fix: ensure the label names are sanitised

[weyert]

Sanitises the attribute names to match the naming convention enforced by
Prometheus

Which problem is this PR solving?

If you have a label name with - then Prometheus will fall over this issue with an error like:
error while linting: text format parsing error in line 282: expected '=' after label name, found '-'

Short description of the changes

The change is to also sanitise the label name and not only the metric names

[weyert]

Alternative way to fix this is to apply this check and when the diag level is DEBUG output a warning that the attribute is not meeting Prometheus requirements

[dyladan]

I think sanitizing is fine. Better than dropping at least. We could add a debug log but it would likely be quite chatty. We could add each bad label name to a Set of names that have already been logged. Only log each bad name once.

Approving for now since I see no immediate concern.

[dyladan]

Looks like your time mock failed

[codecov]

Codecov Report

Merging #2121 (41a7522) into main (c516264) will decrease coverage by 0.03%.
The diff coverage is 100.00%.

❗ Current head 41a7522 differs from pull request most recent head 952f86f. Consider uploading reports for the commit 952f86f to get more accurate results

@@            Coverage Diff             @@
##             main    #2121      +/-   ##
==========================================
- Coverage   92.78%   92.74%   -0.04%     
==========================================
  Files         140      140              
  Lines        4976     4979       +3     
  Branches     1028     1028              
==========================================
+ Hits         4617     4618       +1     
- Misses        359      361       +2     

Impacted Files	Coverage Δ
...ry-exporter-prometheus/src/PrometheusSerializer.ts	98.07% <100.00%> (+0.05%)	⬆️
...ges/opentelemetry-instrumentation-http/src/http.ts	94.82% <0.00%> (-0.80%)	⬇️

[weyert]

I think sanitizing is fine. Better than dropping at least. We could add a debug log but it would likely be quite chatty. We could add each bad label name to a Set of names that have already been logged. Only log each bad name once.

Approving for now since I see no immediate concern.

Yeah, that could work. I am happy to make a change later :)

[dyladan]

This likely won't be merged right away to ensure there is time for people to see it before merged but if it isn't merged by tomorrow I will merge it. If you have time to make the logging change before merge then great but if not it isn't blocking and can be done as follow up.

[obecny]

@weyert you have typo in variable name santizedLabelName should be sanitizedLabelName you are missing i

[dyladan]

@obecny I fixed the typo. I want to merge this for 0.19 release if possible