Makes build faster (#12)

#10

Signed-off-by: Takeshi Yoneda <t.y.mathetake@gmail.com>

Dockerfile

@@ -1,28 +1,34 @@
-FROM --platform=$BUILDPLATFORM rust:1.84 AS rust_fetcher
+# This is the example Dockerfile for building the multi arch Envoy image with the Rust dynamic module.
 
-WORKDIR /app
+# Use https://github.com/rust-cross/cargo-zigbuild to cross-compile the Rust library for both x86_64 and aarch64 architectures.
+# We need it because bindgen relies on the sysroot of the target architecture which makes it
+# a bit hairy to cross-compile.
+#
+# If you don't need multi-arch support, you can use simply `FROM rust:x.y.z` and `cargo build` on the host architecture or,
+# compile the shared library on each architecture separately and copy the shared library to the final image.
+FROM --platform=$BUILDPLATFORM ghcr.io/rust-cross/cargo-zigbuild:0.19.8 AS rust_builder
 
-# Cache dependencies by copying only the Cargo files and fetching them on the build platform.
+WORKDIR /build
+
+# bindgen requires libclang-dev.
+RUN apt update && apt install -y clang
+
+# Fetch the dependencies first to leverage Docker cache.
 COPY ./rust/Cargo.toml ./rust/Cargo.lock ./
 RUN mkdir src && echo "" > src/lib.rs
 RUN cargo fetch
 RUN rm -rf src
 
-FROM rust:1.84 AS rust_builder
-
-# We need libclang to do the bindgen.
-RUN apt update && apt install -y clang
-
-# Copy the dependencies from the previous stage.
-WORKDIR /app
-COPY --from=rust_fetcher /usr/local/cargo/git /usr/local/cargo/git
-COPY --from=rust_fetcher /usr/local/cargo/registry /usr/local/cargo/registry
-
-# Then, copy the entire source code and build.
+# Then copy the rest of the source code and build the library.
 COPY ./rust .
-RUN cargo build
+RUN cargo zigbuild --target aarch64-unknown-linux-gnu
+RUN cargo zigbuild --target x86_64-unknown-linux-gnu
+
+RUN cp /build/target/aarch64-unknown-linux-gnu/debug/librust_module.so /build/arm64_librust_module.so
+RUN cp /build/target/x86_64-unknown-linux-gnu/debug/librust_module.so /build/amd64_librust_module.so
 
 # Finally, copy the built library to the final image.
 FROM envoyproxy/envoy-dev:4a113b5118003682833ba612202eb68628861ac6 AS envoy
+ARG TARGETARCH
 ENV ENVOY_DYNAMIC_MODULES_SEARCH_PATH=/usr/local/lib
-COPY --from=rust_builder /app/target/debug/librust_module.so /usr/local/lib/librust_module.so
+COPY --from=rust_builder /build/${TARGETARCH}_librust_module.so /usr/local/lib/librust_module.so

README.md

@@ -31,7 +31,7 @@ cargo clippy -- -D warnings
 cargo fmt --all -- --check
 ```
 
-### Build Envoy + Rust Dynamic Module Docker Image
+### Build Envoy + Example Rust Dynamic Module Docker Image
 
 To build the example modules and bundle them with Envoy, simply run
 
@@ -41,7 +41,7 @@ docker buildx build . -t envoy-with-dynamic-modules:latest [--platform linux/amd
 
 where `--platform` is optional and can be used to build for multiple platforms.
 
-### Run Envoy + Rust Dynamic Module Docker Image
+### Run Envoy + Example Rust Dynamic Module Docker Image
 
 The example Envoy configuration yaml is in [`integration/envoy.yaml`](integration/envoy.yaml) which is also used
 to run the integration tests. Assuming you built the Docker image with the tag `envoy-with-dynamic-modules:latest`, you can run Envoy with the following command: