diff --git a/sdk/metric/internal/exemplar/hist.go b/sdk/metric/internal/exemplar/hist.go new file mode 100644 index 00000000000..6f4fe5524b1 --- /dev/null +++ b/sdk/metric/internal/exemplar/hist.go @@ -0,0 +1,47 @@ +// Copyright The OpenTelemetry Authors +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package exemplar // import "go.opentelemetry.io/otel/sdk/metric/internal/exemplar" + +import ( + "context" + "sort" + "time" + + "go.opentelemetry.io/otel/attribute" +) + +// Histogram returns a [Reservoir] that samples the last measurement that falls +// within a histogram bucket. The histogram bucket upper-boundaries are define +// by bounds. +// +// The passed bounds will be sorted by this function. +func Histogram[N int64 | float64](bounds []float64) Reservoir[N] { + sort.Float64s(bounds) + return &histRes[N]{ + bounds: bounds, + storage: newStorage[N](len(bounds) + 1), + } +} + +type histRes[N int64 | float64] struct { + *storage[N] + + // bounds are bucket bounds in ascending order. + bounds []float64 +} + +func (r *histRes[N]) Offer(ctx context.Context, t time.Time, n N, a []attribute.KeyValue) { + r.store[sort.SearchFloat64s(r.bounds, float64(n))] = newMeasurement(ctx, t, n, a) +} diff --git a/sdk/metric/internal/exemplar/hist_test.go b/sdk/metric/internal/exemplar/hist_test.go new file mode 100644 index 00000000000..c85694db78c --- /dev/null +++ b/sdk/metric/internal/exemplar/hist_test.go @@ -0,0 +1,28 @@ +// Copyright The OpenTelemetry Authors +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package exemplar + +import "testing" + +func TestHist(t *testing.T) { + bounds := []float64{0, 100} + t.Run("Int64", ReservoirTest[int64](func(int) (Reservoir[int64], int) { + return Histogram[int64](bounds), len(bounds) + })) + + t.Run("Float64", ReservoirTest[float64](func(int) (Reservoir[float64], int) { + return Histogram[float64](bounds), len(bounds) + })) +}