express-locallibrary-tutorial

This is an Express web application that implements a basic library menagement system.

Features

You can browse and manage:

• Lists of all Books, Authors, Book instances and Genres.
• Detailed pages for each item.
• CRUD funcitonality for all entity types.

Tech stack

• Backend: Node.js + Express
• Database: MongoDB (via Mongoose ODM)
• Templating: Pug

Getting started

1) Install dependencies

npm install

2) Create a '.env' file

In the project root, create a file named .env and set your own MongoDB connection string:

MONGODB_URI=<your-mongodb-connection-string>

Example MONGODB_URI string for a local database:

MONGODB_URI=mongodb://localhost:27017/library

3) Run the application

npm start

With debug output run:

npm run serverstart

then open http://localhost:3000

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🐳 Docker Compose Setup

This repository contains a Docker Compose setup for running the Express Local Library app together with a MongoDB database. It also includes a populate service for seeding the database with sample data.

Prerequisites

• Docker & Docker Compose v2+
• Optional: .env file for custom database connection

How It Works

Services

• app – Builds from the included Dockerfile (or uses the prebuilt image sgusic29/express-locallibrary:latest) and serves the library’s web interface and API.
  • Builds from Dockerfile if the image does not exist locally.
  • Reads database connection from MONGODB_URI environment variable.
  • Falls back to the internal mongo service if MONGODB_URI is not provided.
• mongo – MongoDB 6.0 database
  • Stores data in a persistent named volume (mongo-data).
  • Includes a healthcheck so app waits until MongoDB is ready.
• populate – One-off container to run node populatedb.js and seed the database.
  • Waits until mongo is healthy before running.
  • Does not run automatically on docker compose up (it’s opt-in).

Environment Variables

The app reads MONGODB_URI from a .env file in the project root to know which MongoDB instance to use.

Example: connect to an external MongoDB instance

MONGODB_URI=mongodb://user:pass@mongo-host:27017/library?authSource=admin

If MONGODB_URI is not set, the app uses the built-in mongo service at:

mongodb://mongo:27017/library

Usage

Start App + MongoDB

docker compose up -d

Start App + MongoDB

docker compose down

Database Persistence

MongoDB stores its data in the named volume mongo-data, so data survives container restarts and up/down cycles:

volumes:
  - mongo-data:/data/db

to remove the data:

docker compose down -v

Populate Database Service

The populate service runs populatedb.js to insert sample data. It’s meant to be run manually, not automatically, so you only seed when you want to.

# Make sure mongo is running
docker compose up -d mongo

# Run populate once (container removed after it exits)
docker compose run --rm populate

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