Promql use metric value as a new label

Question

I have this metric: task_code{pod="foobar"} 9

I am trying to write an expression to check the value of the mentioned metric to raise an alert as the value of the above metric can be any number.

I can do the following but the values to be matched are plenty.

(task_code{pod="foobar"} == 9 or task_code{pod="foobar"} == 15 or task_code{pod="foobar"} == 29)

But looks like regex can only be applied on a label value and Not on a metric value.

I tried exploring the label_replace function to create a new label out of the metric value but no go.

Looking to have something like

task_code{pod="foobar"} in [9,15,29]

or

task_code{pod="foobar"} =~ "(9|15|29)"

Any pointer is really appreciated.

Answer 1

I suspect that your metric is an anti-pattern and, rather than try to force Prometheus into this somewhat unnatural behavior, you should reconsider the metric (if possible).

Measurements (counters, gauges) etc. should be continuous.

Corollary: measurements that are discrete values (and I think code is a smell here) should be label values.

Unless you can correct the metric, you're limited to PromQL Operators and I suspect you'll be limited to enumerating the many conditions:

task_code{foo="..."}=={value} or ...