A Python module to customize the process title

.. image:: https://github.com/dvarrazzo/py-setproctitle/workflows/Tests/badge.svg :target: https://github.com/dvarrazzo/py-setproctitle/actions?query=workflow%3ATests :alt: Tests

:author: Daniele Varrazzo

The setproctitle module allows a process to change its title (as displayed by system tools such as ps, top or MacOS Activity Monitor).

Changing the title is mostly useful in multi-process systems, for example when a master process is forked: changing the children's title allows to identify the task each process is busy with. The technique is used by PostgreSQL and the OpenSSH Server for example.

The procedure is hardly portable across different systems. PostgreSQL provides a good multi-platform implementation__: this package was born as a wrapper around PostgreSQL code.

• Homepage <https://github.com/dvarrazzo/py-setproctitle>__
• Download <http://pypi.python.org/pypi/setproctitle/>__
• Bug tracker <https://github.com/dvarrazzo/py-setproctitle/issues>__

.. _PostgreSQL: http://www.postgresql.org .. _OpenSSH Server: http://www.openssh.com/ .. : http://doxygen.postgresql.org/psstatus_8c_source.html

Installation

setproctitle is a C extension: in order to build it you will need a C compiler and the Python development support (the python-dev or python3-dev package in most Linux distributions). No further external dependencies are required.

You can use pip to install the module::

pip install setproctitle

You can use pip -t or virtualenv for local installations, sudo pip for a system-wide one... the usual stuff. Read pip or virtualenv docs for all the details.

.. _pip: https://pip.readthedocs.org/ .. _virtualenv: https://virtualenv.readthedocs.org/

Usage

.. note:: You should import and use the module (even just calling getproctitle()) pretty early in your program lifetime: code writing env vars may interfere__ with the module initialisation.

.. __: https://github.com/dvarrazzo/py-setproctitle/issues/42

The setproctitle module exports the following functions:

setproctitle(title) Set title as the title for the current process.

getproctitle() Return the current process title.

The process title is usually visible in files such as /proc/PID/cmdline, /proc/PID/status, /proc/PID/comm, depending on the operating system and kernel version. These information are used by user-space tools such as ps and top.

setthreadtitle(title) Set title as the title for the current thread.

getthreadtitle() Get the current thread title.

The thread title is exposed by some operating systems as the file /proc/PID/task/TID/comm, which is used by certain tools such as htop.

Environment variables

A few environment variables can be used to customize the module behavior:

``SPT_NOENV``
    Avoid clobbering ``/proc/PID/environ``.

    On many platforms, setting the process title will clobber the
    ``environ`` memory area. ``os.environ`` will work as expected from within
    the Python process, but the content of the file ``/proc/PID/environ`` will
    be overwritten.  If you require this file not to be broken you can set the
    ``SPT_NOENV`` environment variable to any non-empty value: in this case
    the maximum length for the title will be limited to the length of the
    command line.

``SPT_DEBUG``
    Print debug information on ``stderr``.

    If the module doesn't work as expected you can set this variable to a
    non-empty value to generate information useful for debugging.  Note that
    the most useful information is printed when the module is imported, not
    when the functions are called.

Module status
-------------

The module can be currently compiled and effectively used on the following
platforms:

- GNU/Linux
- BSD
- MacOS X
- Windows

Note that on Windows there is no way to change the process string:
what the module does is to create a *Named Object* whose value can be read
using a tool such as `Process Explorer`_ (contribution of a more useful tool
to be used together with ``setproctitle`` would be well accepted).

The module can probably work on HP-UX, but I haven't found any to test with.
It is unlikely that it can work on Solaris instead.

.. _Process Explorer: http://technet.microsoft.com/en-us/sysinternals/bb896653.aspx