Update metrics example

[svetlanabrennan]

Which problem is this PR solving?

This metrics example was referencing an older version of opentelemetry packages which was causing an error of TypeError: meter.createObservableGauge is not a function

Fixes # (issue)

Short description of the changes

• Updated opentelemetry packages.
• Updated Oberservable Gauge example to match the example given in the metrics sdk - version 0.27.0

Type of change

How Has This Been Tested?

Tested examples locally.

Checklist:

• Followed the style guidelines of this project
• Unit tests have been added
• Documentation has been updated

[dyladan]

Thanks for taking on all these examples and docs. Its great to have them updated

[svetlanabrennan]

@dyladan @vmarchaud There is one thing in this example that I wasn't sure about which was searching prometheus for "cpu_core_usage". I'm not seeing that option in the metrics explorer in prometheus. I can see other "process_cpu_seconds_total" but not "cpu_core_usage".

If you're able to shed some light on this, I'd appreciate that. Thanks!

[codecov]

Codecov Report

Merging #2658 (c9471f3) into main (27bbb11) will decrease coverage by 0.36%.
The diff coverage is n/a.

❗ Current head c9471f3 differs from pull request most recent head 62eb14f. Consider uploading reports for the commit 62eb14f to get more accurate results

@@            Coverage Diff             @@
##             main    #2658      +/-   ##
==========================================
- Coverage   92.88%   92.52%   -0.37%     
==========================================
  Files         143      144       +1     
  Lines        5158     5177      +19     
  Branches     1102     1102              
==========================================
- Hits         4791     4790       -1     
- Misses        367      387      +20     

Impacted Files	Coverage Δ
...emetry-core/src/platform/node/RandomIdGenerator.ts	87.50% <0.00%> (-6.25%)	⬇️
...-metrics-base/examples/metrics/metrics/observer.js	0.00% <0.00%> (ø)

[legendecas]

The function signatures used in the example are the latest, not published WIP version in api-metrics. I'm not sure if the example should be reverted back to the previous versions. AFAICT, the examples should be updated with the api-metrics change.

People can always find the example that works with v0.27.0 at https://github.com/open-telemetry/opentelemetry-js/blob/experimental/v0.27.0/examples/metrics/metrics/observer.js.

[dyladan]

Hmm @legendecas is right that the current example is actually more up to date than what is here, but I think it's confusing to have an examples directory where the examples don't work with the released features. The average user who comes to the repo looking for examples is going to expect them to work and be confused when they don't. I see a few options to move forward here:

1. Move the examples which use the WIP metrics packages into the wip metrics package directory and use @svetlanabrennan's version in the root examples folder.
2. Create a separate directory for WIP/dev examples/docs

[dyladan]

@MSNev does your approval that you support the examples/ folder containing released versions and not WIP versions?

[MSNev]

@MSNev Nev Wylie FTE does your approval that you support the examples/ folder containing released versions and not WIP versions?

Yes, the examples should be using the production versions as that is what (I assume / expect) new users will be using these for. It does mean that there will be a delay in "adding" new example features.

[dyladan]

Do you think we should have a location for WIP examples? If so, where would you vote? I think I'd like to have the WIP examples directly in the package directory they are an example of.

[vmarchaud]

I think we should remove the example, or move it to the wip sdk but that will require time to keep it up to date so i think removing it make more sense for now

[svetlanabrennan]

I like the idea of moving it to a wip sdk. And if the wip examples are not working (from time to time because of updates/changes) then users will know it's because they're "wip" examples.

[dyladan]

Can you handle that in this PR?

[svetlanabrennan]

@dyladan This is completed.

[dyladan]

A few things to fix the lint step. Otherwise looks good