Implemented count metrics for broker events

Added three new metrics:
- proxyIdleCount counts the number of times a proxy polls and receives
no snowflakes
- clientDeniedCount counts the number of times a client requested a
snowflake but none were available
- clientProxyMatchCount counts the number of times a client successfully
received a snowflake

broker/broker.go

@@ -153,6 +153,7 @@ func proxyPolls(ctx *BrokerContext, w http.ResponseWriter, r *http.Request) {
 	offer := ctx.RequestOffer(id)
 	if nil == offer {
 		log.Println("Proxy " + id + " did not receive a Client offer.")
+		ctx.metrics.proxyIdleCount++
 		w.WriteHeader(http.StatusGatewayTimeout)
 		return
 	}
@@ -176,6 +177,7 @@ func clientOffers(ctx *BrokerContext, w http.ResponseWriter, r *http.Request) {
 	// Immediately fail if there are no snowflakes available.
 	if ctx.snowflakes.Len() <= 0 {
 		log.Println("Client: No snowflake proxies available.")
+		ctx.metrics.clientDeniedCount++
 		w.WriteHeader(http.StatusServiceUnavailable)
 		return
 	}
@@ -189,6 +191,7 @@ func clientOffers(ctx *BrokerContext, w http.ResponseWriter, r *http.Request) {
 	select {
 	case answer := <-snowflake.answerChannel:
 		log.Println("Client: Retrieving answer")
+		ctx.metrics.clientProxyMatchCount++
 		w.Write(answer)
 		// Initial tracking of elapsed time.
 		ctx.metrics.clientRoundtripEstimate = time.Since(startTime) /

broker/metrics.go

@@ -21,11 +21,15 @@ type CountryStats struct {
 
 // Implements Observable
 type Metrics struct {
-	tablev4      *GeoIPv4Table
-	tablev6      *GeoIPv6Table
-	countryStats CountryStats
-	// snowflakes	timeseries.Float
+	logger  *log.Logger
+	tablev4 *GeoIPv4Table
+	tablev6 *GeoIPv6Table
+
+	countryStats            CountryStats
 	clientRoundtripEstimate time.Duration
+	proxyIdleCount          int
+	clientDeniedCount       int
+	clientProxyMatchCount   int
 }
 
 func (s CountryStats) Display() string {
@@ -94,17 +98,25 @@ func NewMetrics(metricsLogger *log.Logger) (*Metrics, error) {
 		counts: make(map[string]int),
 	}
 
+	m.logger = metricsLogger
+
 	// Write to log file every hour with updated metrics
-	go once.Do(func() {
-		heartbeat := time.Tick(metricsResolution)
-		for range heartbeat {
-			metricsLogger.Println("Country stats: ", m.countryStats.Display())
+	go once.Do(m.logMetrics)
+
+	return m, nil
+}
 
-			//restore all metrics to original values
-			m.countryStats.counts = make(map[string]int)
+func (m *Metrics) logMetrics() {
 
-		}
-	})
+	heartbeat := time.Tick(metricsResolution)
+	for range heartbeat {
+		m.logger.Println("snowflake-stats-end ")
+		m.logger.Println("snowflake-ips ", m.countryStats.Display())
+		m.logger.Println("snowflake-idle-count ", m.proxyIdleCount)
+		m.logger.Println("client-denied-count ", m.clientDeniedCount)
+		m.logger.Println("client-snowflake-match-count ", m.clientProxyMatchCount)
 
-	return m, nil
+		//restore all metrics to original values
+		m.countryStats.counts = make(map[string]int)
+	}
 }