opentelemetry-go/sdk/metric/integrator/test/test.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 test

import (
	"fmt"
	"strings"

	"go.opentelemetry.io/otel/api/label"
	"go.opentelemetry.io/otel/api/metric"
	export "go.opentelemetry.io/otel/sdk/export/metric"
	"go.opentelemetry.io/otel/sdk/export/metric/aggregation"
	"go.opentelemetry.io/otel/sdk/metric/aggregator/array"
	"go.opentelemetry.io/otel/sdk/metric/aggregator/ddsketch"
	"go.opentelemetry.io/otel/sdk/metric/aggregator/histogram"
	"go.opentelemetry.io/otel/sdk/metric/aggregator/lastvalue"
	"go.opentelemetry.io/otel/sdk/metric/aggregator/minmaxsumcount"
	"go.opentelemetry.io/otel/sdk/metric/aggregator/sum"
)

type (
	// Output collects distinct metric/label set outputs.
	Output struct {
		Map          map[string]float64
		labelEncoder label.Encoder
	}

	// testAggregationSelector returns aggregators consistent with
	// the test variables below, needed for testing stateful
	// integrators, which clone Aggregators using AggregatorFor(desc).
	testAggregationSelector struct{}
)

func NewOutput(labelEncoder label.Encoder) Output {
	return Output{
		Map:          make(map[string]float64),
		labelEncoder: labelEncoder,
	}
}

// AggregationSelector returns a policy that is consistent with the
// test descriptors above.  I.e., it returns sum.New() for counter
// instruments and lastvalue.New() for lastValue instruments.
func AggregationSelector() export.AggregationSelector {
	return testAggregationSelector{}
}

func (testAggregationSelector) AggregatorFor(desc *metric.Descriptor, aggPtrs ...*export.Aggregator) {

	switch {
	case strings.HasSuffix(desc.Name(), ".disabled"):
		for i := range aggPtrs {
			*aggPtrs[i] = nil
		}
	case strings.HasSuffix(desc.Name(), ".sum"):
		aggs := sum.New(len(aggPtrs))
		for i := range aggPtrs {
			*aggPtrs[i] = &aggs[i]
		}
	case strings.HasSuffix(desc.Name(), ".minmaxsumcount"):
		aggs := minmaxsumcount.New(len(aggPtrs), desc)
		for i := range aggPtrs {
			*aggPtrs[i] = &aggs[i]
		}
	case strings.HasSuffix(desc.Name(), ".lastvalue"):
		aggs := lastvalue.New(len(aggPtrs))
		for i := range aggPtrs {
			*aggPtrs[i] = &aggs[i]
		}
	case strings.HasSuffix(desc.Name(), ".sketch"):
		aggs := ddsketch.New(len(aggPtrs), desc, ddsketch.NewDefaultConfig())
		for i := range aggPtrs {
			*aggPtrs[i] = &aggs[i]
		}
	case strings.HasSuffix(desc.Name(), ".histogram"):
		aggs := histogram.New(len(aggPtrs), desc, nil)
		for i := range aggPtrs {
			*aggPtrs[i] = &aggs[i]
		}
	case strings.HasSuffix(desc.Name(), ".exact"):
		aggs := array.New(len(aggPtrs))
		for i := range aggPtrs {
			*aggPtrs[i] = &aggs[i]
		}
	default:
		panic(fmt.Sprint("Invalid instrument name for test AggregationSelector: ", desc.Name()))
	}
}

// AddTo adds a name/label-encoding entry with the lastValue or counter
// value to the output map.
func (o Output) AddTo(rec export.Record) error {
	encoded := rec.Labels().Encoded(o.labelEncoder)
	rencoded := rec.Resource().Encoded(o.labelEncoder)
	key := fmt.Sprint(rec.Descriptor().Name(), "/", encoded, "/", rencoded)
	var value float64

	if s, ok := rec.Aggregator().(aggregation.Sum); ok {
		sum, _ := s.Sum()
		value = sum.CoerceToFloat64(rec.Descriptor().NumberKind())
	} else if l, ok := rec.Aggregator().(aggregation.LastValue); ok {
		last, _, _ := l.LastValue()
		value = last.CoerceToFloat64(rec.Descriptor().NumberKind())
	} else {
		panic(fmt.Sprintf("Unhandled aggregator type: %T", rec.Aggregator()))
	}
	o.Map[key] = value
	return nil
}