From 54cdd39eb8811db2cef5194c06b01d8d33f92348 Mon Sep 17 00:00:00 2001
From: Julian Kornberger <jk+github@digineo.de>
Date: Sun, 29 Jan 2017 22:26:16 +0100
Subject: [PATCH] Clean up Collector struct

---
 respond/collector.go | 36 ++++++++++++++++++------------------
 1 file changed, 18 insertions(+), 18 deletions(-)

diff --git a/respond/collector.go b/respond/collector.go
index e30422b..1fcf0e0 100644
--- a/respond/collector.go
+++ b/respond/collector.go
@@ -6,7 +6,6 @@ import (
 	"encoding/json"
 	"log"
 	"net"
-	"reflect"
 	"time"
 
 	"github.com/FreifunkBremen/respond-collector/data"
@@ -16,16 +15,13 @@ import (
 
 //Collector for a specificle respond messages
 type Collector struct {
-	CollectType   string
 	connection    *net.UDPConn   // UDP socket
 	queue         chan *Response // received responses
-	msgType       reflect.Type
 	multicastAddr string
 	db            *database.DB
 	nodes         *models.Nodes
-	// Ticker and stopper
-	ticker *time.Ticker
-	stop   chan interface{}
+	interval      time.Duration // Interval for multicast packets
+	stop          chan interface{}
 }
 
 // NewCollector creates a Collector struct
@@ -49,7 +45,7 @@ func NewCollector(db *database.DB, nodes *models.Nodes, iface string) *Collector
 		nodes:         nodes,
 		multicastAddr: net.JoinHostPort(multiCastGroup+"%"+iface, port),
 		queue:         make(chan *Response, 400),
-		stop:          make(chan interface{}, 1),
+		stop:          make(chan interface{}),
 	}
 
 	go collector.receiver()
@@ -64,11 +60,14 @@ func NewCollector(db *database.DB, nodes *models.Nodes, iface string) *Collector
 
 // Start Collector
 func (coll *Collector) Start(interval time.Duration) {
-	if coll.ticker != nil {
+	if coll.interval != 0 {
 		panic("already started")
 	}
+	if interval <= 0 {
+		panic("invalid collector interval")
+	}
+	coll.interval = interval
 
-	coll.ticker = time.NewTicker(interval)
 	go func() {
 		coll.sendOnce() // immediately
 		coll.sender()   // periodically
@@ -77,12 +76,7 @@ func (coll *Collector) Start(interval time.Duration) {
 
 // Close Collector
 func (coll *Collector) Close() {
-	// stop ticker
-	if coll.ticker != nil {
-		coll.ticker.Stop()
-		close(coll.stop)
-	}
-
+	close(coll.stop)
 	coll.connection.Close()
 	close(coll.queue)
 }
@@ -91,7 +85,7 @@ func (coll *Collector) sendOnce() {
 	coll.SendPacket(coll.multicastAddr)
 }
 
-// Sends a UDP request to the given unicast or multicast address
+// SendPacket send a UDP request to the given unicast or multicast address
 func (coll *Collector) SendPacket(address string) {
 	addr, err := net.ResolveUDPAddr("udp", address)
 	if err != nil {
@@ -105,11 +99,13 @@ func (coll *Collector) SendPacket(address string) {
 
 // send packets continously
 func (coll *Collector) sender() {
+	ticker := time.NewTicker(coll.interval)
 	for {
 		select {
 		case <-coll.stop:
+			ticker.Stop()
 			return
-		case <-coll.ticker.C:
+		case <-ticker.C:
 			// send the multicast packet to request per-node statistics
 			coll.sendOnce()
 		}
@@ -149,13 +145,16 @@ func (coll *Collector) saveResponse(addr net.UDPAddr, res *data.ResponseData) {
 		nodeID = val.NodeID
 	}
 
-	// Updates nodes if NodeID found
+	// Check length of nodeID
 	if len(nodeID) != 12 {
 		log.Printf("invalid NodeID '%s' from %s", nodeID, addr.String())
 		return
 	}
+
+	// Process the data
 	node := coll.nodes.Update(nodeID, res)
 
+	// Store statistics in InfluxDB
 	if coll.db != nil && node.Statistics != nil {
 		coll.db.Add(nodeID, node)
 	}
@@ -186,6 +185,7 @@ func (coll *Collector) globalStatsWorker() {
 	for {
 		select {
 		case <-coll.stop:
+			ticker.Stop()
 			return
 		case <-ticker.C:
 			coll.saveGlobalStats()