<quick_start>

• Copy the compose.yml template below for your stack (Postgres, Redis, etc.)

• Create a .env file with database credentials

• Run docker compose up -d to start services

• Use docker compose logs -f to monitor </quick_start>

<success_criteria>

• All services start with docker compose up -d and reach healthy state

• Health checks configured for every database/cache service

• Environment variables externalized to .env (no hardcoded secrets in compose.yml)

• Hot reload working for application code via volume mounts

• docker compose down -v cleanly removes all containers and volumes </success_criteria>

Docker Compose Skill

Local development environments using Docker Compose for multi-service setups.

Quick Start

Common Services

Service Image Default Port

PostgreSQL postgres:16-alpine

5432

Redis redis:7-alpine

6379

MongoDB mongo:7

27017

MySQL mysql:8

3306

Basic compose.yml

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

redis: image: redis:7-alpine ports: - "6379:6379" volumes: - redis_data:/data

volumes: postgres_data: redis_data:

Essential Commands

Start services (detached)

docker compose up -d

Start with logs visible

docker compose up

View logs

docker compose logs -f [service]

Shell into container

docker compose exec db psql -U app

Stop and remove containers

docker compose down

Stop and remove volumes (full reset)

docker compose down -v

Rebuild without cache

docker compose build --no-cache

Environment Variables

Create .env file in project root:

.env

DB_USER=app DB_PASSWORD=secret DB_NAME=myapp_dev REDIS_URL=redis://localhost:6379

Reference in compose.yml:

environment: POSTGRES_USER: ${DB_USER:-app}

Health Checks

Always add health checks for service dependencies:

services: db: healthcheck: test: ["CMD-SHELL", "pg_isready -U ${DB_USER:-app}"] interval: 5s timeout: 5s retries: 5

app: depends_on: db: condition: service_healthy

Hot Reload Setup

Mount source code for development:

services: app: build: . volumes: - .:/app # Source code - /app/node_modules # Preserve node_modules environment: - NODE_ENV=development

Profiles for Optional Services

services: mailhog: image: mailhog/mailhog profiles: ["mail"] ports: - "8025:8025"

Start with: docker compose --profile mail up

Reference Files

• reference/compose-patterns.md

• Common compose file patterns

• reference/services.md

• Database, cache, queue service configs

• reference/networking.md

• Ports, networks, volumes

• reference/dev-workflow.md

• Development workflow commands