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opentelemetry-go/sdk/metric/aggregator/minmaxsumcount/mmsc.go
2020-06-10 00:32:14 -07:00

162 lines
4.6 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 minmaxsumcount // import "go.opentelemetry.io/otel/sdk/metric/aggregator/minmaxsumcount"
import (
"context"
"sync"
"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"
)
type (
// Aggregator aggregates events that form a distribution,
// keeping only the min, max, sum, and count.
Aggregator struct {
lock sync.Mutex
current state
checkpoint state
kind metric.NumberKind
}
state struct {
count metric.Number
sum metric.Number
min metric.Number
max metric.Number
}
)
var _ export.Aggregator = &Aggregator{}
var _ aggregation.MinMaxSumCount = &Aggregator{}
// New returns a new aggregator for computing the min, max, sum, and
// count. It does not compute quantile information other than Min and
// Max.
//
// This type uses a mutex for Update() and Checkpoint() concurrency.
func New(desc *metric.Descriptor) *Aggregator {
kind := desc.NumberKind()
return &Aggregator{
kind: kind,
current: state{
count: metric.NewUint64Number(0),
sum: kind.Zero(),
min: kind.Maximum(),
max: kind.Minimum(),
},
}
}
// Kind returns aggregation.MinMaxSumCountKind.
func (c *Aggregator) Kind() aggregation.Kind {
return aggregation.MinMaxSumCountKind
}
// Sum returns the sum of values in the checkpoint.
func (c *Aggregator) Sum() (metric.Number, error) {
c.lock.Lock()
defer c.lock.Unlock()
return c.checkpoint.sum, nil
}
// Count returns the number of values in the checkpoint.
func (c *Aggregator) Count() (int64, error) {
c.lock.Lock()
defer c.lock.Unlock()
return c.checkpoint.count.CoerceToInt64(metric.Uint64NumberKind), nil
}
// Min returns the minimum value in the checkpoint.
// The error value aggregation.ErrNoData will be returned
// if there were no measurements recorded during the checkpoint.
func (c *Aggregator) Min() (metric.Number, error) {
c.lock.Lock()
defer c.lock.Unlock()
if c.checkpoint.count.IsZero(metric.Uint64NumberKind) {
return c.kind.Zero(), aggregation.ErrNoData
}
return c.checkpoint.min, nil
}
// Max returns the maximum value in the checkpoint.
// The error value aggregation.ErrNoData will be returned
// if there were no measurements recorded during the checkpoint.
func (c *Aggregator) Max() (metric.Number, error) {
c.lock.Lock()
defer c.lock.Unlock()
if c.checkpoint.count.IsZero(metric.Uint64NumberKind) {
return c.kind.Zero(), aggregation.ErrNoData
}
return c.checkpoint.max, nil
}
// Checkpoint saves the current state and resets the current state to
// the empty set.
func (c *Aggregator) Checkpoint(desc *metric.Descriptor) {
c.lock.Lock()
c.checkpoint, c.current = c.current, c.emptyState()
c.lock.Unlock()
}
func (c *Aggregator) emptyState() state {
kind := c.kind
return state{
count: metric.NewUint64Number(0),
sum: kind.Zero(),
min: kind.Maximum(),
max: kind.Minimum(),
}
}
// Update adds the recorded measurement to the current data set.
func (c *Aggregator) Update(_ context.Context, number metric.Number, desc *metric.Descriptor) error {
kind := desc.NumberKind()
c.lock.Lock()
defer c.lock.Unlock()
c.current.count.AddInt64(1)
c.current.sum.AddNumber(kind, number)
if number.CompareNumber(kind, c.current.min) < 0 {
c.current.min = number
}
if number.CompareNumber(kind, c.current.max) > 0 {
c.current.max = number
}
return nil
}
// Merge combines two data sets into one.
func (c *Aggregator) Merge(oa export.Aggregator, desc *metric.Descriptor) error {
o, _ := oa.(*Aggregator)
if o == nil {
return aggregator.NewInconsistentMergeError(c, oa)
}
c.checkpoint.count.AddNumber(metric.Uint64NumberKind, o.checkpoint.count)
c.checkpoint.sum.AddNumber(desc.NumberKind(), o.checkpoint.sum)
if c.checkpoint.min.CompareNumber(desc.NumberKind(), o.checkpoint.min) > 0 {
c.checkpoint.min.SetNumber(o.checkpoint.min)
}
if c.checkpoint.max.CompareNumber(desc.NumberKind(), o.checkpoint.max) < 0 {
c.checkpoint.max.SetNumber(o.checkpoint.max)
}
return nil
}