Dockerfile

Detailed Explanation

A Dockerfile is a recipe that tells Docker how to build a container image for your app. It's a plain text file (named Dockerfile, no extension) at the root of your project.

A typical Dockerfile for a web app does five things:

1. Starts from a base image (like Node.js with Linux)
2. Copies your code into the container
3. Installs dependencies with npm install
4. Runs a Production Build with npm run build
5. Defines the command to start your Server

Cloud services like Google Cloud Run read this file to know exactly how to build and run your app. You don't need to memorize the syntax — Claude Code can generate one for you. Just understand that the Dockerfile is the bridge between your code and Deployment.