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opentelemetry-go/bridge/opencensus/aggregation.go
David Ashpole a1539d4485
OpenCensus metric exporter bridge (#1444)
* add OpenCensus metric exporter bridge

* Update bridge/opencensus/README.md

Co-authored-by: Eric Sirianni <sirianni@users.noreply.github.com>

Co-authored-by: Eric Sirianni <sirianni@users.noreply.github.com>
Co-authored-by: Tyler Yahn <MrAlias@users.noreply.github.com>
2021-03-11 09:49:20 -08:00

181 lines
5.2 KiB
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 opencensus
import (
"errors"
"fmt"
"time"
"go.opencensus.io/metric/metricdata"
"go.opentelemetry.io/otel/metric/number"
"go.opentelemetry.io/otel/sdk/export/metric/aggregation"
)
var (
errIncompatibleType = errors.New("incompatible type for aggregation")
errEmpty = errors.New("points may not be empty")
errBadPoint = errors.New("point cannot be converted")
)
// aggregationWithEndTime is an aggregation that can also provide the timestamp
// of the last recorded point.
type aggregationWithEndTime interface {
aggregation.Aggregation
end() time.Time
}
// newAggregationFromPoints creates an OpenTelemetry aggregation from
// OpenCensus points. Points may not be empty and must be either
// all (int|float)64 or all *metricdata.Distribution.
func newAggregationFromPoints(points []metricdata.Point) (aggregationWithEndTime, error) {
if len(points) == 0 {
return nil, errEmpty
}
switch t := points[0].Value.(type) {
case int64:
return newExactAggregator(points)
case float64:
return newExactAggregator(points)
case *metricdata.Distribution:
return newDistributionAggregator(points)
default:
// TODO add *metricdata.Summary support
return nil, fmt.Errorf("%w: %v", errIncompatibleType, t)
}
}
var _ aggregation.Aggregation = &ocExactAggregator{}
var _ aggregation.LastValue = &ocExactAggregator{}
var _ aggregation.Points = &ocExactAggregator{}
// newExactAggregator creates an OpenTelemetry aggreation from OpenCensus points.
// Points may not be empty, and must only contain integers or floats.
func newExactAggregator(pts []metricdata.Point) (aggregationWithEndTime, error) {
points := make([]aggregation.Point, len(pts))
for i, pt := range pts {
switch t := pt.Value.(type) {
case int64:
points[i] = aggregation.Point{
Number: number.NewInt64Number(pt.Value.(int64)),
Time: pt.Time,
}
case float64:
points[i] = aggregation.Point{
Number: number.NewFloat64Number(pt.Value.(float64)),
Time: pt.Time,
}
default:
return nil, fmt.Errorf("%w: %v", errIncompatibleType, t)
}
}
return &ocExactAggregator{
points: points,
}, nil
}
type ocExactAggregator struct {
points []aggregation.Point
}
// Kind returns the kind of aggregation this is.
func (o *ocExactAggregator) Kind() aggregation.Kind {
return aggregation.ExactKind
}
// Points returns access to the raw data set.
func (o *ocExactAggregator) Points() ([]aggregation.Point, error) {
return o.points, nil
}
// LastValue returns the last point.
func (o *ocExactAggregator) LastValue() (number.Number, time.Time, error) {
last := o.points[len(o.points)-1]
return last.Number, last.Time, nil
}
// end returns the timestamp of the last point
func (o *ocExactAggregator) end() time.Time {
_, t, _ := o.LastValue()
return t
}
var _ aggregation.Aggregation = &ocDistAggregator{}
var _ aggregation.Histogram = &ocDistAggregator{}
// newDistributionAggregator creates an OpenTelemetry aggreation from
// OpenCensus points. Points may not be empty, and must only contain
// Distributions. The most recent disribution will be used in the aggregation.
func newDistributionAggregator(pts []metricdata.Point) (aggregationWithEndTime, error) {
// only use the most recent datapoint for now.
pt := pts[len(pts)-1]
val, ok := pt.Value.(*metricdata.Distribution)
if !ok {
return nil, fmt.Errorf("%w: %v", errBadPoint, pt.Value)
}
bucketCounts := make([]uint64, len(val.Buckets))
for i, bucket := range val.Buckets {
if bucket.Count < 0 {
return nil, fmt.Errorf("%w: bucket count may not be negative", errBadPoint)
}
bucketCounts[i] = uint64(bucket.Count)
}
if val.Count < 0 {
return nil, fmt.Errorf("%w: count may not be negative", errBadPoint)
}
return &ocDistAggregator{
sum: number.NewFloat64Number(val.Sum),
count: uint64(val.Count),
buckets: aggregation.Buckets{
Boundaries: val.BucketOptions.Bounds,
Counts: bucketCounts,
},
endTime: pts[len(pts)-1].Time,
}, nil
}
type ocDistAggregator struct {
sum number.Number
count uint64
buckets aggregation.Buckets
endTime time.Time
}
// Kind returns the kind of aggregation this is.
func (o *ocDistAggregator) Kind() aggregation.Kind {
return aggregation.HistogramKind
}
// Sum returns the sum of values.
func (o *ocDistAggregator) Sum() (number.Number, error) {
return o.sum, nil
}
// Count returns the number of values.
func (o *ocDistAggregator) Count() (uint64, error) {
return o.count, nil
}
// Histogram returns the count of events in pre-determined buckets.
func (o *ocDistAggregator) Histogram() (aggregation.Buckets, error) {
return o.buckets, nil
}
// end returns the time the histogram was measured.
func (o *ocDistAggregator) end() time.Time {
return o.endTime
}