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July 11, 2011 13:59
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Dongsheng Cai revised this gist
Jul 11, 2011 . 1 changed file with 127 additions and 156 deletions.There are no files selected for viewing
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters. Learn more about bidirectional Unicode charactersOriginal file line number Diff line number Diff line change @@ -1,158 +1,129 @@ #!/usr/bin/env python import sys, os, time, atexit from signal import SIGTERM class Daemon: """ 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'): 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: # exit first parent sys.exit(0) except OSError, e: sys.stderr.write("fork #1 failed: %d (%s)\n" % (e.errno, 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: sys.stderr.write("fork #2 failed: %d (%s)\n" % (e.errno, 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) # 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(). """ -
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This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters. Learn more about bidirectional Unicode charactersOriginal file line number Diff line number Diff line change @@ -0,0 +1,158 @@ #!/usr/bin/env python import sys, os, time, atexit from signal import SIGTERM class Daemon: """ 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'): 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: # exit first parent sys.exit(0) except OSError, e: sys.stderr.write("fork #1 failed: %d (%s)\n" % (e.errno, 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: sys.stderr.write("fork #2 failed: %d (%s)\n" % (e.errno, 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) # 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(). """ And here is an example implementation. It implements the daemon as well as it's controlling client. Simply invoke this script with start, stop or restart as it's first argument. Download this file. #!/usr/bin/env python import sys, time from daemon import Daemon class MyDaemon(Daemon): def run(self): while True: time.sleep(1) if __name__ == "__main__": daemon = MyDaemon('/tmp/daemon-example.pid') if len(sys.argv) == 2: if 'start' == sys.argv[1]: daemon.start() elif 'stop' == sys.argv[1]: daemon.stop() elif 'restart' == sys.argv[1]: daemon.restart() else: print "Unknown command" sys.exit(2) sys.exit(0) else: print "usage: %s start|stop|restart" % sys.argv[0] sys.exit(2)
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