Hi,
In principle you can register metric/metric groups dynamically it should be
working just fine. However your code probably won't work, because per every
record you are creating a new group and new counter, that most likely will
be colliding with an old one. So every time you are defining a new group or
new counter, you should remember it in some field.
Best,
Piotrek
pt., 17 gru 2021 o 14:03 Witold Baryluk <witold.bary...@gmail.com>
napisał(a):
> Hi,
>
> I want to track and increment some monitoring counters from `map`,
> but have them broken down by dynamically defined values of a label.
> The set of values is unknown at creation time, but it is bounded
> (less than 100 different values during a 30 day period, usually ~5).
>
> There is no easy way of doing this, compared to other Prometheus
> native systems (i.e. in Go, or C++), but it looks like it might be possible
> using some workarounds:
>
>
> public class MyMapper extends RichMapFunction<String, String> {
> private transient MetricGroup metric_group;
>
> @Override
> public void open(Configuration config) {
> this.metric_group = getRuntimeContext().getMetricGroup();
> }
>
> @Override
> public String map(String value) throws Exception {
> Group group = this.metric_group.addGroup("kind", getKind(value));
> group.counter("latency_sum").inc(getLatencyMicros(value));
> group.counter("latency_count").inc();
> return value;
> }
> }
>
> Will this work? Is there a better way?
>
> But, this does not look nice at all compared to how
> other projects handle Prometheus labels. Flink metrics are not well
> mapped into Prometheus metrics here.
>
> Second question, is it ok to call addGroup and counter, dynamically like
> this,
> or should it be cached? Do I need any such cache (which would be map
> of string to Counter), be protected by some mutex when I lookup or add
> to it?
>
> Cheers,
> Witold
>
