[Task] Build 64bit variant if available

[foosel]

The task

We currently only fetch and build from the 32bit variant of the input image. It might be a good idea to also check during the build if there's a 64bit variant as well and if so build that too and include its data in the rpi-imager.json snippet.

The downside here is a massive increase of testing, as that will require flashing both images in serial - or on two test devices on the testrig in parallel. Will require some testing to make work properly.

Verification

• I'm a maintainer or collaborator of OctoPi-UpToDate and allowed to use this issue type

[oxivanisher]

Is the testing a manual step? I could maybe help to improve this.

[foosel]

No, testing is an automatic step, but it still needs to be created against the testrig sitting on my desk. The challenge here is that there are three Pi3b's as test units, only one can get actively flashed at a time (bandwidth issue), and usually I only target the third one (PiC) with automated tests via CI to ensure I always have two available for running local tests against manually. To be able to test both 32bit and 64bit however, I'd also have to double the test run time (flashing the same test unit twice, once with 32bit, once with 64bit) or reduce the number of available safe devices to use to one (flash PiB and PiC as concurrently as possible and run tests in parallel). It'll probably end up being the second option, and for that I need to experiment a bit with workflows. Will also need a bit of work to figure out how to build both 32bit and 64bit variants in parallel, if a 64bit variant exists, and in all triggering scenarios, but that's another problem.

In short: I fear that's something that requires direct access to my testrig here, and is thus not something that someone else can easily help me.

[oxivanisher]

I see, that makes sense. If I can help you with ansible or bash knowhow or if another raspi would help, just ask. :)