MongoDB Database

Table of contents

1. MongoDB Configuration
   1. Initialization Script
      1. User Creation
      2. Data Seeding
   2. Default User Credentials
   3. Environment Variables
   4. Docker Configuration
   5. Volumes
   6. Data Persistence
   7. Connecting to MongoDB
      1. From Docker Containers
      2. From the Host Machine
      3. Using MongoDB Compass or Robo 3T
   8. Troubleshooting
      1. Resetting the seed data
      2. Connection Issues
      3. Initialization Script Issues
   9. Customizing Seed Data

MongoDB Configuration

This directory contains the MongoDB configuration and seed data for the MEAN Stack Contacts application.

Initialization Script

The main initialization script (init-mongo.sh) performs two primary tasks:

1. Creates a database user with appropriate permissions
2. Seeds the database with initial data (users and contacts)

User Creation

mongosh $MONGO_DB -u $MONGO_INITDB_ROOT_USERNAME -p $MONGO_INITDB_ROOT_PASSWORD --eval "db.createUser({ user: '$MONGO_DB_USERNAME', pwd:  '$MONGO_DB_PASSWORD', roles: [{ role: 'readWrite', db: '$MONGO_DB'}]})" --authenticationDatabase admin

Data Seeding

The script seeds the database with initial data:

• One user account with login credentials
• Three sample contacts

db.users.insertMany([
  {
    "_id": ObjectId("6759daeb097c7d69426b7649"),
    "create_date": new Date("2024-12-11T19:29:19.895Z"),
    "username": "nitin27may@gmail.com",
    "email": "nitin27may@gmail.com",
    "password": "$2a$10$nc0yO2eeCDOLg6sObsAHfuXQY8NnCrhHz5GbkmPYsAGLsQoSZa.qm",
    "firstName": "NItin",
    "lastName": "Singh"
  }
]);

db.contacts.insertMany([
  {
    "_id": ObjectId("6759daeb097c7d69426b7641"),
    "firstName": "Nitin",
    "lastName": "Singh",
    "mobile": "9876543243",
    "email": "nitin27may@gmail.com",
    "city": "Mumbai",
    "postalCode": "421201",
    "create_date": new Date()
  },
  // Additional contacts...
]);

Default User Credentials

The seed data creates a default user with the following credentials:

Username: nitin27may@gmail.com
Password: P@ssword#321

Environment Variables

The MongoDB container uses the following environment variables:

• MONGO_INITDB_ROOT_USERNAME: Root username for MongoDB
• MONGO_INITDB_ROOT_PASSWORD: Root password for MongoDB
• MONGO_DB_USERNAME: Username for the application database
• MONGO_DB_PASSWORD: Password for the application database
• MONGO_DB: Database name

These variables should be defined in the root .env file of the project.

Docker Configuration

The MongoDB container uses the official MongoDB image with custom initialization:

FROM mongo

COPY init-db.d /docker-entrypoint-initdb.d

Volumes

The Docker Compose configuration maps the following volumes:

1. ./mongo/init-db.d/:/docker-entrypoint-initdb.d/: Initialization scripts
2. mongo-data:/data/db: data persistence, in a named volume

Data Persistence

MongoDB data is persisted in the mongo-data named volume, so it survives docker compose down and container restarts. A named volume is used rather than a bind mount so the database does not leave root-owned files in your working tree.

Connecting to MongoDB

From Docker Containers

Other containers can connect to MongoDB using the following connection string:

mongodb://${MONGO_DB_USERNAME}:${MONGO_DB_PASSWORD}@database:27017/${MONGO_DB_DATABASE}?authSource=admin

From the Host Machine

Only in the development mode (docker compose up), which publishes 27017. The Nginx modes deliberately do not — MongoDB is reachable only on the internal network there.

mongodb://${MONGO_DB_USERNAME}:${MONGO_DB_PASSWORD}@localhost:27017/${MONGO_DB_DATABASE}?authSource=admin

Using MongoDB Compass or Robo 3T

To connect using GUI tools like MongoDB Compass or Robo 3T:

1. Host: localhost
2. Port: 27017
3. Authentication: Username/Password
4. Username: Value of MONGO_DB_USERNAME from your .env file
5. Password: Value of MONGO_DB_PASSWORD from your .env file
6. Authentication Database: admin
7. Database: Value of MONGO_DB_DATABASE from your .env file

Troubleshooting

Resetting the seed data

mongo/init-db.d/init-mongo.sh runs only against an empty data volume, so editing it has no effect on a database that already exists. Drop the volume and bring the stack back up:

docker compose -f docker-compose.nginx.yml down -v
docker compose -f docker-compose.nginx.yml up --build

Connection Issues

If you cannot connect to MongoDB, check:

1. The MongoDB container is running: docker ps
2. Environment variables are set correctly in .env
3. Ports are not blocked by a firewall
4. No other process is using port 27017

Initialization Script Issues

If the initialization script fails, check:

1. The script has proper permissions: chmod +x ./mongo/init-db.d/init-mongo.sh
2. Line endings are set to LF: git config --global core.autocrlf input
3. No syntax errors in the script

Customizing Seed Data

To modify the seed data:

1. Edit the init-mongo.sh file in the init-db.d directory
2. Rebuild and restart the containers:

   docker compose down
   docker compose -f docker-compose.nginx.yml up --build