Make NodeJS profiling attachable

[kwisniewski98]

Description

Adds --nodejs-mode=attachable, which injects DSO into already running NodeJS processes.

Related Issue

#418

Motivation and Context

At current state, resolving function addresses in NodeJS requires restarting each process, which might be very hard if not impossible in production. This features allows generating perf maps at runtime.

How Has This Been Tested?

Tested manually in container and as executable. NodeJS targets were tested in both same namespace as gprofiler and in separate namespace (docker container)

Checklist:

• I have read the CONTRIBUTING document.
• I have updated the relevant documentation.
• I have added tests for new logic.

[Jongy]

Looks very good @kwisniewski98 !

I left some comments (did not complete reviewing, will continue this week).

Please add a test like test_nodejs that uses the new attach mode. Also, the target nodejs app should not be started with the jitdump flags like we do now - we can add another Dockerfile, or just control the extra flags passed to node via a parameter when starting the container (so the existing test_nodejs can pass the flags; and your new test won't pass them)

[Jongy]

I ran the CI

[Jongy]

The attach causes this to be printed:

Debugger attached.
Debugger listening on ws://127.0.0.1:9229/9e541850-fa6d-4e4c-b566-97bf6c786205
For help, see: https://nodejs.org/en/docs/inspector

Not too bad but if it can be avoided somehow, that's best.

[kwisniewski98]

The attach causes this to be printed:

Debugger attached.
Debugger listening on ws://127.0.0.1:9229/9e541850-fa6d-4e4c-b566-97bf6c786205
For help, see: https://nodejs.org/en/docs/inspector

Not too bad but if it can be avoided somehow, that's best.

I didn't find any way inside nodeJS to hide that message, Seems like it is printed unconditionally ref

[Jongy]

Finished 4th round

[Jongy]

Reviewed again. Left 3 final comments. Please fix the lint errors as well, and the one comment from earlier that wasn't fixed yet as far as I can tell, and we're good to merge this :)

[Jongy]

LGTM.

Lint errors are what I described in #517 (comment), so I ignore them. I will merge after tests pass.

[Jongy]

@kwisniewski98 only the Dockerifle lint error seems relevant -

/home/runner/work/gprofiler/gprofiler/pyi.Dockerfile:319 SC2086 info: Double quote to prevent globbing and word splitting.

[Jongy]

Also, you can merge from master, I fixed the flake8 issue

[kwisniewski98]

@kwisniewski98 only the Dockerifle lint error seems relevant -

/home/runner/work/gprofiler/gprofiler/pyi.Dockerfile:319 SC2086 info: Double quote to prevent globbing and word splitting.

I've added ignore for that, double quote seems to be not working.

[Jongy]

At last :) Congrats @kwisniewski98 !