// 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 trace
import (
"sync"
"time"
"go.opencensus.io/internal"
)
const (
maxBucketSize = 100000
defaultBucketSize = 10
)
var (
ssmu sync.RWMutex // protects spanStores
spanStores = make(map[string]*spanStore)
)
// This exists purely to avoid exposing internal methods used by z-Pages externally.
type internalOnly struct{}
func init() {
//TODO(#412): remove
internal.Trace = &internalOnly{}
}
// ReportActiveSpans returns the active spans for the given name.
func (i internalOnly) ReportActiveSpans(name string) []*SpanData {
s := spanStoreForName(name)
if s == nil {
return nil
}
var out []*SpanData
s.mu.Lock()
defer s.mu.Unlock()
for activeSpan := range s.active {
if s, ok := activeSpan.(*span); ok {
out = append(out, s.makeSpanData())
}
}
return out
}
// ReportSpansByError returns a sample of error spans.
//
// If code is nonzero, only spans with that status code are returned.
func (i internalOnly) ReportSpansByError(name string, code int32) []*SpanData {
s := spanStoreForName(name)
if s == nil {
return nil
}
var out []*SpanData
s.mu.Lock()
defer s.mu.Unlock()
if code != 0 {
if b, ok := s.errors[code]; ok {
for _, sd := range b.buffer {
if sd == nil {
break
}
out = append(out, sd)
}
}
} else {
for _, b := range s.errors {
for _, sd := range b.buffer {
if sd == nil {
break
}
out = append(out, sd)
}
}
}
return out
}
// ConfigureBucketSizes sets the number of spans to keep per latency and error
// bucket for different span names.
func (i internalOnly) ConfigureBucketSizes(bcs []internal.BucketConfiguration) {
for _, bc := range bcs {
latencyBucketSize := bc.MaxRequestsSucceeded
if latencyBucketSize < 0 {
latencyBucketSize = 0
}
if latencyBucketSize > maxBucketSize {
latencyBucketSize = maxBucketSize
}
errorBucketSize := bc.MaxRequestsErrors
if errorBucketSize < 0 {
errorBucketSize = 0
}
if errorBucketSize > maxBucketSize {
errorBucketSize = maxBucketSize
}
spanStoreSetSize(bc.Name, latencyBucketSize, errorBucketSize)
}
}
// ReportSpansPerMethod returns a summary of what spans are being stored for each span name.
func (i internalOnly) ReportSpansPerMethod() map[string]internal.PerMethodSummary {
out := make(map[string]internal.PerMethodSummary)
ssmu.RLock()
defer ssmu.RUnlock()
for name, s := range spanStores {
s.mu.Lock()
p := internal.PerMethodSummary{
Active: len(s.active),
}
for code, b := range s.errors {
p.ErrorBuckets = append(p.ErrorBuckets, internal.ErrorBucketSummary{
ErrorCode: code,
Size: b.size(),
})
}
for i, b := range s.latency {
min, max := latencyBucketBounds(i)
p.LatencyBuckets = append(p.LatencyBuckets, internal.LatencyBucketSummary{
MinLatency: min,
MaxLatency: max,
Size: b.size(),
})
}
s.mu.Unlock()
out[name] = p
}
return out
}
// ReportSpansByLatency returns a sample of successful spans.
//
// minLatency is the minimum latency of spans to be returned.
// maxLatency, if nonzero, is the maximum latency of spans to be returned.
func (i internalOnly) ReportSpansByLatency(name string, minLatency, maxLatency time.Duration) []*SpanData {
s := spanStoreForName(name)
if s == nil {
return nil
}
var out []*SpanData
s.mu.Lock()
defer s.mu.Unlock()
for i, b := range s.latency {
min, max := latencyBucketBounds(i)
if i+1 != len(s.latency) && max <= minLatency {
continue
}
if maxLatency != 0 && maxLatency < min {
continue
}
for _, sd := range b.buffer {
if sd == nil {
break
}
if minLatency != 0 || maxLatency != 0 {
d := sd.EndTime.Sub(sd.StartTime)
if d < minLatency {
continue
}
if maxLatency != 0 && d > maxLatency {
continue
}
}
out = append(out, sd)
}
}
return out
}
// spanStore keeps track of spans stored for a particular span name.
//
// It contains all active spans; a sample of spans for failed requests,
// categorized by error code; and a sample of spans for successful requests,
// bucketed by latency.
type spanStore struct {
mu sync.Mutex // protects everything below.
active map[SpanInterface]struct{}
errors map[int32]*bucket
latency []bucket
maxSpansPerErrorBucket int
}
// newSpanStore creates a span store.
func newSpanStore(name string, latencyBucketSize int, errorBucketSize int) *spanStore {
s := &spanStore{
active: make(map[SpanInterface]struct{}),
latency: make([]bucket, len(defaultLatencies)+1),
maxSpansPerErrorBucket: errorBucketSize,
}
for i := range s.latency {
s.latency[i] = makeBucket(latencyBucketSize)
}
return s
}
// spanStoreForName returns the spanStore for the given name.
//
// It returns nil if it doesn't exist.
func spanStoreForName(name string) *spanStore {
var s *spanStore
ssmu.RLock()
s, _ = spanStores[name]
ssmu.RUnlock()
return s
}
// spanStoreForNameCreateIfNew returns the spanStore for the given name.
//
// It creates it if it didn't exist.
func spanStoreForNameCreateIfNew(name string) *spanStore {
ssmu.RLock()
s, ok := spanStores[name]
ssmu.RUnlock()
if ok {
return s
}
ssmu.Lock()
defer ssmu.Unlock()
s, ok = spanStores[name]
if ok {
return s
}
s = newSpanStore(name, defaultBucketSize, defaultBucketSize)
spanStores[name] = s
return s
}
// spanStoreSetSize resizes the spanStore for the given name.
//
// It creates it if it didn't exist.
func spanStoreSetSize(name string, latencyBucketSize int, errorBucketSize int) {
ssmu.RLock()
s, ok := spanStores[name]
ssmu.RUnlock()
if ok {
s.resize(latencyBucketSize, errorBucketSize)
return
}
ssmu.Lock()
defer ssmu.Unlock()
s, ok = spanStores[name]
if ok {
s.resize(latencyBucketSize, errorBucketSize)
return
}
s = newSpanStore(name, latencyBucketSize, errorBucketSize)
spanStores[name] = s
}
func (s *spanStore) resize(latencyBucketSize int, errorBucketSize int) {
s.mu.Lock()
for i := range s.latency {
s.latency[i].resize(latencyBucketSize)
}
for _, b := range s.errors {
b.resize(errorBucketSize)
}
s.maxSpansPerErrorBucket = errorBucketSize
s.mu.Unlock()
}
// add adds a span to the active bucket of the spanStore.
func (s *spanStore) add(span SpanInterface) {
s.mu.Lock()
s.active[span] = struct{}{}
s.mu.Unlock()
}
// finished removes a span from the active set, and adds a corresponding
// SpanData to a latency or error bucket.
func (s *spanStore) finished(span SpanInterface, sd *SpanData) {
latency := sd.EndTime.Sub(sd.StartTime)
if latency < 0 {
latency = 0
}
code := sd.Status.Code
s.mu.Lock()
delete(s.active, span)
if code == 0 {
s.latency[latencyBucket(latency)].add(sd)
} else {
if s.errors == nil {
s.errors = make(map[int32]*bucket)
}
if b := s.errors[code]; b != nil {
b.add(sd)
} else {
b := makeBucket(s.maxSpansPerErrorBucket)
s.errors[code] = &b
b.add(sd)
}
}
s.mu.Unlock()
}
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