yaml datatype for charm configuration settings

[Stuart Bishop]

Charm configuration in config.yaml allows integer, boolean and string datatypes. Some charms require more complex data structures for their configuration, for example a list of (database_name, user_name, access_type) tuples or charm-helper's install_sources and install_keys lists.

One current work around, used by charm-helpers, is to use the 'string' type and allow the user to embed a fragment of yaml. This works, but requires the yaml fragment to be quoted as a string and does not have basic validation.

Other more common work arounds are comma separated lists, space separated lists, base64 and other arbitrary, inconsistent and ad-hoc methods.

It would be lovely if 'yaml' could be specified as a config item datatype, allowing an arbitrary yaml data structure to be embedded as configuration. This would bring consistency, and reduce bugs in charms' custom serialization routines.

[Evan (ev)]

We'd also like to see this in UE, as we keep having to do grotty things like:

$ juju set uci-ci-tarmac branches="'lp:uci-engine':
    verify_command: '/usr/bin/env python bin/called-by-tarmac.py'
    commit_message_template: '[r=<approved_by>] <commit_message>'
    voting_criteria: 'Approve >= 1'
'lp:uci-team':
    commit_message_template: '[r=<approved_by>] <commit_message>'
    voting_criteria: 'Approve >= 1'"

[Anastasia (anastasia-macmood)]

@Stuart Bishop (stub),

This is currently against 'juju-core' project which is limited to Juju 1.25.x.

Since you have added new tags, I am guessing you wanted it on 'juju' project for Juju 2.x. I'll add a project and will triage this report as Wishlist item.

[Canonical Juju QA Bot (juju-qa-bot)]

This bug has not been updated in 2 years, so we're marking it Low importance. If you believe this is incorrect, please update the importance.