fix the SOURCE_DATE_EPOCH issue within dockerfile

Author: MoeMahhouk

Dockerfile.reproducible

@@ -12,13 +12,12 @@ ARG RUST_TARGET="x86_64-unknown-linux-gnu"
 COPY . /app
 WORKDIR /app
 
-# Get the latest commit timestamp and set SOURCE_DATE_EPOCH
-RUN SOURCE_DATE_EPOCH=$(git log -1 --pretty=%ct) && \
-    echo "SOURCE_DATE_EPOCH=$SOURCE_DATE_EPOCH" >> /etc/environment
+# Get the latest commit timestamp and set SOURCE_DATE_EPOCH (default it to 0 if not passed)
+ARG SOURCE_DATE=0
 
 # Set environment variables for reproducibility
-ARG RUSTFLAGS="-C target-feature=+crt-static -C link-arg=-Wl,--build-id=none -Clink-arg=-static-libgcc -C metadata='' --remap-path-prefix $(pwd)=."
-ENV SOURCE_DATE_EPOCH=$SOURCE_DATE_EPOCH \
+ARG RUSTFLAGS="-C link-arg=-Wl,--build-id=none -C metadata='' --remap-path-prefix $(pwd)=."
+ENV SOURCE_DATE_EPOCH=$SOURCE_DATE \
     CARGO_INCREMENTAL=0 \
     LC_ALL=C \
     TZ=UTC \
@@ -31,14 +30,13 @@ ARG FEATURES="gnosis,slasher-lmdb,slasher-mdbx,slasher-redb,jemalloc"
 ARG PROFILE="reproducible"
 
 # Build the project with the reproducible settings
-RUN . /etc/environment && \
-    cargo build --bin lighthouse \
+RUN cargo build --bin lighthouse \
     --features "${FEATURES}" \
     --profile "${PROFILE}" \
     --locked \
     --target "${RUST_TARGET}"
 
-RUN . /etc/environment && mv /app/target/${RUST_TARGET}/${PROFILE}/lighthouse /lighthouse
+RUN mv /app/target/${RUST_TARGET}/${PROFILE}/lighthouse /lighthouse
 
 # Create a minimal final image with just the binary
 FROM gcr.io/distroless/cc-debian12:nonroot-6755e21ccd99ddead6edc8106ba03888cbeed41a

Makefile

@@ -70,6 +70,9 @@ build-lcli-x86_64:
 build-lcli-aarch64:
 	cross build --bin lcli --target aarch64-unknown-linux-gnu --features "portable" --profile "$(CROSS_PROFILE)" --locked
 
+# extracts the current source date for reproducible builds
+SOURCE_DATE := $(shell git log -1 --pretty=%ct)
+
 # Default image for x86_64
 RUST_IMAGE_AMD64 ?= rust:1.82-bullseye@sha256:ac7fe7b0c9429313c0fe87d3a8993998d1fe2be9e3e91b5e2ec05d3a09d87128
 
@@ -78,6 +81,7 @@ build-reproducible-x86_64:
 	DOCKER_BUILDKIT=1 docker build \
 		--build-arg RUST_TARGET="x86_64-unknown-linux-gnu" \
 		--build-arg RUST_IMAGE=$(RUST_IMAGE_AMD64) \
+		--build-arg SOURCE_DATE=$(SOURCE_DATE) \
 		-f Dockerfile.reproducible \
 		-t lighthouse:reproducible-amd64 .
 
@@ -90,6 +94,7 @@ build-reproducible-aarch64:
 		--platform linux/arm64 \
 		--build-arg RUST_TARGET="aarch64-unknown-linux-gnu" \
 		--build-arg RUST_IMAGE=$(RUST_IMAGE_ARM64) \
+		--build-arg SOURCE_DATE=$(SOURCE_DATE) \
 		-f Dockerfile.reproducible \
 		-t lighthouse:reproducible-arm64 .