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daemonize is a library for writing system daemons in Python. It is distributed under MIT license. Latest version can be downloaded from PyPI. Full documentation can be found at ReadTheDocs.


It is tested under following Python versions:

  • 2.6
  • 2.7
  • 3.3
  • 3.4
  • 3.5


You can install it from Python Package Index (PyPI):

$ pip install daemonize


from time import sleep
from daemonize import Daemonize

pid = "/tmp/test.pid"

def main():
    while True:

daemon = Daemonize(app="test_app", pid=pid, action=main)

File descriptors

Daemonize object’s constructor understands the optional argument keep_fds which contains a list of FDs which should not be closed. For example:

import logging
from daemonize import Daemonize

pid = "/tmp/test.pid"
logger = logging.getLogger(__name__)
logger.propagate = False
fh = logging.FileHandler("/tmp/test.log", "w")
keep_fds = [fh.stream.fileno()]

def main():

daemon = Daemonize(app="test_app", pid=pid, action=main, keep_fds=keep_fds)


class daemonize.Daemonize(app, pid, action, keep_fds=None, auto_close_fds=True, privileged_action=None, user=None, group=None, verbose=False, logger=None, foreground=False, chdir='/')[source]

Daemonize object.

Object constructor expects three arguments.

  • app – contains the application name which will be sent to syslog.
  • pid – path to the pidfile.
  • action – your custom function which will be executed after daemonization.
  • keep_fds – optional list of fds which should not be closed.
  • auto_close_fds – optional parameter to not close opened fds.
  • privileged_action – action that will be executed before drop privileges if user or group parameter is provided. If you want to transfer anything from privileged_action to action, such as opened privileged file descriptor, you should return it from privileged_action function and catch it inside action function.
  • user – drop privileges to this user if provided.
  • group – drop privileges to this group if provided.
  • verbose – send debug messages to logger if provided.
  • logger – use this logger object instead of creating new one, if provided.
  • foreground – stay in foreground; do not fork (for debugging)
  • chdir – change working directory if provided or /

Cleanup pid file at exit.

sigterm(signum, frame)[source]

These actions will be done after SIGTERM.


Start daemonization process.

Indices and tables