Pass pid to UprobeOptions

[RonFed]

This PR passes the PID to UprobeOptions.
The scenario where this makes a difference is when multiple processes use the same executable, we want to make sure we only probe the relevant process.

[damemi]

Thanks @RonFed, do you think it would be possible to add a pid fork in the e2e samples to test this?

also sorry to nag about tests... our infra is lacking and it should be a lot easier than it currently is to test changes like this

[RonFed]

Thanks @RonFed, do you think it would be possible to add a pid fork in the e2e samples to test this?

also sorry to nag about tests... our infra is lacking and it should be a lot easier than it currently is to test changes like this

I'm in favor of improving our tests, however I can't think of a way to test this case without a big refactor to the test infra.
Currently in sample-job.yml we use OTEL_GO_AUTO_TARGET_EXE which should potentially cause the instrumentation of every process running the specified executable. So assuming 2 processes using the same binary the only way to configure the instrumentation to a specific one is passing the InstrumentationOption of WithPID (we don't have an equielent env var for this option as it does not really make sense for env var to contain pid I think).
If you have something in mind that we can do with the current infra to test this case, I'll be happy to add it.

[grcevski]

LGTM! This looks good to me.

[damemi]

So assuming 2 processes using the same binary the only way to configure the instrumentation to a specific one is passing the InstrumentationOption of WithPID (we don't have an equielent env var for this option as it does not really make sense for env var to contain pid I think).

Ah, I thought this PR would automatically instrument every process under an executable.

So this really only impacts users that are directly creating an Instrumentation object? (Fwiw, we should expose those options to users of the agent image too)