Update Contributing docs

[ShohamBit]

1. Explain what the PR does

This PR is about #4406

• remove and add the documentation to the guidelines
• add sections on how to contribute to tracee source code
• improve docs on how to build tracee
• improve docs on how to build environment

"Replace me with make check-pr output"

2. Explain how to test it

Read the docs and check if its properly align with tracee design

3. Other comments

Close #4406

[geyslan]

First pass.

[geyslan]

I believe that's better to guide the contributor to always use VM and/or the docker images for that, so the formatting will be aligned with what we expect. But, a huge but, currently alpine image lack some tooling like clang-format-12 and ubuntu image is crashing when running check-pr - they are focused to building and release process.

We have some specific docker images for helping in the contribute process as:

You might notice that Makefile.man, by instance, has a pattern to run the Dockerfile.man.

Said that, perhaps bringing a Dockerfile.checkers would be the solution here.

[ShohamBit]

I don't think I completely understand what you are saying.
Do you say that we should encourage people to run the docker file or container instead of locally?

Also, do you say we should prefer to use the Dockerfiles or that the make file run the docker file?

[geyslan]

Do you say that we should encourage people to run the docker file or container instead of locally?

Yep, as it avoids conflicts with the contributor's host system.

Also, do you say we should prefer to use the Dockerfiles or that the make file run the docker file?

Makefile should run docker under the hood for us. As it does in protoc, man rules etc.

[geyslan]

Suggested change

	9. Build with embedded metrics (pprof) by setting `METRICS=1`
	9. Build enabling BPF metrics by setting `METRICS=1`.
	BPF metrics are only available if the BPF object is built with `METRICS` debug flag defined.

Just a suggestion to explain what it really enables:

tracee/pkg/ebpf/c/tracee.bpf.c

Line 5574 in f8963e0

#ifdef METRICS

Since we avoid having code in BPF as much as possible to reduce cpu time, metrics coming from it are disabled by default until requested otherwise.