Charm hooks to be called "upgrade" and "config"

[Mark Shuttleworth]

For Juju 2.0 I would ask that we support charms which use a slightly different schema for hook names:

 * "upgrade" instead of "upgrade-charm"
 * "config" instead of "config-changed"

Happy to discuss the rationale for the original naming or the new naming. We should use the min-juju-version of course to ensure that these charms don't b0rk on older juju.

[Marco Ceppi (marcoceppi)]

I fear this might break forward compatibility for charms that still have upgrade-charm and config-changed hooks. Could this be amended to have the following logic instead?

Juju 2.0 Upgrade sequence:
 - Look for upgrade hook, if fail
 - Look for upgrade-charm, if fail
 - Skip

Juju 2.0 Configure sequence:
 - Look for config hook, if fail
 - Look for config-changed, if fail
 - Skip

This way charms developed with <=1.25 will still work in 2.0 since we don't have a max-juju-version field

Also, nitpick, since we're renaming things, `configure` seems more complete than `config` but that's just the color of the shed I'd prefer.

[Dean Henrichsmeyer (dean)]

I just want to point out that there will be a substantial cost for existing consumers of Juju to pay if this actually happens and we're already asking a lot of them with 2.0.

[Richard Harding (rharding)]

The bug states that we'll allow the new names. I see this as a completely forward compatible addition to Juju that we can apply.

As Marco notes, it'd be a check, first for this new hook and if not found fall back to the upgrade-charm hook.

Juju 2.0 is getting frozen and the 2.0 release cut in the next 2 days for Xenial. We do not have the resources to make this change in the next 48hrs, however, I would like oi discuss the goal and when we want to have the charm that can utilize this in place and make sure that we add this as a point release to Juju 2.0 soon after it's released.

We know we'll have a minimun of two of those in the coming months and so I think we can align this with those very easily.

[Adam Collard (adam-collard)]

Can I humbly suggest that such a change would be too much of an impact for a point release? At the very least it should be a minor version bump IMHO.

[Mark Shuttleworth (sabdfl)]

Thanks Marco, I did intend for it to be easily forward-compatible, with
symlinks, unless min-juju-version is used.

Mark

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

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