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Provision: API

Provivion has 2 APIs. They are very simple to make the barrier-to-entry low.

Local_decision API

To create a local_decision plugin, start with the template in lib/provision/local_decision/template.pm. Make a copy of this that matches the "group" part of your hostname. We'll pretend your group is "web" so you make a "web.pm". Web.pm will already be setup as a subclass of provision::local_decision, which means you only need to implement a few functions to start, and more as you feel the need.

Start by changing the name of the package from "provision::local_decision::template" to "privision::local_decision::web". Now, look through lib/provision/local_decision.pm. These are all the callbacks you have access to change. Most of the functions in local_decision.pm are implemented with some sane defaults. In cases where there's no obvious way to make it generic, a '-1' is returned to denote 'NOT SUPPORTED.' You may override ANY function in local_decision.pm with your own simply by defining it in web.pm.

If a function is required to be implemented for some plugin or another, but a generic way of doing it wasn't obvious a best-effort was implimented in lib/provision/generic.pm. At the time of writing, that's simply get_vol() and get_fls(). These are required for the filer plugin (unless you choose to specify these on the command-line).

IMPORTANT NOTE: If you're writing your own plugin, provision will always fail back to the 'generic' plugin if loading the 'group' plugin fails for any reason. However, since using the generic plugin is likely to be common, we don't throw an error. To find out which plugin is being used, you'll want to run provision in debug mode.

Plugins

Provisioning Plugins must implement three functions:

  • run() - we call this to tell the plugin to provision something
  • local_opts() - returns a hash of command-line options desired (only "long" opts are supported)
  • get_dst() - Where to head to, to provision whatever your plugin will provision. This is usually a wrapper around some local_decision functions. Feel free to add local_decision functions as needed.


RUN
run() is passed a config object and a host object. The action to be taken is specified in the host-object (provision, deprovision, or alias), and we expect a positive integer as success, and a 0 on failure. Just print errors for the users, provision will handle picking them ip.

LOCAL_OPTS
This returns a hash that looks like this:

     someoption
     }

You can request as many command-line options as you'd like. They'll show up in a help. args is a description of args for the help, and getopts is the bits to be tack'd on to tell getops what arguments, if any, are required. Finally, provision will check for collisions and report them.

GET_DST
As mentioned above, this likely wraps some local_decision functions, and puts together a hostname to ssh to to provision whatever your plugin provisions for the host passed in.

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