This feature is to be included in the yet-to-be-released 0.4.7 ...
Suppose you are working with a 3rd party system of some kind and want to
interact with it when cobbler commands are run.
Examples potentially include doing some custom logging, or perhaps
interacting with some remote resource (power management? networking
hardware? who knows?).
Triggers provide a way to do this.
Cobbler 0.4.7 will include the following trigger directories:
/var/lib/cobbler/triggers/add/profile
/var/lib/cobbler/triggers/add/system
/var/lib/cobbler/triggers/add/distro
/var/lib/cobbler/triggers/add/repo
/var/lib/cobbler/triggers/delete/profile
/var/lib/cobbler/triggers/delete/system
/var/lib/cobbler/triggers/delete/distro
/var/lib/cobbler/triggers/delete/repo
When an object is added or deleted through the cobbler command line (or
the API), all trigger scripts in these directories will be executed.
The parameter to the script will be the name of the object
being added or deleted. If you have a trigger for "delete/system", and
run "cobbler system delete --name=AA:BB:CC:DD:EE:FF", the script's
parameter will be "AA:BB:CC:DD:EE:FF" (no quotes).
The most simple example would just printing out the name of what is
being added.
A more complex example would be showing all of the details of the object.
Here's a more complex example using the Cobbler API. Triggers don't
have to use the Cobbler API, but if they want to interact with the
Cobbler object tree, they can learn a lot by doing so...
Here's an example echo trigger --
/var/lib/cobbler/triggers/add/profile/echo.py -- I've left it rather
short and compressed for demo purposes ... it can definitely be made a
lot cleaner :)
#!/usr/bin/python
import sys
import cobbler.api as cobbler_api
if __name__ == "__main__":
print sys.argv
print cobbler_api.BootAPI().distros().find(sys.argv[1]).printable()
This was originally written as a suggestion from the Stateless Project
(http://fedoraproject.org/wiki/StatelessLinux) -- if anyone has any
suggestions on other things they might like triggers for, or questions
about how they work,
please comment.
For those interested in playing with the source, I've already pushed an
initial version of the above ... "make rpms" will build cobbler, and
install the RPM from the "rpm-build" directory...
--Michael DeHaan
