Cloned from launchpad blueprint https://blueprints.launchpad.net/heat/+spec/function-plugins.

Description:

The idea here is to be able to extend the templating system with your own functions.

This will be based on the same plugin system as used for resources. However functions are a bit trickier: there are two sets of functions we run at different times - ones dealing with static data and ones dealing with runtime data. We may need to provide a way to register each type separately.

We also currently apply functions in a fixed order, which is likely (although not guaranteed) to result in everything in the template being able to be resolved. We'll probably need to fix this so that all functions are guaranteed to resolve no matter their order of nesting.

Specification URL (additional information):

None