Daemonize

A little tech talk for rannts#16 meetup on correct daemonization in UNIXes before systed era

Transcript

1. Правильная демонизация Сергей Архипов, 2017
2. Чего хотим #!/usr/bin/env python3 # -*- coding: utf-8 -*- import contextlib import syslog import time @contextlib.contextmanager def daemonize(): yield if __name__ == "__main__": with daemonize(): syslog.openlog(facility=syslog.LOG_USER) syslog.syslog("Daemon start.") time.sleep(10) syslog.syslog("Daemon done.")
3. Подход 1 def daemonize(): first_pid = os.fork() if first_pid: sys.exit(0) yield
4. Подход 2 def daemonize(): first_pid = os.fork() if first_pid: sys.exit(0) syslog.syslog("Session={0}, Group={1}, Parent={2}, Self={3}".format( os.getsid(0), os.getpgid(0), os.getppid(), os.getpid() )) yield … Session=7087, Group=14115, Parent=14115, Self=14151 … Daemon start. … Daemon done.
5. Подход 2 def daemonize(): first_pid = os.fork() if first_pid: sys.exit(0) syslog.syslog("Session={0}, Group={1}, Parent={2}, Self={3}".format( os.getsid(0), os.getpgid(0), os.getppid(), os.getpid() )) os.setsid() syslog.syslog("Session={0}, Group={1}, Parent={2}, Self={3}".format( os.getsid(0), os.getpgid(0), os.getppid(), os.getpid() )) yield … Session=7087, Group=17364, Parent=17364, Self=17400 … Session=17400, Group=17400, Parent=17364, Self=17400 … Daemon start … Daemon done.
6. Подход 3 def daemonize(): if os.fork(): sys.exit(0) os.setsid() if os.fork(): sys.exit(0) yield
7. Подход 4 def daemonize(): if os.fork(): sys.exit(0) os.setsid() if os.fork(): sys.exit(0) os.chdir("/") os.umask(0o002) yield
8. Подход 5 def daemonize(): if os.fork(): sys.exit(0) os.setsid() if os.fork(): sys.exit(0) os.chdir("/") os.umask(0o002) sys.stdout.flush() sys.stderr.flush() _, max_fds = resource.getrlimit(resource.RLIMIT_NOFILE) max_fds = max_fds if max_fds!=resource.RLIM_INFINITY else 1024 os.closerange(0, max_fds) sys.stdout = sys.stderr = open(os.devnull, "w") sys.stdin = open(os.devnull, "r") yield
9. Подход 6 def daemonize(): if os.getppid() != 1: return if os.fork(): sys.exit(0) os.setsid() if os.fork(): sys.exit(0) os.chdir("/") os.umask(0o002) sys.stdout.flush() sys.stderr.flush() _, max_fds = resource.getrlimit(resource.RLIMIT_NOFILE) max_fds = max_fds if max_fds != resource.RLIM_INFINITY else 1024 os.closerange(0, max_fds) sys.stdout = sys.stderr = open(os.devnull, "w") sys.stdin = open(os.devnull, "r") yield
10. def daemonize(): if os.getppid() != 1: return if os.fork(): sys.exit(0) os.setsid() if os.fork(): sys.exit(0) os.chdir("/") os.umask(0o002) sys.stdout.flush() sys.stderr.flush() _, max_fds = resource.getrlimit(resource.RLIMIT_NOFILE) max_fds = max_fds if max_fds != resource.RLIM_INFINITY else 1024 os.closerange(0, max_fds) sys.stdout = sys.stderr = open(os.devnull, "w") sys.stdin = open(os.devnull, "r") yield