Well behaved unix daemons for every occasion.
Consider this project to be in maintenance mode.
This project went v1.0.0 in 2014. Since then it has only received two patches that contained code changes. All other patches have been maintenance updates to keep automated testing and static analysis running. I do not expect and am not entertaining new feature asks.
I will still respond to PRs and issues that address bugs or security issues. Please send these to https://github.com/kevinconway/daemons.
What Is Daemons?
Daemons is a resource library for Python developers that want to create daemon processes. The classes in this library provide the basic daemonization, signal handling, and pid management functionality while allowing for any implementation of behaviour and logic.
Example Custom Daemon
import time from daemons.prefab import run class SleepyDaemon(run.RunDaemon): def run(self): while True: time.sleep(1)
Now to create a simple init script which can launch the daemon.
#!/usr/bin/env python import logging import os import sys import time from mypackage import SleepyDaemon if __name__ == '__main__': action = sys.argv logfile = os.path.join(os.getcwd(), "sleepy.log") pidfile = os.path.join(os.getcwd(), "sleepy.pid") logging.basicConfig(filename=logfile, level=logging.DEBUG) d = SleepyDaemon(pidfile=pidfile) if action == "start": d.start() elif action == "stop": d.stop() elif action == "restart": d.restart()
There are more daemon types than the simple RunDaemon. Check the docs for more.
Wrapping Existing Code
Daemons can also be used to daemonize an arbitrary Python function.
import time from daemons import daemonizer @daemonizer.run(pidfile="/tmp/sleepy.pid") def sleepy(sleep_time): while True: time.sleep(sleep_time) sleepy(20) # Daemon started with 20 second sleep time.
The daemonizer also supports adding signal handlers. Check the docs for more.
The daemons in the 'prefab' module come bundled with the following features:
- pidfile management
- signal handling
- start/stop/restart functionality
- unix process daemonization
The default implementation of these feature are all driven by Python standard library modules. Each component may be overridden or extended by adding another base class to your daemon that implements the component interface. Check the 'interfaces' package for items to implement.
The 'prefab' daemons come in three flavors. The 'RunDaemon' requires that you implement the 'run' method which should use some form of a loop. If the 'run' method completes the process will stop. The 'StepDaemon' requires that you implement the 'step' method. The process will call 'step' on an infinite loop. The eventlet and gevent message daemons require that you implement the 'get_message' and 'handle_message' methods. These will fetch and handle messages within green-threads.
Copyright 2013 Kevin Conway Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.
All contributions to this project are protected under the agreement found in the CONTRIBUTING file. All contributors should read the agreement but, as a summary:
You give us the rights to maintain and distribute your code and we promise to maintain an open source distribution of anything you contribute.