[VOL-3187]Pass Context down the execution call hierarchy across ofagent codebase
Change-Id: Ia5f2fa1509beefe0ddc427b83e39d2702782db8f
diff --git a/vendor/github.com/uber/jaeger-client-go/span.go b/vendor/github.com/uber/jaeger-client-go/span.go
new file mode 100644
index 0000000..42c9112
--- /dev/null
+++ b/vendor/github.com/uber/jaeger-client-go/span.go
@@ -0,0 +1,487 @@
+// Copyright (c) 2017-2018 Uber Technologies, Inc.
+//
+// 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 jaeger
+
+import (
+ "sync"
+ "sync/atomic"
+ "time"
+
+ "github.com/opentracing/opentracing-go"
+ "github.com/opentracing/opentracing-go/ext"
+ "github.com/opentracing/opentracing-go/log"
+)
+
+// Span implements opentracing.Span
+type Span struct {
+ // referenceCounter used to increase the lifetime of
+ // the object before return it into the pool.
+ referenceCounter int32
+
+ sync.RWMutex
+
+ tracer *Tracer
+
+ // TODO: (breaking change) change to use a pointer
+ context SpanContext
+
+ // The name of the "operation" this span is an instance of.
+ // Known as a "span name" in some implementations.
+ operationName string
+
+ // firstInProcess, if true, indicates that this span is the root of the (sub)tree
+ // of spans in the current process. In other words it's true for the root spans,
+ // and the ingress spans when the process joins another trace.
+ firstInProcess bool
+
+ // startTime is the timestamp indicating when the span began, with microseconds precision.
+ startTime time.Time
+
+ // duration returns duration of the span with microseconds precision.
+ // Zero value means duration is unknown.
+ duration time.Duration
+
+ // tags attached to this span
+ tags []Tag
+
+ // The span's "micro-log"
+ logs []opentracing.LogRecord
+
+ // The number of logs dropped because of MaxLogsPerSpan.
+ numDroppedLogs int
+
+ // references for this span
+ references []Reference
+
+ observer ContribSpanObserver
+}
+
+// Tag is a simple key value wrapper.
+// TODO (breaking change) deprecate in the next major release, use opentracing.Tag instead.
+type Tag struct {
+ key string
+ value interface{}
+}
+
+// NewTag creates a new Tag.
+// TODO (breaking change) deprecate in the next major release, use opentracing.Tag instead.
+func NewTag(key string, value interface{}) Tag {
+ return Tag{key: key, value: value}
+}
+
+// SetOperationName sets or changes the operation name.
+func (s *Span) SetOperationName(operationName string) opentracing.Span {
+ s.Lock()
+ s.operationName = operationName
+ s.Unlock()
+ if !s.isSamplingFinalized() {
+ decision := s.tracer.sampler.OnSetOperationName(s, operationName)
+ s.applySamplingDecision(decision, true)
+ }
+ s.observer.OnSetOperationName(operationName)
+ return s
+}
+
+// SetTag implements SetTag() of opentracing.Span
+func (s *Span) SetTag(key string, value interface{}) opentracing.Span {
+ return s.setTagInternal(key, value, true)
+}
+
+func (s *Span) setTagInternal(key string, value interface{}, lock bool) opentracing.Span {
+ s.observer.OnSetTag(key, value)
+ if key == string(ext.SamplingPriority) && !setSamplingPriority(s, value) {
+ return s
+ }
+ if !s.isSamplingFinalized() {
+ decision := s.tracer.sampler.OnSetTag(s, key, value)
+ s.applySamplingDecision(decision, lock)
+ }
+ if s.isWriteable() {
+ if lock {
+ s.Lock()
+ defer s.Unlock()
+ }
+ s.appendTagNoLocking(key, value)
+ }
+ return s
+}
+
+// SpanContext returns span context
+func (s *Span) SpanContext() SpanContext {
+ s.Lock()
+ defer s.Unlock()
+ return s.context
+}
+
+// StartTime returns span start time
+func (s *Span) StartTime() time.Time {
+ s.Lock()
+ defer s.Unlock()
+ return s.startTime
+}
+
+// Duration returns span duration
+func (s *Span) Duration() time.Duration {
+ s.Lock()
+ defer s.Unlock()
+ return s.duration
+}
+
+// Tags returns tags for span
+func (s *Span) Tags() opentracing.Tags {
+ s.Lock()
+ defer s.Unlock()
+ var result = make(opentracing.Tags, len(s.tags))
+ for _, tag := range s.tags {
+ result[tag.key] = tag.value
+ }
+ return result
+}
+
+// Logs returns micro logs for span
+func (s *Span) Logs() []opentracing.LogRecord {
+ s.Lock()
+ defer s.Unlock()
+
+ logs := append([]opentracing.LogRecord(nil), s.logs...)
+ if s.numDroppedLogs != 0 {
+ fixLogs(logs, s.numDroppedLogs)
+ }
+
+ return logs
+}
+
+// References returns references for this span
+func (s *Span) References() []opentracing.SpanReference {
+ s.Lock()
+ defer s.Unlock()
+
+ if s.references == nil || len(s.references) == 0 {
+ return nil
+ }
+
+ result := make([]opentracing.SpanReference, len(s.references))
+ for i, r := range s.references {
+ result[i] = opentracing.SpanReference{Type: r.Type, ReferencedContext: r.Context}
+ }
+ return result
+}
+
+func (s *Span) appendTagNoLocking(key string, value interface{}) {
+ s.tags = append(s.tags, Tag{key: key, value: value})
+}
+
+// LogFields implements opentracing.Span API
+func (s *Span) LogFields(fields ...log.Field) {
+ s.Lock()
+ defer s.Unlock()
+ if !s.context.IsSampled() {
+ return
+ }
+ s.logFieldsNoLocking(fields...)
+}
+
+// this function should only be called while holding a Write lock
+func (s *Span) logFieldsNoLocking(fields ...log.Field) {
+ lr := opentracing.LogRecord{
+ Fields: fields,
+ Timestamp: time.Now(),
+ }
+ s.appendLogNoLocking(lr)
+}
+
+// LogKV implements opentracing.Span API
+func (s *Span) LogKV(alternatingKeyValues ...interface{}) {
+ s.RLock()
+ sampled := s.context.IsSampled()
+ s.RUnlock()
+ if !sampled {
+ return
+ }
+ fields, err := log.InterleavedKVToFields(alternatingKeyValues...)
+ if err != nil {
+ s.LogFields(log.Error(err), log.String("function", "LogKV"))
+ return
+ }
+ s.LogFields(fields...)
+}
+
+// LogEvent implements opentracing.Span API
+func (s *Span) LogEvent(event string) {
+ s.Log(opentracing.LogData{Event: event})
+}
+
+// LogEventWithPayload implements opentracing.Span API
+func (s *Span) LogEventWithPayload(event string, payload interface{}) {
+ s.Log(opentracing.LogData{Event: event, Payload: payload})
+}
+
+// Log implements opentracing.Span API
+func (s *Span) Log(ld opentracing.LogData) {
+ s.Lock()
+ defer s.Unlock()
+ if s.context.IsSampled() {
+ if ld.Timestamp.IsZero() {
+ ld.Timestamp = s.tracer.timeNow()
+ }
+ s.appendLogNoLocking(ld.ToLogRecord())
+ }
+}
+
+// this function should only be called while holding a Write lock
+func (s *Span) appendLogNoLocking(lr opentracing.LogRecord) {
+ maxLogs := s.tracer.options.maxLogsPerSpan
+ if maxLogs == 0 || len(s.logs) < maxLogs {
+ s.logs = append(s.logs, lr)
+ return
+ }
+
+ // We have too many logs. We don't touch the first numOld logs; we treat the
+ // rest as a circular buffer and overwrite the oldest log among those.
+ numOld := (maxLogs - 1) / 2
+ numNew := maxLogs - numOld
+ s.logs[numOld+s.numDroppedLogs%numNew] = lr
+ s.numDroppedLogs++
+}
+
+// rotateLogBuffer rotates the records in the buffer: records 0 to pos-1 move at
+// the end (i.e. pos circular left shifts).
+func rotateLogBuffer(buf []opentracing.LogRecord, pos int) {
+ // This algorithm is described in:
+ // http://www.cplusplus.com/reference/algorithm/rotate
+ for first, middle, next := 0, pos, pos; first != middle; {
+ buf[first], buf[next] = buf[next], buf[first]
+ first++
+ next++
+ if next == len(buf) {
+ next = middle
+ } else if first == middle {
+ middle = next
+ }
+ }
+}
+
+func fixLogs(logs []opentracing.LogRecord, numDroppedLogs int) {
+ // We dropped some log events, which means that we used part of Logs as a
+ // circular buffer (see appendLog). De-circularize it.
+ numOld := (len(logs) - 1) / 2
+ numNew := len(logs) - numOld
+ rotateLogBuffer(logs[numOld:], numDroppedLogs%numNew)
+
+ // Replace the log in the middle (the oldest "new" log) with information
+ // about the dropped logs. This means that we are effectively dropping one
+ // more "new" log.
+ numDropped := numDroppedLogs + 1
+ logs[numOld] = opentracing.LogRecord{
+ // Keep the timestamp of the last dropped event.
+ Timestamp: logs[numOld].Timestamp,
+ Fields: []log.Field{
+ log.String("event", "dropped Span logs"),
+ log.Int("dropped_log_count", numDropped),
+ log.String("component", "jaeger-client"),
+ },
+ }
+}
+
+func (s *Span) fixLogsIfDropped() {
+ if s.numDroppedLogs == 0 {
+ return
+ }
+ fixLogs(s.logs, s.numDroppedLogs)
+ s.numDroppedLogs = 0
+}
+
+// SetBaggageItem implements SetBaggageItem() of opentracing.SpanContext
+func (s *Span) SetBaggageItem(key, value string) opentracing.Span {
+ s.Lock()
+ defer s.Unlock()
+ s.tracer.setBaggage(s, key, value)
+ return s
+}
+
+// BaggageItem implements BaggageItem() of opentracing.SpanContext
+func (s *Span) BaggageItem(key string) string {
+ s.RLock()
+ defer s.RUnlock()
+ return s.context.baggage[key]
+}
+
+// Finish implements opentracing.Span API
+// After finishing the Span object it returns back to the allocator unless the reporter retains it again,
+// so after that, the Span object should no longer be used because it won't be valid anymore.
+func (s *Span) Finish() {
+ s.FinishWithOptions(opentracing.FinishOptions{})
+}
+
+// FinishWithOptions implements opentracing.Span API
+func (s *Span) FinishWithOptions(options opentracing.FinishOptions) {
+ if options.FinishTime.IsZero() {
+ options.FinishTime = s.tracer.timeNow()
+ }
+ s.observer.OnFinish(options)
+ s.Lock()
+ s.duration = options.FinishTime.Sub(s.startTime)
+ s.Unlock()
+ if !s.isSamplingFinalized() {
+ decision := s.tracer.sampler.OnFinishSpan(s)
+ s.applySamplingDecision(decision, true)
+ }
+ if s.context.IsSampled() {
+ s.Lock()
+ s.fixLogsIfDropped()
+ if len(options.LogRecords) > 0 || len(options.BulkLogData) > 0 {
+ // Note: bulk logs are not subject to maxLogsPerSpan limit
+ if options.LogRecords != nil {
+ s.logs = append(s.logs, options.LogRecords...)
+ }
+ for _, ld := range options.BulkLogData {
+ s.logs = append(s.logs, ld.ToLogRecord())
+ }
+ }
+ s.Unlock()
+ }
+ // call reportSpan even for non-sampled traces, to return span to the pool
+ // and update metrics counter
+ s.tracer.reportSpan(s)
+}
+
+// Context implements opentracing.Span API
+func (s *Span) Context() opentracing.SpanContext {
+ s.Lock()
+ defer s.Unlock()
+ return s.context
+}
+
+// Tracer implements opentracing.Span API
+func (s *Span) Tracer() opentracing.Tracer {
+ return s.tracer
+}
+
+func (s *Span) String() string {
+ s.RLock()
+ defer s.RUnlock()
+ return s.context.String()
+}
+
+// OperationName allows retrieving current operation name.
+func (s *Span) OperationName() string {
+ s.RLock()
+ defer s.RUnlock()
+ return s.operationName
+}
+
+// Retain increases object counter to increase the lifetime of the object
+func (s *Span) Retain() *Span {
+ atomic.AddInt32(&s.referenceCounter, 1)
+ return s
+}
+
+// Release decrements object counter and return to the
+// allocator manager when counter will below zero
+func (s *Span) Release() {
+ if atomic.AddInt32(&s.referenceCounter, -1) == -1 {
+ s.tracer.spanAllocator.Put(s)
+ }
+}
+
+// reset span state and release unused data
+func (s *Span) reset() {
+ s.firstInProcess = false
+ s.context = emptyContext
+ s.operationName = ""
+ s.tracer = nil
+ s.startTime = time.Time{}
+ s.duration = 0
+ s.observer = nil
+ atomic.StoreInt32(&s.referenceCounter, 0)
+
+ // Note: To reuse memory we can save the pointers on the heap
+ s.tags = s.tags[:0]
+ s.logs = s.logs[:0]
+ s.numDroppedLogs = 0
+ s.references = s.references[:0]
+}
+
+func (s *Span) serviceName() string {
+ return s.tracer.serviceName
+}
+
+func (s *Span) applySamplingDecision(decision SamplingDecision, lock bool) {
+ if !decision.Retryable {
+ s.context.samplingState.setFinal()
+ }
+ if decision.Sample {
+ s.context.samplingState.setSampled()
+ if len(decision.Tags) > 0 {
+ if lock {
+ s.Lock()
+ defer s.Unlock()
+ }
+ for _, tag := range decision.Tags {
+ s.appendTagNoLocking(tag.key, tag.value)
+ }
+ }
+ }
+}
+
+// Span can be written to if it is sampled or the sampling decision has not been finalized.
+func (s *Span) isWriteable() bool {
+ state := s.context.samplingState
+ return !state.isFinal() || state.isSampled()
+}
+
+func (s *Span) isSamplingFinalized() bool {
+ return s.context.samplingState.isFinal()
+}
+
+// setSamplingPriority returns true if the flag was updated successfully, false otherwise.
+// The behavior of setSamplingPriority is surprising
+// If noDebugFlagOnForcedSampling is set
+// setSamplingPriority(span, 1) always sets only flagSampled
+// If noDebugFlagOnForcedSampling is unset, and isDebugAllowed passes
+// setSamplingPriority(span, 1) sets both flagSampled and flagDebug
+// However,
+// setSamplingPriority(span, 0) always only resets flagSampled
+//
+// This means that doing a setSamplingPriority(span, 1) followed by setSamplingPriority(span, 0) can
+// leave flagDebug set
+func setSamplingPriority(s *Span, value interface{}) bool {
+ val, ok := value.(uint16)
+ if !ok {
+ return false
+ }
+ if val == 0 {
+ s.context.samplingState.unsetSampled()
+ s.context.samplingState.setFinal()
+ return true
+ }
+ if s.tracer.options.noDebugFlagOnForcedSampling {
+ s.context.samplingState.setSampled()
+ s.context.samplingState.setFinal()
+ return true
+ } else if s.tracer.isDebugAllowed(s.operationName) {
+ s.context.samplingState.setDebugAndSampled()
+ s.context.samplingState.setFinal()
+ return true
+ }
+ return false
+}
+
+// EnableFirehose enables firehose flag on the span context
+func EnableFirehose(s *Span) {
+ s.Lock()
+ defer s.Unlock()
+ s.context.samplingState.setFirehose()
+}