🐳 Docker Compose Tutorial (Development Focused)¶

Welcome to the Docker Compose Tutorial for Development.
This guide explains how to use Docker Compose to run multi-container applications in a development environment, where:

Source code changes are reflected in containers
Containers can be rebuilt easily
No hot reload tools are required
Behavior stays close to production

📌 Introduction¶

Docker Compose is a tool that allows you to define and run multiple Docker containers as a single application.

Instead of running containers one by one, Docker Compose lets you: - Define services - Configure networks - Attach volumes - Start everything with one command

This tutorial focuses on development usage, not production.

✅ Prerequisites¶

Ensure the following are installed:

Docker
Docker Compose (included with Docker Desktop)

Verify installation:

docker --version
docker compose version
````

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## ⚙ Installation

Follow the official installation guide if Docker is not installed:

* [https://docs.docker.com/get-docker/](https://docs.docker.com/get-docker/)

Docker Compose comes bundled with Docker Desktop (Windows/macOS/Linux).

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## 🧠 How Docker Compose Works

Conceptually:

docker-compose.yml ↓ Defines services (app, db, cache, etc.) ↓ Docker builds images (if needed) ↓ Docker runs containers ↓ Containers share network & volumes

Key points:

* Each service = one container
* Services can talk using service names
* Volumes persist data
* Bind mounts sync source code

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## 🚀 Getting Started

### 📁 Project Structure

Example Node.js project:

project-root/ ├── docker-compose.yml ├── Dockerfile ├── package.json ├── server.js └── src/

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### 🧩 Creating a `docker-compose.yml` File

This example defines:

* A backend service
* A PostgreSQL database
* Source code mounted for development

```yaml
version: "3.8"

services:
  app:
    build: .
    container_name: dev-app
    ports:
      - "3000:3000"
    volumes:
      - .:/app
    depends_on:
      - db
    environment:
      NODE_ENV: development

  db:
    image: postgres:15
    container_name: dev-db
    environment:
      POSTGRES_DB: devdb
      POSTGRES_USER: devuser
      POSTGRES_PASSWORD: devpass
    volumes:
      - db_data:/var/lib/postgresql/data

volumes:
  db_data:

📄 Dockerfile for Development¶

This Dockerfile is simple and explicit.

FROM node:18

WORKDIR /app

COPY package*.json ./
RUN npm install

COPY . .

EXPOSE 3000

CMD ["node", "server.js"]

⚠ No hot reload tools (nodemon, pm2) are used.

🔁 Development Workflow (Important Section)¶

This setup follows a manual-rebuild dev workflow:

When you change code:¶

Source code updates inside container (via volume)
App does NOT auto-restart

To reflect changes:¶

docker compose restart app

If dependencies change:¶

docker compose build
docker compose up -d

Full clean rebuild:¶

docker compose down
docker compose up -d --build

This approach:

Matches production behavior
Avoids dev-only tooling
Keeps environment predictable

🧪 Common Docker Compose Commands¶

Start Services¶

docker compose up
docker compose up -d

Stop Services¶

docker compose down

Rebuild Images¶

docker compose build

Restart a Service¶

docker compose restart app

View Logs¶

docker compose logs
docker compose logs -f app

List Containers¶

docker compose ps

Execute Inside Container¶

docker compose exec app bash

📦 Examples¶

Node.js + PostgreSQL¶

Backend service
Database service
Persistent DB volume

Frontend + Backend¶

Frontend container (React/Vue build)
Backend API container

Backend + Redis¶

Cache layer
API service dependency

🧠 Tips and Best Practices¶

✔ Use bind mounts only in development ✔ Avoid hot reload in Docker unless needed ✔ Keep Dockerfile simple ✔ Use .dockerignore ✔ One service = one responsibility ✔ Restart containers explicitly

Example .dockerignore:

node_modules
.git
.env

🛠 Troubleshooting¶

Containers not updating after code change¶

Restart the service
Check volume mounts

Port already in use¶

Change host port
Stop conflicting service

Database data lost¶

Ensure named volumes are used

📚 Resources¶

Docker Compose Docs: https://docs.docker.com/compose/
Docker Docs: https://docs.docker.com/
Docker Hub: https://hub.docker.com/

📄 License¶

This project is licensed under the MIT License.

🎯 Final Notes¶

This Docker Compose setup is ideal for:

Backend development
API services
Local testing
CI consistency

It avoids: ❌ Hot reload complexity ❌ Dev-only runtime hacks