Getting Started with Docker

We have a simple Nodejs app built using less than 10 lines.

We are going to containerise this app into a Docker Container.

Resources & Requirements

• Simple Nodejs & Express App
• Official Node Image
• Get Started Docker
• Docker Desktop
• VSCode & Official Docker Extension
• Learn Docker in 7 Easy Steps - Full Beginner's Tutorial

Quickstart

1. Clone this repo gh repo clone cloudbrilliant/cuddly-chainsaw
2. Run npm i to install express
3. Run & test the app locally npm start
4. Local test url http://localhost:8080

Dockerfile

Dockerfile is required in order to create image/container version of your app.

FROM node:14

WORKDIR /app

COPY package.json package.json
COPY package-lock.json package-lock.json

RUN npm install

COPY . .

ENV PORT=8080

EXPOSE 8080

CMD ["npm", "start"]

Docker Build

Build an image from a Dockerfile

the -t flag tags our image. Think of this simply as a human-readable name for the final image. Since we named the image getting-started, we can refer to that image when we run a container.

The . at the end of the docker build command tells that Docker should look for the Dockerfile in the current directory.

 docker build -t getting-started/demoapp:1.0 . 

Build Reference

Docker Run

Run the command below to start your new image / container

The -p command maps the container port to a local port, in our case this opens up https://localhost:3000

docker run -p 3000:8080 getting-started/demoapp:1.0

Run Reference