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Diffstat (limited to 'vstf/vstf/common/daemon.py')
| -rwxr-xr-x | vstf/vstf/common/daemon.py | 145 |
1 files changed, 145 insertions, 0 deletions
diff --git a/vstf/vstf/common/daemon.py b/vstf/vstf/common/daemon.py new file mode 100755 index 00000000..8a298614 --- /dev/null +++ b/vstf/vstf/common/daemon.py @@ -0,0 +1,145 @@ +#!/usr/bin/env python +import sys, os, time, atexit +import logging +from signal import SIGTERM + +LOG = logging.getLogger(__name__) + + +class Daemon(object): + """ + A generic daemon class. + + Usage: subclass the Daemon class and override the run() method + """ + def __init__(self, pidfile, stdin='/dev/null', stdout='/dev/null', stderr='/dev/null'): + super(Daemon, self).__init__() + self.stdin = stdin + self.stdout = stdout + self.stderr = stderr + self.pidfile = pidfile + + def daemonize(self): + """ + do the UNIX double-fork magic, see Stevens' "Advanced + Programming in the UNIX Environment" for details (ISBN 0201563177) + http://www.erlenstar.demon.co.uk/unix/faq_2.html#SEC16 + """ + try: + pid = os.fork() + if pid > 0: + sys.exit(0) + except OSError, e: + LOG.error("fork #1 failed: %(errno)s, %(strerror)s", + {'errno':e.errno, 'strerror': e.strerror}) + 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, e: + LOG.error("fork #1 failed: %(errno)s, %(strerror)s", + {'errno':e.errno, 'strerror': e.strerror}) + sys.exit(1) + + # redirect standard file descriptors + sys.stdout.flush() + sys.stderr.flush() + si = file(self.stdin, 'r') + so = file(self.stdout, 'a+') + se = file(self.stderr, 'a+', 0) + os.dup2(si.fileno(), sys.stdin.fileno()) + os.dup2(so.fileno(), sys.stdout.fileno()) + os.dup2(se.fileno(), sys.stderr.fileno()) + + # write pidfile + atexit.register(self.delpid) + pid = str(os.getpid()) + file(self.pidfile,'w+').write("%s\n" % pid) + + def delpid(self): + os.remove(self.pidfile) + + def start(self): + """ + Start the daemon + """ + + # Check for a pidfile to see if the daemon already runs + try: + pf = file(self.pidfile,'r') + pid = int(pf.read().strip()) + pf.close() + except IOError: + pid = None + + if pid: + message = "pidfile %s already exist. Daemon already running?\n" + sys.stderr.write(message % self.pidfile) + sys.exit(1) + LOG.info("daemon start to run daemonize") + # Start the daemon + self.daemonize() + self.run() + + def stop(self): + """ + Stop the daemon + """ + # Get the pid from the pidfile + try: + pf = file(self.pidfile,'r') + pid = int(pf.read().strip()) + pf.close() + except IOError: + pid = None + + if not pid: + message = "pidfile %s does not exist. Daemon not running?\n" + sys.stderr.write(message % self.pidfile) + return # not an error in a restart + + # Try killing the daemon process + try: + while 1: + os.kill(pid, SIGTERM) + time.sleep(0.1) + except OSError, err: + err = str(err) + if err.find("No such process") > 0: + if os.path.exists(self.pidfile): + os.remove(self.pidfile) + else: + print str(err) + sys.exit(1) + + def restart(self): + """ + Restart the daemon + """ + self.stop() + self.start() + + def run(self): + """ + You should override this method when you subclass Daemon. + It will be called after the process has been + daemonized by start() or restart(). + + """ + pass + + def daemon_die(self): + """You should this method when you shutdown daemon + this func will be call by stop() before kill the process + + """ + pass
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