# Best Practices for Integrated System

**Date**: 2025-01-27
**Purpose**: Best practices and guidelines for working with integrated workspace
**Status**: Complete

---

## Overview

This document outlines best practices for developing, maintaining, and operating projects in the integrated workspace.

---

## Code Organization

### Use Shared Packages
- **Always prefer** shared packages over duplicate code
- **Check** `workspace-shared/` before creating new utilities
- **Contribute** common code to shared packages

### Project Structure
```
project/
├── src/              # Source code
├── tests/            # Tests
├── docs/             # Project documentation
├── package.json      # Dependencies
└── README.md         # Project overview
```

### Naming Conventions
- **Files**: kebab-case (`user-service.ts`)
- **Classes**: PascalCase (`UserService`)
- **Functions**: camelCase (`getUserById`)
- **Constants**: UPPER_SNAKE_CASE (`MAX_RETRIES`)

---

## Dependency Management

### Use Workspace Packages
```json
{
  "dependencies": {
    "@workspace/shared-types": "workspace:*",
    "@workspace/shared-auth": "workspace:*"
  }
}
```

### Version Pinning
- **Production**: Pin exact versions
- **Development**: Use `workspace:*` for shared packages
- **External**: Use semantic versioning ranges

### Dependency Updates
- **Regular audits**: Run `pnpm audit` monthly
- **Security updates**: Apply immediately
- **Major updates**: Test thoroughly before applying

---

## Testing

### Test Coverage
- **Minimum**: 80% code coverage
- **Critical paths**: 100% coverage
- **Edge cases**: Test all error scenarios

### Test Organization
```
tests/
├── unit/             # Unit tests
├── integration/      # Integration tests
├── e2e/              # End-to-end tests
└── fixtures/         # Test data
```

### Testing Best Practices
- Write tests before code (TDD)
- Use descriptive test names
- Mock external dependencies
- Test error cases
- Keep tests fast and isolated

---

## Documentation

### README Requirements
- Project overview
- Setup instructions
- Usage examples
- API documentation
- Contributing guidelines

### Code Documentation
- JSDoc for public APIs
- Inline comments for complex logic
- Architecture diagrams for complex systems
- Update docs with code changes

---

## CI/CD

### Workflow Standards
- **Lint**: Run on all PRs
- **Test**: Run on all PRs
- **Build**: Run on all PRs
- **Deploy**: Run on main branch

### Pipeline Best Practices
- Fast feedback (< 10 minutes)
- Parallel execution where possible
- Caching for dependencies
- Clear error messages

---

## Infrastructure

### Infrastructure as Code
- **Always use** Terraform for infrastructure
- **Use shared modules** from `infrastructure/terraform/modules/`
- **Version control** all infrastructure changes
- **Test** infrastructure changes in dev first

### Resource Naming
- Use consistent naming conventions
- Include environment prefix
- Include project identifier
- Use descriptive names

---

## Security

### Secrets Management
- **Never commit** secrets to git
- **Use** environment variables or secret managers
- **Rotate** secrets regularly
- **Audit** secret access

### Authentication
- Use shared auth package (`@workspace/shared-auth`)
- Implement proper RBAC
- Use JWT tokens with expiration
- Validate all inputs

### Dependencies
- **Regular audits**: `pnpm audit`
- **Update promptly**: Security patches
- **Review**: New dependencies before adding
- **Pin versions**: For production

---

## Performance

### Code Optimization
- Profile before optimizing
- Use shared utilities
- Cache expensive operations
- Optimize database queries

### Infrastructure
- Right-size resources
- Use auto-scaling
- Monitor resource usage
- Optimize costs

---

## Monitoring

### Logging
- Use structured logging (JSON)
- Include correlation IDs
- Log at appropriate levels
- Don't log sensitive data

### Metrics
- Track key business metrics
- Monitor error rates
- Track performance metrics
- Set up alerts

---

## Git Workflow

### Branching Strategy
- **main**: Production-ready code
- **develop**: Integration branch
- **feature/**: New features
- **fix/**: Bug fixes
- **hotfix/**: Critical fixes

### Commit Messages
```
feat: add user authentication
fix: resolve login timeout issue
docs: update API documentation
refactor: simplify payment processing
test: add integration tests
```

### Pull Requests
- **Small PRs**: Easier to review
- **Clear description**: What and why
- **Tests**: Include tests
- **Documentation**: Update docs
- **Review**: Get approval before merging

---

## Error Handling

### Error Types
- **Validation errors**: Return 400
- **Authentication errors**: Return 401
- **Authorization errors**: Return 403
- **Not found**: Return 404
- **Server errors**: Return 500

### Error Messages
- **User-friendly**: Clear messages
- **Actionable**: What to do next
- **Secure**: Don't leak sensitive info
- **Logged**: Log detailed errors

---

## API Design

### RESTful APIs
- Use standard HTTP methods
- Use proper status codes
- Version APIs (`/v1/`, `/v2/`)
- Document with OpenAPI/Swagger

### Response Format
```json
{
  "data": { ... },
  "meta": {
    "pagination": { ... }
  },
  "errors": []
}
```

---

## Database

### Migrations
- Version all migrations
- Test migrations in dev
- Backup before production
- Rollback plan ready

### Queries
- Use parameterized queries
- Index frequently queried fields
- Avoid N+1 queries
- Monitor slow queries

---

## Deployment

### Deployment Strategy
- **Blue-Green**: Zero downtime
- **Canary**: Gradual rollout
- **Rolling**: Incremental updates
- **Feature flags**: Control feature rollout

### Pre-Deployment
- Run all tests
- Check dependencies
- Review security
- Update documentation

### Post-Deployment
- Monitor metrics
- Check logs
- Verify functionality
- Update status page

---

## Collaboration

### Code Reviews
- **Be constructive**: Focus on code, not person
- **Be timely**: Review within 24 hours
- **Be thorough**: Check logic, tests, docs
- **Be respectful**: Professional tone

### Communication
- **Clear**: Be specific
- **Timely**: Respond promptly
- **Documented**: Important decisions in ADRs
- **Transparent**: Share progress and blockers

---

## Continuous Improvement

### Regular Reviews
- **Code reviews**: Every PR
- **Architecture reviews**: Quarterly
- **Security reviews**: Monthly
- **Performance reviews**: As needed

### Learning
- **Stay updated**: Follow tech trends
- **Share knowledge**: Tech talks, docs
- **Experiment**: Try new approaches
- **Measure**: Track improvements

---

## Related Documents

- [Onboarding Guide](./ONBOARDING_GUIDE.md)
- [Testing Standards](./TESTING_STANDARDS.md)
- [Deployment Guide](./DEPLOYMENT_GUIDE.md)
- [Monorepo Governance](./MONOREPO_GOVERNANCE.md)

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**Last Updated**: 2025-01-27