Make display_name more configurable

[yoshi314]

I use grafana -> alertmanager -> signalilo -> icinga2. This way my users don't have to meddle with prometheus/alertmanager yaml files for their alerting needs.

The issue:

It seems display_name gets set from alertname.

However, icinga won't accept certain characters in that field. I think even spaces are invalid. So i have to use simple definitions like "ALERT_01_for_some_service". Which seem to go into service definition (object name, which has restrictions) and display name (which doesn't have a lot of restrictions).

I thought i could pass specific field to signalilo to overwrite this, but i think i cannot.

So, I tried setting icinga_string_display_name with custom display_name and providing a template :

template Service "fix-display-name" {
        if (vars.display_name) {
                display_name = vars.display_name
        }
}

What happens is - signalilo creates an object like this :

object Service "CMB_PVC_K8S_6f0bc2786b5c6528" {
        import "generic-service"

(...)
        display_name = "CMB_PVC_K8S"
(.....)        vars["display_name"] = "Capacity of PVC spool-cc-cmb-test-aggregator-0"

And my custom display_name does not apply.

The problem is that template inheritance happens BEFORE all variables are parsed.

The fix is to import the template at the very end of service definition. I have no way to configure that in signalilo, but such feaure Would Be Nice To Have.