According to the person who did the python2.7 Plan 9 port, python3 has more dependencies on GCC or Clang (both unavailable on Plan 9), so getting that working would not be trivial.

As for virtualisation, I can only speak for plan9-arm, maybe @0intro can comment about other platforms.

The plan9-arm builders are real hardware (currently a cluster of Raspbery Pi 4 boards); to my knowledge Plan 9 hasn't been ported to qemu for ARM. In any case, I don't think testing Go in a virtual machine is the same as testing on real hardware. The most interesting bugs are usually the ones that depend on timing or caches or other nuances which are likely to be simplified away by emulation.

Do the tasks run by the LUCI bot need to interact with each other (apart from through the shared file system)? If not, it should be feasible to add a linux machine to the plan9-arn cluster to run LUCI bots, which would do a remote execution of tasks on a Plan 9 machine (sharing the bot's file sysem) in place of local execution as a subprocess.

How is testing going to be done for things like android and iOS, which presumably aren't able to run a python3 bot?

How is testing going to be done for things like android and iOS, which presumably aren't able to run a python3 bot?

I would expect that the android OS can run a python3 executable directly, although I would also expect that the LUCI bot will run on a Linux host machine and send commands to an emulator to run the tests. (That more closely mimics what a typical Android developer would experience using Go anyway.)

The ios builder currently uses a virtualized environment provided by Corellium, which allows it to exec programs that would normally be disallowed by iOS, presumably including python3.

Adding a Linux machine that sends remote commands to a Plan9 instance sounds like a reasonable architecture to me.

Yeah, that sounds viable if you're willing to maintain the extra hop. We'll have to add some kind of interceptor logic to our build script, but that doesn't seem prohibitive.

I think the easiest way would indeed be to execute the commands in a remote Plan 9 instance, running in either a virtual machine (386 and amd64) or on real hardware (arm).

@heschi Could you indicate where the build scripts are located? I'd like to take a look and see how this could be achieved.

I think the idea would be to execute the commands remotely (think ssh glenda@plan9 ls /), then retrieve the output.

Gentle reminder -- we'd like to proceed with moving Plan 9 builders to LUCI, but we're somewhat in the dark. I've found https://chromium.googlesource.com/infra/luci/luci-py -- is this the relevant source or does golang have its own fork? The documentation in that repository refers to "device bots", which is I think what we need, because the Plan 9 tests will run on devices or qemu instances separate from the (linux) platform where the swarming bot runs. It would be helpful to see documentation on setting up a device bot, and -- as @0intro asked a few months ago -- to see examples of how existing build scripts work. I'm guessing android will be the most similar. Also in #63599 a problem launching the swarming bot was reported; we are stalled waiting for a response to that too.