tacker/tacker/agent/linux/utils.py

99 lines
3.5 KiB
Python

# Copyright 2012 Locaweb.
# 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 os
import shlex
from eventlet.green import subprocess
from eventlet import greenthread
from oslo_log import log as logging
from oslo_utils import excutils
from tacker.common import utils
LOG = logging.getLogger(__name__)
def create_process(cmd, root_helper=None, addl_env=None,
debuglog=True):
"""Create a process object for the given command.
The return value will be a tuple of the process object and the
list of command arguments used to create it.
"""
if root_helper:
cmd = shlex.split(root_helper) + cmd
cmd = map(str, cmd)
if debuglog:
LOG.debug("Running command: %s", cmd)
env = os.environ.copy()
if addl_env:
env.update(addl_env)
obj = utils.subprocess_popen(cmd, shell=False,
stdin=subprocess.PIPE,
stdout=subprocess.PIPE,
stderr=subprocess.PIPE,
env=env)
return obj, cmd
def execute(cmd, root_helper=None, process_input=None, addl_env=None,
check_exit_code=True, return_stderr=False, debuglog=True):
# Note(gongysh) not use log_levels in config file because
# some other codes that are not in a loop probably need the debug log
try:
obj, cmd = create_process(cmd, root_helper=root_helper,
addl_env=addl_env, debuglog=debuglog)
_stdout, _stderr = (process_input and
obj.communicate(process_input) or
obj.communicate())
obj.stdin.close()
m = _("\nCommand: %(cmd)s\nExit code: %(code)s\nStdout: %(stdout)r\n"
"Stderr: %(stderr)r") % {'cmd': cmd, 'code': obj.returncode,
'stdout': _stdout, 'stderr': _stderr}
if obj.returncode:
LOG.error(m)
if check_exit_code:
raise RuntimeError(m)
elif debuglog:
LOG.debug(m)
finally:
# NOTE(termie): this appears to be necessary to let the subprocess
# call clean something up in between calls, without
# it two execute calls in a row hangs the second one
greenthread.sleep(0)
return return_stderr and (_stdout, _stderr) or _stdout
def find_child_pids(pid):
"""Retrieve a list of the pids of child processes of the given pid."""
try:
raw_pids = execute(['ps', '--ppid', pid, '-o', 'pid='])
except RuntimeError as e:
# Unexpected errors are the responsibility of the caller
with excutils.save_and_reraise_exception() as ctxt:
# Exception has already been logged by execute
no_children_found = 'Exit code: 1' in str(e)
if no_children_found:
ctxt.reraise = False
return []
return [x.strip() for x in raw_pids.split('\n') if x.strip()]