feat(docker): Optimize build for cross-compilation and caching deps

Author: FoxxMD

.dockerignore

@@ -1,5 +1,6 @@
 /target/
-Cargo.lock
 .env
 .git
-docker/
+docker/
+.devcontainer/
+.vscode/

docker/Dockerfile

@@ -2,13 +2,29 @@ FROM rust:1.90-bookworm as Builder
 
 ENV RUST_LOG=info,docker_proxy_filter=debug
 
-WORKDIR /usr/src/app
-COPY . .
+WORKDIR /app
 
+RUN cargo init
 
-RUN cargo install --target x86_64-unknown-linux-gnu --path .
+COPY Cargo.lock Cargo.toml ./
+
+# build dummy project with dependencies to get them compiled and cached
+RUN cargo build --release --target $(rustc --print host-tuple)
+
+# copy full app code
+COPY src/ src/
+# updated modified timestamp so build runs again
+RUN touch src/main.rs
+
+# build full app to host arch and copy to generic location
+RUN export ARCH=$(rustc --print host-tuple); \
+    cargo build --release --target $ARCH \
+    && mkdir build \
+    && cp target/$ARCH/release/docker-proxy-filter build/docker-proxy-filter
 
 FROM debian:bookworm-slim
+# need ssl for web server
 RUN apt-get update && apt-get upgrade -y && apt-get install openssl -y && apt clean && rm -rf /var/lib/apt/lists/*
-COPY --from=builder /usr/src/app/target/x86_64-unknown-linux-gnu/release/docker-proxy-filter /usr/local/bin/docker-proxy-filter
+# copy built app from generic location
+COPY --from=builder /app/build/docker-proxy-filter /usr/local/bin/docker-proxy-filter
 CMD ["docker-proxy-filter"]