Docker Notes App

A microservices-based application using Docker containers for managing notes with a Node.js API, PostgreSQL database, and Redis caching.

Project Architecture

graph TB
    Client[Client] --> API[API Service]
    subgraph Docker Environment
        API --> Redis[Redis Cache]
        API --> PostgreSQL[PostgreSQL DB]
        Redis --> PostgreSQL
    end
    
    style Client fill:#f9f,stroke:#333,stroke-width:2px
    style API fill:#bbf,stroke:#333,stroke-width:2px
    style Redis fill:#fb7,stroke:#333,stroke-width:2px
    style PostgreSQL fill:#bfb,stroke:#333,stroke-width:2px

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Microservices Overview

The application is built using a microservices architecture with Docker containers:

1. API Service

   • Node.js-based REST API
   • Handles note operations (CRUD)
   • Communicates with both Redis and PostgreSQL
   • Located in /api_service

2. PostgreSQL Service

   • Primary data storage
   • Persists notes and user data
   • Custom initialization scripts
   • Located in /postgres_service

3. Redis Service

   • In-memory caching
   • Improves read performance
   • Reduces database load
   • Located in /redis_service

Docker Commands Guide

Here are some essential Docker commands used in this project:

Container Management

# Build an image
docker build -t api-service ./api_service

# Run a container
docker run -d -p 3000:3000 --name api api-service

# List running containers
docker ps

# Stop a container
docker stop api

# Remove a container
docker rm api

# View container logs
docker logs api

# Execute command inside container
docker exec -it api bash

Image Management

# List images
docker images

# Remove an image
docker rmi api-service

# Clean up unused images
docker image prune

# Pull an image
docker pull node:16-alpine

Network Management

# Create a network
docker network create notes-network

# List networks
docker network ls

# Connect container to network
docker network connect notes-network api

# Inspect network
docker network inspect notes-network

Volume Management

# Create a volume
docker volume create postgres-data

# List volumes
docker volume ls

# Remove a volume
docker volume rm postgres-data

# Clean up unused volumes
docker volume prune

Docker Compose Guide

Docker Compose simplifies managing multi-container applications. Here are key commands and examples:

Basic Commands

# Start services
docker-compose up

# Start in detached mode
docker-compose up -d

# Stop services
docker-compose down

# View logs
docker-compose logs

# View service status
docker-compose ps

# Rebuild services
docker-compose build

Service-Specific Operations

# Start specific service
docker-compose up api

# View service logs
docker-compose logs api

# Execute command in service
docker-compose exec api npm install

# Scale service (if configured)
docker-compose up -d --scale api=3

Configuration Examples

Our docker-compose.yml manages three services. Here's an example structure:

version: '3.8'

services:
  api:
    build: ./api_service
    ports:
      - "3000:3000"
    environment:
      - NODE_ENV=development
    depends_on:
      - postgres
      - redis

  postgres:
    build: ./postgres_service
    volumes:
      - postgres-data:/var/lib/postgresql/data
    environment:
      - POSTGRES_PASSWORD=secret

  redis:
    build: ./redis_service
    volumes:
      - redis-data:/data

volumes:
  postgres-data:
  redis-data:

Environment Variables

Use .env files for environment-specific configuration:

# Development
docker-compose --env-file .env.dev up

# Production
docker-compose --env-file .env.prod up

Getting Started

1. Clone the repository
2. Create necessary .env files
3. Start services: docker-compose up -d
4. Access API at http://localhost:3000

Development Workflow

1. Make changes to service code
2. Rebuild affected service: docker-compose build api
3. Restart services: docker-compose up -d
4. View logs: docker-compose logs -f