traefik/vendor/github.com/uber/jaeger-client-go/tracer.go

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// Copyright (c) 2017-2018 Uber Technologies, Inc.
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//
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// 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
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//
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// 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.
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package jaeger
import (
"fmt"
"io"
"os"
"reflect"
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"strconv"
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"sync"
"time"
"github.com/opentracing/opentracing-go"
"github.com/opentracing/opentracing-go/ext"
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"github.com/uber/jaeger-client-go/internal/baggage"
"github.com/uber/jaeger-client-go/internal/throttler"
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"github.com/uber/jaeger-client-go/log"
"github.com/uber/jaeger-client-go/utils"
)
// Tracer implements opentracing.Tracer.
type Tracer struct {
serviceName string
hostIPv4 uint32 // this is for zipkin endpoint conversion
sampler Sampler
reporter Reporter
metrics Metrics
logger log.Logger
timeNow func() time.Time
randomNumber func() uint64
options struct {
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poolSpans bool
gen128Bit bool // whether to generate 128bit trace IDs
zipkinSharedRPCSpan bool
highTraceIDGenerator func() uint64 // custom high trace ID generator
maxTagValueLength int
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// more options to come
}
// pool for Span objects
spanPool sync.Pool
injectors map[interface{}]Injector
extractors map[interface{}]Extractor
observer compositeObserver
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tags []Tag
process Process
baggageRestrictionManager baggage.RestrictionManager
baggageSetter *baggageSetter
debugThrottler throttler.Throttler
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}
// NewTracer creates Tracer implementation that reports tracing to Jaeger.
// The returned io.Closer can be used in shutdown hooks to ensure that the internal
// queue of the Reporter is drained and all buffered spans are submitted to collectors.
func NewTracer(
serviceName string,
sampler Sampler,
reporter Reporter,
options ...TracerOption,
) (opentracing.Tracer, io.Closer) {
t := &Tracer{
serviceName: serviceName,
sampler: sampler,
reporter: reporter,
injectors: make(map[interface{}]Injector),
extractors: make(map[interface{}]Extractor),
metrics: *NewNullMetrics(),
spanPool: sync.Pool{New: func() interface{} {
return &Span{}
}},
}
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for _, option := range options {
option(t)
}
// register default injectors/extractors unless they are already provided via options
textPropagator := newTextMapPropagator(getDefaultHeadersConfig(), t.metrics)
t.addCodec(opentracing.TextMap, textPropagator, textPropagator)
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httpHeaderPropagator := newHTTPHeaderPropagator(getDefaultHeadersConfig(), t.metrics)
t.addCodec(opentracing.HTTPHeaders, httpHeaderPropagator, httpHeaderPropagator)
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binaryPropagator := newBinaryPropagator(t)
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t.addCodec(opentracing.Binary, binaryPropagator, binaryPropagator)
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// TODO remove after TChannel supports OpenTracing
interopPropagator := &jaegerTraceContextPropagator{tracer: t}
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t.addCodec(SpanContextFormat, interopPropagator, interopPropagator)
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zipkinPropagator := &zipkinPropagator{tracer: t}
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t.addCodec(ZipkinSpanFormat, zipkinPropagator, zipkinPropagator)
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if t.baggageRestrictionManager != nil {
t.baggageSetter = newBaggageSetter(t.baggageRestrictionManager, &t.metrics)
} else {
t.baggageSetter = newBaggageSetter(baggage.NewDefaultRestrictionManager(0), &t.metrics)
}
if t.debugThrottler == nil {
t.debugThrottler = throttler.DefaultThrottler{}
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}
if t.randomNumber == nil {
rng := utils.NewRand(time.Now().UnixNano())
t.randomNumber = func() uint64 {
return uint64(rng.Int63())
}
}
if t.timeNow == nil {
t.timeNow = time.Now
}
if t.logger == nil {
t.logger = log.NullLogger
}
// Set tracer-level tags
t.tags = append(t.tags, Tag{key: JaegerClientVersionTagKey, value: JaegerClientVersion})
if hostname, err := os.Hostname(); err == nil {
t.tags = append(t.tags, Tag{key: TracerHostnameTagKey, value: hostname})
}
if ip, err := utils.HostIP(); err == nil {
t.tags = append(t.tags, Tag{key: TracerIPTagKey, value: ip.String()})
t.hostIPv4 = utils.PackIPAsUint32(ip)
} else {
t.logger.Error("Unable to determine this host's IP address: " + err.Error())
}
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if t.options.gen128Bit {
if t.options.highTraceIDGenerator == nil {
t.options.highTraceIDGenerator = t.randomNumber
}
} else if t.options.highTraceIDGenerator != nil {
t.logger.Error("Overriding high trace ID generator but not generating " +
"128 bit trace IDs, consider enabling the \"Gen128Bit\" option")
}
if t.options.maxTagValueLength == 0 {
t.options.maxTagValueLength = DefaultMaxTagValueLength
}
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t.process = Process{
Service: serviceName,
UUID: strconv.FormatUint(t.randomNumber(), 16),
Tags: t.tags,
}
if throttler, ok := t.debugThrottler.(ProcessSetter); ok {
throttler.SetProcess(t.process)
}
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return t, t
}
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// addCodec adds registers injector and extractor for given propagation format if not already defined.
func (t *Tracer) addCodec(format interface{}, injector Injector, extractor Extractor) {
if _, ok := t.injectors[format]; !ok {
t.injectors[format] = injector
}
if _, ok := t.extractors[format]; !ok {
t.extractors[format] = extractor
}
}
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// StartSpan implements StartSpan() method of opentracing.Tracer.
func (t *Tracer) StartSpan(
operationName string,
options ...opentracing.StartSpanOption,
) opentracing.Span {
sso := opentracing.StartSpanOptions{}
for _, o := range options {
o.Apply(&sso)
}
return t.startSpanWithOptions(operationName, sso)
}
func (t *Tracer) startSpanWithOptions(
operationName string,
options opentracing.StartSpanOptions,
) opentracing.Span {
if options.StartTime.IsZero() {
options.StartTime = t.timeNow()
}
// Predicate whether the given span context is a valid reference
// which may be used as parent / debug ID / baggage items source
isValidReference := func(ctx SpanContext) bool {
return ctx.IsValid() || ctx.isDebugIDContainerOnly() || len(ctx.baggage) != 0
}
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var references []Reference
var parent SpanContext
var hasParent bool // need this because `parent` is a value, not reference
for _, ref := range options.References {
ctx, ok := ref.ReferencedContext.(SpanContext)
if !ok {
t.logger.Error(fmt.Sprintf(
"Reference contains invalid type of SpanReference: %s",
reflect.ValueOf(ref.ReferencedContext)))
continue
}
if !isValidReference(ctx) {
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continue
}
references = append(references, Reference{Type: ref.Type, Context: ctx})
if !hasParent {
parent = ctx
hasParent = ref.Type == opentracing.ChildOfRef
}
}
if !hasParent && isValidReference(parent) {
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// If ChildOfRef wasn't found but a FollowFromRef exists, use the context from
// the FollowFromRef as the parent
hasParent = true
}
rpcServer := false
if v, ok := options.Tags[ext.SpanKindRPCServer.Key]; ok {
rpcServer = (v == ext.SpanKindRPCServerEnum || v == string(ext.SpanKindRPCServerEnum))
}
var samplerTags []Tag
var ctx SpanContext
newTrace := false
if !hasParent || !parent.IsValid() {
newTrace = true
ctx.traceID.Low = t.randomID()
if t.options.gen128Bit {
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ctx.traceID.High = t.options.highTraceIDGenerator()
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}
ctx.spanID = SpanID(ctx.traceID.Low)
ctx.parentID = 0
ctx.flags = byte(0)
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if hasParent && parent.isDebugIDContainerOnly() && t.isDebugAllowed(operationName) {
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ctx.flags |= (flagSampled | flagDebug)
samplerTags = []Tag{{key: JaegerDebugHeader, value: parent.debugID}}
} else if sampled, tags := t.sampler.IsSampled(ctx.traceID, operationName); sampled {
ctx.flags |= flagSampled
samplerTags = tags
}
} else {
ctx.traceID = parent.traceID
if rpcServer && t.options.zipkinSharedRPCSpan {
// Support Zipkin's one-span-per-RPC model
ctx.spanID = parent.spanID
ctx.parentID = parent.parentID
} else {
ctx.spanID = SpanID(t.randomID())
ctx.parentID = parent.spanID
}
ctx.flags = parent.flags
}
if hasParent {
// copy baggage items
if l := len(parent.baggage); l > 0 {
ctx.baggage = make(map[string]string, len(parent.baggage))
for k, v := range parent.baggage {
ctx.baggage[k] = v
}
}
}
sp := t.newSpan()
sp.context = ctx
sp.observer = t.observer.OnStartSpan(sp, operationName, options)
return t.startSpanInternal(
sp,
operationName,
options.StartTime,
samplerTags,
options.Tags,
newTrace,
rpcServer,
references,
)
}
// Inject implements Inject() method of opentracing.Tracer
func (t *Tracer) Inject(ctx opentracing.SpanContext, format interface{}, carrier interface{}) error {
c, ok := ctx.(SpanContext)
if !ok {
return opentracing.ErrInvalidSpanContext
}
if injector, ok := t.injectors[format]; ok {
return injector.Inject(c, carrier)
}
return opentracing.ErrUnsupportedFormat
}
// Extract implements Extract() method of opentracing.Tracer
func (t *Tracer) Extract(
format interface{},
carrier interface{},
) (opentracing.SpanContext, error) {
if extractor, ok := t.extractors[format]; ok {
return extractor.Extract(carrier)
}
return nil, opentracing.ErrUnsupportedFormat
}
// Close releases all resources used by the Tracer and flushes any remaining buffered spans.
func (t *Tracer) Close() error {
t.reporter.Close()
t.sampler.Close()
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if mgr, ok := t.baggageRestrictionManager.(io.Closer); ok {
mgr.Close()
}
if throttler, ok := t.debugThrottler.(io.Closer); ok {
throttler.Close()
}
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return nil
}
// Tags returns a slice of tracer-level tags.
func (t *Tracer) Tags() []opentracing.Tag {
tags := make([]opentracing.Tag, len(t.tags))
for i, tag := range t.tags {
tags[i] = opentracing.Tag{Key: tag.key, Value: tag.value}
}
return tags
}
// newSpan returns an instance of a clean Span object.
// If options.PoolSpans is true, the spans are retrieved from an object pool.
func (t *Tracer) newSpan() *Span {
if !t.options.poolSpans {
return &Span{}
}
sp := t.spanPool.Get().(*Span)
sp.context = emptyContext
sp.tracer = nil
sp.tags = nil
sp.logs = nil
return sp
}
func (t *Tracer) startSpanInternal(
sp *Span,
operationName string,
startTime time.Time,
internalTags []Tag,
tags opentracing.Tags,
newTrace bool,
rpcServer bool,
references []Reference,
) *Span {
sp.tracer = t
sp.operationName = operationName
sp.startTime = startTime
sp.duration = 0
sp.references = references
sp.firstInProcess = rpcServer || sp.context.parentID == 0
if len(tags) > 0 || len(internalTags) > 0 {
sp.tags = make([]Tag, len(internalTags), len(tags)+len(internalTags))
copy(sp.tags, internalTags)
for k, v := range tags {
sp.observer.OnSetTag(k, v)
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if k == string(ext.SamplingPriority) && !setSamplingPriority(sp, v) {
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continue
}
sp.setTagNoLocking(k, v)
}
}
// emit metrics
if sp.context.IsSampled() {
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t.metrics.SpansStartedSampled.Inc(1)
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if newTrace {
// We cannot simply check for parentID==0 because in Zipkin model the
// server-side RPC span has the exact same trace/span/parent IDs as the
// calling client-side span, but obviously the server side span is
// no longer a root span of the trace.
t.metrics.TracesStartedSampled.Inc(1)
} else if sp.firstInProcess {
t.metrics.TracesJoinedSampled.Inc(1)
}
} else {
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t.metrics.SpansStartedNotSampled.Inc(1)
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if newTrace {
t.metrics.TracesStartedNotSampled.Inc(1)
} else if sp.firstInProcess {
t.metrics.TracesJoinedNotSampled.Inc(1)
}
}
return sp
}
func (t *Tracer) reportSpan(sp *Span) {
t.metrics.SpansFinished.Inc(1)
if sp.context.IsSampled() {
t.reporter.Report(sp)
}
if t.options.poolSpans {
t.spanPool.Put(sp)
}
}
// randomID generates a random trace/span ID, using tracer.random() generator.
// It never returns 0.
func (t *Tracer) randomID() uint64 {
val := t.randomNumber()
for val == 0 {
val = t.randomNumber()
}
return val
}
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// (NB) span must hold the lock before making this call
func (t *Tracer) setBaggage(sp *Span, key, value string) {
t.baggageSetter.setBaggage(sp, key, value)
}
// (NB) span must hold the lock before making this call
func (t *Tracer) isDebugAllowed(operation string) bool {
return t.debugThrottler.IsAllowed(operation)
}