Misc improvements

agent/agent.go

@@ -183,8 +183,10 @@ func (a *Agent) Process(t model.Trace) {
 
 			if priority == 0 {
 				priorityPtr = &ts.TracesPriority0
-			} else {
+			} else if priority == 1 {
 				priorityPtr = &ts.TracesPriority1
+			} else {
+				priorityPtr = &ts.TracesPriority2
 			}
 		}
 	}

agent/receiver.go

@@ -313,7 +313,10 @@ func (r *HTTPReceiver) logStats() {
 		if now.Sub(lastLog) >= time.Minute {
 			// We expose the stats accumulated to expvar
 			updateReceiverStats(accStats)
-			log.Info(accStats.String())
+
+			for logStr := range accStats.Strings() {
+				log.Info(logStr)
+			}
 
 			// We reset the stats accumulated during the last minute
 			accStats.reset()

agent/stats.go

@@ -51,25 +51,32 @@ func (rs *receiverStats) publish() {
 
 func (rs *receiverStats) reset() {
 	rs.Lock()
-	for _, tagStats := range rs.Stats {
+	for key, tagStats := range rs.Stats {
+		// If a tagStats was empty, let's drop it.
+		// That's a way to avoid empty stats entries or over-time leaks.
+		if tagStats.isEmpty() {
+			delete(rs.Stats, key)
+		}
 		tagStats.reset()
 	}
 	rs.Unlock()
 }
 
-// String gives a string representation of the receiverStats struct.
-func (rs *receiverStats) String() string {
+// Strings gives a multi strings representation of the receiverStats struct.
+func (rs *receiverStats) Strings() []string {
 	rs.RLock()
 	defer rs.RUnlock()
 
-	str := ""
 	if len(rs.Stats) == 0 {
-		return "no data received"
+		return []string{"no data received"}
 	}
+
+	strings := make([]string, len(rs.Stats))
+
 	for _, ts := range rs.Stats {
-		str += fmt.Sprintf("\n\t%v -> %s", ts.Tags.toArray(), ts.String())
+		strings = append(strings, fmt.Sprintf("%v -> %s", ts.Tags.toArray(), ts.String()))
 	}
-	return str
+	return strings
 }
 
 // tagStats is the struct used to associate the stats with their set of tags.
@@ -90,6 +97,7 @@ func (ts *tagStats) publish() {
 	tracesPriorityNone := atomic.LoadInt64(&ts.TracesPriorityNone)
 	tracesPriority0 := atomic.LoadInt64(&ts.TracesPriority0)
 	tracesPriority1 := atomic.LoadInt64(&ts.TracesPriority1)
+	tracesPriority2 := atomic.LoadInt64(&ts.TracesPriority2)
 	tracesBytes := atomic.LoadInt64(&ts.TracesBytes)
 	spansReceived := atomic.LoadInt64(&ts.SpansReceived)
 	spansDropped := atomic.LoadInt64(&ts.SpansDropped)
@@ -107,6 +115,7 @@ func (ts *tagStats) publish() {
 	statsd.Client.Count("datadog.trace_agent.receiver.traces_priority", tracesPriorityNone, append(tags, "priority:none"), 1)
 	statsd.Client.Count("datadog.trace_agent.receiver.traces_priority", tracesPriority0, append(tags, "priority:0"), 1)
 	statsd.Client.Count("datadog.trace_agent.receiver.traces_priority", tracesPriority1, append(tags, "priority:1"), 1)
+	statsd.Client.Count("datadog.trace_agent.receiver.traces_priority", tracesPriority2, append(tags, "priority:2"), 1)
 	statsd.Client.Count("datadog.trace_agent.receiver.traces_bytes", tracesBytes, tags, 1)
 	statsd.Client.Count("datadog.trace_agent.receiver.spans_received", spansReceived, tags, 1)
 	statsd.Client.Count("datadog.trace_agent.receiver.spans_dropped", spansDropped, tags, 1)
@@ -128,8 +137,10 @@ type Stats struct {
 	TracesPriorityNone int64
 	// TracesPriority0 is the number of traces with sampling priority set to zero.
 	TracesPriority0 int64
-	// TracesPriority1 is the number of traces with sampling priority set to a non-zero value.
+	// TracesPriority1 is the number of traces with sampling priority automatically set to 1.
 	TracesPriority1 int64
+	// TracesPriority2 is the number of traces with sampling priority manually set to 2 or more.
+	TracesPriority2 int64
 	// TracesBytes is the amount of data received on the traces endpoint (raw data, encoded, compressed).
 	TracesBytes int64
 	// SpansReceived is the total number of spans received, including the dropped ones.
@@ -151,6 +162,7 @@ func (s *Stats) update(recent Stats) {
 	atomic.AddInt64(&s.TracesPriorityNone, recent.TracesPriorityNone)
 	atomic.AddInt64(&s.TracesPriority0, recent.TracesPriority0)
 	atomic.AddInt64(&s.TracesPriority1, recent.TracesPriority1)
+	atomic.AddInt64(&s.TracesPriority2, recent.TracesPriority2)
 	atomic.AddInt64(&s.TracesBytes, recent.TracesBytes)
 	atomic.AddInt64(&s.SpansReceived, recent.SpansReceived)
 	atomic.AddInt64(&s.SpansDropped, recent.SpansDropped)
@@ -166,6 +178,7 @@ func (s *Stats) reset() {
 	atomic.StoreInt64(&s.TracesPriorityNone, 0)
 	atomic.StoreInt64(&s.TracesPriority0, 0)
 	atomic.StoreInt64(&s.TracesPriority1, 0)
+	atomic.StoreInt64(&s.TracesPriority2, 0)
 	atomic.StoreInt64(&s.TracesBytes, 0)
 	atomic.StoreInt64(&s.SpansReceived, 0)
 	atomic.StoreInt64(&s.SpansDropped, 0)
@@ -174,6 +187,12 @@ func (s *Stats) reset() {
 	atomic.StoreInt64(&s.ServicesBytes, 0)
 }
 
+func (s *Stats) isEmpty() bool {
+	tracesBytes := atomic.LoadInt64(&s.TracesBytes)
+
+	return tracesBytes == 0
+}
+
 // String returns a string representation of the Stats struct
 func (s *Stats) String() string {
 	// Atomically load the stats