node

ExpressJS Node example

Create a new directory for this example (or clone this repository with git clone https://github.com/danial-k/docker-intro.git):

mkdir -p docker-intro/node/app
cd docker-intro/node/app

Setting up development container

Start a Node development container with:

docker run \
-it \
--name node \
--hostname node \
--mount type=bind,src=`pwd`,dst=/app \
--publish 3700:3000/tcp \
-w //app \
node:12.3 \
bash

Install nodemon globally to enable hot-reloading:

npm install -g nodemon

Install the ExpressJS application generator globally:

npm install -g express-generator

Create a new express application in the current directory:

express

Edit package.json and replace node ./bin/www in scripts.start with nodemon ./bin/www. This will use nodemon to monitor for file changes instead of node. Note that on Windows hosts, --legacy-watch should be added (i.e. nodemon --legacy-watch ./bin/www) because of a Windows file system limitation.

To run the application with hot-reloading:

DEBUG=app:* npm start

The application should then be available at http://127.0.0.1:3700.

Building deployment container

To publish the application as a self-contained image, we will use a multi-stage build process (see the Dockerfile[Dockerfile] for this project (place in the maven directory). This Dockerfule will first build the source (using on the Maven image) and then produce a deployable image (based on the Jetty image):

docker build -t express:1.0.0 .

This will send all files in the current directory to the Docker daemon's build context (excluding paths specified in .dockerignore), then create and tag the image. Once the image has been built, run with:

docker run -p 3710:3000 express:1.0.0

The application should then be available at http://127.0.0.1:3710