distcloud/distributedcloud/dccommon/subprocess_cleanup.py

74 lines
2.3 KiB
Python

#
# Copyright (c) 2022 Wind River Systems, Inc.
#
# SPDX-License-Identifier: Apache-2.0
#
import os
import signal
import time
from oslo_concurrency import lockutils
from oslo_log import log as logging
LOG = logging.getLogger(__name__)
class SubprocessCleanup(object):
"""Lifecycle manager for subprocesses spawned via python subprocess.
Notes:
- This is a best-effort cleanup. We need to preserve fast shutdown
times in case of a SWACT.
- There could potentially be multiple hundreds of subprocesses needing
to be cleaned up here.
"""
LOCK_NAME = 'subprocess-cleanup'
SUBPROCESS_GROUPS = {}
@staticmethod
def register_subprocess_group(subprocess_p):
SubprocessCleanup.SUBPROCESS_GROUPS[subprocess_p.pid] = subprocess_p
@staticmethod
def unregister_subprocess_group(subprocess_p):
SubprocessCleanup.SUBPROCESS_GROUPS.pop(subprocess_p.pid, None)
@staticmethod
@lockutils.synchronized(LOCK_NAME)
def shutdown_cleanup(origin='service'):
SubprocessCleanup._shutdown_subprocess_groups(origin)
@staticmethod
def _shutdown_subprocess_groups(origin):
num_process_groups = len(SubprocessCleanup.SUBPROCESS_GROUPS)
if num_process_groups > 0:
LOG.warn("Shutting down %d process groups via %s",
num_process_groups, origin)
start_time = time.time()
for _, subp in SubprocessCleanup.SUBPROCESS_GROUPS.items():
kill_subprocess_group(subp)
LOG.info("Time for %s child processes to exit: %s",
num_process_groups,
time.time() - start_time)
def kill_subprocess_group(subp, logmsg=None):
"""Kill the subprocess and any children."""
exitcode = subp.poll()
if exitcode:
LOG.info("kill_subprocess_tree: subprocess has already "
"terminated, pid: %s, exitcode=%s", subp.pid, exitcode)
return
if logmsg:
LOG.warn(logmsg)
else:
LOG.warn("Killing subprocess group for pid: %s, args: %s",
subp.pid, subp.args)
# Send a SIGTERM (normal kill). We do not verify if the processes
# are shutdown (best-effort), since we don't want to wait around before
# issueing a SIGKILL (fast shutdown)
os.killpg(subp.pid, signal.SIGTERM)