A generic daemon class.
Usage: subclass the Daemon class and override the run() method
+
+ Daemon([pidfile[, stdin[, stdout[, stderr]]]])
+
+ pidfile : file to write pid to (default no pid file writen)
+ stdin : standard input file descriptor (default to /dev/null)
+ stdout : standard output file descriptor (default to /dev/null)
+ stderr : standard error file descriptorr (default to /dev/null)
"""
- version = "0.5"
+ version = '0.6'
def __init__(self, pidfile,
- stdin='/dev/null',
- stdout='/dev/null',
- stderr='/dev/null'):
+ stdin = os.devnull,
+ stdout = os.devnull,
+ stderr = os.devnull):
self.stdin = stdin
self.stdout = stdout
self.stderr = stderr
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))
+ except OSError as e:
+ sys.stderr.write('fork #1 failed: {0.errno:d} ({0.strerror})\n'.format(e))
sys.exit(1)
# Decouple from parent environment
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))
+ except OSError as e:
+ sys.stderr.write('fork #2 failed: {0.errno:d} ({0.strerror})\n'.format(e))
sys.exit(1)
self.write_pid()
# 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)
+ # TODO: binary or txt mode?
+ si = open(self.stdin, mode='rb')
+ so = open(self.stdout, mode='ab+')
+ se = open(self.stderr, mode='ab+', buffering=0)
os.dup2(si.fileno(), sys.stdin.fileno())
os.dup2(so.fileno(), sys.stdout.fileno())
os.dup2(se.fileno(), sys.stderr.fileno())
pid = str(os.getpid())
try:
os.umask(self.umask)
- file(self.pidfile, 'w').write('%s\n' % pid)
- except Exception, wpid_err:
- sys.stderr.write(u'Error trying to write pid file: %s\n' % wpid_err)
+ open(self.pidfile, 'w').write('%s\n' % pid)
+ except Exception as wpid_err:
+ sys.stderr.write('Error trying to write pid file: {}\n'.format(wpid_err))
sys.exit(1)
os.umask(0)
atexit.register(self.delpid)
def signal_management(self):
- # Declare signal handlers
+ """Declare signal handlers
+ """
signal(SIGTERM, self.exit_handler)
def exit_handler(self, signum, frame):
sys.exit(1)
def delpid(self):
+ """Remove PID file"""
try:
os.unlink(self.pidfile)
except OSError as err:
- message = 'Error trying to remove PID file: %s\n'
- sys.stderr.write(message % err)
+ message = 'Error trying to remove PID file: {}\n'
+ sys.stderr.write(message.format(err))
def start(self):
"""
"""
# Check for a pidfile to see if the daemon already runs
try:
- pf = file(self.pidfile, 'r')
+ pf = open(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)
+ message = 'pidfile {0.pidfile} already exist. Daemon already running?\n'
+ sys.stderr.write(message.format(self))
sys.exit(1)
# Start the daemon
"""
# Get the pid from the pidfile
try:
- pf = file(self.pidfile, 'r')
+ pf = open(self.pidfile, 'r')
pid = int(pf.read().strip())
pf.close()
except IOError:
pid = None
if not pid:
- message = 'pidfile %s does not exist. Is the Daemon running?\n'
- sys.stderr.write(message % self.pidfile)
+ message = 'pidfile {0.pidfile} does not exist. Is the Daemon running?\n'
+ sys.stderr.write(message.format(self))
return # not an error in a restart
# Try killing the daemon process
try:
os.kill(pid, SIGTERM)
time.sleep(0.1)
- except OSError, err:
+ except OSError as err:
if err.errno == 3:
if os.path.exists(self.pidfile):
- message = "Daemon's not running? removing pid file %s.\n"
- sys.stderr.write(message % self.pidfile)
+ message = "Daemon's not running? removing pid file {0.pidfile}.\n"
+ sys.stderr.write(message.format(self))
os.remove(self.pidfile)
else:
sys.stderr.write(err.strerror)