[ci-visibility] Do not instrument tests if agentless is setup but no API key is provided

[juan-fernandez]

What does this PR do?

Do not call tracer.init if DD_CIVISIBILITY_AGENTLESS_ENABLED and no DATADOG_API_KEY is set, instead of falling back to the agent-based intake.

ℹ️ This is a breaking change but the feature is not GA yet, so no need for a major release.

Motivation

• It aligns with the rest of the libraries.
• The user has decided to explicitly opt in through DD_CIVISIBILITY_AGENTLESS_ENABLED but they have misconfigured the library, so it shouldn't fallback to the agent-based intake.

Plugin Checklist

• Unit tests.
• TypeScript definitions.
• TypeScript tests.
• API documentation.
• CircleCI jobs/workflows.
• Plugin is exported.

Additional Notes

[codecov]

Codecov Report

Merging #2072 (ad1b2bc) into master (edc3406) will decrease coverage by 0.08%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #2072      +/-   ##
==========================================
- Coverage   92.89%   92.81%   -0.09%     
==========================================
  Files         207      207              
  Lines        8264     8291      +27     
==========================================
+ Hits         7677     7695      +18     
- Misses        587      596       +9     

Impacted Files	Coverage Δ
packages/datadog-plugin-amqplib/src/index.js
packages/datadog-instrumentations/src/amqplib.js
packages/datadog-plugin-kafkajs/src/index.js	97.14% <0.00%> (ø)
packages/datadog-instrumentations/src/kafkajs.js	87.09% <0.00%> (ø)

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[bengl]

Since the tracer is loaded, but not initialized, is the logger available at this point? If so, it should be used here. If not, then nevermind.

[juan-fernandez]

that's a good question. I'll try

[juan-fernandez]

indeed, log.error won't work because it's not enabled (https://github.com/DataDog/dd-trace-js/blob/master/packages/dd-trace/src/log.js#L115). Using console.error is a bit aggressive but the way to get it is not straightforward. You have to use ci visibility's entrypoint and opt in to agentless via the flag. At that point I think it's fine to warn users that they've messed up their setup (by missing their API key)

[juan-fernandez]

@bengl did you have time to have a look at this again?