linspector/linspector/core/linspectord.py

132 lines
4.2 KiB
Python

"""
This file is part of Linspector (https://linspector.org/)
Copyright (c) 2022 Johannes Findeisen <you@hanez.org>. All Rights Reserved.
See LICENSE.txt (MIT license).
"""
import atexit
import os
import signal
import sys
import time
# TODO: there is a bug when stopping the daemon. the pid_file is not being deleted. NEEDS A FIX!
class Linspectord:
def __init__(self, configuration, environment, linspector, log):
self.__configuration = configuration
self.__environment = environment
self.__linspector = linspector
self.__log = log
try:
self.__pid_file = configuration.get_option('linspector', 'pid_file')
except Exception as err:
log.critical('daemonize error (no pid_file set): {0}'.str(format(err)))
def daemonize(self):
# daemonize the class using the UNIX double fork mechanism.
# do first fork.
try:
pid = os.fork()
if pid > 0:
# exit first parent.
sys.exit(0)
except OSError as err:
self.__log.critical('fork #1 failed: {0}'.str(format(err)))
sys.exit(1)
# decouple from parent environment.
os.chdir('/')
os.setsid()
os.umask(0)
# do second fork.
try:
pid = os.fork()
if pid > 0:
# Exit from second parent.
sys.exit(0)
except OSError as err:
self.__log.critical('fork #2 failed: {0}'.str(format(err)))
sys.exit(1)
# redirect standard file descriptors.
sys.stdout.flush()
sys.stderr.flush()
si = open(os.devnull, 'r')
so = open(os.devnull, 'a+')
se = open(os.devnull, 'a+')
os.dup2(si.fileno(), sys.stdin.fileno())
os.dup2(so.fileno(), sys.stdout.fileno())
os.dup2(se.fileno(), sys.stderr.fileno())
# write pid file.
atexit.register(self.delete_pid)
pid = str(os.getpid())
with open(self.__pid_file, 'w+') as f:
f.write(pid + '\n')
def delete_pid(self):
os.remove(self.__pid_file)
def start(self):
# start the daemon. check for a pidfile to see if the daemon already runs before.
self.__log.info('starting daemon using pid_file: ' + str(self.__pid_file))
try:
with open(self.__pid_file, 'r') as pf:
pid = int(pf.read().strip())
except IOError:
pid = None
if pid:
message = 'pid_file {0} already exist. daemon already running?'
self.__log.critical(str(message.format(self.__pid_file)))
sys.exit(1)
# start the daemon.
self.daemonize()
self.run()
def stop(self):
# stop the daemon.
self.__log.info('stopping daemon using pid_file: ' + str(self.__pid_file))
# get the pid from the pid file.
try:
with open(self.__pid_file, 'r') as pf:
pid = int(pf.read().strip())
except IOError:
pid = None
if not pid:
message = 'pid_file {0} does not exist. daemon not running?'
self.__log.error(str(message.format(self.__pid_file)))
return # not an error in a restart
# try killing the daemon process.
try:
while 1:
os.kill(pid, signal.SIGTERM)
time.sleep(0.1)
except OSError as err:
e = str(err.args)
if e.find('no such process') > 0:
if os.path.exists(self.__pid_file):
os.remove(self.__pid_file)
else:
self.__log.critical(str(err.args))
sys.exit(1)
def restart(self):
# restart the daemon.
self.__log.info('restarting daemon using pid_file: ' + str(self.__pid_file))
self.stop()
self.start()
# maybe this function can be removed in the future because Linspector should rund endless when
# starting scheduled jobs. need to cover this in the future. for now, it is useful for testing
# while development because the daemon even runs when internally is nothing to do.
@staticmethod
def run():
signal.pause()