54 lines
2.1 KiB
Go
54 lines
2.1 KiB
Go
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// Copyright The OpenTelemetry Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package aggregate // import "go.opentelemetry.io/otel/sdk/metric/internal/aggregate"
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import "go.opentelemetry.io/otel/attribute"
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// overflowSet is the attribute set used to record a measurement when adding
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// another distinct attribute set to the aggregate would exceed the aggregate
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// limit.
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var overflowSet = attribute.NewSet(attribute.Bool("otel.metric.overflow", true))
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// limiter limits aggregate values.
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type limiter[V any] struct {
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// aggLimit is the maximum number of metric streams that can be aggregated.
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//
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// Any metric stream with attributes distinct from any set already
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// aggregated once the aggLimit will be meet will instead be aggregated
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// into an "overflow" metric stream. That stream will only contain the
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// "otel.metric.overflow"=true attribute.
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aggLimit int
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}
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// newLimiter returns a new Limiter with the provided aggregation limit.
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func newLimiter[V any](aggregation int) limiter[V] {
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return limiter[V]{aggLimit: aggregation}
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}
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// Attributes checks if adding a measurement for attrs will exceed the
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// aggregation cardinality limit for the existing measurements. If it will,
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// overflowSet is returned. Otherwise, if it will not exceed the limit, or the
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// limit is not set (limit <= 0), attr is returned.
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func (l limiter[V]) Attributes(attrs attribute.Set, measurements map[attribute.Set]V) attribute.Set {
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if l.aggLimit > 0 {
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_, exists := measurements[attrs]
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if !exists && len(measurements) >= l.aggLimit-1 {
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return overflowSet
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}
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}
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return attrs
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}
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