mr.laforge 0.9

Plugins and utilities for supervisor

Introduction

mr.laforge is a utility and plugin for supervisord.

It let’s you easily make sure that supervisord and specific processes controlled by it are running from within shell and Python scripts.

The plugin part adds a kill command to send signals to processes.

Usage

Installation as a script

One way to use it, is by installing it as a script. That’s also the way to use it in shell scripts. You can either just install it as an egg or you can install it in a buildout:

[mr.laforge]
recipe = zc.recipe.egg
eggs = mr.laforge

Either way you will get a supervisorup, a supervisordown and a waitforports script.

Running supervisorup without arguments will check whether supervisord is running and if not will start it. You can also provide process names on the command line and those will be started if they are not already running.

The supervisordown script does the same as supervisorup, but makes sure the process is stopped. This is useful for scripts which initialize a development database and similar tasks.

With waitforports you can check whether one or more processes are listening on the specified ports. The script has some additional arguments you can list with -h or --help.

You can set the supervisor_args keyword argument to set supervisor arguments for the supervisorup script like the config file location:

[mr.laforge]
recipe = zc.recipe.egg
eggs = mr.laforge
arguments = supervisor_args=['-c', 'etc/my_supervisord.conf']

Alternatively, supervisor arguments can also be set via the MR_LAFORGE_SUPERVISOR_ARGS environment variable.

Usage from a Python script

You can use the up method in mr.laforge which similar to the supervisorup script takes process names as arguments.

One example is a zc.recipe.testrunner part in a buildout like this:

[test]
recipe = zc.recipe.testrunner
eggs =
    ...
    mr.laforge
initialization =
    import mr.laforge
    mr.laforge.up('solr-test')

As you can see, you have to add the egg, so it can be imported by the initialization code added to the test script created by zc.recipe.testrunner. The up call gets solr-test as an argument to make sure that the solr-test process is running for the tests.

Another example is an initialization snippet in a script created by zc.recipe.egg:

[paster]
recipe = zc.recipe.egg
eggs =
    ...
    mr.laforge
dependent-scripts = true
scripts = paster
initialization =
    import mr.laforge
    mr.laforge.up('solr')

Now everytime you run the paster script created by this, it’s checked that supervisord and the solr process controlled by it are running.

The down method can be used to make sure a process is stopped and is the base of the supervisordown script. It’s used like the up method above.

The equivalent for the waitforports script is mr.laforge.waitforports. It takes a list of ports as arguments, which can be integers or strings which can also contain the host separated with a colon. You can also set the default host with the host keyword argument and the timeout value with the timeout keyword argument. Here is an example:

mr.laforge.waitforports(8080, 'db-server.example.com:5432', timeout=10)

There is also a shutdown function with which you can shutdown supervisord from Python code.

Add as plugin to supervisord

To use the plugin part of mr.laforge, you have to add the following to your supervisord config:

[rpcinterface:laforge]
supervisor.rpcinterface_factory = mr.laforge.rpcinterface:make_laforge_rpcinterface

[ctlplugin:laforge]
supervisor.ctl_factory = mr.laforge.controllerplugin:make_laforge_controllerplugin

You have to make sure that mr.laforge is importable by supervisord. In a buildout you would have to add the egg to supervisor like this:

[supervisor]
recipe = zc.recipe.egg
eggs =
    supervisor
    mr.laforge

Now you can use the kill command:

./bin/supervisorctl kill HUP nginx

Changelog

0.9 - 2019-09-15

• Fix import of controllerplugin for Python 3.x. [fschulze]

0.8 - 2018-07-10

• Fix do_kill for Python 3.x. [fschulze]

0.7 - 2018-07-02

• Add Python 3.x support. [fschulze]

• Add timeout to socket, so we don’t hang on unavailable hosts. [fschulze]

0.6 - 2012-10-06

• Added supervisordown script and matching down method to make sure a process is stopped. [fschulze]

0.5 - 2012-05-23

• Allow setting supervisor arguments via the MR_LAFORGE_SUPERVISOR_ARGS environment variable. [witsch]

• Added shutdown function to shutdown supervisord from Python code. [fschulze]

0.4 - 2012-05-09

• Added waitforports script and function to wait until a process is listening on specified ports. [fschulze, witsch]

0.3 - 2012-04-03

• Don’t pass command line options to supervisor code. [fschulze]

• Add supervisor_args keyword argument to up function. [fschulze, witsch (Andreas Zeidler)]

0.2 - 2011-04-20

• Added supervisord plugin with kill command to send signals to processes. [fschulze]

0.1 - 2011-04-20

• Initial release