traefik/vendor/github.com/uber/jaeger-client-go/tracer.go
2018-01-10 17:48:04 +01:00

371 lines
10 KiB
Go

// Copyright (c) 2016 Uber Technologies, Inc.
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
package jaeger
import (
"fmt"
"io"
"os"
"reflect"
"sync"
"time"
"github.com/opentracing/opentracing-go"
"github.com/opentracing/opentracing-go/ext"
"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 {
poolSpans bool
gen128Bit bool // whether to generate 128bit trace IDs
zipkinSharedRPCSpan bool
// more options to come
}
// pool for Span objects
spanPool sync.Pool
injectors map[interface{}]Injector
extractors map[interface{}]Extractor
observer compositeObserver
tags []Tag
}
// 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{}
}},
}
// register default injectors/extractors
textPropagator := newTextMapPropagator(t)
t.injectors[opentracing.TextMap] = textPropagator
t.extractors[opentracing.TextMap] = textPropagator
httpHeaderPropagator := newHTTPHeaderPropagator(t)
t.injectors[opentracing.HTTPHeaders] = httpHeaderPropagator
t.extractors[opentracing.HTTPHeaders] = httpHeaderPropagator
binaryPropagator := newBinaryPropagator(t)
t.injectors[opentracing.Binary] = binaryPropagator
t.extractors[opentracing.Binary] = binaryPropagator
// TODO remove after TChannel supports OpenTracing
interopPropagator := &jaegerTraceContextPropagator{tracer: t}
t.injectors[SpanContextFormat] = interopPropagator
t.extractors[SpanContextFormat] = interopPropagator
zipkinPropagator := &zipkinPropagator{tracer: t}
t.injectors[ZipkinSpanFormat] = zipkinPropagator
t.extractors[ZipkinSpanFormat] = zipkinPropagator
for _, option := range options {
option(t)
}
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())
}
return t, t
}
// 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()
}
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 !(ctx.IsValid() || ctx.isDebugIDContainerOnly() || len(ctx.baggage) != 0) {
continue
}
references = append(references, Reference{Type: ref.Type, Context: ctx})
if !hasParent {
parent = ctx
hasParent = ref.Type == opentracing.ChildOfRef
}
}
if !hasParent && parent.IsValid() {
// 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 {
ctx.traceID.High = t.randomID()
}
ctx.spanID = SpanID(ctx.traceID.Low)
ctx.parentID = 0
ctx.flags = byte(0)
if hasParent && parent.isDebugIDContainerOnly() {
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()
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)
if k == string(ext.SamplingPriority) && setSamplingPriority(sp, v) {
continue
}
sp.setTagNoLocking(k, v)
}
}
// emit metrics
t.metrics.SpansStarted.Inc(1)
if sp.context.IsSampled() {
t.metrics.SpansSampled.Inc(1)
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 {
t.metrics.SpansNotSampled.Inc(1)
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
}