NodeJS Multistage Build

Docker multi-stage builds are a powerful tool that can significantly improve the build time and efficiency of Docker images. They work by breaking the build process into multiple stages, each of which performs a specific task. This allows you to create images that are smaller and more secure, as they only contain the dependencies that are necessary for the desired functionality of the final application.

Why use multi-stage builds for Node.js applications?

There are a number of benefits to using multi-stage builds for Node.js applications, including:

• Reduced image size: Multi-stage builds allow you to create images that are smaller and more efficient, as they only contain the dependencies that are necessary for the desired functionality of the final application. This can be especially important for Node.js applications, which can often have a large number of development dependencies.
• Improved security: Multi-stage builds can help to improve the security of your images by reducing the attack surface. This is because each stage in the build process is isolated from the next, and only the dependencies that are necessary for the final image are included.
• Simplified build process: Multi-stage builds can help to simplify the build process by making it easier to maintain and debug. This is because each stage in the build process is self-contained, and you can easily test and troubleshoot each stage individually.

How to create a Node.js multi-stage build

To create a Node.js multi-stage build, you will need to create a Dockerfile that contains multiple stages. Each stage should perform a specific task, such as installing dependencies, building the application, or running tests.

Here is an example of a simple Node.js multi-stage build Dockerfile:

FROM node:18 AS build

WORKDIR /app

COPY package.json .

RUN npm install

COPY . .

RUN npm run build

FROM node:18

WORKDIR /app

COPY --from=build /app/build .

CMD ["npm", "start"]

This Dockerfile defines two stages:

• The build stage uses the official Node.js image to install the application's dependencies and build the application.
• The runtime stage uses the same Node.js image, but only copies the built application files into the image. This stage also defines the command that will be used to start the application when the image is run.

To build the image, you can use the following command:

docker build -t my-nodejs-app .

This will build the image using the Dockerfile in the current directory.

Once the image is built, you can run it using the following command:

docker run -p 8080:8080 my-nodejs-app

This will start the application on port 8080.

Conclusion

Multi-stage builds are a powerful tool that can help you to create smaller, more secure, and more efficient Docker images for your Node.js applications. If you are not already using multi-stage builds, I encourage you to give them a try.