/
spanprocessor.go
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/
spanprocessor.go
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// Copyright The OpenTelemetry Authors
// Copyright 2017, OpenCensus 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 zpages // import "go.opentelemetry.io/contrib/zpages"
import (
"context"
"sync"
"go.opentelemetry.io/otel/codes"
sdktrace "go.opentelemetry.io/otel/sdk/trace"
"go.opentelemetry.io/otel/trace"
)
var _ sdktrace.SpanProcessor = (*SpanProcessor)(nil)
// perMethodSummary is a summary of the spans stored for a single span name.
type perMethodSummary struct {
activeSpans int
latencySpans []int
errorSpans int
}
// SpanProcessor is an sdktrace.SpanProcessor implementation that exposes zpages functionality for opentelemetry-go.
//
// It tracks all active spans, and stores samples of spans based on latency for non errored spans,
// and samples for errored spans.
type SpanProcessor struct {
// Cannot keep track of the active Spans per name because the Span interface,
// allows the name to be changed, and that will leak memory.
activeSpansStore sync.Map
spanSampleStores sync.Map
}
// NewSpanProcessor returns a new SpanProcessor.
func NewSpanProcessor() *SpanProcessor {
return &SpanProcessor{}
}
// OnStart adds span as active and reports it with zpages.
func (ssm *SpanProcessor) OnStart(_ context.Context, span sdktrace.ReadWriteSpan) {
sc := span.SpanContext()
if sc.IsValid() {
ssm.activeSpansStore.Store(spanKey(sc), span)
}
}
// OnEnd processes all spans and reports them with zpages.
func (ssm *SpanProcessor) OnEnd(span sdktrace.ReadOnlySpan) {
sc := span.SpanContext()
if sc.IsValid() {
ssm.activeSpansStore.Delete(spanKey(sc))
}
name := span.Name()
value, ok := ssm.spanSampleStores.Load(name)
if !ok {
value, _ = ssm.spanSampleStores.LoadOrStore(name, newSampleStore(defaultBucketCapacity, defaultBucketCapacity))
}
value.(*sampleStore).sampleSpan(span)
}
// Shutdown does nothing.
func (ssm *SpanProcessor) Shutdown(context.Context) error {
// Do nothing
return nil
}
// ForceFlush does nothing.
func (ssm *SpanProcessor) ForceFlush(context.Context) error {
// Do nothing
return nil
}
// spanStoreForName returns the sampleStore for the given name.
//
// It returns nil if it doesn't exist.
func (ssm *SpanProcessor) spanStoreForName(name string) *sampleStore {
if value, ok := ssm.spanSampleStores.Load(name); ok {
return value.(*sampleStore)
}
return nil
}
// spansPerMethod returns a summary of what spans are being stored for each span name.
func (ssm *SpanProcessor) spansPerMethod() map[string]*perMethodSummary {
out := make(map[string]*perMethodSummary)
ssm.spanSampleStores.Range(func(name, s interface{}) bool {
out[name.(string)] = s.(*sampleStore).perMethodSummary()
return true
})
ssm.activeSpansStore.Range(func(_, sp interface{}) bool {
span := sp.(sdktrace.ReadOnlySpan)
if pms, ok := out[span.Name()]; ok {
pms.activeSpans++
return true
}
out[span.Name()] = &perMethodSummary{activeSpans: 1}
return true
})
return out
}
// activeSpans returns the active spans for the given name.
func (ssm *SpanProcessor) activeSpans(name string) []sdktrace.ReadOnlySpan {
var out []sdktrace.ReadOnlySpan
ssm.activeSpansStore.Range(func(_, sp interface{}) bool {
span := sp.(sdktrace.ReadOnlySpan)
if span.Name() == name {
out = append(out, span)
}
return true
})
return out
}
// errorSpans returns a sample of error spans.
func (ssm *SpanProcessor) errorSpans(name string) []sdktrace.ReadOnlySpan {
s := ssm.spanStoreForName(name)
if s == nil {
return nil
}
return s.errorSpans()
}
// spansByLatency returns a sample of successful spans.
//
// minLatency is the minimum latency of spans to be returned.
// maxDuration, if nonzero, is the maximum latency of spans to be returned.
func (ssm *SpanProcessor) spansByLatency(name string, latencyBucketIndex int) []sdktrace.ReadOnlySpan {
s := ssm.spanStoreForName(name)
if s == nil {
return nil
}
return s.spansByLatency(latencyBucketIndex)
}
// sampleStore stores a sampled of spans for a particular span name.
//
// It contains sample of spans for error requests (status code is codes.Error);
// and a sample of spans for successful requests, bucketed by latency.
type sampleStore struct {
sync.Mutex // protects everything below.
latency []*bucket
errors *bucket
}
// newSampleStore creates a sampleStore.
func newSampleStore(latencyBucketSize uint, errorBucketSize uint) *sampleStore {
s := &sampleStore{
latency: make([]*bucket, defaultBoundaries.numBuckets()),
errors: newBucket(errorBucketSize),
}
for i := range s.latency {
s.latency[i] = newBucket(latencyBucketSize)
}
return s
}
func (ss *sampleStore) perMethodSummary() *perMethodSummary {
ss.Lock()
defer ss.Unlock()
p := &perMethodSummary{}
p.errorSpans = ss.errors.len()
for _, b := range ss.latency {
p.latencySpans = append(p.latencySpans, b.len())
}
return p
}
func (ss *sampleStore) spansByLatency(latencyBucketIndex int) []sdktrace.ReadOnlySpan {
ss.Lock()
defer ss.Unlock()
if latencyBucketIndex < 0 || latencyBucketIndex >= len(ss.latency) {
return nil
}
return ss.latency[latencyBucketIndex].spans()
}
func (ss *sampleStore) errorSpans() []sdktrace.ReadOnlySpan {
ss.Lock()
defer ss.Unlock()
return ss.errors.spans()
}
// sampleSpan removes adds to the corresponding latency or error bucket.
func (ss *sampleStore) sampleSpan(span sdktrace.ReadOnlySpan) {
code := span.Status().Code
ss.Lock()
defer ss.Unlock()
if code == codes.Error {
ss.errors.add(span)
return
}
latency := span.EndTime().Sub(span.StartTime())
// In case of time skew or wrong time, sample as 0 latency.
if latency < 0 {
latency = 0
}
ss.latency[defaultBoundaries.getBucketIndex(latency)].add(span)
}
func spanKey(sc trace.SpanContext) [24]byte {
var sk [24]byte
tid := sc.TraceID()
copy(sk[0:16], tid[:])
sid := sc.SpanID()
copy(sk[16:24], sid[:])
return sk
}