166 lines
4.6 KiB
Python
166 lines
4.6 KiB
Python
#!/usr/bin/env python
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import sys, os, time, atexit, signal, subprocess
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class Daemon:
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"""
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A generic daemon class.
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Usage: subclass the Daemon class and override the run() method
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From: http://bit.ly/TnPxwp
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Developed by Sander Marechal
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Minor modifications by Massimo Di Pierro
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"""
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def __init__(self,
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pidfile,
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stdin='/dev/null',
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stdout='/dev/null',
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stderr=None):
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self.stdin = stdin
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self.stdout = stdout
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self.stderr = stderr
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self.pidfile = pidfile
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def daemonize(self):
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"""
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do the UNIX double-fork magic, see Stevens
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"Advanced Programming in the UNIX Environment"
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for details (ISBN 0201563177)
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http://www.erlenstar.demon.co.uk/unix/faq_2.html#SEC16
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"""
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try:
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pid = os.fork()
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if pid > 0:
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# exit first parent
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sys.exit(0)
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except OSError, e:
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sys.stderr.write("fork #1 failed: %d (%s)\n" % (
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e.errno, e.strerror))
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sys.exit(1)
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# decouple from parent environment
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os.chdir("/")
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os.setsid()
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os.umask(0)
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# do second fork
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try:
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pid = os.fork()
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if pid > 0:
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# exit from second parent
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sys.exit(0)
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except OSError, e:
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sys.stderr.write("fork #2 failed: %d (%s)\n" % (
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e.errno, e.strerror))
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sys.exit(1)
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# redirect standard file descriptors
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sys.stdout.flush()
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sys.stderr.flush()
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if self.stdin != '/dev/null':
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os.mkfifo(self.stdin)
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si = open(self.stdin, 'r')
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if self.stdout != '/dev/null':
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os.mkfifo(self.stdout)
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so = open(self.stdout, 'a+')
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if self.stderr is None:
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se = so
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else:
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if self.stderr != '/dev/null':
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os.mkfifo(self.stderr)
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se = open(self.stderr, 'a+', 0)
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os.dup2(si.fileno(), sys.stdin.fileno())
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os.dup2(so.fileno(), sys.stdout.fileno())
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os.dup2(se.fileno(), sys.stderr.fileno())
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# write pidfile
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# atexit.register(self.delpid)
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pid = str(os.getpid())
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open(self.pidfile,'w+').write("%s\n" % pid)
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def delpid(self):
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os.remove(self.pidfile)
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def start(self):
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"""
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Start the daemon
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"""
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# Check for a pidfile to see if the daemon already runs
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try:
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pf = open(self.pidfile,'r')
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pid = int(pf.read().strip())
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pf.close()
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except IOError:
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pid = None
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if pid:
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message = "pidfile %s already exist. Daemon already running?\n"
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sys.stderr.write(message % self.pidfile)
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sys.exit(1)
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# Start the daemon
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self.daemonize()
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self.run()
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def stop(self):
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"""
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Stop the daemon
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"""
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# Get the pid from the pidfile
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try:
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pf = open(self.pidfile,'r')
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pid = int(pf.read().strip())
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pf.close()
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except IOError:
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pid = None
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if not pid:
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message = "pidfile %s does not exist. Daemon not running?\n"
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sys.stderr.write(message % self.pidfile)
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return # not an error in a restart
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# Try killing the daemon process
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try:
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while 1:
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os.kill(pid, signal.SIGTERM)
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time.sleep(0.1)
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except OSError, err:
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err = str(err)
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if err.find("No such process") > 0:
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if os.path.exists(self.pidfile):
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os.remove(self.pidfile)
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else:
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print str(err)
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sys.exit(1)
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def restart(self):
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"""
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Restart the daemon
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"""
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self.stop()
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self.start()
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def run(self):
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"""
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You should override this method when you subclass Daemon.
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It will be called after the process has been
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daemonized by start() or restart().
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"""
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if hasattr(self,'args'):
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subprocess.call(self.args,
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stdin=sys.stdin,
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stdout=sys.stdout,
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stderr=sys.stderr,
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shell=True)
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os.system('rm t1/*')
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d = Daemon(
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pidfile = '/Users/massimodipierro/Dropbox/web2py/temps/t1/process.pid',
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stdin = '/Users/massimodipierro/Dropbox/web2py/temps/t1/fifo.in',
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stdout = '/Users/massimodipierro/Dropbox/web2py/temps/t1/fifo.out',
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stderr = None)
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d.args = ['python looping.py']
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d.start()
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