add prod build id fetching

Dockerfile

@@ -34,6 +34,9 @@ COPY --from=builder --chown=nextjs:nodejs /app/public ./public
 COPY --from=builder --chown=nextjs:nodejs /app/package.json ./package.json
 COPY --from=builder --chown=nextjs:nodejs /app/next.config.js ./next.config.js
 
+ARG GIT_REV
+ENV GIT_REV ${GIT_REV}
+
 USER nextjs
 EXPOSE 80
 ENV HOSTNAME "0.0.0.0"

next.config.js

@@ -5,7 +5,8 @@ const nextConfig = {
   generateEtags: true,
   compress: true,
   env: {
-    NEXT_PUBLIC_BUILD_ID: nextBuildId.sync({ dir: __dirname }),
+    NEXT_PUBLIC_BUILD_ID:
+      process.env.GIT_REV || nextBuildId.sync({ dir: __dirname }),
   },
   images: {
     remotePatterns: [