feat(@opentelemetry-instrumentation-fetch): optionally ignore network events

[gregolsen]

Which problem is this PR solving?

Summary: This PR allows to optionally disable adding network events as span events to control the total volume of telemetry data produced.

Some of the modern vendors treat spans and span events (annotations) equally – both are counted towards the overall retained events volume. Similarly, vendors that charge for the overall size of data retained will count span annotations as part of the data. Typically, span produced by the @opentelemetry-instrumentation-fetch includes 9 network events – 10 event items along with the span itself. It would be great to have ability to optionally disable network events being added as span annotations to reduce the overall volume of data/events generated and eventually retained.

Short description of the changes

This PR adds an optional boolean flag ignoreNetworkEvents to the FetchInstrumentation. When set to true network events are not added to the span.

Type of change

Please delete options that are not relevant.

• New feature (non-breaking change which adds functionality)
• This change requires a documentation update

How Has This Been Tested?

Running npm run test:browser will run the newly added test as part of the suite:

    ...
    when network events are ignored
      ✓ should NOT add network events

Checklist:

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

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: gregolsen / name: Inokentii Mykhailov (4f9feef)

[vmarchaud]

@gregolsen you'll need to add a entry in the global CHANGELOG, apart from that lgtm

[codecov]

Codecov Report

Merging #3028 (e36c928) into main (c8c4ec6) will decrease coverage by 0.01%.
The diff coverage is 100.00%.

❗ Current head e36c928 differs from pull request most recent head 07a3f0f. Consider uploading reports for the commit 07a3f0f to get more accurate results

@@            Coverage Diff             @@
##             main    #3028      +/-   ##
==========================================
- Coverage   92.65%   92.64%   -0.02%     
==========================================
  Files         187      187              
  Lines        6167     6169       +2     
  Branches     1301     1303       +2     
==========================================
+ Hits         5714     5715       +1     
- Misses        453      454       +1     

Impacted Files	Coverage Δ
...s/opentelemetry-instrumentation-fetch/src/fetch.ts	96.47% <100.00%> (+0.04%)	⬆️
...emetry-core/src/platform/node/RandomIdGenerator.ts	87.50% <0.00%> (-6.25%)	⬇️

[gregolsen]

Ah, thank you @vmarchaud. I modified experimental/CHANGELOG – I hope that's what you've meant by "global" – I figured the one in experimental fits better as my change is for the package located under experimental directory.

[vmarchaud]

I hope that's what you've meant by "global" – I figured the one in experimental fits better as my change is for the package located under experimental directory.

Yeah sorry that was exactly what i meant, thanks