108 lines
3.0 KiB
Go
108 lines
3.0 KiB
Go
// 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"
|
|
"time"
|
|
|
|
"go.opentelemetry.io/otel/attribute"
|
|
"go.opentelemetry.io/otel/sdk/metric/metricdata"
|
|
"go.opentelemetry.io/otel/trace"
|
|
)
|
|
|
|
// storage is an exemplar storage for [Reservoir] implementations.
|
|
type storage[N int64 | float64] struct {
|
|
// store are the measurements sampled.
|
|
//
|
|
// This does not use []metricdata.Exemplar because it potentially would
|
|
// require an allocation for trace and span IDs in the hot path of Offer.
|
|
store []measurement[N]
|
|
}
|
|
|
|
func newStorage[N int64 | float64](n int) *storage[N] {
|
|
return &storage[N]{store: make([]measurement[N], n)}
|
|
}
|
|
|
|
// Collect returns all the held exemplars.
|
|
//
|
|
// The Reservoir state is preserved after this call.
|
|
func (r *storage[N]) Collect(dest *[]metricdata.Exemplar[N]) {
|
|
*dest = reset(*dest, len(r.store), len(r.store))
|
|
var n int
|
|
for _, m := range r.store {
|
|
if !m.valid {
|
|
continue
|
|
}
|
|
|
|
m.Exemplar(&(*dest)[n])
|
|
n++
|
|
}
|
|
*dest = (*dest)[:n]
|
|
}
|
|
|
|
// measurement is a measurement made by a telemetry system.
|
|
type measurement[N int64 | float64] struct {
|
|
// FilteredAttributes are the attributes dropped during the measurement.
|
|
FilteredAttributes []attribute.KeyValue
|
|
// Time is the time when the measurement was made.
|
|
Time time.Time
|
|
// Value is the value of the measurement.
|
|
Value N
|
|
// SpanContext is the SpanContext active when a measurement was made.
|
|
SpanContext trace.SpanContext
|
|
|
|
valid bool
|
|
}
|
|
|
|
// newMeasurement returns a new non-empty Measurement.
|
|
func newMeasurement[N int64 | float64](ctx context.Context, ts time.Time, v N, droppedAttr []attribute.KeyValue) measurement[N] {
|
|
return measurement[N]{
|
|
FilteredAttributes: droppedAttr,
|
|
Time: ts,
|
|
Value: v,
|
|
SpanContext: trace.SpanContextFromContext(ctx),
|
|
valid: true,
|
|
}
|
|
}
|
|
|
|
// Exemplar returns m as a [metricdata.Exemplar].
|
|
func (m measurement[N]) Exemplar(dest *metricdata.Exemplar[N]) {
|
|
dest.FilteredAttributes = m.FilteredAttributes
|
|
dest.Time = m.Time
|
|
dest.Value = m.Value
|
|
|
|
if m.SpanContext.HasTraceID() {
|
|
traceID := m.SpanContext.TraceID()
|
|
dest.TraceID = traceID[:]
|
|
} else {
|
|
dest.TraceID = dest.TraceID[:0]
|
|
}
|
|
|
|
if m.SpanContext.HasSpanID() {
|
|
spanID := m.SpanContext.SpanID()
|
|
dest.SpanID = spanID[:]
|
|
} else {
|
|
dest.SpanID = dest.SpanID[:0]
|
|
}
|
|
}
|
|
|
|
func reset[T any](s []T, length, capacity int) []T {
|
|
if cap(s) < capacity {
|
|
return make([]T, length, capacity)
|
|
}
|
|
return s[:length]
|
|
}
|