feat(nice-grpc-prometheus): add metrics customization #423
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| export const labelNames = [ | ||
| typeLabel, | ||
| serviceLabel, | ||
| methodLabel, | ||
| pathLabel, | ||
| codeLabel, | ||
| ]; |
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The set of labels is not the same for every metric. Particularly the code label is missing in some of them.
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I thought about it.
- There is indeed an extra label, but it looks like it has absolutely no effect on behavior.
- Attempting to separate labels leads to more complexity for the user and more possibility of mistakes.
An alternative way is to create custom wrappers for each metric that encapsulate the necessary parts. But this is too cumbersome.
What are your thoughts on this? Maybe there are some suggestions?
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Indeed it seems that putting a label to that list does not make it required and does not affect the metrics where we don't use it.
However according to the code of prom-client it would break if we use the metric.label(...) method: it checks that the array lengths are the same.
That said, since we don't use that method, I'm ok with having it this way.
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I've decided to separate labelNames and labelNamesWithCode for better reliability. Doesn't look as bad as I expected.
| import {Histogram} from 'prom-client'; | ||
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| const clientHandlingSecondsMetric = new Histogram({ | ||
| registers: [registry], |
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The example here reuses the lib's registry, which means that you won't be able to use the same metric names. So to change the buckets you would have to use custom names, which does not sound convenient.
The tests use a separate registry, which I think is the correct way to go. But we need an example to mention this and also show how to merge the registries.
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You're right. It's updated now.
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Looks great, thanks! I'm going to merge it and release shortly. |
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Published 📦 |
Hi!
I've found that the default buckets for histograms are not always suitable, and it would be useful to be able to customize them.
In looking for a way to change this I came to the conclusion that the most versatile and flexible way is to allow all metrics to be overridden.