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mirror of https://github.com/open-telemetry/opentelemetry-go.git synced 2025-02-03 13:11:53 +02:00
Joshua MacDonald 3475d5575e
Fix incorrect aggregation; Prometheus exporter behavior (#903)
* Avoid applying stale udpates; add a test

* Add Memory option to basic processor

* Always use memory in the pull controller

* Test the memory option

* Precommit

* Add a Prometheus-specific test

* More comment on Memory option

* Link to 862

* Remove sleep

* Update changelog

* Comment on stale and stateless aggregators

* Update sdk/metric/processor/basic/config.go

Co-authored-by: Tyler Yahn <MrAlias@users.noreply.github.com>

Co-authored-by: Liz Fong-Jones <lizf@honeycomb.io>
Co-authored-by: Tyler Yahn <MrAlias@users.noreply.github.com>
2020-07-07 12:52:35 -07:00

117 lines
3.6 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 pull // import "go.opentelemetry.io/otel/sdk/metric/controller/pull"
import (
"context"
"time"
"go.opentelemetry.io/otel/api/metric"
"go.opentelemetry.io/otel/api/metric/registry"
export "go.opentelemetry.io/otel/sdk/export/metric"
sdk "go.opentelemetry.io/otel/sdk/metric"
controllerTime "go.opentelemetry.io/otel/sdk/metric/controller/time"
processor "go.opentelemetry.io/otel/sdk/metric/processor/basic"
"go.opentelemetry.io/otel/sdk/resource"
)
// DefaultCachePeriod determines how long a recently-computed result
// will be returned without gathering metric data again.
const DefaultCachePeriod time.Duration = 10 * time.Second
// Controller manages access to a *sdk.Accumulator and
// *basic.Processor. Use Provider() for obtaining Meters. Use
// Foreach() for accessing current records.
type Controller struct {
accumulator *sdk.Accumulator
processor *processor.Processor
provider *registry.Provider
period time.Duration
lastCollect time.Time
clock controllerTime.Clock
checkpoint export.CheckpointSet
}
// New returns a *Controller configured with an aggregation selector and options.
func New(aselector export.AggregatorSelector, eselector export.ExportKindSelector, options ...Option) *Controller {
config := &Config{
Resource: resource.Empty(),
CachePeriod: DefaultCachePeriod,
}
for _, opt := range options {
opt.Apply(config)
}
// This controller uses WithMemory() as a requirement to
// support multiple readers.
processor := processor.New(aselector, eselector, processor.WithMemory(true))
accum := sdk.NewAccumulator(
processor,
sdk.WithResource(config.Resource),
)
return &Controller{
accumulator: accum,
processor: processor,
provider: registry.NewProvider(accum),
period: config.CachePeriod,
checkpoint: processor.CheckpointSet(),
clock: controllerTime.RealClock{},
}
}
// SetClock sets the clock used for caching. For testing purposes.
func (c *Controller) SetClock(clock controllerTime.Clock) {
c.processor.Lock()
defer c.processor.Unlock()
c.clock = clock
}
// Provider returns a metric.Provider for the implementation managed
// by this controller.
func (c *Controller) Provider() metric.Provider {
return c.provider
}
// Foreach gives the caller read-locked access to the current
// export.CheckpointSet.
func (c *Controller) ForEach(ks export.ExportKindSelector, f func(export.Record) error) error {
c.processor.RLock()
defer c.processor.RUnlock()
return c.checkpoint.ForEach(ks, f)
}
// Collect requests a collection. The collection will be skipped if
// the last collection is aged less than the CachePeriod.
func (c *Controller) Collect(ctx context.Context) error {
c.processor.Lock()
defer c.processor.Unlock()
if c.period > 0 {
now := c.clock.Now()
elapsed := now.Sub(c.lastCollect)
if elapsed < c.period {
return nil
}
c.lastCollect = now
}
c.processor.StartCollection()
c.accumulator.Collect(ctx)
err := c.processor.FinishCollection()
c.checkpoint = c.processor.CheckpointSet()
return err
}