Feature Req: Set the target directory

[flukejones]

I was evaluating how I could use Neon to leverage Rust for use on AWS Lambdas and bumped up against a small issue.

The Lambdas require building against amazon Linux if you want to use native code due to the Amazon glibc being a different version to most Linux distros - as such I do all my compilation for them through a Docker image. This results in the final compiled libraries being located in target/x86_64-unknown-linux-gnu/<release/debug> though, and so the neon build (or npm install) fails since it can't find the library in target/release.

Is there a way to set the directory that neon build gets the compiled library from?

[muditsaurabh]

Please refer to https://dev.to/kayis/rust-on-aws-lambda-with-neon--cloud9--4el7

[flukejones]

That is helpful, but not convenient at all for local development.

[kjvalencik]

Would something like this work?

FROM lambci/lambda:build-nodejs6.10

RUN curl https://sh.rustup.rs -sSf | sh /dev/stdin -y

ENV PATH="$PATH:/root/.cargo/bin"

docker build -t lambda-neon-dev .

docker run --rm \
    -w /src \
    -v $(pwd):/src \
    -v $(pwd)/node_modules/.cargo/registry:/root/.cargo/registry \
  lambda-neon-dev npm install

I don't use lambda, but I do all of my development in docker and this pattern works well. You can substitute any preferered location for the shared cargo cache. It can even be removed, but keeping it improves build times.

[dherman]

@Luke-Nukem Totally legit request! Right now we're just inferring the target info from the current machine, which means we don't support cross-compilation. I've filed an RFC issue here:

neon-bindings/rfcs#16

In the meantime can any of the suggestions above get you unstuck? If not we can try to prioritize getting the CLI options fleshed out and implemented.

[kjvalencik]

Workaround is using .cargo/config to set target directory.

[kjvalencik]

This was fixed in neon-cli, but is also not relevant for cargo-cp-artifact which reads metadata directly from cargo output.