name: 'Build Static Binary'
description: 'Build a statically-linked Linux binary using musl'

runs:
  using: 'composite'
  steps:
    - name: Install dependencies
      shell: sh
      run: |
        apk add --no-cache \
          musl-dev libpcap-dev pkgconfig build-base perl \
          elfutils-dev zlib-dev zlib-static zstd-dev zstd-static \
          clang llvm linux-headers git
        rustup component add rustfmt

    - name: Build static binary
      shell: sh
      env:
        # -C strip=symbols: Strip debug symbols for smaller binary
        # -C link-arg=-l:libzstd.a: Fix elfutils 0.189+ zstd dependency (libbpf/bpftool#152)
        RUSTFLAGS: "-C strip=symbols -C link-arg=-l:libzstd.a"
      run: cargo build --release

    - name: Verify static linking
      shell: sh
      run: |
        file target/release/rustnet
        # Use file command to verify (ldd behaves differently inside Alpine)
        file target/release/rustnet | grep -q "static.* linked" || \
          (echo "ERROR: Binary is not statically linked" && exit 1)