feat(aggregators.basicstats): Add "last" field (#15030)

plugins/aggregators/basicstats/README.md

@@ -1,6 +1,6 @@
 # BasicStats Aggregator Plugin
 
-The BasicStats aggregator plugin give us count, diff, max, min, mean,
+The BasicStats aggregator plugin gives count, diff, max, min, mean,
 non_negative_diff, sum, s2(variance), stdev for a set of values, emitting the
 aggregate every `period` seconds.
 
@@ -26,14 +26,13 @@ See the [CONFIGURATION.md][CONFIGURATION.md] for more details.
   drop_original = false
 
   ## Configures which basic stats to push as fields
-  # stats = ["count","diff","rate","min","max","mean","non_negative_diff","non_negative_rate","percent_change","stdev","s2","sum","interval"]
+  # stats = ["count","diff","rate","min","max","mean","non_negative_diff","non_negative_rate","percent_change","stdev","s2","sum","interval","last"]
 ```
 
 - stats
   - If not specified, then `count`, `min`, `max`, `mean`, `stdev`, and `s2` are
-  aggregated and pushed as fields.  `sum`, `diff`, `non_negative_diff`,
+  aggregated and pushed as fields. Other fields are not aggregated by default
-  `percent_change` are not aggregated by default to maintain backwards
+  to maintain backwards compatibility.
-  compatibility.
   - If empty array, no stats are aggregated
 
 ## Measurements & Fields
@@ -52,6 +51,7 @@ See the [CONFIGURATION.md][CONFIGURATION.md] for more details.
   - field1_s2 (variance)
   - field1_stdev (standard deviation)
   - field1_interval (interval in nanoseconds)
+  - field1_last (last aggregated value)
 
 ## Tags
 
@@ -62,8 +62,8 @@ No tags are applied by this aggregator.
 ```text
 system,host=tars load1=1 1475583980000000000
 system,host=tars load1=1 1475583990000000000
-system,host=tars load1_count=2,load1_diff=0,load1_rate=0,load1_max=1,load1_min=1,load1_mean=1,load1_sum=2,load1_s2=0,load1_stdev=0,load1_interval=10000000000i 1475584010000000000
+system,host=tars load1_count=2,load1_diff=0,load1_rate=0,load1_max=1,load1_min=1,load1_mean=1,load1_sum=2,load1_s2=0,load1_stdev=0,load1_interval=10000000000i,load1_last=1 1475584010000000000
 system,host=tars load1=1 1475584020000000000
 system,host=tars load1=3 1475584030000000000
-system,host=tars load1_count=2,load1_diff=2,load1_rate=0.2,load1_max=3,load1_min=1,load1_mean=2,load1_sum=4,load1_s2=2,load1_stdev=1.414162,load1_interval=10000000000i 1475584010000000000
+system,host=tars load1_count=2,load1_diff=2,load1_rate=0.2,load1_max=3,load1_min=1,load1_mean=2,load1_sum=4,load1_s2=2,load1_stdev=1.414162,load1_interval=10000000000i,load1_last=3 1475584010000000000
 ```

plugins/aggregators/basicstats/basicstats.go

@@ -35,6 +35,7 @@ type configuredStats struct {
 	nonNegativeRate bool
 	percentChange   bool
 	interval        bool
+	last            bool
 }
 
 func NewBasicStats() *BasicStats {
@@ -58,8 +59,9 @@ type basicstats struct {
 	diff     float64
 	rate     float64
 	interval time.Duration
+	last     float64
 	M2       float64   //intermediate value for variance/stdev
-	LAST     float64   //intermediate value for diff
+	PREVIOUS float64   //intermediate value for diff
 	TIME     time.Time //intermediate value for rate
 }
 
@@ -79,16 +81,17 @@ func (b *BasicStats) Add(in telegraf.Metric) {
 		for _, field := range in.FieldList() {
 			if fv, ok := convert(field.Value); ok {
 				a.fields[field.Key] = basicstats{
-					count: 1,
+					count:    1,
-					min:   fv,
+					min:      fv,
-					max:   fv,
+					max:      fv,
-					mean:  fv,
+					mean:     fv,
-					sum:   fv,
+					sum:      fv,
-					diff:  0.0,
+					diff:     0.0,
-					rate:  0.0,
+					rate:     0.0,
-					M2:    0.0,
+					last:     fv,
-					LAST:  fv,
+					M2:       0.0,
-					TIME:  in.Time(),
+					PREVIOUS: fv,
+					TIME:     in.Time(),
 				}
 			}
 		}
@@ -107,8 +110,9 @@ func (b *BasicStats) Add(in telegraf.Metric) {
 						diff:     0.0,
 						rate:     0.0,
 						interval: 0,
+						last:     fv,
 						M2:       0.0,
-						LAST:     fv,
+						PREVIOUS: fv,
 						TIME:     in.Time(),
 					}
 					continue
@@ -139,13 +143,15 @@ func (b *BasicStats) Add(in telegraf.Metric) {
 				//sum compute
 				tmp.sum += fv
 				//diff compute
-				tmp.diff = fv - tmp.LAST
+				tmp.diff = fv - tmp.PREVIOUS
 				//interval compute
 				tmp.interval = in.Time().Sub(tmp.TIME)
 				//rate compute
 				if !in.Time().Equal(tmp.TIME) {
 					tmp.rate = tmp.diff / tmp.interval.Seconds()
 				}
+				//last compute
+				tmp.last = fv
 				//store final data
 				b.cache[id].fields[field.Key] = tmp
 			}
@@ -172,6 +178,9 @@ func (b *BasicStats) Push(acc telegraf.Accumulator) {
 			if b.statsConfig.sum {
 				fields[k+"_sum"] = v.sum
 			}
+			if b.statsConfig.last {
+				fields[k+"_last"] = v.last
+			}
 
 			//v.count always >=1
 			if v.count > 1 {
@@ -193,7 +202,7 @@ func (b *BasicStats) Push(acc telegraf.Accumulator) {
 					fields[k+"_rate"] = v.rate
 				}
 				if b.statsConfig.percentChange {
-					fields[k+"_percent_change"] = v.diff / v.LAST * 100
+					fields[k+"_percent_change"] = v.diff / v.PREVIOUS * 100
 				}
 				if b.statsConfig.nonNegativeRate && v.diff >= 0 {
 					fields[k+"_non_negative_rate"] = v.rate
@@ -243,6 +252,8 @@ func (b *BasicStats) parseStats() *configuredStats {
 			parsed.percentChange = true
 		case "interval":
 			parsed.interval = true
+		case "last":
+			parsed.last = true
 		default:
 			b.Log.Warnf("Unrecognized basic stat %q, ignoring", name)
 		}
@@ -261,10 +272,13 @@ func (b *BasicStats) getConfiguredStats() {
 			variance:        true,
 			stdev:           true,
 			sum:             false,
+			diff:            false,
 			nonNegativeDiff: false,
 			rate:            false,
 			nonNegativeRate: false,
 			percentChange:   false,
+			interval:        false,
+			last:            false,
 		}
 	} else {
 		b.statsConfig = b.parseStats()

plugins/aggregators/basicstats/basicstats_test.go

@@ -111,6 +111,7 @@ func TestBasicStatsWithPeriod(t *testing.T) {
 func TestBasicStatsDifferentPeriods(t *testing.T) {
 	acc := testutil.Accumulator{}
 	minmax := NewBasicStats()
+	minmax.Stats = []string{"count", "max", "min", "mean", "last"}
 	minmax.Log = testutil.Logger{}
 	minmax.getConfiguredStats()
 
@@ -121,22 +122,27 @@ func TestBasicStatsDifferentPeriods(t *testing.T) {
 		"a_max":   float64(1),
 		"a_min":   float64(1),
 		"a_mean":  float64(1),
+		"a_last":  float64(1),
 		"b_count": float64(1), //b
 		"b_max":   float64(1),
 		"b_min":   float64(1),
 		"b_mean":  float64(1),
+		"b_last":  float64(1),
 		"c_count": float64(1), //c
 		"c_max":   float64(2),
 		"c_min":   float64(2),
 		"c_mean":  float64(2),
+		"c_last":  float64(2),
 		"d_count": float64(1), //d
 		"d_max":   float64(2),
 		"d_min":   float64(2),
 		"d_mean":  float64(2),
+		"d_last":  float64(2),
 		"g_count": float64(1), //g
 		"g_max":   float64(3),
 		"g_min":   float64(3),
 		"g_mean":  float64(3),
+		"g_last":  float64(3),
 	}
 	expectedTags := map[string]string{
 		"foo": "bar",
@@ -152,30 +158,37 @@ func TestBasicStatsDifferentPeriods(t *testing.T) {
 		"a_max":   float64(1),
 		"a_min":   float64(1),
 		"a_mean":  float64(1),
+		"a_last":  float64(1),
 		"b_count": float64(1), //b
 		"b_max":   float64(3),
 		"b_min":   float64(3),
 		"b_mean":  float64(3),
+		"b_last":  float64(3),
 		"c_count": float64(1), //c
 		"c_max":   float64(4),
 		"c_min":   float64(4),
 		"c_mean":  float64(4),
+		"c_last":  float64(4),
 		"d_count": float64(1), //d
 		"d_max":   float64(6),
 		"d_min":   float64(6),
 		"d_mean":  float64(6),
+		"d_last":  float64(6),
 		"e_count": float64(1), //e
 		"e_max":   float64(200),
 		"e_min":   float64(200),
 		"e_mean":  float64(200),
+		"e_last":  float64(200),
 		"f_count": float64(1), //f
 		"f_max":   float64(200),
 		"f_min":   float64(200),
 		"f_mean":  float64(200),
+		"f_last":  float64(200),
 		"g_count": float64(1), //g
 		"g_max":   float64(1),
 		"g_min":   float64(1),
 		"g_mean":  float64(1),
+		"g_last":  float64(1),
 	}
 	expectedTags = map[string]string{
 		"foo": "bar",
@@ -616,7 +629,7 @@ func TestBasicStatsWithAllStats(t *testing.T) {
 	acc := testutil.Accumulator{}
 	minmax := NewBasicStats()
 	minmax.Log = testutil.Logger{}
-	minmax.Stats = []string{"count", "min", "max", "mean", "stdev", "s2", "sum"}
+	minmax.Stats = []string{"count", "min", "max", "mean", "stdev", "s2", "sum", "last"}
 	minmax.getConfiguredStats()
 
 	minmax.Add(m1)
@@ -631,12 +644,14 @@ func TestBasicStatsWithAllStats(t *testing.T) {
 		"a_stdev": float64(0),
 		"a_s2":    float64(0),
 		"a_sum":   float64(2),
+		"a_last":  float64(1),
 		"b_count": float64(2), //b
 		"b_max":   float64(3),
 		"b_min":   float64(1),
 		"b_mean":  float64(2),
 		"b_s2":    float64(2),
 		"b_sum":   float64(4),
+		"b_last":  float64(3),
 		"b_stdev": math.Sqrt(2),
 		"c_count": float64(2), //c
 		"c_max":   float64(4),
@@ -645,6 +660,7 @@ func TestBasicStatsWithAllStats(t *testing.T) {
 		"c_s2":    float64(2),
 		"c_stdev": math.Sqrt(2),
 		"c_sum":   float64(6),
+		"c_last":  float64(4),
 		"d_count": float64(2), //d
 		"d_max":   float64(6),
 		"d_min":   float64(2),
@@ -652,16 +668,19 @@ func TestBasicStatsWithAllStats(t *testing.T) {
 		"d_s2":    float64(8),
 		"d_stdev": math.Sqrt(8),
 		"d_sum":   float64(8),
+		"d_last":  float64(6),
 		"e_count": float64(1), //e
 		"e_max":   float64(200),
 		"e_min":   float64(200),
 		"e_mean":  float64(200),
 		"e_sum":   float64(200),
+		"e_last":  float64(200),
 		"f_count": float64(1), //f
 		"f_max":   float64(200),
 		"f_min":   float64(200),
 		"f_mean":  float64(200),
 		"f_sum":   float64(200),
+		"f_last":  float64(200),
 		"g_count": float64(2), //g
 		"g_max":   float64(3),
 		"g_min":   float64(1),
@@ -669,6 +688,7 @@ func TestBasicStatsWithAllStats(t *testing.T) {
 		"g_s2":    float64(2),
 		"g_stdev": math.Sqrt(2),
 		"g_sum":   float64(4),
+		"g_last":  float64(1),
 	}
 	expectedTags := map[string]string{
 		"foo": "bar",
@@ -731,3 +751,30 @@ func TestBasicStatsWithDefaultStats(t *testing.T) {
 	require.True(t, acc.HasField("m1", "a_s2"))
 	require.False(t, acc.HasField("m1", "a_sum"))
 }
+
+func TestBasicStatsWithOnlyLast(t *testing.T) {
+	aggregator := NewBasicStats()
+	aggregator.Stats = []string{"last"}
+	aggregator.Log = testutil.Logger{}
+	aggregator.getConfiguredStats()
+
+	aggregator.Add(m1)
+	aggregator.Add(m2)
+
+	acc := testutil.Accumulator{}
+	aggregator.Push(&acc)
+
+	expectedFields := map[string]interface{}{
+		"a_last": float64(1),
+		"b_last": float64(3),
+		"c_last": float64(4),
+		"d_last": float64(6),
+		"e_last": float64(200),
+		"f_last": float64(200),
+		"g_last": float64(1),
+	}
+	expectedTags := map[string]string{
+		"foo": "bar",
+	}
+	acc.AssertContainsTaggedFields(t, "m1", expectedFields, expectedTags)
+}

plugins/aggregators/basicstats/sample.conf

@@ -8,4 +8,4 @@
   drop_original = false
 
   ## Configures which basic stats to push as fields
-  # stats = ["count","diff","rate","min","max","mean","non_negative_diff","non_negative_rate","percent_change","stdev","s2","sum","interval"]
+  # stats = ["count","diff","rate","min","max","mean","non_negative_diff","non_negative_rate","percent_change","stdev","s2","sum","interval","last"]