Docker

You can containerize this stack and deploy it as a single container using Docker, or as a part of a group of containers using docker-compose.

Please note that Next.js requires a different process for buildtime (available in the frontend, prefixed by NEXT_PUBLIC) and runtime environment, server-side only, variables. In this demo we are using two variables, DATABASE_URL (used by the server) and NEXT_PUBLIC_CLIENTVAR (used by the client). Pay attention to their positions in the Dockerfile, command-line arguments, and docker-compose.yml.

In your next.config.mjs, add the standalone output-option to your config:

  export default defineNextConfig({
    reactStrictMode: true,
    swcMinify: true,
+   output: "standalone",
  });

Remove the env-import from next.config.mjs:

- import { env } from "./src/env/server.mjs";

Create a .dockerignore file with the following contents:

.dockerignore

.env
Dockerfile
.dockerignore
node_modules
npm-debug.log
README.md
.next
.git

Create a Dockerfile with the following contents:

Dockerfile

########################
#         DEPS         #
########################

# Install dependencies only when needed
# TODO: re-evaluate if emulation is still necessary on arm64 after moving to node 18
FROM --platform=linux/amd64 node:16-alpine 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 openssl
WORKDIR /app

# Install Prisma Client - remove if not using Prisma
copy prisma ./

# Install dependencies based on the preferred package manager
COPY package.json yarn.lock* package-lock.json* pnpm-lock.yaml* ./
RUN \
  if [ -f yarn.lock ]; then yarn --frozen-lockfile; \
  elif [ -f package-lock.json ]; then npm ci; \
  elif [ -f pnpm-lock.yaml ]; then yarn global add pnpm && pnpm i; \
  else echo "Lockfile not found." && exit 1; \
  fi

########################
#        BUILDER       #
########################

# Rebuild the source code only when needed
# TODO: re-evaluate if emulation is still necessary on arm64 after moving to node 18
FROM --platform=linux/amd64 node:16-alpine AS builder

ARG DATABASE_URL
ARG NEXT_PUBLIC_CLIENTVAR

WORKDIR /app
COPY --from=deps /app/node_modules ./node_modules
COPY . .

# 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 build; \
  elif [ -f package-lock.json ]; then npm run build; \
  elif [ -f pnpm-lock.yaml ]; then yarn global add pnpm && pnpm run build; \
  else echo "Lockfile not found." && exit 1; \
  fi

########################
#        RUNNER        #
########################

# Production image, copy all the files and run next
# TODO: re-evaluate if emulation is still necessary after moving to node 18
FROM --platform=linux/amd64 node:16-alpine AS runner
# WORKDIR /usr/app
WORKDIR /app

ENV NODE_ENV production
# Uncomment the following line in case you want to disable telemetry during runtime.
# ENV NEXT_TELEMETRY_DISABLED 1

RUN addgroup --system --gid 1001 nodejs
RUN adduser --system --uid 1001 nextjs

COPY --from=builder /app/next.config.mjs ./
COPY --from=builder /app/public ./public
COPY --from=builder /app/package.json ./package.json

# 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

ENV PORT 3000

CMD ["node", "server.js"]

To build and run this image locally, run:

docker build -t ct3a -e NEXT_PUBLIC_CLIENTVAR=clientvar .
docker run -p 3000:3000 -e DATABASE_URL="database_url_goes_here" ct3a

You can also use a PaaS such as Railway’s automated Dockerfile deployments to deploy your app.

Docker Compose

You can also use docker compose to build the image and run the container.

Follow steps 1-4 above

Create a docker-compose.yml file with the following:

docker-compose.yml

version: "3.9"
services:
  app:
    platform: "linux/amd64"
    build:
      context: .
      dockerfile: Dockerfile
      args:
        NEXT_PUBLIC_CLIENTVAR: "clientvar"
    working_dir: /app
    ports:
      - "3000:3000"
    image: t3-app
    environment:
      - DATABASE_URL=database_url_goes_here

Run this using docker compose up.

Docker

Docker Compose

Further reading