Prevent use_juju_for_storage=True on Juju 4

[benhoyt]

Per juju/juju#17721, controller storage is being removed in Juju 4.0, so we should prevent its use there. We should also update the various documentation (Ops reference docs, any SDK docs or tutorials).

Note that it's already deprecated with a deprecation warning in ops/main.py.

[dimaqq]

Would this rather be a charmcraft lint item requiring an assumes setting?

Or a run-time fail that's only triggered if Juju is indeed 4.x?

[benhoyt]

@james-garner-canonical Another small one for you. I'd recommend just a run-time fail if Juju is indeed >=4.x.

[jameinel]

Juju isn't dropping state-set/state-get in 4.0 (afaict), which is what is used by JujuStorage <https://github.com/canonical/operator/blob/98a4e4f44d37d3361a253bc1eff49eee2ca6d140/ops/storage.py#L219>. That specific PR is about charms that used a Persistent Volume Claim for their local state. I'll reach out to confirm. I'd be open to dropping "use_juju_for_storage", but more in favor of explicit lifetimes for StoredState objects. (Are they persistent for the lifetime of a unit, vs persistent for the lifetime of this container.) I don't think the one-big-hammer for all StoredState is what we want to have. FWIW, that particular PR was also rejected. John =:->

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On Tue, Sep 24, 2024 at 12:22 AM Ben Hoyt ***@***.***> wrote: @james-garner-canonical <https://github.com/james-garner-canonical> Another small one for you. I'd recommend just a run-time fail if Juju is indeed >=4.x. — Reply to this email directly, view it on GitHub <#1284 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AABRQ7OMCCKFICPZNW2OHODZYDLHNAVCNFSM6AAAAABK5KLVPOVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDGNZQGEZDANJYGI> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>