[[pythondaemon]]
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pythondaemon [2014/10/26 01:52] (current) |
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| + | ==== Daemon example ==== | ||
| + | <code lang='python'> | ||
| + | import sys, os | ||
| + | def main(): | ||
| + | """ A demo daemon main routine, write a datestamp to | ||
| + | /tmp/daemon-log every 10 seconds. | ||
| + | """ | ||
| + | import time | ||
| + | |||
| + | f = open("/tmp/daemon-log", "w") | ||
| + | while 1: | ||
| + | f.write('%s\n' % time.ctime(time.time())) | ||
| + | f.flush() | ||
| + | time.sleep(10) | ||
| + | |||
| + | |||
| + | if __name__ == "__main__": | ||
| + | # do the UNIX double-fork magic, see Stevens' "Advanced | ||
| + | # Programming in the UNIX Environment" for details (ISBN 0201563177) | ||
| + | try: | ||
| + | pid = os.fork() | ||
| + | if pid > 0: | ||
| + | # exit first parent | ||
| + | sys.exit(0) | ||
| + | except OSError, e: | ||
| + | print >>sys.stderr, "fork #1 failed: %d (%s)" % (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, print eventual PID before | ||
| + | print "Daemon PID %d" % pid | ||
| + | sys.exit(0) | ||
| + | except OSError, e: | ||
| + | print >>sys.stderr, "fork #2 failed: %d (%s)" % (e.errno, e.strerror) | ||
| + | sys.exit(1) | ||
| + | |||
| + | # start the daemon main loop | ||
| + | main() | ||
| + | |||
| + | </code> | ||
| + | ---- | ||
| + | * [[pythoninfo|Back to Python]] | ||
