build: Use commit timestamp for reproducible builds

Author: sheurich

.github/workflows/release.yml

@@ -43,7 +43,9 @@ jobs:
       - name: Set version output
         id: version
         run: |
-          VERSION="${{ matrix.GO_VERSION }}.$(date +%s)"
+          # Use commit timestamp for reproducible builds
+          COMMIT_TIMESTAMP="$(git show -s --format=%ct HEAD)"
+          VERSION="${{ matrix.GO_VERSION }}.${COMMIT_TIMESTAMP}"
           echo "version=${VERSION}" >> $GITHUB_OUTPUT
 
       - name: Build Boulder container and .deb

tools/container-build.sh

@@ -13,7 +13,9 @@ if [ -z "${GO_VERSION}" ] ; then
 fi
 
 COMMIT_ID="$(git rev-parse --short=8 HEAD)"
-VERSION="${GO_VERSION}.$(date +%s)"
+# Use commit timestamp for reproducible builds
+COMMIT_TIMESTAMP="$(git show -s --format=%ct HEAD)"
+VERSION="${GO_VERSION}.${COMMIT_TIMESTAMP}"
 
 # Determine what architecture to build for
 if [ -n "${DOCKER_DEFAULT_PLATFORM}" ]; then