First code

collector.go

@@ -0,0 +1,118 @@
+package main
+
+import (
+	"encoding/json"
+	"log"
+	"net"
+	"time"
+)
+
+const (
+	maxDatagramSize = 8192
+)
+
+type Node struct {
+	Firstseen  time.Time   `json:"firstseen"`
+	Lastseen   time.Time   `json:"lastseen"`
+	Statistics interface{} `json:"statistics"`
+	Nodeinfo   interface{} `json:"nodeinfo"`
+}
+
+type Collector struct {
+	connection *net.UDPConn     // UDP socket
+	queue      chan string      // received responses
+	nodes      map[string]*Node // the current nodemap
+}
+
+func NewCollector() *Collector {
+	// Parse address
+	addr, err := net.ResolveUDPAddr("udp", "[::]:1001")
+	if err != nil {
+		log.Panic(err)
+	}
+
+	// Open socket
+	conn, err := net.ListenUDP("udp", addr)
+	if err != nil {
+		log.Panic(err)
+	}
+	conn.SetReadBuffer(maxDatagramSize)
+
+	collector := &Collector{
+		connection: conn,
+		queue:      make(chan string, 100),
+		nodes:      make(map[string]*Node),
+	}
+
+	go collector.receiver()
+	go collector.parser()
+
+	return collector
+}
+
+func (coll *Collector) Close() {
+	coll.connection.Close()
+	close(coll.queue)
+}
+
+func (coll *Collector) send(address string) {
+	addr, err := net.ResolveUDPAddr("udp", address)
+	if err != nil {
+		log.Panic(err)
+	}
+	coll.connection.WriteToUDP([]byte("nodeinfo"), addr)
+}
+
+func (coll *Collector) print() {
+	b, err := json.Marshal(coll.nodes)
+	if err != nil {
+		log.Panic(err)
+	}
+	log.Println(string(b))
+}
+
+func (coll *Collector) parser() {
+	for str := range coll.queue {
+		coll.parseSingle(str)
+		coll.print()
+	}
+}
+
+// Parst die Rückgabe
+func (coll *Collector) parseSingle(str string) {
+	var result map[string]interface{}
+	json.Unmarshal([]byte(str), &result)
+
+	nodeId, _ := result["node_id"].(string)
+
+	if nodeId == "" {
+		log.Println("unable to parse node_id")
+		return
+	}
+
+	now := time.Now()
+	node, _ := coll.nodes[nodeId]
+
+	if node == nil {
+		node = &Node{
+			Firstseen: now,
+		}
+		coll.nodes[nodeId] = node
+	}
+
+	node.Lastseen = now
+	node.Nodeinfo = result
+}
+
+func (coll *Collector) receiver() {
+	b := make([]byte, maxDatagramSize)
+	for {
+		n, _, err := coll.connection.ReadFromUDP(b)
+
+		if err != nil {
+			log.Println("ReadFromUDP failed:", err)
+		} else {
+			coll.queue <- string(b[:n])
+		}
+	}
+}

main.go

@@ -0,0 +1,22 @@
+package main
+
+import (
+	"log"
+	"os"
+	"os/signal"
+	"syscall"
+)
+
+func main() {
+	collector := NewCollector()
+	defer collector.Close()
+	collector.send("[2a06:8782:ffbb:1337:c24a:ff:fe2c:c7ac]:1001")
+	collector.send("[2001:bf7:540:0:32b5:c2ff:fe6e:99d5]:1001")
+
+	// Wait for SIGINT or SIGTERM
+	sigs := make(chan os.Signal, 1)
+	signal.Notify(sigs, syscall.SIGINT, syscall.SIGTERM)
+	sig := <-sigs
+	log.Println("received", sig)
+
+}