Reduce bloat in docker image

Dockerfile

@@ -1,58 +1,69 @@
-# Double-container Dockerfile for separated build process.
+# https://github.com/vercel/next.js/blob/canary/examples/with-docker/Dockerfile
+FROM node:18-alpine AS base
 
-FROM node:18-alpine AS deps
-
-# libc is needed for deps
+# Install dependencies only when needed
+FROM base AS deps
+# Check https://github.com/nodejs/docker-node/tree/b4117f9333da4138b03a546ec926ef50a31506c3#nodealpine to understand why libc6-compat might be needed.
 RUN apk add --no-cache libc6-compat
-
-# Copy over ONLY the package.json and package-lock.json
 WORKDIR /app
-COPY package*.json ./
-RUN npm ci 
 
-# END DEPS IMAGE
+# Install dependencies based on the preferred package manager
+COPY package.json yarn.lock* package-lock.json* pnpm-lock.yaml* .npmrc* ./
+RUN \
+  if [ -f yarn.lock ]; then yarn --frozen-lockfile; \
+  elif [ -f package-lock.json ]; then npm ci; \
+  elif [ -f pnpm-lock.yaml ]; then corepack enable pnpm && pnpm i --frozen-lockfile; \
+  else echo "Lockfile not found." && exit 1; \
+  fi
 
-# container to handle our Build
-FROM node:18-alpine AS BUILD_IMAGE
 
-# Set up our work directory again
+# Rebuild the source code only when needed
+FROM base AS builder
 WORKDIR /app
-
-# Bring over installed deps and source code
 COPY --from=deps /app/node_modules ./node_modules
 COPY . .
-COPY .env.local .
 
-RUN npm run build
+# Next.js collects completely anonymous telemetry data about general usage.
+# Learn more here: https://nextjs.org/telemetry
+# Uncomment the following line in case you want to disable telemetry during the build.
+# ENV NEXT_TELEMETRY_DISABLED=1
 
+RUN \
+  if [ -f yarn.lock ]; then yarn run build; \
+  elif [ -f package-lock.json ]; then npm run build; \
+  elif [ -f pnpm-lock.yaml ]; then corepack enable pnpm && pnpm run build; \
+  else echo "Lockfile not found." && exit 1; \
+  fi
 
-# END OF BUILD_IMAGE
+# Production image, copy all the files and run next
+FROM base AS runner
+WORKDIR /app
 
-# This starts our application's run image - the final output of build.
-FROM node:18-alpine
+ENV NODE_ENV=production
+# Uncomment the following line in case you want to disable telemetry during runtime.
+# ENV NEXT_TELEMETRY_DISABLED=1
 
-ENV NODE_ENV production
+RUN addgroup --system --gid 1001 nodejs
+RUN adduser --system --uid 1001 nextjs
 
-RUN addgroup -g 1001 -S nodejs
-RUN adduser -S nextjs -u 1001
+COPY --from=builder /app/public ./public
 
-# Pull the built files out of BUILD_IMAGE - we need:
-# 1. the package.json and yarn.lock
-# 2. the Next build output and static files
-# 3. the node_modules.
-WORKDIR /app
-COPY --from=BUILD_IMAGE --chown=nextjs:nodejs /app/package*.json ./
-COPY --from=BUILD_IMAGE --chown=nextjs:nodejs /app/node_modules ./node_modules
-COPY --from=BUILD_IMAGE --chown=nextjs:nodejs /app/public ./public
-COPY --from=BUILD_IMAGE --chown=nextjs:nodejs /app/.next ./.next
+# Set the correct permission for prerender cache
+RUN mkdir .next
+RUN chown nextjs:nodejs .next
 
-# 4. the next.config.js
-# 5. the .env.local
-COPY --from=BUILD_IMAGE --chown=nextjs:nodejs /app/next.config.js  ./
-COPY --from=BUILD_IMAGE --chown=nextjs:nodejs /app/.env.local  ./
+# Automatically leverage output traces to reduce image size
+# https://nextjs.org/docs/advanced-features/output-file-tracing
+COPY --from=builder --chown=nextjs:nodejs /app/.next/standalone ./
+COPY --from=builder --chown=nextjs:nodejs /app/.next/static ./.next/static
 
 USER nextjs
 
 EXPOSE 3000
 
-CMD [ "npm", "start" ]
+ENV PORT=3000
+
+# server.js is created by next build from the standalone output
+# https://nextjs.org/docs/pages/api-reference/next-config-js/output
+ENV HOSTNAME="0.0.0.0"
+CMD ["node", "server.js"]

next.config.js

@@ -8,6 +8,7 @@ const securityHeaders = [
 ];
 
 module.exports = {
+	output: 'standalone',
 	i18n: {
 		locales: ["en"],
 		defaultLocale: "en",