traefik_k8s.v1.ingress relation relies on deprecated controller storage

[gnuoy]

Bug Description

The interface relies on deprecated controller storage (canonical/operator#882). If a charm respects this deprecation notice and sets use_juju_for_storage=False then the state stored in self._stored.current_url (for example) can be lost.

To Reproduce

Deploy a charm which uses the ingress relation and amend the charm to echo the value of url property of the ingress requires interface. This should return a url. Build a new copy of the charm with use_juju_for_storage=False and upgrade the existing charm. The url property will now be None.

A more longwinded way:

$ git clone  https://opendev.org/openstack/charm-placement-k8s 
$ cd charm-placement-k8s/
$ juju download --series jammy --channel yoga/edge placement-k8s
$ mv placement*.charm  placement-k8s.charm
$ tox -e func-smoke
...
$ juju status placement
Model              Controller  Cloud/Region        Version  SLA          Timestamp
zaza-df54e5a6cf87  micro       microk8s/localhost  2.9.34   unsupported  11:42:18Z

App        Version  Status  Scale  Charm          Channel  Rev  Address        Exposed  Message
placement           active      1  placement-k8s             0  10.152.183.48  no       

Unit          Workload  Agent  Address      Ports  Message
placement/0*  active    idle   10.1.124.51         

$ mkdir /tmp/charm-tmp
$ unzip -d /tmp/charm-tmp  placement-k8s.charm

$ sed -i -e 's/use_juju_for_storage=True/use_juju_for_storage=False/' /tmp/charm-tmp/src/charm.py 
$ cd /tmp/charm-tmp
$ zip -r /tmp/placement.charm *
$ juju upgrade-charm --switch /tmp/placement.charm placement
$ juju status placement
Model              Controller  Cloud/Region        Version  SLA          Timestamp
zaza-df54e5a6cf87  micro       microk8s/localhost  2.9.34   unsupported  11:48:15Z

App        Version  Status   Scale  Charm          Channel  Rev  Address        Exposed  Message
placement           waiting      1  placement-k8s             1  10.152.183.48  no       waiting for units to settle down

Unit          Workload  Agent  Address      Ports  Message
placement/0*  waiting   idle   10.1.124.32         (ingress-internal) integration incomplete

This is because the placement charm checks the url property of the relation to check it is ready.

Environment

Running in microk8s. The library version is:

LIBAPI = 1
LIBPATCH = 5

Relevant log output

N/A

Additional context

N/A

[dstathis]

Ingress v1 has been deprecated for some time now. I would recommend updating to ingress v2.