mr.laforge
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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.
.. _supervisord
: http://supervisord.org/
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:
.. code-block:: ini
[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:
.. code-block:: ini
[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:
.. code-block:: ini
[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
_:
.. code-block:: ini
[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:
.. code-block:: python
mr.laforge.waitforports(8080, 'db-server.example.com:5432', timeout=10)
.. _zc.recipe.testrunner
: http://pypi.python.org/pypi/zc.recipe.testrunner
.. _zc.recipe.egg
: http://pypi.python.org/pypi/zc.recipe.egg
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:
.. code-block:: ini
[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:
.. code-block:: ini
[supervisor]
recipe = zc.recipe.egg
eggs =
supervisor
mr.laforge
Now you can use the kill
command:
.. code-block:: bash
./bin/supervisorctl kill HUP nginx