't provide sane timeout on 2.x and we most likely don't have
# permisions to do so
# Invalidate manager's state so that proxy won't try to do decref
manager._state.value = managers.State.SHUTDOWN
def _ensure_initialized(self):
with self._mutex:
if not self._initialized:
self._initialize()
def _restart(self, proxy):
with self._mutex:
assert self._initialized
# Verify if someone has already restarted this.
if self._proxy is proxy:
self._finalize()
self._manager = None
self._proxy = None
self._initialized = False
self._initialize()
return self._proxy
def execute(self, cmd, stdin=None):
self._ensure_initialized()
proxy = self._proxy
retry = False
try:
res = proxy.run_one_command(cmd, stdin)
except (EOFError, IOError):
retry = True
# res can be None if we received final None sent by dying server thread
# instead of response to our request. Process is most likely to be dead
# at this point.
if retry or res is None:
proxy = self._restart(proxy)
res = proxy.run_one_command(cmd, stdin)
return res