fix: support multi-arch musl builds in Dockerfile

.github/workflows/publish-docker.yml

@@ -1,4 +1,4 @@
-name: Create and publish a Docker image
+name: Publish Docker Images
 
 on:
   push:
@@ -18,8 +18,10 @@ env:
 # There is a single job in this workflow. It's configured to run on the latest available version of Ubuntu.
 jobs:
   build-and-push-image:
+    name: Build and push Docker image
     runs-on: ubuntu-latest
     strategy:
+      fail-fast: false
       matrix:
         os: [ 'scratch', 'ubuntu', 'alpine' ]
     # Sets the permissions granted to the `GITHUB_TOKEN` for the actions in this job.

Dockerfile

@@ -21,8 +21,9 @@ FROM rust:latest AS musl-builder
 
     WORKDIR /worker
     COPY ./ .
-    RUN rustup target add x86_64-unknown-linux-musl 
+    RUN ARCH=$(rustc -vV | sed -nE 's/host:\s*([^-]+).*/\1/p') \
-    RUN cargo build --release --target x86_64-unknown-linux-musl
+        && rustup target add "$ARCH-unknown-linux-musl" \
+        && cargo build --release --target "$ARCH-unknown-linux-musl"
 
     RUN mkdir /.etc \
         && touch /.etc/resolv.conf \
@@ -35,7 +36,7 @@ FROM rust:latest AS musl-builder
 ####################################################################################################
 FROM alpine:latest AS tun2proxy-alpine
 
-    COPY --from=musl-builder /worker/target/x86_64-unknown-linux-musl/release/tun2proxy-bin /usr/bin/tun2proxy-bin
+    COPY --from=musl-builder /worker/target/*/release/tun2proxy-bin /usr/bin/tun2proxy-bin
 
     ENTRYPOINT ["/usr/bin/tun2proxy-bin", "--setup"]
 
@@ -55,6 +56,6 @@ FROM scratch AS tun2proxy-scratch
 
     COPY --from=musl-builder ./tmp /tmp
     COPY --from=musl-builder ./etc /etc
-    COPY --from=musl-builder /worker/target/x86_64-unknown-linux-musl/release/tun2proxy-bin /usr/bin/tun2proxy-bin
+    COPY --from=musl-builder /worker/target/*/release/tun2proxy-bin /usr/bin/tun2proxy-bin
 
     ENTRYPOINT ["/usr/bin/tun2proxy-bin", "--setup"]