Allow disabling nodejs auto-instrumentations via environment variables

[mderazon]

Hi. I would like to disable an instrumentation. Seems like @opentelemetry/instrumentation-fs is causing a lot of unnecessary traces and is recommended to be disabled:
open-telemetry/opentelemetry-js-contrib#1344 (comment)

It's possible to disable it via node auto instrumentation:
open-telemetry/opentelemetry.io#2988 (review)

https://github.com/open-telemetry/opentelemetry.io/blob/16328c6c00bb5c163f200b22ef90b881a80a86d1/content/en/docs/languages/js/libraries.md?plain=1#L145-L154

But I am not sure how to do it through otel operator ?

Originally posted by @mderazon in #1283 (comment)

[pavolloffay]

Is there a way to disable it with env var?

Can it be disabled here https://github.com/open-telemetry/opentelemetry-operator/blob/main/autoinstrumentation/nodejs/src/autoinstrumentation.ts#L35 ? We could define an env var (specific for the operator) to enable it conditionally.

[atsu85]

Hi @mderazon and @pavolloffay!

I think we'd need a generic solution to disable any instrumentations, not just specific environment variable for disabling @opentelemetry/instrumentation-fs instrumentation.

There are different approaches we could take:
a) disabling instrumentations in opentelemetry-operator code based on opentelemetry-operator specific environment variables, like @pavolloffay mentioned
b) disabling instrumentations in @opentelemetry/auto-instrumentations-node package (that this operator is using) based on environment variables. Note that there are at least two issues created there related to it:

• NodeJS auto-instrumentation: Allow disabling specific instrumentations with environment variables opentelemetry-js-contrib#1672
• Support to disable specific library or middleware instrumentation via environment variable opentelemetry-js-contrib#1331 - automatically closed because of no activity

While both approaches would work without much effort, I'd prefer the the @opentelemetry/auto-instrumentations-node package specific solution, that would make life easier also for developers that don't use it with opentelemetry-operator.

I hope that people will agree to environment variable naming conventions for disabling nodejs auto-instrumentations. For now Java, Python and .Net have different naming conventions (as mentioned in this comment) and it would be bad if this library implemented its own naming convention that @opentelemetry/auto-instrumentations-node might not start using

[atsu85]

FYI: i created a PR #2745 to address this issue.

@mderazon, could you rename this issue from

Disable @opentelemetry/instrumentation-fs instrumentation

to

Allow disabling @opentelemetry/instrumentation-fs instrumentation

or even better:

Allow disabling nodejs auto-instrumentations via environment variables

so it could be closed after merging my PR without causing confusion if it is now disabled by default or can be disabled