Document observing/increasing multiple labels

[jlouis]

Hi!

Thank you for a really nice library!

How do I increase multiple labels in a safe way? Suppose I have something like

prometheus_counter:new([{name, foo}, {help, "foo"}, {labels, [class, status]}])

If I want to bump this counter, I do:

prometheus_counter:inc(foo, [x, success]),
prometheus_counter:inc(foo, [y, failure]),

My question is: what if I add another label or provide the wrong order of labels? Can I send in a map, like:

prometheus_counter:inc(foo, #{ class => x, status => success })

or do I have to be precise? There is no documentation examples of this, and I dug in the tests but found no coverage of this, but perhaps I didn't look with enough conviction :)

So:

I expected

documentation on how one observes multiple labels for an observation/increase.

I found

nothing of this sort in the README.md file. If I run into this, surely others are going to do the same, so if there is documentation somewhere, please make this into a "point to the correct documentation" issue :)

Thanks!

[deadtrickster]

Hi, currently it's not possible to increase multiple labels, shouldn't be hard to add though ;-).

Labels must be a properly ordered list, yes. Also it will complains if not enough/too many labels. I vaguely remember sticking to list happened because of performance and sticking to other prometheus libs conventions.