Dockerize your React app

Hey, welcome back. This article is part of the Dockerize series, make sure to checkout the Introduction where I go over some concepts we are going to use.

Today we'll dockerize our React application by taking advantage of builder pattern with multi stage builds for optimization!

I've also made a video, if you'd like to follow along

Project setup

I've initialized a pretty standard react project using the default create react app (CRA) template.

All the code from this article will be available in this repo

├── node_modules
├── public
│   ├── favicon.ico
│   ├── index.html
│   ├── manifest.json
│   └── robots.txt
├── src
│   ├── App.css
│   ├── App.js
│   ├── index.css
│   ├── index.js
│   └── logo.svg
├── package.json
└── yarn.lock

For development

Let's start by adding a Dockerfile

FROM node:14-alpine AS development
ENV NODE_ENV development
# Add a work directory
WORKDIR /app
# Cache and Install dependencies
COPY package.json .
COPY yarn.lock .
RUN yarn install
# Copy app files
COPY . .
# Expose port
EXPOSE 3000
# Start the app
CMD [ "yarn", "start" ]

Add a .dockerignore, this will help us ignore node_modules, .env etc

**/node_modules
**/npm-debug.log
build

Let's create a docker-compose.dev.yml. Here we'll also mount our code in a volume so that we can sync our changes with the container while developing.

version: "3.8"

services:
  app:
    container_name: app-dev
    image: app-dev
    build:
      context: .
      target: development
    volumes:
      - ./src:/app/src
    ports:
      - 3000:3000

Let's start our react app for development!

docker-compose -f docker-compose.dev.yml up

We can also add it to our package.json

"dev": "docker-compose -f docker-compose.dev.yml up"

we can use the -d flag to run in daemon mode

Let's check our container!

docker ps

REPOSITORY          TAG                   IMAGE ID       CREATED              SIZE
app-dev            latest                5064f3e40c97   About a minute ago    436MB

Over 400mb!! Don't worry, this is just for development. We'll optimize our production build with builder pattern!

For production

We'll use nginx to serve our static assets and will help resolve routes when we're using React Router or any kind of routing.

Note: Personally, I do not recommend using static server packages like serve in production, nginx gives us much more performance and control

Let's create a nginx.conf

server {
  listen 80;

  location / {
    root /usr/share/nginx/html/;
    include /etc/nginx/mime.types;
    try_files $uri $uri/ /index.html;
  }
}

Let's update our Dockerfile for production

FROM node:14-alpine AS builder
ENV NODE_ENV production
# Add a work directory
WORKDIR /app
# Cache and Install dependencies
COPY package.json .
COPY yarn.lock .
RUN yarn install --production
# Copy app files
COPY . .
# Build the app
RUN yarn build

# Bundle static assets with nginx
FROM nginx:1.21.0-alpine as production
ENV NODE_ENV production
# Copy built assets from builder
COPY --from=builder /app/build /usr/share/nginx/html
# Add your nginx.conf
COPY nginx.conf /etc/nginx/conf.d/default.conf
# Expose port
EXPOSE 80
# Start nginx
CMD ["nginx", "-g", "daemon off;"]

Let's add a docker-compose.prod.yml file

version: "3.8"

services:
  app:
    container_name: app-prod
    image: app-prod
    build:
      context: .
      target: production

Build production image

docker-compose -f docker-compose.prod.yml build

Let's check out our built production image

docker images

Using builder pattern we reduced out image size to just ~23mb!!

REPOSITORY          TAG                   IMAGE ID       CREATED              SIZE
app-prod           latest                c5db8d308bb9   About a minute ago   23.1MB

let's start our production container on port 80 with the name react-app

docker run -p 80:80 --name react-app app-prod

Optimizing static assets (Bonus)

You can also add the following inside the location block to introduce caching for our static assets and javascript bundle.

You can refer this guide to dive deep into optimizing

# Cache static assets
location ~* \.(?:jpg|jpeg|gif|png|ico|svg)$ {
  expires 7d;
  add_header Cache-Control "public";
}

# Cache css and js bundle
location ~* \.(?:css|js)$ {
  add_header Cache-Control "no-cache, public, must-revalidate, proxy-revalidate";
}