gotosocial/vendor/go.opentelemetry.io/otel/sdk/metric/internal/aggregate/limit.go

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// 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 aggregate // import "go.opentelemetry.io/otel/sdk/metric/internal/aggregate"
import "go.opentelemetry.io/otel/attribute"
// overflowSet is the attribute set used to record a measurement when adding
// another distinct attribute set to the aggregate would exceed the aggregate
// limit.
var overflowSet = attribute.NewSet(attribute.Bool("otel.metric.overflow", true))
// limiter limits aggregate values.
type limiter[V any] struct {
// aggLimit is the maximum number of metric streams that can be aggregated.
//
// Any metric stream with attributes distinct from any set already
// aggregated once the aggLimit will be meet will instead be aggregated
// into an "overflow" metric stream. That stream will only contain the
// "otel.metric.overflow"=true attribute.
aggLimit int
}
// newLimiter returns a new Limiter with the provided aggregation limit.
func newLimiter[V any](aggregation int) limiter[V] {
return limiter[V]{aggLimit: aggregation}
}
// Attributes checks if adding a measurement for attrs will exceed the
// aggregation cardinality limit for the existing measurements. If it will,
// overflowSet is returned. Otherwise, if it will not exceed the limit, or the
// limit is not set (limit <= 0), attr is returned.
func (l limiter[V]) Attributes(attrs attribute.Set, measurements map[attribute.Set]V) attribute.Set {
if l.aggLimit > 0 {
_, exists := measurements[attrs]
if !exists && len(measurements) >= l.aggLimit-1 {
return overflowSet
}
}
return attrs
}