How to coordinate status messaging between layers?

[Merlijn Sebrechts]

Hi all


I'm having a hard time doing status reporting from a reactive Charm. I
can't find a good way to coordinate status messaging between different
handlers and layers.

Let me explain one of my use-cases.

1. We have a service that connects to a gateway to request a port forward.
When the service receives such a forward, it displays this forward in its
status message. Our management software uses this message to figure out how
to connect to the service from the internet.

2. The service has the ability to deploy a bundle. When the bundle
deployment fails, it goes into blocked state and shows a message explaining
what went wrong.


At this point, the port-forward message isn't visible anymore meaning our
management program can't connect to the service anymore.


Message 1 and 2 are displayed by two different layers. I can't find a good
way to coordinate status messaging between the two layers in a way that
keeps compatibility with all the existing layers at
interfaces.juju.solutions.

I guess what I'd like to do is have status messages that consist of
multiple parts. Each handler can choose what part of the message to update.
This would enable my charm to keep the port-forward information in the
message even though another layer displays a "bundle deployment failed"
message.

Any idea how I can solve this? Have other people experienced similar issues?



Kind regards
Merlijn Sebrechts
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