unit data not removed from relation

[james beedy]

I remove a unit, but the unit data never gets removed from the peer relation, see https://paste.ubuntu.com/p/TcNTf6Sy9h/

Furthermore, the other units of the application don't get a relation-changed hook fired when a unit leaves.

[james beedy (jamesbeedy)]

code where we add 'hostname' to the units data https://gist.github.com/jamesbeedy/2bd8429995f609919834f69d7a8b481f

[Tim Penhey (thumper)]

Hi James,

Could you provide the unit logs from the units left? That would show if it was trying to call the event but for some reason couldn't.

How is this charm built? Is it possible that there is a typo in the departed hook name?

Is the charm public?

[Tim Penhey (thumper)]

Also would be good to know if the charm has different behaviour on Juju 2.7 vs. 2.8

[james beedy (jamesbeedy)]

@thumper https://github.com/jamesbeedy/charm-peerer, I've also attached this as built charm.

[james beedy (jamesbeedy)]

@thumper is there anything else I can do to help move this along?

[John A Meinel (jameinel)]

So it concretely look like:

'relation-list' is correctly reporting that the unit is gone but
'relation-get' still lets you read the old data, because that data isn't removed from the database.

Probably we are missing a cleanup step that ensures a departing unit's data is removed from the settings collections.

We could paper around it by having the Unit agent refuse to return the data if it isn't currently part of the units joined in the relation, but we should really fix it at the source.