Simple UDP packet catcher and displayer for DataDog statsd stats

udp.go

package main

import (
	"bytes"
	"log"
	"net"
	"strings"
	"time"
)

func main() {
	// listen to incoming udp packets
	pc, err := net.ListenPacket("udp", ":8130")
	if err != nil {
		log.Fatal(err)
	}
	defer pc.Close()

	for {
		buf := make([]byte, 2048)
		pc.ReadFrom(buf)
		parselines(buf)
	}

}

func parselines(b []byte) {
	lines := bytes.Split(b, []byte{'\n'})
	for _, l := range lines {
		parseline(l)
	}
}

func parseline(b []byte) {
	parts := bytes.Split(b, []byte{'|', 'h', '|', '#'})
	if len(parts) == 0 {
		return
	}
	if len(parts) == 1 {
		showStat(parts[0], []byte{})
		return
	}
	showStat(parts[0], parts[1])
}

func showStat(h, b []byte) {
	sb := strings.Builder{}
	sb.WriteString(time.Now().Format(time.StampMicro) + "\n")
	sb.Write(h)
	s := bytes.Split(b, []byte{','})
	for i := 0; i < len(s); i++ {
		sb.Write([]byte{'\n', '\t'})
		sb.Write(s[i])
	}
	sb.WriteByte('\n')
	println(sb.String())
}