Chart Structure

The Docker Compose Wrapper uses a chart-based structure for managing configurations and deployments.

Chart Directory Structure

.
├── Chart.yaml              # Chart metadata
├── values.yaml            # Default values
├── environments/          # Environment-specific values
│   ├── dev.yaml
│   ├── staging.yaml
│   └── prod.yaml
├── templates/             # Template files
│   ├── docker-compose.yaml
│   ├── networks.yaml
│   └── _helpers.tpl
└── releases/             # Release history
    └── v1/
        ├── values.yaml
        └── docker-compose.yaml

Chart.yaml

The main chart metadata file:

name: myapp
version: 1.0.0
description: My Application Chart
type: application

Values Structure

Default Values (values.yaml)

global:
  projectName: myapp
  environment: development

services:
  web:
    image: myapp/web:latest
    replicas: 1
    ports:
      - "8080:80"
    environment:
      - NODE_ENV=development
    volumes:
      - ./data:/app/data
    networks:
      - frontend
    rollingUpdate:
      replicas: 2
      retryCount: 5
      retryInterval: 10

  api:
    image: myapp/api:latest
    replicas: 1
    ports:
      - "3000:3000"
    environment:
      - DB_HOST=db
    networks:
      - frontend
      - backend
    rollingUpdate:
      replicas: 2
      retryCount: 5
      retryInterval: 10

  db:
    image: postgres:13
    environment:
      - POSTGRES_DB=myapp
      - POSTGRES_USER=myapp
    volumes:
      - db_data:/var/lib/postgresql/data
    networks:
      - backend

networks:
  frontend:
    driver: bridge
  backend:
    driver: bridge

volumes:
  db_data:

Environment-specific Values

Example for production (environments/prod.yaml):

global:
  environment: production

services:
  web:
    image: myapp/web:prod
    replicas: 3
    rollingUpdate:
      replicas: 3
      retryCount: 10
      retryInterval: 30
    environment:
      - NODE_ENV=production

  api:
    image: myapp/api:prod
    replicas: 3
    rollingUpdate:
      replicas: 3
      retryCount: 10
      retryInterval: 30
    environment:
      - NODE_ENV=production

Template Files

docker-compose.yaml

version: '3.8'

services:
  :
    image: 
    deploy:
      replicas: 
    ports:
    environment:
    volumes:
    networks:

networks:

volumes:

_helpers.tpl

Value Precedence

Values are merged in the following order (highest to lowest precedence):

1. Command-line arguments
2. Environment-specific values
3. Default values from values.yaml
4. Chart defaults

Release Management

Each release is stored in the releases directory with:

• Versioned values
• Rendered templates
• Release metadata

Example release structure:

releases/
└── v1/
    ├── values.yaml
    ├── docker-compose.yaml
    └── metadata.yaml

Best Practices

1. Value Organization
   • Keep global values at the root level
   • Group service-specific values under services
   • Use environment-specific overrides for differences
2. Template Usage
   • Use helper templates for common patterns
   • Keep templates DRY (Don’t Repeat Yourself)
   • Use conditional rendering for optional features
3. Environment Management
   • Keep environment-specific changes minimal
   • Use environment variables for sensitive data
   • Document environment-specific requirements
4. Release Management
   • Version all releases
   • Keep release history for rollbacks
   • Document release changes