frappy/secop/lib/pidfile.py
Enrico Faulhaber 8efd1df92c fix isort
Change-Id: I5486e1f9b3143c6bb0804c49c7ca21adb9b84de1
Reviewed-on: https://forge.frm2.tum.de/review/19524
Reviewed-by: Enrico Faulhaber <enrico.faulhaber@frm2.tum.de>
Tested-by: Enrico Faulhaber <enrico.faulhaber@frm2.tum.de>
2018-12-04 10:18:55 +01:00

58 lines
1.8 KiB
Python

# -*- coding: utf-8 -*-
# *****************************************************************************
#
# This program is free software; you can redistribute it and/or modify it under
# the terms of the GNU General Public License as published by the Free Software
# Foundation; either version 2 of the License, or (at your option) any later
# version.
#
# This program is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
# details.
#
# You should have received a copy of the GNU General Public License along with
# this program; if not, write to the Free Software Foundation, Inc.,
# 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
#
# Module authors:
# Enrico Faulhaber <enrico.faulhaber@frm2.tum.de>
#
# *****************************************************************************
"""Define pidfile helpers"""
from __future__ import division, print_function
import atexit
import os
import psutil
def read_pidfile(pidfile):
"""read the given pidfile, return the pid as an int
or None upon errors (file not existing)"""
try:
with open(pidfile, 'r') as f:
return int(f.read())
except (OSError, IOError):
return None
def remove_pidfile(pidfile):
"""remove the given pidfile, typically at end of the process"""
os.remove(pidfile)
def write_pidfile(pidfile, pid):
"""write the given pid to the given pidfile"""
with open(pidfile, 'w') as f:
f.write('%d\n' % pid)
atexit.register(remove_pidfile, pidfile)
def check_pidfile(pidfile):
"""check if the process from a given pidfile is still running"""
pid = read_pidfile(pidfile)
return False if pid is None else psutil.pid_exists(pid)