Document how to set the Buildbarn PATH

[stagnation]

Following the discussion in #532 .

[JakobDegen]

I'm having some trouble parsing this sentence, did a part of it get cut out?

[stagnation]

Good point, thanks! I will revise it.

What I try to say (concisely) is: update whichever of the two paths you use, as you can choose either hardlinking or FUSE. Which for the sake of the example is problably bad. Hardlinking is the simplest but a little slower, we could clarify the example by dropping FUSE. Next, to update the proto file, which is a simple insertion but in a big structure, so here is a jq-style path for where to add it. Unfortunately this cannot be done with yq or jq.
And then, there is the big diff listing because it is still annoying to describe what to do :S.

I hope this is better:

---

Add the environment variables to the worker configs: worker-fuse-ubuntu22-04.jsonnet and worker-hardlinking-ubuntu22-04.jsonnet. The proto configuration specifies a buildDirectories list, with a runner list inside. There is only one runner in each config file. That runner should be modified to have the environment variables values:

environment_variables: {
  PATH: '/bin:/usr/bin:/usr/local/bin',
},

They can be put anywhere in the runner. The example diff below adds them at the end, after workerId.

It is also possible to make a crude insertion with sed:

sed -i \
    '/workerId/i \      environment_variables: { PATH: \'/bin:/usr/bin:/usr/local/bin\'},' \
    docker-compose/config/worker-*-ubuntu22-04.jsonnet

[JakobDegen]

I think your original explanation was fine in principle, I just didn't quite understand the grammatical structure. Something like this would clear it up for me if it's accurate

Add the environment variables to the worker config you want - normally either path1 or path2 - after the workerId field like this:

But the more detailed one is just as good, completely up to you

[JakobDegen]

Thanks!

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