Add control over which stats to gather in basicstats aggregator (#3580)

plugins/aggregators/basicstats/README.md

@@ -8,14 +8,26 @@ emitting the aggregate every `period` seconds.
 ```toml
 # Keep the aggregate basicstats of each metric passing through.
 [[aggregators.basicstats]]
+
   ## General Aggregator Arguments:
+
   ## The period on which to flush & clear the aggregator.
   period = "30s"
+
   ## If true, the original metric will be dropped by the
   ## aggregator and will not get sent to the output plugins.
   drop_original = false
+
+  ## BasicStats Arguments:
+
+  ## Configures which basic stats to push as fields
+  stats = ["count","min","max","mean","stdev","s2"]
 ```
 
+- stats
+    - If not specified, all stats are aggregated and pushed as fields
+    - If empty array, no stats are aggregated
+
 ### Measurements & Fields:
 
 - measurement1

plugins/aggregators/basicstats/basicstats.go

@@ -1,6 +1,7 @@
 package basicstats
 
 import (
+	"log"
 	"math"
 
 	"github.com/influxdata/telegraf"
@@ -8,10 +9,22 @@ import (
 )
 
 type BasicStats struct {
+	Stats []string `toml:"stats"`
+
 	cache       map[uint64]aggregate
+	statsConfig *configuredStats
 }
 
-func NewBasicStats() telegraf.Aggregator {
+type configuredStats struct {
+	count    bool
+	min      bool
+	max      bool
+	mean     bool
+	variance bool
+	stdev    bool
+}
+
+func NewBasicStats() *BasicStats {
 	mm := &BasicStats{}
 	mm.Reset()
 	return mm
@@ -114,24 +127,102 @@ func (m *BasicStats) Add(in telegraf.Metric) {
 }
 
 func (m *BasicStats) Push(acc telegraf.Accumulator) {
+
+	config := getConfiguredStats(m)
+
 	for _, aggregate := range m.cache {
 		fields := map[string]interface{}{}
 		for k, v := range aggregate.fields {
+
+			if config.count {
 				fields[k+"_count"] = v.count
+			}
+			if config.min {
 				fields[k+"_min"] = v.min
+			}
+			if config.max {
 				fields[k+"_max"] = v.max
+			}
+			if config.mean {
 				fields[k+"_mean"] = v.mean
+			}
+
 			//v.count always >=1
 			if v.count > 1 {
 				variance := v.M2 / (v.count - 1)
+
+				if config.variance {
 					fields[k+"_s2"] = variance
+				}
+				if config.stdev {
 					fields[k+"_stdev"] = math.Sqrt(variance)
 				}
+			}
 			//if count == 1 StdDev = infinite => so I won't send data
 		}
+
+		if len(fields) > 0 {
 			acc.AddFields(aggregate.name, fields, aggregate.tags)
 		}
 	}
+}
+
+func parseStats(names []string) *configuredStats {
+
+	parsed := &configuredStats{}
+
+	for _, name := range names {
+
+		switch name {
+
+		case "count":
+			parsed.count = true
+		case "min":
+			parsed.min = true
+		case "max":
+			parsed.max = true
+		case "mean":
+			parsed.mean = true
+		case "s2":
+			parsed.variance = true
+		case "stdev":
+			parsed.stdev = true
+
+		default:
+			log.Printf("W! Unrecognized basic stat '%s', ignoring", name)
+		}
+	}
+
+	return parsed
+}
+
+func defaultStats() *configuredStats {
+
+	defaults := &configuredStats{}
+
+	defaults.count = true
+	defaults.min = true
+	defaults.max = true
+	defaults.mean = true
+	defaults.variance = true
+	defaults.stdev = true
+
+	return defaults
+}
+
+func getConfiguredStats(m *BasicStats) *configuredStats {
+
+	if m.statsConfig == nil {
+
+		if m.Stats == nil {
+			m.statsConfig = defaultStats()
+		} else {
+			m.statsConfig = parseStats(m.Stats)
+		}
+	}
+
+	return m.statsConfig
+}
 
 func (m *BasicStats) Reset() {
 	m.cache = make(map[uint64]aggregate)

plugins/aggregators/basicstats/basicstats_test.go

@@ -149,3 +149,211 @@ func TestBasicStatsDifferentPeriods(t *testing.T) {
 	}
 	acc.AssertContainsTaggedFields(t, "m1", expectedFields, expectedTags)
 }
+
+// Test only aggregating count
+func TestBasicStatsWithOnlyCount(t *testing.T) {
+
+	aggregator := NewBasicStats()
+	aggregator.Stats = []string{"count"}
+
+	aggregator.Add(m1)
+	aggregator.Add(m2)
+
+	acc := testutil.Accumulator{}
+	aggregator.Push(&acc)
+
+	expectedFields := map[string]interface{}{
+		"a_count": float64(2),
+		"b_count": float64(2),
+		"c_count": float64(2),
+		"d_count": float64(2),
+		"e_count": float64(1),
+	}
+	expectedTags := map[string]string{
+		"foo": "bar",
+	}
+	acc.AssertContainsTaggedFields(t, "m1", expectedFields, expectedTags)
+}
+
+// Test only aggregating minimum
+func TestBasicStatsWithOnlyMin(t *testing.T) {
+
+	aggregator := NewBasicStats()
+	aggregator.Stats = []string{"min"}
+
+	aggregator.Add(m1)
+	aggregator.Add(m2)
+
+	acc := testutil.Accumulator{}
+	aggregator.Push(&acc)
+
+	expectedFields := map[string]interface{}{
+		"a_min": float64(1),
+		"b_min": float64(1),
+		"c_min": float64(2),
+		"d_min": float64(2),
+		"e_min": float64(200),
+	}
+	expectedTags := map[string]string{
+		"foo": "bar",
+	}
+	acc.AssertContainsTaggedFields(t, "m1", expectedFields, expectedTags)
+}
+
+// Test only aggregating maximum
+func TestBasicStatsWithOnlyMax(t *testing.T) {
+
+	aggregator := NewBasicStats()
+	aggregator.Stats = []string{"max"}
+
+	aggregator.Add(m1)
+	aggregator.Add(m2)
+
+	acc := testutil.Accumulator{}
+	aggregator.Push(&acc)
+
+	expectedFields := map[string]interface{}{
+		"a_max": float64(1),
+		"b_max": float64(3),
+		"c_max": float64(4),
+		"d_max": float64(6),
+		"e_max": float64(200),
+	}
+	expectedTags := map[string]string{
+		"foo": "bar",
+	}
+	acc.AssertContainsTaggedFields(t, "m1", expectedFields, expectedTags)
+}
+
+// Test only aggregating mean
+func TestBasicStatsWithOnlyMean(t *testing.T) {
+
+	aggregator := NewBasicStats()
+	aggregator.Stats = []string{"mean"}
+
+	aggregator.Add(m1)
+	aggregator.Add(m2)
+
+	acc := testutil.Accumulator{}
+	aggregator.Push(&acc)
+
+	expectedFields := map[string]interface{}{
+		"a_mean": float64(1),
+		"b_mean": float64(2),
+		"c_mean": float64(3),
+		"d_mean": float64(4),
+		"e_mean": float64(200),
+	}
+	expectedTags := map[string]string{
+		"foo": "bar",
+	}
+	acc.AssertContainsTaggedFields(t, "m1", expectedFields, expectedTags)
+}
+
+// Test only aggregating variance
+func TestBasicStatsWithOnlyVariance(t *testing.T) {
+
+	aggregator := NewBasicStats()
+	aggregator.Stats = []string{"s2"}
+
+	aggregator.Add(m1)
+	aggregator.Add(m2)
+
+	acc := testutil.Accumulator{}
+	aggregator.Push(&acc)
+
+	expectedFields := map[string]interface{}{
+		"a_s2": float64(0),
+		"b_s2": float64(2),
+		"c_s2": float64(2),
+		"d_s2": float64(8),
+	}
+	expectedTags := map[string]string{
+		"foo": "bar",
+	}
+	acc.AssertContainsTaggedFields(t, "m1", expectedFields, expectedTags)
+}
+
+// Test only aggregating standard deviation
+func TestBasicStatsWithOnlyStandardDeviation(t *testing.T) {
+
+	aggregator := NewBasicStats()
+	aggregator.Stats = []string{"stdev"}
+
+	aggregator.Add(m1)
+	aggregator.Add(m2)
+
+	acc := testutil.Accumulator{}
+	aggregator.Push(&acc)
+
+	expectedFields := map[string]interface{}{
+		"a_stdev": float64(0),
+		"b_stdev": math.Sqrt(2),
+		"c_stdev": math.Sqrt(2),
+		"d_stdev": math.Sqrt(8),
+	}
+	expectedTags := map[string]string{
+		"foo": "bar",
+	}
+	acc.AssertContainsTaggedFields(t, "m1", expectedFields, expectedTags)
+}
+
+// Test only aggregating minimum and maximum
+func TestBasicStatsWithMinAndMax(t *testing.T) {
+
+	aggregator := NewBasicStats()
+	aggregator.Stats = []string{"min", "max"}
+
+	aggregator.Add(m1)
+	aggregator.Add(m2)
+
+	acc := testutil.Accumulator{}
+	aggregator.Push(&acc)
+
+	expectedFields := map[string]interface{}{
+		"a_max": float64(1), //a
+		"a_min": float64(1),
+		"b_max": float64(3), //b
+		"b_min": float64(1),
+		"c_max": float64(4), //c
+		"c_min": float64(2),
+		"d_max": float64(6), //d
+		"d_min": float64(2),
+		"e_max": float64(200), //e
+		"e_min": float64(200),
+	}
+	expectedTags := map[string]string{
+		"foo": "bar",
+	}
+	acc.AssertContainsTaggedFields(t, "m1", expectedFields, expectedTags)
+}
+
+// Test that if an empty array is passed, no points are pushed
+func TestBasicStatsWithNoStats(t *testing.T) {
+
+	aggregator := NewBasicStats()
+	aggregator.Stats = []string{}
+
+	aggregator.Add(m1)
+	aggregator.Add(m2)
+
+	acc := testutil.Accumulator{}
+	aggregator.Push(&acc)
+
+	acc.AssertDoesNotContainMeasurement(t, "m1")
+}
+
+// Test that if an unknown stat is configured, it doesn't explode
+func TestBasicStatsWithUnknownStat(t *testing.T) {
+
+	aggregator := NewBasicStats()
+	aggregator.Stats = []string{"crazy"}
+
+	aggregator.Add(m1)
+	aggregator.Add(m2)
+
+	acc := testutil.Accumulator{}
+	aggregator.Push(&acc)
+
+	acc.AssertDoesNotContainMeasurement(t, "m1")
+}