unix_daemon 0.1.3

Function emulating Daemon(3) on Linux and Unix OS.

unix_daemon is a python module emulating BSD daemon(3).

This module provides a function named daemon.

If this function is called, the process become a daemon and start to run background.

Requirements

• Python 2.6 or 2.7

• Unix or Linux platform.

Tested

• Ubuntu 12.04 (x86_64)

• CentOS 6.4 (x86_64)

• Mac OS X 10.9

Setup

• Install using pip

  $ sudo pip install unix_daemon

• Install from git.

  $ git clone https://github.com/wbcchsyn/unix_daemon.git
  $ cd unix_daemon
  $ sudo python setup.py install

Usage

unix_daemon.daemon(nochdir=False, noclose=False)

The process become a daemon and start to run background.

Arguments

If argument 1 ‘nochdir’ is False, the process changes the calling process’s current working directory to the root directory (“/”);

otherwise, the current working directory is left unchanged.

The default value of the nochdir is False.

If argument 2 ‘noclose’ is False, this function redirects stdin, stdout and stderr to /dev/null;

otherwise, leaves them.

The default value is False.

Return Value

daemon returns the pid of new process.

Note

This function call fork internally to detach tty safely.

Be careful to call this function when two or more than two threads is run.

(It is a good idea to call this function before creating a new thread.)

Example

Call unix_daemon.daemon(), then the process run backgrond.

import unix_daemon
import os

print('pid: %s\n' % os.getpid())

pid = unix_daemon.daemon()
with file('/tmp/foo', 'a') as f:
    print('pid: %s\n' % os.getpid())
    f.write('new pid: %s\n' % pid)

You can see the process id changes and the 2nd print is not displayed.

Development

Install requirements to developing copy pre-commit hook from repository.

$ git clone https://github.com/wbcchsyn/unix_daemon.git
$ cd unix_daemon
$ pip install -r dev_utils/requirements.txt
$ ln -s ../../dev_utils/pre-commit .git/hooks/pre-commit