Is it possible to make vscode/RLS use a cross-compiler in a Docker container?

I'm currently working on OSX, cross-compiling my code targeting Raspberry Pi 3 on this docker container: https://github.com/dlecan/rust-crosscompiler-arm
I've set up a docker command that mounts the source and cargo registry inside the container, so running the script is (roughly) equivalent to running cargo.

This works fine, but rls-vscode doesn't work, since my code doesn't compile for OSX.

Is it possible to set up vscode/RLS/cargo in such a way that it would compile using this setup on save?

Is it possible to set up cargo in such a way that I could invoke my build command through cargo?

Alternatively, is there a better way to cross-compile for Raspberry Pi?

It depends on your dependencies. If all your dependencies are native rust crates, i.e. do not link to C-libraries, you can simply compile your project from cargo by invocing --target=armv7-unknown-linux-gnueabihf (you need to add the target first with rustup target add armv7-unknown-linux-gnueabihf).
If you have C-dependencies then things get messy, like it is stated in your referenced git.

You can read more about cross-compiling in Rust at this git.

Thank you for your answer. I have tried what you described before, and unfortunately that doesn't work. This got me thinking, however, and I found something that does work for my simple program:

  1. rustup target add armv7-unknown-linux-musleabihf
  2. brew install arm-linux-gnueabihf-binutils
  3. Add the following to .cargo/config:
[build]
target = "armv7-unknown-linux-musleabihf"
[target.armv7-unknown-linux-musleabihf]
linker = "arm-linux-gnueabihf-ld
  1. cargo build

I'm uncertain about the applicability specifically for cross-compilation, but you could look into the vscode "remote development" addon. That includes options to run the vscode backend in the docker container, via ssh, or in WSL.