xmpp-srv-tester.go

package main

import (
	"fmt"
	"log"
	"net"
	"os"
	"strconv"
	"time"
)

func main() {
	if len(os.Args) < 2 {
		fmt.Fprintln(os.Stderr, "Usage: xmpp-srv-tester <NAME> [TIMEOUT]")
		os.Exit(1)
	}
	srv := os.Args[1]
	fmt.Fprintln(os.Stderr, "name:", srv)

	cname, addr, err := lookupSRV(srv)
	if err != nil {
		fmt.Fprintln(os.Stderr, "[ERROR]", err)
	}
	fmt.Println("cname:", cname)
	for _, a := range addr {
		fmt.Printf("   %d %d %s %d\n", a.Priority, a.Weight, a.Target, a.Port)
	}

	for _, a := range addr {
		go checkTCP(a)
	}

	var timeout time.Duration = 1
	if len(os.Args) >= 3 {
		argTimeout := os.Args[2]
		i, err := strconv.Atoi(argTimeout)
		if err == nil {
			timeout = time.Duration(i)
		}

	}
	time.Sleep(time.Second * timeout)
}

func lookupSRV(srv string) (string, []*net.SRV, error) {
	defer timeTrack(time.Now(), "DNS request")
	return net.LookupSRV("xmpp-client", "tcp", srv)
}

func checkTCP(addr *net.SRV) {
	defer timeTrack(time.Now(), fmt.Sprintf("Dial to %s:%d", addr.Target[0:len(addr.Target)-1], addr.Port))
	conn, err := net.Dial("tcp", fmt.Sprintf("%s:%d", addr.Target[0:len(addr.Target)-1], addr.Port))
	//fmt.Printf("DNS %s remote address %s\n", addr.Target, conn.RemoteAddr().String())
	defer conn.Close()
	if err != nil {
		fmt.Println("Error", err)
	}
}

func timeTrack(start time.Time, name string) {
	elapsed := time.Since(start)
	log.Printf("%s took %s", name, elapsed)
}