package reducer

import "go.opentelemetry.io/otel/sdk/metric/processor/reducer"

Package reducer implements a metrics Processor component that applies a `label.Filter` to each processed `export.Accumulation` to remove labels before passing the result to another Processor. This Processor can be used to reduce inherent dimensionality in the data, as a way to control the cost of collecting high cardinality metric data.

For example, to compose a push controller with a reducer and a basic metric processor:

type someFilter struct{
        // configuration for this filter
        // ...
}

func (someFilter) LabelFilterFor(_ *metric.Descriptor) label.Filter {
        return func(label kv.KeyValue) bool {
                // return true to keep this label, false to drop this label
                // ...
        }
}

func setupMetrics(exporter export.Exporter) (stop func()) {
        basicProcessor := basic.New(
                simple.NewWithExactDistribution(),
                exporter,
        )

        reducerProcessor := reducer.New(someFilter{...}, basicProcessor)

        pusher := push.New(
                reducerProcessor,
                exporter,
                pushOpts...,
        )
        pusher.Start()
        global.SetMeterProvider(pusher.Provider())
        return pusher.Stop

Index ¶

• type LabelFilterSelector
• type Processor
• func New(filterSelector LabelFilterSelector, ckpter export.Checkpointer) *Processor
• func (p *Processor) Process(accum export.Accumulation) error

Types ¶

type LabelFilterSelector ¶

type LabelFilterSelector interface {
	LabelFilterFor(*metric.Descriptor) label.Filter
}

LabelFilterSelector is the interface used to configure a specific Filter to an instrument.

type Processor ¶

type Processor struct {
	export.Checkpointer
	// contains filtered or unexported fields
}

Processor implements "dimensionality reduction" by filtering keys from export label sets.

func New ¶

func New(filterSelector LabelFilterSelector, ckpter export.Checkpointer) *Processor

New returns a dimensionality-reducing Processor that passes data to the next stage in an export pipeline.

func (*Processor) Process ¶

func (p *Processor) Process(accum export.Accumulation) error

Process implements export.Processor.

Source Files ¶

doc.go reducer.go