discosrv: Refactor handler loop

discover/cmd/discosrv/main.go

@@ -28,10 +28,10 @@ var (
 	lock     sync.Mutex
 	queries  = 0
 	answered = 0
+	debug    = false
 )
 
 func main() {
-	var debug bool
 	var listen string
 	var timestamp bool
 
@@ -48,36 +48,17 @@ func main() {
 	addr, _ := net.ResolveUDPAddr("udp", listen)
 	conn, err := net.ListenUDP("udp", addr)
 	if err != nil {
-		panic(err)
+		log.Fatal(err)
 	}
 
-	go func() {
-		for {
-			time.Sleep(600 * time.Second)
-
-			lock.Lock()
-
-			var deleted = 0
-			for id, node := range nodes {
-				if time.Since(node.Updated) > 60*time.Minute {
-					delete(nodes, id)
-					deleted++
-				}
-			}
-			log.Printf("Expired %d nodes; %d nodes in registry; %d queries (%d answered)", deleted, len(nodes), queries, answered)
-			queries = 0
-			answered = 0
-
-			lock.Unlock()
-		}
-	}()
+	go logStats()
 
 	var buf = make([]byte, 1024)
 	for {
 		buf = buf[:cap(buf)]
 		n, addr, err := conn.ReadFromUDP(buf)
 		if err != nil {
-			panic(err)
+			log.Fatal(err)
 		}
 		if n < 4 {
 			log.Printf("Received short packet (%d bytes)", n)
@@ -89,12 +70,27 @@ func main() {
 
 		switch magic {
 		case discover.AnnouncementMagicV1:
+			handleAnnounceV1(addr, buf)
+
+		case discover.QueryMagicV1:
+			handleQueryV1(conn, addr, buf)
+
+		case discover.AnnouncementMagicV2:
+			handleAnnounceV2(addr, buf)
+
+		case discover.QueryMagicV2:
+			handleQueryV2(conn, addr, buf)
+		}
+	}
+}
+
+func handleAnnounceV1(addr *net.UDPAddr, buf []byte) {
 	var pkt discover.AnnounceV1
 	err := pkt.UnmarshalXDR(buf)
 	if err != nil {
 		log.Println("AnnounceV1 Unmarshal:", err)
 		log.Println(hex.Dump(buf))
-				continue
+		return
 	}
 	if debug {
 		log.Printf("<- %v %#v", addr, pkt)
@@ -115,14 +111,15 @@ func main() {
 	lock.Lock()
 	nodes[pkt.NodeID] = node
 	lock.Unlock()
+}
 
-		case discover.QueryMagicV1:
+func handleQueryV1(conn *net.UDPConn, addr *net.UDPAddr, buf []byte) {
 	var pkt discover.QueryV1
 	err := pkt.UnmarshalXDR(buf)
 	if err != nil {
 		log.Println("QueryV1 Unmarshal:", err)
 		log.Println(hex.Dump(buf))
-				continue
+		return
 	}
 	if debug {
 		log.Printf("<- %v %#v", addr, pkt)
@@ -154,14 +151,15 @@ func main() {
 		answered++
 		lock.Unlock()
 	}
+}
 
-		case discover.AnnouncementMagicV2:
+func handleAnnounceV2(addr *net.UDPAddr, buf []byte) {
 	var pkt discover.AnnounceV2
 	err := pkt.UnmarshalXDR(buf)
 	if err != nil {
 		log.Println("AnnounceV2 Unmarshal:", err)
 		log.Println(hex.Dump(buf))
-				continue
+		return
 	}
 	if debug {
 		log.Printf("<- %v %#v", addr, pkt)
@@ -192,14 +190,15 @@ func main() {
 	lock.Lock()
 	nodes[pkt.NodeID] = node
 	lock.Unlock()
+}
 
-		case discover.QueryMagicV2:
+func handleQueryV2(conn *net.UDPConn, addr *net.UDPAddr, buf []byte) {
 	var pkt discover.QueryV2
 	err := pkt.UnmarshalXDR(buf)
 	if err != nil {
 		log.Println("QueryV2 Unmarshal:", err)
 		log.Println(hex.Dump(buf))
-				continue
+		return
 	}
 	if debug {
 		log.Printf("<- %v %#v", addr, pkt)
@@ -233,5 +232,24 @@ func main() {
 		lock.Unlock()
 	}
 }
+
+func logStats() {
+	for {
+		time.Sleep(600 * time.Second)
+
+		lock.Lock()
+
+		var deleted = 0
+		for id, node := range nodes {
+			if time.Since(node.Updated) > 60*time.Minute {
+				delete(nodes, id)
+				deleted++
+			}
+		}
+		log.Printf("Expired %d nodes; %d nodes in registry; %d queries (%d answered)", deleted, len(nodes), queries, answered)
+		queries = 0
+		answered = 0
+
+		lock.Unlock()
 	}
 }