Removed Mean aggregation (#638)

Fixes: #637

exporter/prometheus/prometheus.go

@@ -233,20 +233,14 @@ func (c *collector) toMetric(desc *prometheus.Desc, v *view.View, row *view.Row)
 	switch data := row.Data.(type) {
 	case *view.CountData:
 		return prometheus.NewConstMetric(desc, prometheus.CounterValue, float64(*data), tagValues(row.Tags)...)
-
 	case *view.DistributionData:
 		points := make(map[float64]uint64)
 		for i, b := range v.Aggregation.Buckets {
 			points[b] = uint64(data.CountPerBucket[i])
 		}
 		return prometheus.NewConstHistogram(desc, uint64(data.Count), data.Sum(), points, tagValues(row.Tags)...)
-
-	case *view.MeanData:
-		return prometheus.NewConstSummary(desc, uint64(data.Count), data.Sum(), make(map[float64]float64), tagValues(row.Tags)...)
-
 	case *view.SumData:
 		return prometheus.NewConstMetric(desc, prometheus.UntypedValue, float64(*data), tagValues(row.Tags)...)
-
 	default:
 		return nil, fmt.Errorf("aggregation %T is not yet supported", v.Aggregation)
 	}

exporter/prometheus/prometheus_test.go

@@ -49,10 +49,6 @@ func newView(measureName string, agg *view.Aggregation) *view.View {
 func TestOnlyCumulativeWindowSupported(t *testing.T) {
 	// See Issue https://github.com/census-instrumentation/opencensus-go/issues/214.
 	count1 := view.CountData(1)
-	mean1 := view.MeanData{
-		Mean:  4.5,
-		Count: 5,
-	}
 	tests := []struct {
 		vds  *view.Data
 		want int
@@ -72,15 +68,6 @@ func TestOnlyCumulativeWindowSupported(t *testing.T) {
 			},
 			want: 1,
 		},
-		2: {
-			vds: &view.Data{
-				View: newView("TestOnlyCumulativeWindowSupported/m3", view.Mean()),
-				Rows: []*view.Row{
-					{Data: &mean1},
-				},
-			},
-			want: 1,
-		},
 	}
 
 	for i, tt := range tests {
@@ -144,9 +131,7 @@ func TestCollectNonRacy(t *testing.T) {
 
 		for i := 0; i < 1e3; i++ {
 			count1 := view.CountData(1)
-			mean1 := &view.MeanData{Mean: 4.5, Count: 5}
 			vds := []*view.Data{
-				{View: newView(fmt.Sprintf("TestCollectNonRacy/m1-%d", i), view.Mean()), Rows: []*view.Row{{Data: mean1}}},
 				{View: newView(fmt.Sprintf("TestCollectNonRacy/m2-%d", i), view.Count()), Rows: []*view.Row{{Data: &count1}}},
 			}
 			for _, v := range vds {

exporter/stackdriver/stats.go

@@ -317,22 +317,6 @@ func newTypedValue(vd *view.View, r *view.Row) *monitoringpb.TypedValue {
 		return &monitoringpb.TypedValue{Value: &monitoringpb.TypedValue_DoubleValue{
 			DoubleValue: float64(*v),
 		}}
-	case *view.MeanData:
-		return &monitoringpb.TypedValue{Value: &monitoringpb.TypedValue_DistributionValue{
-			DistributionValue: &distributionpb.Distribution{
-				Count: int64(v.Count),
-				Mean:  v.Mean,
-				SumOfSquaredDeviation: 0,
-				BucketOptions: &distributionpb.Distribution_BucketOptions{
-					Options: &distributionpb.Distribution_BucketOptions_ExplicitBuckets{
-						ExplicitBuckets: &distributionpb.Distribution_BucketOptions_Explicit{
-							Bounds: []float64{0},
-						},
-					},
-				},
-				BucketCounts: []int64{0, int64(v.Count)},
-			},
-		}}
 	case *view.DistributionData:
 		return &monitoringpb.TypedValue{Value: &monitoringpb.TypedValue_DistributionValue{
 			DistributionValue: &distributionpb.Distribution{

exporter/stackdriver/stats_test.go

@@ -26,7 +26,6 @@ import (
 	"go.opencensus.io/stats/view"
 	"go.opencensus.io/tag"
 	"google.golang.org/api/option"
-	distributionpb "google.golang.org/genproto/googleapis/api/distribution"
 	"google.golang.org/genproto/googleapis/api/label"
 	"google.golang.org/genproto/googleapis/api/metric"
 	metricpb "google.golang.org/genproto/googleapis/api/metric"
@@ -101,14 +100,6 @@ func TestExporter_makeReq(t *testing.T) {
 	count2 := view.CountData(16)
 	sum1 := view.SumData(5.5)
 	sum2 := view.SumData(-11.1)
-	mean1 := view.MeanData{
-		Mean:  3.3,
-		Count: 7,
-	}
-	mean2 := view.MeanData{
-		Mean:  -7.7,
-		Count: 5,
-	}
 	taskValue := getTaskValue()
 
 	tests := []struct {
@@ -253,98 +244,6 @@ func TestExporter_makeReq(t *testing.T) {
 				},
 			}},
 		},
-		{
-			name:   "mean agg + timeline",
-			projID: "proj-id",
-			vd:     newTestViewData(v, start, end, &mean1, &mean2),
-			want: []*monitoringpb.CreateTimeSeriesRequest{{
-				Name: monitoring.MetricProjectPath("proj-id"),
-				TimeSeries: []*monitoringpb.TimeSeries{
-					{
-						Metric: &metricpb.Metric{
-							Type: "custom.googleapis.com/opencensus/testview",
-							Labels: map[string]string{
-								"test_key":        "test-value-1",
-								opencensusTaskKey: taskValue,
-							},
-						},
-						Resource: &monitoredrespb.MonitoredResource{
-							Type: "global",
-						},
-						Points: []*monitoringpb.Point{
-							{
-								Interval: &monitoringpb.TimeInterval{
-									StartTime: &timestamp.Timestamp{
-										Seconds: start.Unix(),
-										Nanos:   int32(start.Nanosecond()),
-									},
-									EndTime: &timestamp.Timestamp{
-										Seconds: end.Unix(),
-										Nanos:   int32(end.Nanosecond()),
-									},
-								},
-								Value: &monitoringpb.TypedValue{Value: &monitoringpb.TypedValue_DistributionValue{
-									DistributionValue: &distributionpb.Distribution{
-										Count: 7,
-										Mean:  3.3,
-										SumOfSquaredDeviation: 0,
-										BucketOptions: &distributionpb.Distribution_BucketOptions{
-											Options: &distributionpb.Distribution_BucketOptions_ExplicitBuckets{
-												ExplicitBuckets: &distributionpb.Distribution_BucketOptions_Explicit{
-													Bounds: []float64{0},
-												},
-											},
-										},
-										BucketCounts: []int64{0, 7},
-									},
-								}},
-							},
-						},
-					},
-					{
-						Metric: &metricpb.Metric{
-							Type: "custom.googleapis.com/opencensus/testview",
-							Labels: map[string]string{
-								"test_key":        "test-value-2",
-								opencensusTaskKey: taskValue,
-							},
-						},
-						Resource: &monitoredrespb.MonitoredResource{
-							Type: "global",
-						},
-						Points: []*monitoringpb.Point{
-							{
-								Interval: &monitoringpb.TimeInterval{
-									StartTime: &timestamp.Timestamp{
-										Seconds: start.Unix(),
-										Nanos:   int32(start.Nanosecond()),
-									},
-									EndTime: &timestamp.Timestamp{
-										Seconds: end.Unix(),
-										Nanos:   int32(end.Nanosecond()),
-									},
-								},
-								Value: &monitoringpb.TypedValue{Value: &monitoringpb.TypedValue_DistributionValue{
-									DistributionValue: &distributionpb.Distribution{
-										Count: 5,
-										Mean:  -7.7,
-										SumOfSquaredDeviation: 0,
-										BucketOptions: &distributionpb.Distribution_BucketOptions{
-											Options: &distributionpb.Distribution_BucketOptions_ExplicitBuckets{
-												ExplicitBuckets: &distributionpb.Distribution_BucketOptions_Explicit{
-													Bounds: []float64{0},
-												},
-											},
-										},
-										BucketCounts: []int64{0, 5},
-									},
-								}},
-							},
-						},
-					},
-				},
-			}},
-		},
 		{
 			name:   "dist agg + time window",
 			projID: "proj-id",
@@ -479,16 +378,6 @@ func TestEqualAggWindowTagKeys(t *testing.T) {
 			agg:     view.Sum(),
 			wantErr: false,
 		},
-		{
-			name: "mean agg",
-			md: &metricpb.MetricDescriptor{
-				MetricKind: metricpb.MetricDescriptor_CUMULATIVE,
-				ValueType:  metricpb.MetricDescriptor_DISTRIBUTION,
-				Labels:     []*label.LabelDescriptor{{Key: opencensusTaskKey}},
-			},
-			agg:     view.Mean(),
-			wantErr: false,
-		},
 		{
 			name: "distribution agg - mismatch",
 			md: &metricpb.MetricDescriptor{
@@ -499,16 +388,6 @@ func TestEqualAggWindowTagKeys(t *testing.T) {
 			agg:     view.Count(),
 			wantErr: true,
 		},
-		{
-			name: "mean agg - mismatch",
-			md: &metricpb.MetricDescriptor{
-				MetricKind: metricpb.MetricDescriptor_CUMULATIVE,
-				ValueType:  metricpb.MetricDescriptor_DOUBLE,
-				Labels:     []*label.LabelDescriptor{{Key: opencensusTaskKey}},
-			},
-			agg:     view.Mean(),
-			wantErr: true,
-		},
 		{
 			name: "distribution agg with keys",
 			md: &metricpb.MetricDescriptor{

internal/readme/stats.go

@@ -38,10 +38,9 @@ func statsExamples() {
 	distAgg := view.Distribution(0, 1<<32, 2<<32, 3<<32)
 	countAgg := view.Count()
 	sumAgg := view.Sum()
-	meanAgg := view.Mean()
 	// END aggs
 
-	_, _, _, _ = distAgg, countAgg, sumAgg, meanAgg
+	_, _, _ = distAgg, countAgg, sumAgg
 
 	// START view
 	if err = view.Subscribe(&view.View{

plugin/ocgrpc/client_metrics.go

@@ -43,7 +43,7 @@ var (
 		Description: "RPC Errors",
 		TagKeys:     []tag.Key{KeyStatus, KeyMethod},
 		Measure:     ClientErrorCount,
-		Aggregation: view.Mean(),
+		Aggregation: view.Count(),
 	}
 
 	ClientRoundTripLatencyView = &view.View{

plugin/ocgrpc/client_metrics_test.go

@@ -40,7 +40,7 @@ func TestViewsAggregationsConform(t *testing.T) {
 		}
 	}
 
-	assertTypeOf(ClientErrorCountView, view.Mean())
+	assertTypeOf(ClientErrorCountView, view.Sum())
 	assertTypeOf(ClientRoundTripLatencyView, view.Distribution())
 	assertTypeOf(ClientRequestBytesView, view.Distribution())
 	assertTypeOf(ClientResponseBytesView, view.Distribution())

plugin/ocgrpc/client_stats_handler_test.go

@@ -158,7 +158,7 @@ func TestClientDefaultCollections(t *testing.T) {
 								{Key: KeyStatus, Value: "Canceled"},
 								{Key: KeyMethod, Value: "package.service/method"},
 							},
-							Data: newMeanData(1, 1),
+							Data: newCountData(1),
 						},
 					},
 				},
@@ -238,14 +238,14 @@ func TestClientDefaultCollections(t *testing.T) {
 								{Key: KeyStatus, Value: "Canceled"},
 								{Key: KeyMethod, Value: "package.service/method"},
 							},
-							Data: newMeanData(1, 1),
+							Data: newCountData(1),
 						},
 						{
 							Tags: []tag.Tag{
 								{Key: KeyStatus, Value: "Aborted"},
 								{Key: KeyMethod, Value: "package.service/method"},
 							},
-							Data: newMeanData(1, 1),
+							Data: newCountData(1),
 						},
 					},
 				},

plugin/ocgrpc/server_stats_handler_test.go

@@ -358,11 +358,6 @@ func newCountData(v int) *view.CountData {
 	return &cav
 }
 
-func newMeanData(count int64, mean float64) *view.MeanData {
-	mav := view.MeanData{Count: count, Mean: mean}
-	return &mav
-}
-
 func newDistributionData(countPerBucket []int64, count int64, min, max, mean, sumOfSquaredDev float64) *view.DistributionData {
 	return &view.DistributionData{
 		Count:           count,

stats/view/aggregation.go

@@ -50,12 +50,6 @@ var (
 			return newSumData(0)
 		},
 	}
-	aggMean = &Aggregation{
-		Type: AggTypeMean,
-		newData: func() AggregationData {
-			return newMeanData(0, 0)
-		},
-	}
 )
 
 // Count indicates that data collected and aggregated
@@ -74,14 +68,6 @@ func Sum() *Aggregation {
 	return aggSum
 }
 
-// Mean indicates that collect and aggregate data and maintain
-// the mean value.
-// For example, average latency in milliseconds can be aggregated by using
-// Mean, although in most cases it is preferable to use a Distribution.
-func Mean() *Aggregation {
-	return aggMean
-}
-
 // Distribution indicates that the desired aggregation is
 // a histogram distribution.
 //

stats/view/aggregation_data.go

@@ -90,48 +90,6 @@ func (a *SumData) equal(other AggregationData) bool {
 	return math.Pow(float64(*a)-float64(*a2), 2) < epsilon
 }
 
-// MeanData is the aggregated data for the Mean aggregation.
-// A mean aggregation processes data and maintains the mean value.
-//
-// Most users won't directly access mean data.
-type MeanData struct {
-	Count int64   // number of data points aggregated
-	Mean  float64 // mean of all data points
-}
-
-func newMeanData(mean float64, count int64) *MeanData {
-	return &MeanData{
-		Mean:  mean,
-		Count: count,
-	}
-}
-
-// Sum returns the sum of all samples collected.
-func (a *MeanData) Sum() float64 { return a.Mean * float64(a.Count) }
-
-func (a *MeanData) isAggregationData() bool { return true }
-
-func (a *MeanData) addSample(f float64) {
-	a.Count++
-	if a.Count == 1 {
-		a.Mean = f
-		return
-	}
-	a.Mean = a.Mean + (f-a.Mean)/float64(a.Count)
-}
-
-func (a *MeanData) clone() AggregationData {
-	return newMeanData(a.Mean, a.Count)
-}
-
-func (a *MeanData) equal(other AggregationData) bool {
-	a2, ok := other.(*MeanData)
-	if !ok {
-		return false
-	}
-	return a.Count == a2.Count && math.Pow(a.Mean-a2.Mean, 2) < epsilon
-}
-
 // DistributionData is the aggregated data for the
 // Distribution aggregation.
 //

stats/view/aggregation_data_test.go

@@ -41,10 +41,6 @@ func TestDataClone(t *testing.T) {
 			name: "distribution data",
 			src:  dist,
 		},
-		{
-			name: "mean data",
-			src:  newMeanData(11.0, 5),
-		},
 		{
 			name: "sum data",
 			src:  newSumData(65.7),