Use uint64 Count consistently in metric aggregation

CHANGELOG.md

@@ -25,6 +25,7 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 - `NewExporter` from `exporters/otlp` now takes a `ProtocolDriver` as a parameter. (#1369)
 - Many OTLP Exporter options became gRPC ProtocolDriver options. (#1369)
 - Unify endpoint API that related to OTel exporter. (#1401)
+- Metric aggregator Count() and histogram Bucket.Counts are consistently `uint64`. (1430)
 
 ### Removed
 

exporters/otlp/internal/transform/metric.go

@@ -458,7 +458,7 @@ func sumPoint(record export.Record, num number.Number, start, end time.Time, ek
 
 // minMaxSumCountValue returns the values of the MinMaxSumCount Aggregator
 // as discrete values.
-func minMaxSumCountValues(a aggregation.MinMaxSumCount) (min, max, sum number.Number, count int64, err error) {
+func minMaxSumCountValues(a aggregation.MinMaxSumCount) (min, max, sum number.Number, count uint64, err error) {
 	if min, err = a.Min(); err != nil {
 		return
 	}
@@ -531,7 +531,7 @@ func minMaxSumCount(record export.Record, a aggregation.MinMaxSumCount) (*metric
 	return m, nil
 }
 
-func histogramValues(a aggregation.Histogram) (boundaries []float64, counts []float64, err error) {
+func histogramValues(a aggregation.Histogram) (boundaries []float64, counts []uint64, err error) {
 	var buckets aggregation.Buckets
 	if buckets, err = a.Histogram(); err != nil {
 		return
@@ -563,10 +563,6 @@ func histogramPoint(record export.Record, ek export.ExportKind, a aggregation.Hi
 		return nil, err
 	}
 
-	buckets := make([]uint64, len(counts))
-	for i := 0; i < len(counts); i++ {
-		buckets[i] = uint64(counts[i])
-	}
 	m := &metricpb.Metric{
 		Name:        desc.Name(),
 		Description: desc.Description(),
@@ -584,7 +580,7 @@ func histogramPoint(record export.Record, ek export.ExportKind, a aggregation.Hi
 						StartTimeUnixNano: toNanos(record.StartTime()),
 						TimeUnixNano:      toNanos(record.EndTime()),
 						Count:             uint64(count),
-						BucketCounts:      buckets,
+						BucketCounts:      counts,
 						ExplicitBounds:    boundaries,
 					},
 				},
@@ -601,7 +597,7 @@ func histogramPoint(record export.Record, ek export.ExportKind, a aggregation.Hi
 						StartTimeUnixNano: toNanos(record.StartTime()),
 						TimeUnixNano:      toNanos(record.EndTime()),
 						Count:             uint64(count),
-						BucketCounts:      buckets,
+						BucketCounts:      counts,
 						ExplicitBounds:    boundaries,
 					},
 				},

exporters/otlp/internal/transform/metric_test.go

@@ -117,7 +117,7 @@ func TestMinMaxSumCountValue(t *testing.T) {
 		assert.Equal(t, min, number.NewInt64Number(1))
 		assert.Equal(t, max, number.NewInt64Number(10))
 		assert.Equal(t, sum, number.NewInt64Number(11))
-		assert.Equal(t, count, int64(2))
+		assert.Equal(t, count, uint64(2))
 	}
 }
 
@@ -369,7 +369,7 @@ func (te *testErrMinMaxSumCount) Max() (number.Number, error) {
 	return 0, te.err
 }
 
-func (te *testErrMinMaxSumCount) Count() (int64, error) {
+func (te *testErrMinMaxSumCount) Count() (uint64, error) {
 	return 0, te.err
 }
 

sdk/export/metric/aggregation/aggregation.go

@@ -43,7 +43,7 @@ type (
 	// Count returns the number of values that were aggregated.
 	Count interface {
 		Aggregation
-		Count() (int64, error)
+		Count() (uint64, error)
 	}
 
 	// Min returns the minimum value over the set of values that were aggregated.
@@ -86,16 +86,14 @@ type (
 		// aggregating integers.
 		Boundaries []float64
 
-		// Counts are floating point numbers to account for
-		// the possibility of sampling which allows for
-		// non-integer count values.
-		Counts []float64
+		// Counts holds the count in each bucket.
+		Counts []uint64
 	}
 
 	// Histogram returns the count of events in pre-determined buckets.
 	Histogram interface {
 		Aggregation
-		Count() (int64, error)
+		Count() (uint64, error)
 		Sum() (number.Number, error)
 		Histogram() (Buckets, error)
 	}
@@ -106,7 +104,7 @@ type (
 		Min() (number.Number, error)
 		Max() (number.Number, error)
 		Sum() (number.Number, error)
-		Count() (int64, error)
+		Count() (uint64, error)
 	}
 
 	// Distribution supports the Min, Max, Sum, Count, and Quantile
@@ -116,7 +114,7 @@ type (
 		Min() (number.Number, error)
 		Max() (number.Number, error)
 		Sum() (number.Number, error)
-		Count() (int64, error)
+		Count() (uint64, error)
 		Quantile(float64) (number.Number, error)
 	}
 )

sdk/metric/aggregator/aggregatortest/test.go

@@ -134,8 +134,8 @@ func (n *Numbers) Sum() number.Number {
 	return sum
 }
 
-func (n *Numbers) Count() int64 {
-	return int64(len(n.numbers))
+func (n *Numbers) Count() uint64 {
+	return uint64(len(n.numbers))
 }
 
 func (n *Numbers) Min() number.Number {
@@ -223,7 +223,7 @@ func SynchronizedMoveResetTest(t *testing.T, mkind metric.InstrumentKind, nf fun
 
 			if count, ok := agg.(aggregation.Count); ok {
 				c, err := count.Count()
-				require.Equal(t, int64(0), c)
+				require.Equal(t, uint64(0), c)
 				require.NoError(t, err)
 			}
 
@@ -270,7 +270,7 @@ func SynchronizedMoveResetTest(t *testing.T, mkind metric.InstrumentKind, nf fun
 
 			if count, ok := agg.(aggregation.Count); ok {
 				c, err := count.Count()
-				require.Equal(t, int64(1), c)
+				require.Equal(t, uint64(1), c)
 				require.NoError(t, err)
 			}
 

sdk/metric/aggregator/array/array.go

@@ -68,8 +68,8 @@ func (c *Aggregator) Sum() (number.Number, error) {
 }
 
 // Count returns the number of values in the checkpoint.
-func (c *Aggregator) Count() (int64, error) {
-	return int64(len(c.points)), nil
+func (c *Aggregator) Count() (uint64, error) {
+	return uint64(len(c.points)), nil
 }
 
 // Max returns the maximum value in the checkpoint.

sdk/metric/aggregator/array/array_test.go

@@ -42,7 +42,7 @@ func checkZero(t *testing.T, agg *Aggregator, desc *metric.Descriptor) {
 
 	count, err := agg.Count()
 	require.NoError(t, err)
-	require.Equal(t, int64(0), count)
+	require.Equal(t, uint64(0), count)
 
 	max, err := agg.Max()
 	require.True(t, errors.Is(err, aggregation.ErrNoData))
@@ -237,7 +237,7 @@ func TestArrayErrors(t *testing.T) {
 		require.NoError(t, agg.SynchronizedMove(ckpt, descriptor))
 
 		count, err := ckpt.Count()
-		require.Equal(t, int64(1), count, "NaN value was not counted")
+		require.Equal(t, uint64(1), count, "NaN value was not counted")
 		require.Nil(t, err)
 
 		num, err := ckpt.Quantile(0)

sdk/metric/aggregator/ddsketch/ddsketch.go

@@ -79,8 +79,8 @@ func (c *Aggregator) Sum() (number.Number, error) {
 }
 
 // Count returns the number of values in the checkpoint.
-func (c *Aggregator) Count() (int64, error) {
-	return c.sketch.Count(), nil
+func (c *Aggregator) Count() (uint64, error) {
+	return uint64(c.sketch.Count()), nil
 }
 
 // Max returns the maximum value in the checkpoint.

sdk/metric/aggregator/ddsketch/ddsketch_test.go

@@ -51,7 +51,7 @@ func checkZero(t *testing.T, agg *Aggregator, desc *metric.Descriptor) {
 
 	count, err := agg.Count()
 	require.NoError(t, err)
-	require.Equal(t, int64(0), count)
+	require.Equal(t, uint64(0), count)
 
 	max, err := agg.Max()
 	require.True(t, errors.Is(err, aggregation.ErrNoData))

sdk/metric/aggregator/histogram/histogram.go

@@ -45,9 +45,9 @@ type (
 	// the sum and counts for all observed values and
 	// the less than equal bucket count for the pre-determined boundaries.
 	state struct {
-		bucketCounts []float64
+		bucketCounts []uint64
 		sum          number.Number
-		count        int64
+		count        uint64
 	}
 )
 
@@ -100,7 +100,7 @@ func (c *Aggregator) Sum() (number.Number, error) {
 }
 
 // Count returns the number of values in the checkpoint.
-func (c *Aggregator) Count() (int64, error) {
+func (c *Aggregator) Count() (uint64, error) {
 	return c.state.count, nil
 }
 
@@ -135,7 +135,7 @@ func (c *Aggregator) SynchronizedMove(oa export.Aggregator, desc *metric.Descrip
 
 func emptyState(boundaries []float64) state {
 	return state{
-		bucketCounts: make([]float64, len(boundaries)+1),
+		bucketCounts: make([]uint64, len(boundaries)+1),
 	}
 }
 

sdk/metric/aggregator/histogram/histogram_test.go

@@ -78,7 +78,7 @@ func checkZero(t *testing.T, agg *histogram.Aggregator, desc *metric.Descriptor)
 	require.NoError(t, err)
 
 	count, err := agg.Count()
-	require.Equal(t, int64(0), count, "Empty checkpoint count = 0")
+	require.Equal(t, uint64(0), count, "Empty checkpoint count = 0")
 	require.NoError(t, err)
 
 	buckets, err := agg.Histogram()

sdk/metric/aggregator/minmaxsumcount/mmsc.go

@@ -38,7 +38,7 @@ type (
 		sum   number.Number
 		min   number.Number
 		max   number.Number
-		count int64
+		count uint64
 	}
 )
 
@@ -78,7 +78,7 @@ func (c *Aggregator) Sum() (number.Number, error) {
 }
 
 // Count returns the number of values in the checkpoint.
-func (c *Aggregator) Count() (int64, error) {
+func (c *Aggregator) Count() (uint64, error) {
 	return c.count, nil
 }
 

sdk/metric/aggregator/minmaxsumcount/mmsc_test.go

@@ -97,7 +97,7 @@ func checkZero(t *testing.T, agg *Aggregator, desc *metric.Descriptor) {
 
 	count, err := agg.Count()
 	require.NoError(t, err)
-	require.Equal(t, int64(0), count)
+	require.Equal(t, uint64(0), count)
 
 	max, err := agg.Max()
 	require.True(t, errors.Is(err, aggregation.ErrNoData))
@@ -228,7 +228,7 @@ func TestMaxSumCountNotSet(t *testing.T) {
 		require.Nil(t, err)
 
 		count, err := ckpt.Count()
-		require.Equal(t, int64(0), count, "Empty checkpoint count = 0")
+		require.Equal(t, uint64(0), count, "Empty checkpoint count = 0")
 		require.Nil(t, err)
 
 		max, err := ckpt.Max()

sdk/metric/correct_test.go

@@ -168,7 +168,7 @@ func TestInputRangeValueRecorder(t *testing.T) {
 	checkpointed = sdk.Collect(ctx)
 
 	count, err := processor.accumulations[0].Aggregator().(aggregation.Distribution).Count()
-	require.Equal(t, int64(2), count)
+	require.Equal(t, uint64(2), count)
 	require.Equal(t, 1, checkpointed)
 	require.Nil(t, testHandler.Flush())
 	require.Nil(t, err)

sdk/metric/histogram_stress_test.go

@@ -54,10 +54,9 @@ func TestStressInt64Histogram(t *testing.T) {
 		b, _ := ckpt.Histogram()
 		c, _ := ckpt.Count()
 
-		var realCount int64
+		var realCount uint64
 		for _, c := range b.Counts {
-			v := int64(c)
-			realCount += v
+			realCount += c
 		}
 
 		if realCount != c {

sdk/metric/minmaxsumcount_stress_test.go

@@ -63,7 +63,7 @@ func TestStressInt64MinMaxSumCount(t *testing.T) {
 			}
 			lo, hi, sum := min.AsInt64(), max.AsInt64(), s.AsInt64()
 
-			if hi-lo+1 != c {
+			if uint64(hi-lo)+1 != c {
 				t.Fail()
 			}
 			if c == 1 {