[mysqld-mixin] How do we use it as a library?

[sdurrheimer]

Is there a way to properly use the mysqld-mixin/mixin.libsonnet to import rules and alerts?

For example with prometheus/kube-prometheus, I was trying to do:

local thanosMixin = import 'thanos-mixin/mixin.libsonnet';
local corednsMixin = import 'coredns-mixin/mixin.libsonnet';
local certManagerMixin = import 'cert-manager-mixin/mixin.libsonnet';

// trying to use mysqld-mixin the same way as others
local mysqldMixin = import 'mysqld-mixin/mixin.libsonnet';

local kp =
  (import 'kube-prometheus/kube-prometheus.libsonnet') +
  (import 'thanos-mixin/config.libsonnet') +
  {
    _config+:: {
      namespace: 'monitoring',
    },
    prometheusRules+::
      thanosMixin.prometheusRules +
      certManagerMixin.prometheusRules +
      // trying to use mysqld-mixin the same way as others
      mysqldMixin.prometheusRules +
      {
        // groups+: [],
      },
    prometheusAlerts+:: 
      thanosMixin.prometheusAlerts +
      corednsMixin.prometheusAlerts +
      certManagerMixin.prometheusAlerts +
      // trying to use mysqld-mixin the same way as others
      mysqldMixin.prometheusAlerts +
      {
        // cat existingrule.yaml | gojsontoyaml -yamltojson > existingrule.json
        // groups+: (import 'existingrule.json').groups,
      },
  }

But I end up with the following error:

+ jsonnet -J vendor -m manifests kube-prometheus.jsonnet
+ xargs '-I{}' sh -c 'cat {} | gojsontoyaml > {}.yaml' -- '{}'
RUNTIME ERROR: only functions can be called, got null
	vendor/mysqld-mixin/mixin.libsonnet:9:14-44	object <anonymous>