Introduce process API

[dmlloyd]

As promised in quarkusio/quarkus#48223, here's the draft Process API.

The tests (so far) pass. I want to add more tests and try replacing some usages in Quarkus itself before I will call this ready to merge, but feel free to review now.

[maxandersen]

is reusing ProcessBuilder name that overlaps with jdk ProcessBuilder a good thing?

asking as I hit that IDE default imported java.lang.ProcessBuilder when pasting code :)

[dmlloyd]

Maybe. I don't know. I thought that any code using this would definitely not be using the JDK one. The fact that the JDK one is in java.lang is a bit annoying though. But I couldn't actually think of any better name... 🤔

[maxandersen]

is this stderr only ? what about stdout?

[dmlloyd]

We could capture stdout here, but doing so would mean adding "tee" support broadly. This can be done, but would require more effort. It's also possible that we could introduce this in the future.

[dmlloyd]

Not implemented, and not sure about relative importance:

• Background process execution
• Terminate-process-gracefully on shutdown (this would not work on Windows, so I'm hesitant)
• Terminate-process-forcefully on shutdown (not sure this is a good idea)
• I/O thread timeouts (implement via interruption)
• General output and error tee support
• Any kind of overall "result" abstraction (if you want to know the success exit code, you have to capture it in your error checker)
• Virtual thread support (this would be done via MR-JAR, to automatically use a VT thread factory if the calling thread is a VT; we'd also need to check to see if process I/O is VT-friendly)
• Incremental environment editing (addEnv(), removeEnv() etc.)
• Debug log of process command name, arguments, output (the concern here is security)

[dmlloyd]

I'm going to provisionally merge this so that I can push up a beta release, which will allow for comprehensive testing and review in Quarkus. We should not release a final version until we have a broad consensus that the API is OK.