Docker Patterns

Dockerfile - Java Spring Boot

# Build stage
FROM maven:3.9-eclipse-temurin-21 AS build
WORKDIR /app
COPY pom.xml .
RUN mvn dependency:go-offline -B
COPY src ./src
RUN mvn package -DskipTests -B

# Runtime stage
FROM eclipse-temurin:21-jre-alpine
WORKDIR /app

# Security: non-root user
RUN addgroup -S appgroup && adduser -S appuser -G appgroup
USER appuser

COPY --from=build /app/target/*.jar app.jar

EXPOSE 8080
HEALTHCHECK --interval=30s --timeout=3s \
  CMD wget -q --spider http://localhost:8080/actuator/health || exit 1

ENTRYPOINT ["java", "-jar", "app.jar"]

Dockerfile - Node.js

# Build stage
FROM node:20-alpine AS build
WORKDIR /app
COPY package*.json ./
RUN npm ci
COPY . .
RUN npm run build

# Runtime stage
FROM node:20-alpine
WORKDIR /app
ENV NODE_ENV=production

RUN addgroup -S appgroup && adduser -S appuser -G appgroup
USER appuser

COPY --from=build /app/dist ./dist
COPY --from=build /app/node_modules ./node_modules
COPY package*.json ./

EXPOSE 3000
HEALTHCHECK --interval=30s --timeout=3s \
  CMD wget -q --spider http://localhost:3000/health || exit 1

CMD ["node", "dist/index.js"]

Dockerfile - React (Vite)

# Build stage
FROM node:20-alpine AS build
WORKDIR /app
COPY package*.json ./
RUN npm ci
COPY . .
RUN npm run build

# Runtime stage
FROM nginx:alpine
COPY --from=build /app/dist /usr/share/nginx/html
COPY nginx.conf /etc/nginx/conf.d/default.conf
EXPOSE 80
HEALTHCHECK --interval=30s --timeout=3s \
  CMD wget -q --spider http://localhost:80 || exit 1

Docker Compose - Full Stack

version: '3.8'

services:
  app:
    build:
      context: .
      dockerfile: Dockerfile
    ports:
      - "${APP_PORT:-8080}:8080"
    environment:
      - SPRING_PROFILES_ACTIVE=docker
      - DB_HOST=db
      - DB_PORT=5432
      - DB_NAME=${DB_NAME}
      - DB_USER=${DB_USER}
      - DB_PASSWORD=${DB_PASSWORD}
      - REDIS_HOST=redis
    depends_on:
      db:
        condition: service_healthy
      redis:
        condition: service_healthy
    networks:
      - app-network

  db:
    image: postgres:16-alpine
    environment:
      POSTGRES_DB: ${DB_NAME}
      POSTGRES_USER: ${DB_USER}
      POSTGRES_PASSWORD: ${DB_PASSWORD}
    volumes:
      - postgres_data:/var/lib/postgresql/data
    ports:
      - "${DB_PORT:-5432}:5432"
    healthcheck:
      test: ["CMD-SHELL", "pg_isready -U ${DB_USER} -d ${DB_NAME}"]
      interval: 5s
      timeout: 5s
      retries: 5
    networks:
      - app-network

  redis:
    image: redis:7-alpine
    command: redis-server --appendonly yes
    volumes:
      - redis_data:/data
    ports:
      - "${REDIS_PORT:-6379}:6379"
    healthcheck:
      test: ["CMD", "redis-cli", "ping"]
      interval: 5s
      timeout: 3s
      retries: 5
    networks:
      - app-network

  mongo:
    image: mongo:7
    environment:
      MONGO_INITDB_ROOT_USERNAME: ${MONGO_USER}
      MONGO_INITDB_ROOT_PASSWORD: ${MONGO_PASSWORD}
    volumes:
      - mongo_data:/data/db
    ports:
      - "${MONGO_PORT:-27017}:27017"
    healthcheck:
      test: ["CMD", "mongosh", "--eval", "db.adminCommand('ping')"]
      interval: 10s
      timeout: 5s
      retries: 5
    networks:
      - app-network

volumes:
  postgres_data:
  redis_data:
  mongo_data:

networks:
  app-network:
    driver: bridge

.dockerignore

.git
.gitignore
*.md
!README.md
.env
.env.*
target/
node_modules/
dist/
.idea/
*.iml
.vscode/
*.log
Dockerfile*
docker-compose*

.env.example

# Application
APP_PORT=8080

# PostgreSQL
DB_NAME=myapp
DB_USER=postgres
DB_PASSWORD=changeme
DB_PORT=5432

# Redis
REDIS_PORT=6379

# MongoDB
MONGO_USER=admin
MONGO_PASSWORD=changeme
MONGO_PORT=27017

Commands

# Build and start
docker compose up -d --build

# View logs
docker compose logs -f app

# Stop all
docker compose down

# Stop and remove volumes
docker compose down -v

# Rebuild single service
docker compose up -d --build app

# Execute command in container
docker compose exec app sh

# Check health
docker compose ps

Best Practices

• Use multi-stage builds to reduce image size
• Always use specific image tags, not latest
• Run as non-root user
• Include health checks
• Use .dockerignore to exclude unnecessary files
• Use environment variables for configuration
• Never include secrets in images
• Use named volumes for persistent data