Add option to generate google managed prometheus kubernetes resources

[alxndr13]

We had the problem that we were using Google's Managed Prometheus and there is no API like prometheusrules.monitoring.coreos.com.

Instead they're using this CRD:

apiVersion: monitoring.googleapis.com/v1
kind: Rules
metadata:
  creationTimestamp: null
  labels:
    app.kubernetes.io/component: SLO
    app.kubernetes.io/managed-by: sloth

Currently we are now transforming the generated YAML, but it would be cool if we could generate it in place. They're also expecting an interval to be set for each group:

groups:
  - name: sloth-slo-sli-recordings-api-success-rate
    interval: 30s

So the thing is they don't differ that much, but it would be nice if we could generate it like with an additional option.

[cxdy]

We don't use Google Managed Prometheus so I'm not entirely sure how we'd test this out but we can try to look into it.

Are you proposing a CLI flag to toggle this or something? Like ./sloth -i file.yaml --google?

[alxndr13]

@cxdy yes something like this :)

i basically have it already done using yq.

    yq eval '
        del(.kind, .apiVersion) |
        .kind = "GlobalRules" |
        .apiVersion = "monitoring.googleapis.com/v1" |
        (.spec.groups[] |= . + {"interval": "30s"})

kind needs to be changed, apiVersion as well and the groups is missing an interval setting :)