Add global statistics

models/nodes.go

@@ -170,7 +170,8 @@ func (nodes *Nodes) worker() {
 }
 
 // Returns global statistics for InfluxDB
-func (nodes *Nodes) GlobalStats() (result GlobalStats) {
+func (nodes *Nodes) GlobalStats() (result *GlobalStats) {
+	result = &GlobalStats{}
 	nodes.Lock()
 	for _, node := range nodes.List {
 		if node.Flags.Online {

respond/collector.go

@@ -20,7 +20,7 @@ type Collector struct {
 	connection    *net.UDPConn   // UDP socket
 	queue         chan *Response // received responses
 	msgType       reflect.Type
-	iface       string // interface name for the multicast binding
+	multicastAddr string
 	db            *database.DB
 	nodes         *models.Nodes
 	// Ticker and stopper
@@ -44,10 +44,9 @@ func NewCollector(db *database.DB, nodes *models.Nodes, interval time.Duration,
 	conn.SetReadBuffer(maxDataGramSize)
 
 	collector := &Collector{
-		CollectType: "nodeinfo statistics neighbours",
 		connection:    conn,
 		nodes:         nodes,
-		iface:       iface,
+		multicastAddr: net.JoinHostPort(multiCastGroup+"%"+iface, port),
 		queue:         make(chan *Response, 400),
 		ticker:        time.NewTicker(interval),
 		stop:          make(chan interface{}, 1),
@@ -69,15 +68,14 @@ func NewCollector(db *database.DB, nodes *models.Nodes, interval time.Duration,
 func (coll *Collector) Close() {
 	// stop ticker
 	coll.ticker.Stop()
-	coll.stop <- nil
+	close(coll.stop)
 
 	coll.connection.Close()
 	close(coll.queue)
 }
 
 func (coll *Collector) sendOnce() {
-	coll.sendPacket(net.JoinHostPort(multiCastGroup+"%"+coll.iface, port))
+	coll.sendPacket(coll.multicastAddr)
-	log.Println("request", coll.CollectType)
 }
 
 func (coll *Collector) sendPacket(address string) {
@@ -86,7 +84,7 @@ func (coll *Collector) sendPacket(address string) {
 		log.Panic(err)
 	}
 
-	if _, err := coll.connection.WriteToUDP([]byte("GET "+coll.CollectType), addr); err != nil {
+	if _, err := coll.connection.WriteToUDP([]byte("GET nodeinfo statistics neighbours"), addr); err != nil {
 		log.Println("WriteToUDP failed:", err)
 	}
 }
@@ -98,6 +96,10 @@ func (coll *Collector) sender() {
 		case <-coll.stop:
 			return
 		case <-coll.ticker.C:
+			// save global statistics
+			coll.db.AddPoint(database.MeasurementGlobal, nil, coll.nodes.GlobalStats().Fields(), time.Now())
+
+			// send the multicast packet to request per-node statistics
 			coll.sendOnce()
 		}
 	}