build: add cross-compile support (#506)

* build: add cross-compile support

* fix: switch to musl

Author: bernot-dev

.cargo/config.toml

@@ -1,2 +1,8 @@
 [alias]
-xtask = "run --package xtask --bin xtask --"
+xtask = "run --package xtask --bin xtask --"
+
+[target.aarch64-unknown-linux-musl]
+linker = "aarch64-linux-gnu-gcc"
+
+[target.x86_64-unknown-linux-musl]
+linker = "x86_64-linux-gnu-gcc"

.dockerignore

@@ -1,6 +1,5 @@
 # Rust related build artifacts.
 /target
-.cargo/
 wix/
 scripts/
 examples/

Dockerfile

@@ -1,31 +1,33 @@
-
 # The build image
-FROM rust:1.83.0-alpine3.20 AS weaver-build
-RUN apk add musl-dev
+FROM --platform=$BUILDPLATFORM docker.io/rust:1.83.0 AS weaver-build
 WORKDIR /build
+ARG BUILDPLATFORM
+ARG TARGETPLATFORM
 
 # list out directories to avoid pulling local cargo `target/`
 COPY Cargo.toml /build/Cargo.toml
 COPY Cargo.lock /build/Cargo.lock
+COPY .cargo /build/.cargo
 COPY crates /build/crates
 COPY data /build/data
 COPY src /build/src
 COPY tests /build/tests
 COPY defaults /build/defaults
+COPY cross-arch-build.sh /build/cross-arch-build.sh
 
 # Build weaver
-RUN cargo build --release
+RUN ./cross-arch-build.sh
 
 # The runtime image
-FROM alpine:3.20.3
+FROM docker.io/alpine:3.20.3
 LABEL maintainer="The OpenTelemetry Authors"
 RUN addgroup weaver \
   && adduser \
   --ingroup weaver \
   --disabled-password \
   weaver
 WORKDIR /home/weaver
-COPY --from=weaver-build /build/target/release/weaver /weaver/weaver
+COPY --from=weaver-build --chown=weaver:weaver /build/weaver /weaver/weaver
 USER weaver
 RUN mkdir /home/weaver/target
 ENTRYPOINT ["/weaver/weaver"]

cross-arch-build.sh

@@ -0,0 +1,20 @@
+set -exu
+
+if [ "${TARGETPLATFORM}" = "linux/amd64" ]; then
+  RUST_TARGET=x86_64-unknown-linux-musl
+  if [ "${TARGETPLATFORM}" != "${BUILDPLATFORM}" ]; then
+    apt-get update && apt-get install -y gcc-x86-64-linux-gnu
+  fi
+elif [ "${TARGETPLATFORM}" = "linux/arm64" ]; then
+  RUST_TARGET=aarch64-unknown-linux-musl
+  if [ "${TARGETPLATFORM}" != "${BUILDPLATFORM}" ]; then
+    apt-get update && apt-get install -y gcc-aarch64-linux-gnu
+  fi
+else
+  echo "Unsupported target platform: ${TARGETPLATFORM}"
+  exit 1
+fi
+
+rustup target add "${RUST_TARGET}"
+cargo build --release --target="${RUST_TARGET}"
+cp "target/${RUST_TARGET}/release/weaver" .