func main() {
    caddyfile := `

        # Define the service to be load balanced
        service my-web-service {
            load_balance
            responses {
                success healthy 200-299
                unhealthy 500-599
            }
            route / {
                switch route_health {
                    case healthy {
                        proxy / http://backend:80
                    }
                    case unhealthy {
                        proxy / http://backup:81
                    }
                }
            }
        }
        
    `
    // 因特网服务提供商 {
    //     listen :2015
    //     tls { auto_https }
    //     handle * my-web-service {
    //         header_down X-Caddy-Server { server.address }
    //     }
    // }
    // listen http://80.80.80.80:2015
    // handle / {}
}