Comprehensive comparison for DevOps technology in Software Development applications

# Caddyfile - Production-grade reverse proxy configuration
# This example demonstrates a complete microservices setup with:
# - Multiple service routing
# - Health checks
# - Rate limiting
# - Security headers
# - CORS configuration
# - Logging and monitoring
# - TLS automation

# Global options
{
    # Email for Let's Encrypt notifications
    email devops@example.com
    
    # Enable admin API for metrics
    admin :2019
    
    # Logging configuration
    log {
        output file /var/log/caddy/access.log {
            roll_size 100mb
            roll_keep 10
            roll_keep_for 720h
        }
        format json
        level INFO
    }
}

# Main application domain
api.example.com {
    # Security headers
    header {
        # Enable HSTS
        Strict-Transport-Security "max-age=31536000; includeSubDomains; preload"
        # Prevent clickjacking
        X-Frame-Options "DENY"
        # XSS protection
        X-Content-Type-Options "nosniff"
        X-XSS-Protection "1; mode=block"
        # Remove server identification
        -Server
    }

    # CORS configuration for web clients
    @cors_preflight {
        method OPTIONS
    }
    
    handle @cors_preflight {
        header {
            Access-Control-Allow-Origin "https://app.example.com"
            Access-Control-Allow-Methods "GET, POST, PUT, DELETE, OPTIONS"
            Access-Control-Allow-Headers "Content-Type, Authorization"
            Access-Control-Max-Age "3600"
        }
        respond 204
    }

    # Rate limiting for authentication endpoints
    @auth_endpoints {
        path /api/v1/auth/*
    }
    
    handle @auth_endpoints {
        rate_limit {
            zone auth_zone {
                key {remote_host}
                events 10
                window 1m
            }
        }
        reverse_proxy auth-service:8001 {
            health_uri /health
            health_interval 10s
            health_timeout 5s
            health_status 2xx
            lb_policy least_conn
        }
    }

    # User service routing
    handle /api/v1/users/* {
        reverse_proxy user-service:8002 user-service-replica:8002 {
            health_uri /health
            health_interval 10s
            health_timeout 5s
            health_status 2xx
            lb_policy round_robin
            
            # Request buffering
            flush_interval -1
            
            # Timeouts
            transport http {
                dial_timeout 5s
                response_header_timeout 10s
            }
        }
    }

    # Payment processing service with strict security
    handle /api/v1/payments/* {
        # Additional rate limiting for payment endpoints
        rate_limit {
            zone payment_zone {
                key {remote_host}
                events 5
                window 1m
            }
        }
        
        reverse_proxy payment-service:8003 {
            health_uri /health
            health_interval 5s
            health_timeout 3s
            health_status 2xx
            
            # Retry logic for payment service
            lb_try_duration 5s
            lb_try_interval 500ms
        }
    }

    # Static content and default routing
    handle /* {
        reverse_proxy web-service:8000 {
            health_uri /health
            health_interval 15s
            health_timeout 5s
            health_status 2xx
        }
    }

    # Custom error pages
    handle_errors {
        @5xx expression {http.error.status_code} >= 500
        handle @5xx {
            respond "Service temporarily unavailable" 503
        }
        
        @4xx expression {http.error.status_code} >= 400 && {http.error.status_code} < 500
        handle @4xx {
            respond "Bad request" {http.error.status_code}
        }
    }

    # Access logging
    log {
        output file /var/log/caddy/api-access.log {
            roll_size 50mb
            roll_keep 20
        }
        format json
    }
}

# Metrics endpoint for monitoring
metrics.example.com {
    handle /metrics {
        metrics /metrics
    }
    
    # Restrict access to internal network
    @internal {
        remote_ip 10.0.0.0/8 172.16.0.0/12 192.168.0.0/16
    }
    
    handle @internal {
        reverse_proxy prometheus:9090
    }
    
    handle {
        respond "Forbidden" 403
    }
}