As per the proposal, non-numeric values should be handled the following way:
Out of all the metrics emitted by Kafka brokers and clients, a few of them have non-numeric values. Prometheus only supports numeric values for metrics. When using jmx_exporter it is possible to write rules that move the non-numeric value to a label. For example we do it in kafka-connect-metrics for the status metric which has a string value.
I propose to do this automatically in the reporters. For example a metric named: kafka.connect:type=connector-task-metrics,connector="{connector}",task="{task}"<>status with the value running will be converted into kafka_connect_connector_task_metrics_status{connector="heartbeats",task="0",status="running"} and its value will be set to 1.0.
As per the proposal, non-numeric values should be handled the following way: