feat: add temporality tag for statsd counters

plugins/inputs/statsd/README.md

@@ -56,6 +56,12 @@ See the [CONFIGURATION.md][CONFIGURATION.md] for more details.
   ## Reset timings & histograms every interval (default=true)
   delete_timings = true
 
+  ## Enable start_time field, which adds the start time of the metric accumulation
+  ## You should use this together with enable_temporality_tag when using OpenTelemetry output.
+  enable_start_time_field = false
+  ## Enable temporality tag adds temporality=delta or temporality=commulative tag to the metrics.
+  enable_temporality_tag = false
+
   ## Percentiles to calculate for timing & histogram stats.
   percentiles = [50.0, 90.0, 99.0, 99.9, 99.95, 100.0]
 

plugins/inputs/statsd/sample.conf

@@ -29,6 +29,12 @@
   ## Reset timings & histograms every interval (default=true)
   delete_timings = true
 
+  ## Enable start_time field, which adds the start time of the metric accumulation
+  ## You should use this together with enable_temporality_tag when using OpenTelemetry output.
+  enable_start_time_field = false
+  ## Enable temporality tag adds temporality=delta or temporality=commulative tag to the metrics.
+  enable_temporality_tag = false
+
   ## Percentiles to calculate for timing & histogram stats.
   percentiles = [50.0, 90.0, 99.0, 99.9, 99.95, 100.0]
 

plugins/inputs/statsd/statsd.go

@@ -77,6 +77,9 @@ type Statsd struct {
 	DeleteTimings   bool     `toml:"delete_timings"`
 	ConvertNames    bool     `toml:"convert_names" deprecated:"0.12.0;2.0.0;use 'metric_separator' instead"`
 
+	EnableStartTimeField bool `toml:"enable_start_time_field"`
+	EnableTemporalityTag bool `toml:"enable_temporality_tag"`
+
 	// MetricSeparator is the separator between parts of the metric name.
 	MetricSeparator string `toml:"metric_separator"`
 	// This flag enables parsing of tags in the dogstatsd extension to the
@@ -156,6 +159,8 @@ type Statsd struct {
 	UDPBytesRecv       selfstat.Stat
 	ParseTimeNS        selfstat.Stat
 	PendingMessages    selfstat.Stat
+
+	lastGatherTime time.Time
 }
 
 type input struct {
@@ -226,6 +231,9 @@ func (s *Statsd) Gather(acc telegraf.Accumulator) error {
 		fields := map[string]interface{}{
 			defaultFieldName: m.value,
 		}
+		if s.EnableStartTimeField {
+			fields["start_time"] = s.lastGatherTime.Format(time.RFC3339)
+		}
 		acc.AddFields(m.name, fields, m.tags, now)
 	}
 	s.distributions = make([]cacheddistributions, 0)
@@ -252,6 +260,9 @@ func (s *Statsd) Gather(acc telegraf.Accumulator) error {
 				fields[name] = stats.Percentile(float64(percentile))
 			}
 		}
+		if s.EnableStartTimeField {
+			fields["start_time"] = s.lastGatherTime.Format(time.RFC3339)
+		}
 
 		acc.AddFields(m.name, fields, m.tags, now)
 	}
@@ -260,13 +271,21 @@ func (s *Statsd) Gather(acc telegraf.Accumulator) error {
 	}
 
 	for _, m := range s.gauges {
+		if s.EnableStartTimeField && m.fields != nil {
+			m.fields["start_time"] = s.lastGatherTime.Format(time.RFC3339)
+		}
+
 		acc.AddGauge(m.name, m.fields, m.tags, now)
 	}
 	if s.DeleteGauges {
 		s.gauges = make(map[string]cachedgauge)
 	}
 
 	for _, m := range s.counters {
+		if s.EnableStartTimeField && m.fields != nil {
+			m.fields["start_time"] = s.lastGatherTime.Format(time.RFC3339)
+		}
+
 		acc.AddCounter(m.name, m.fields, m.tags, now)
 	}
 	if s.DeleteCounters {
@@ -278,6 +297,10 @@ func (s *Statsd) Gather(acc telegraf.Accumulator) error {
 		for field, set := range m.fields {
 			fields[field] = int64(len(set))
 		}
+		if s.EnableStartTimeField {
+			fields["start_time"] = s.lastGatherTime.Format(time.RFC3339)
+		}
+
 		acc.AddFields(m.name, fields, m.tags, now)
 	}
 	if s.DeleteSets {
@@ -286,6 +309,7 @@ func (s *Statsd) Gather(acc telegraf.Accumulator) error {
 
 	s.expireCachedMetrics()
 
+	s.lastGatherTime = now
 	return nil
 }
 
@@ -297,6 +321,7 @@ func (s *Statsd) Start(ac telegraf.Accumulator) error {
 	s.acc = ac
 
 	// Make data structures
+	s.lastGatherTime = time.Now()
 	s.gauges = make(map[string]cachedgauge)
 	s.counters = make(map[string]cachedcounter)
 	s.sets = make(map[string]cachedset)
@@ -305,6 +330,7 @@ func (s *Statsd) Start(ac telegraf.Accumulator) error {
 
 	s.Lock()
 	defer s.Unlock()
+
 	//
 	tags := map[string]string{
 		"address": s.ServiceAddress,
@@ -644,6 +670,14 @@ func (s *Statsd) parseStatsdLine(line string) error {
 		switch m.mtype {
 		case "c":
 			m.tags["metric_type"] = "counter"
+
+			if s.EnableTemporalityTag {
+				if s.DeleteCounters {
+					m.tags["temporality"] = "delta"
+				} else {
+					m.tags["temporality"] = "cumulative"
+				}
+			}
 		case "g":
 			m.tags["metric_type"] = "gauge"
 		case "s":

plugins/inputs/statsd/statsd_test.go

@@ -1995,3 +1995,68 @@ func TestParse_InvalidAndRecoverIntegration(t *testing.T) {
 
 	require.NoError(t, conn.Close())
 }
+
+func TestParse_DeltaCounter(t *testing.T) {
+	statsd := Statsd{
+		Log:                    testutil.Logger{},
+		Protocol:               "tcp",
+		ServiceAddress:         "localhost:8125",
+		AllowedPendingMessages: 10000,
+		MaxTCPConnections:      250,
+		TCPKeepAlive:           true,
+		NumberWorkerThreads:    5,
+		// Delete Counters causes Delta temporality to be added
+		DeleteCounters:       true,
+		lastGatherTime:       time.Now(),
+		EnableTemporalityTag: true,
+		EnableStartTimeField: true,
+	}
+
+	acc := &testutil.Accumulator{}
+	require.NoError(t, statsd.Start(acc))
+	defer statsd.Stop()
+
+	addr := statsd.TCPlistener.Addr().String()
+	conn, err := net.Dial("tcp", addr)
+	require.NoError(t, err)
+
+	_, err = conn.Write([]byte("cpu.time_idle:42|c\n"))
+	require.NoError(t, err)
+
+	require.Eventuallyf(t, func() bool {
+		require.NoError(t, statsd.Gather(acc))
+		acc.Lock()
+		defer acc.Unlock()
+
+		fmt.Println(acc.NMetrics())
+		expected := []telegraf.Metric{
+			testutil.MustMetric(
+				"cpu_time_idle",
+				map[string]string{
+					"metric_type": "counter",
+					"temporality": "delta",
+				},
+				map[string]interface{}{
+					"value": 42,
+				},
+				time.Now(),
+				telegraf.Counter,
+			),
+		}
+		got := acc.GetTelegrafMetrics()
+		testutil.RequireMetricsEqual(t, expected, got, testutil.IgnoreTime(), testutil.IgnoreFields("start_time"))
+
+		startTime, ok := got[0].GetField("start_time")
+		require.True(t, ok, "expected start_time field")
+
+		startTimeStr, ok := startTime.(string)
+		require.True(t, ok, "expected start_time field to be a string")
+
+		_, err = time.Parse(time.RFC3339Nano, startTimeStr)
+		require.NoError(t, err, "execpted start_time field to be in RFC3339Nano format")
+
+		return acc.NMetrics() >= 1
+	}, time.Second, 100*time.Millisecond, "Expected 1 metric found %d", acc.NMetrics())
+
+	require.NoError(t, conn.Close())
+}