Feature add config and action parameter type: set

[Erik Lönroth]

I would like to propose a new config type for juju charms: Set

The set type would allow a charmer to specify a set of allowed values for a config level declared in config.yaml for a given config item. As

fruit: [ 'apple', 'banana', 'citrus' ]
  mode: single-value or multi-value
  non-empty: true or false
  default: [ 'banana', 'citrus' ]

This would allow juju to validate input of config early to simplify parameter validation when config values are a few.

The mode attribute to the set would allow more than one selection.

The non-empty would control the value to be [] or not.

The default would be as expected a predefined list of items already chosen.

This very same feature should be implemented also for juju-action parameters.

This feature would assist alot also to prevent and inform users in situations when juju-actions are run incorrect, as for example in this bug: https://bugs.launchpad.net/juju/+bug/1880846

In the web GUI, the presentational widget for this option/config type would be presented as a drop down or a

[Pen Gale (pengale)]

This fits with our general long term plans are a config schema. Added appropriate tags, to remind us to loop back.

[Erik Lönroth (erik-lonroth)]

Its been a year since I logged this and I want to come back to this since this is the most common question I get from developers which also connects well with: https://bugs.launchpad.net/juju/+bug/1941925

Its about time that juju gets more interesting config types.