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@leafsummer
Last active May 8, 2021 09:31
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daemonize a process class of python script
import os
import sys
import time
import atexit
class Daemon(object):
def __init__(self, pidfile="/dev/null", stdin="/dev/null", stdout="/dev/null", stderr="/dev/null"):
self.stdin = stdin
self.stdout = stdout
self.stderr = stderr
self.pidfile = pidfile
def _daemonize(self):
try:
# the first fork to leave the parent process
pid = os.fork()
if pid > 0:
sys.exit(0)
except OSError, e:
sys.stderr.write("fork #1 failed: %d (%s)\n" % (e.errno, e.strerror))
sys.exit(1)
# leave the term
os.setsid()
os.chdir("/")
# set file permission
os.umask(0)
try:
# the second fork to forbid opening the term
pid = os.fork()
if pid > 0:
sys.exit(0)
except OSError, e:
sys.stderr.write("fork #2 failed: %d (%s)\n" % (e.errno, e.strerror))
sys.exit(1)
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())
atexit.register(self.delpid)
pid = str(os.getpid())
f = file(self.pidfile,'w')
f.write("%s\n" % pid)
f.close()
self.pid = pid
def delpid(self):
os.remove(self.pidfile)
def start(self):
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)
try:
self._daemonize()
self._run()
except Exception, e:
print e
def stop(self):
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
try:
while True:
os.kill(pid, signal.SIGTERM)
time.sleep(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):
self.stop()
self.start()
def _run(self):
"""
you must inherit to implement this function
"""
print "I'm Daemon Parent Class!"
class TestDaemon(Daemon):
def _run(self):
while True:
test_file = file("/tmp/test_file.log",'a+')
test_file.write("Test Daemon ok! time:" + str(time.time()) + " Pid:" + str(os.getpid()) + "\n")
test_file.close()
time.sleep(1)
if __name__ == "__main__":
daemon = TestDaemon("/tmp/test.pid")
daemon.start()
time.sleep(10)
daemon.stop()
daemon.restart()
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