Can't build on Alpine: target aarch64-unknown-linux-musl does not support these crate types

[gitmalong]

Dockerfile

FROM rust:alpine3.14 as builder
WORKDIR /usr/src/myapp
COPY src_rust/ .
RUN npm run build-release --prefix my-app-rust-bindings

Error

error: cannot produce cdylib for `my-app-rust-bindings v0.1.0 (/usr/src/myapp/my-app-rust-bindings)` as the target `aarch64-unknown-linux-musl` does not support these crate types
Did not copy "cdylib:my-app-rust-bindings"

While the local build on my machine works with npm run build-release --prefix my-app-rust-bindings

[kjvalencik]

Building cdylib with Rust is not fully supported. See rust-lang/rust#59302 for more details.

There is some support by using the crt-static feature to switch to dynamic linking the C runtime (default is static). This can be set either with the environment variable RUSTFLAGS="-C target-feature=-crt-static" or with a .cargo/config.toml. Please note that you will also need apk add musl-dev to build with this flag.

[build]
rustflags = ["-C", "target-feature=-crt-static"]

After adding that flag, I am able to successfully build and execute a simple Neon module. However, since this is not a fully implemented feature, you may run into other issues. For dockerizing Neon apps, I highly recommend using debian:stable-slim docker container. It's nearly as small alpine, but since it's glibc based instead of musl, it won't have as many issues building native code.

Thanks for your interest. I'm going to close this issue since it is a limitation of Rust and outside the scope of Neon.

[rtritto]

@kjvalencik currently what's the best distro to use with Docker and build with cross-compiling all tier 1 platforms?
Alpine still have some issue?

[kjvalencik]

I believe alpine works these days with cdylib targets.