chore(portability): Support all platforms without 64 bit atomics

[navaati]

Notably, RISC-V 32 for ESP32-C3 chips. Fixes #201. Closes #202.

[mxinden]

target_has_atomic is neat! Thank you @navaati. Good work.

Do you have experience cross-compiling Rust for RISC-V? If so, want to add another target to the matrix here within this pull request?

client_rust/.github/workflows/rust.yml

Lines 160 to 178 in bf196d7

	cross-compile:
	name: Cross compile
	runs-on: ubuntu-latest
	strategy:
	matrix:
	target:
	- armv7-unknown-linux-gnueabihf
	- powerpc-unknown-linux-gnu
	- powerpc64-unknown-linux-gnu
	- wasm32-unknown-unknown
	steps:
	- uses: actions/checkout@v2
	- uses: dtolnay/rust-toolchain@stable
	with:
	target: ${{ matrix.target }}
	# Note that this does not test the `protobuf` feature (for now). See reasoning in https://github.com/prometheus/client_rust/pull/98/.
	- run: cargo check --target=${{ matrix.target }}

[navaati]

Ah, yes. It very much depends on the support from that Github Action you use, which I’m not super familiar with.

The target I actually use, riscv32imc-esp-espidf, is Tier 3 and I’m not sure it’ll be supported (among other things, it requires building the std lib), the closest would be riscv32imc-unknown-none-elf but it is a no-std target so it makes no sense here…

I’ll put out a commit with riscv32imc-esp-espidf in the list and we’ll see how it goes, can you allow the CI to run once it’s here ?

[mxinden]

I’ll put out a commit with riscv32imc-esp-espidf in the list and we’ll see how it goes, can you allow the CI to run once it’s here ?

Yep. Will do. Thanks.

[mxinden]

Also note, you will need to sign off your commits, see failing CI step.

[mxinden]

Just triggered a CI run.

[navaati]

Just triggered a CI run.

Thanks. And it fails, as I feared the target needs the rust-std component and it’s nightly only… But you have powerpc and wasm32 which are 32-bit platforms, so it should be ok.

Should I just drop that CI commit and we go as is ?

[navaati]

I’ve done that. Let’s merge as-is if you’re good with it !

[mxinden]

🙏