82 lines
2.8 KiB
Go
82 lines
2.8 KiB
Go
// Copyright The OpenTelemetry Authors
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// SPDX-License-Identifier: Apache-2.0
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package fanoutconsumer // import "go.opentelemetry.io/collector/internal/fanoutconsumer"
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import (
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"context"
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"go.uber.org/multierr"
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"go.opentelemetry.io/collector/consumer"
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"go.opentelemetry.io/collector/pdata/pmetric"
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)
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// NewMetrics wraps multiple metrics consumers in a single one.
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// It fans out the incoming data to all the consumers, and does smart routing:
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// - Clones only to the consumer that needs to mutate the data.
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// - If all consumers needs to mutate the data one will get the original mutable data.
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func NewMetrics(mcs []consumer.Metrics) consumer.Metrics {
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// Don't wrap if there is only one non-mutating consumer.
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if len(mcs) == 1 && !mcs[0].Capabilities().MutatesData {
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return mcs[0]
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}
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mc := &metricsConsumer{}
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for i := 0; i < len(mcs); i++ {
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if mcs[i].Capabilities().MutatesData {
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mc.mutable = append(mc.mutable, mcs[i])
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} else {
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mc.readonly = append(mc.readonly, mcs[i])
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}
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}
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return mc
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}
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type metricsConsumer struct {
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mutable []consumer.Metrics
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readonly []consumer.Metrics
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}
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func (msc *metricsConsumer) Capabilities() consumer.Capabilities {
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// If all consumers are mutating, then the original data will be passed to one of them.
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return consumer.Capabilities{MutatesData: len(msc.mutable) > 0 && len(msc.readonly) == 0}
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}
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// ConsumeMetrics exports the pmetric.Metrics to all consumers wrapped by the current one.
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func (msc *metricsConsumer) ConsumeMetrics(ctx context.Context, md pmetric.Metrics) error {
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var errs error
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if len(msc.mutable) > 0 {
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// Clone the data before sending to all mutating consumers except the last one.
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for i := 0; i < len(msc.mutable)-1; i++ {
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errs = multierr.Append(errs, msc.mutable[i].ConsumeMetrics(ctx, cloneMetrics(md)))
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}
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// Send data as is to the last mutating consumer only if there are no other non-mutating consumers and the
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// data is mutable. Never share the same data between a mutating and a non-mutating consumer since the
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// non-mutating consumer may process data async and the mutating consumer may change the data before that.
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lastConsumer := msc.mutable[len(msc.mutable)-1]
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if len(msc.readonly) == 0 && !md.IsReadOnly() {
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errs = multierr.Append(errs, lastConsumer.ConsumeMetrics(ctx, md))
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} else {
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errs = multierr.Append(errs, lastConsumer.ConsumeMetrics(ctx, cloneMetrics(md)))
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}
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}
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// Mark the data as read-only if it will be sent to more than one read-only consumer.
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if len(msc.readonly) > 1 && !md.IsReadOnly() {
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md.MarkReadOnly()
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}
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for _, mc := range msc.readonly {
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errs = multierr.Append(errs, mc.ConsumeMetrics(ctx, md))
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}
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return errs
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}
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func cloneMetrics(md pmetric.Metrics) pmetric.Metrics {
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clonedMetrics := pmetric.NewMetrics()
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md.CopyTo(clonedMetrics)
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return clonedMetrics
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}
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