/
zipkin.go
294 lines (260 loc) · 7.66 KB
/
zipkin.go
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package openzipkin
import (
"errors"
"fmt"
"strings"
"time"
"github.com/TykTechnologies/tyk/config"
opentracing "github.com/opentracing/opentracing-go"
"github.com/opentracing/opentracing-go/log"
zipkin "github.com/openzipkin/zipkin-go"
"github.com/openzipkin/zipkin-go/model"
"github.com/openzipkin/zipkin-go/propagation/b3"
"github.com/openzipkin/zipkin-go/reporter"
"github.com/openzipkin/zipkin-go/reporter/http"
)
var _ opentracing.Tracer = (*zipkinTracer)(nil)
var _ opentracing.SpanContext = (*spanContext)(nil)
var _ opentracing.Span = (*Span)(nil)
const Name = "zipkin"
type Span struct {
span zipkin.Span
tr *zipkinTracer
}
func (s Span) Context() opentracing.SpanContext {
return spanContext{s.span.Context()}
}
func (s Span) Finish() {
s.span.Finish()
}
func (s Span) FinishWithOptions(opts opentracing.FinishOptions) {
s.span.Finish()
}
func (s Span) SetOperationName(operationName string) opentracing.Span {
s.span.SetName(operationName)
return s
}
func (s Span) SetTag(key string, value interface{}) opentracing.Span {
s.span.Tag(key, fmt.Sprint(value))
return s
}
func (s Span) LogFields(fields ...log.Field) {
now := time.Now()
lg := &logEncoder{h: func(key string, value interface{}) {
s.span.Annotate(now, fmt.Sprintf("%s %s", key, value))
}}
for _, field := range fields {
field.Marshal(lg)
}
}
type logEncoder struct {
h func(string, interface{})
}
func (e *logEncoder) emit(key string, value interface{}) {
if e.h != nil {
e.h(key, value)
}
}
func (e *logEncoder) EmitString(key, value string) { e.emit(key, value) }
func (e *logEncoder) EmitBool(key string, value bool) { e.emit(key, value) }
func (e *logEncoder) EmitInt(key string, value int) { e.emit(key, value) }
func (e *logEncoder) EmitInt32(key string, value int32) { e.emit(key, value) }
func (e *logEncoder) EmitInt64(key string, value int64) { e.emit(key, value) }
func (e *logEncoder) EmitUint32(key string, value uint32) { e.emit(key, value) }
func (e *logEncoder) EmitUint64(key string, value uint64) { e.emit(key, value) }
func (e *logEncoder) EmitFloat32(key string, value float32) { e.emit(key, value) }
func (e *logEncoder) EmitFloat64(key string, value float64) { e.emit(key, value) }
func (e *logEncoder) EmitObject(key string, value interface{}) { e.emit(key, value) }
func (e *logEncoder) EmitLazyLogger(value log.LazyLogger) {}
func (s Span) LogKV(alternatingKeyValues ...interface{}) {}
func (s Span) SetBaggageItem(restrictedKey, value string) opentracing.Span { return s }
func (Span) BaggageItem(restrictedKey string) string { return "" }
func (s Span) Tracer() opentracing.Tracer { return s.tr }
func (s Span) LogEvent(event string) {}
func (s Span) LogEventWithPayload(event string, payload interface{}) {}
func (s Span) Log(data opentracing.LogData) {}
type spanContext struct {
model.SpanContext
}
func (spanContext) ForeachBaggageItem(handler func(k, v string) bool) {}
type extractor interface {
extract(carrier interface{}) (spanContext, error)
}
var emptyContext spanContext
func extractHTTPHeader(carrier interface{}) (spanContext, error) {
c, ok := carrier.(opentracing.HTTPHeadersCarrier)
if !ok {
return emptyContext, opentracing.ErrInvalidCarrier
}
var (
traceIDHeader string
spanIDHeader string
parentSpanIDHeader string
sampledHeader string
flagsHeader string
singleHeader string
)
err := c.ForeachKey(func(key, val string) error {
switch strings.ToLower(key) {
case b3.TraceID:
traceIDHeader = val
case b3.SpanID:
spanIDHeader = val
case b3.ParentSpanID:
parentSpanIDHeader = val
case b3.Sampled:
sampledHeader = val
case b3.Flags:
flagsHeader = val
case b3.Context:
singleHeader = val
}
return nil
})
if err != nil {
return emptyContext, err
}
if singleHeader != "" {
ctx, err := b3.ParseSingleHeader(singleHeader)
if err != nil {
return emptyContext, err
}
return spanContext{*ctx}, nil
}
ctx, err := b3.ParseHeaders(
traceIDHeader, spanIDHeader, parentSpanIDHeader,
sampledHeader, flagsHeader,
)
if err != nil {
return emptyContext, err
}
return spanContext{*ctx}, nil
}
type extractorFn func(carrier interface{}) (spanContext, error)
func (fn extractorFn) extract(carrier interface{}) (spanContext, error) {
return fn(carrier)
}
type injector interface {
inject(ctx spanContext, carrier interface{}) error
}
func injectHTTPHeaders(ctx spanContext, carrier interface{}) error {
c, ok := carrier.(opentracing.HTTPHeadersCarrier)
if !ok {
return opentracing.ErrInvalidCarrier
}
if ctx == emptyContext {
return nil
}
c.Set(b3.Context, b3.BuildSingleHeader(ctx.SpanContext))
return nil
}
type injectorFn func(ctx spanContext, carrier interface{}) error
func (fn injectorFn) inject(ctx spanContext, carrier interface{}) error {
return fn(ctx, carrier)
}
type zipkinTracer struct {
zip *zipkin.Tracer
extractors map[interface{}]extractor
injectors map[interface{}]injector
}
func NewTracer(zip *zipkin.Tracer) *zipkinTracer {
return &zipkinTracer{
zip: zip,
extractors: map[interface{}]extractor{
opentracing.HTTPHeaders: extractorFn(extractHTTPHeader),
},
injectors: map[interface{}]injector{
opentracing.HTTPHeaders: injectorFn(injectHTTPHeaders),
},
}
}
func (z *zipkinTracer) StartSpan(operationName string, opts ...opentracing.StartSpanOption) opentracing.Span {
var o []zipkin.SpanOption
if len(opts) > 0 {
var os opentracing.StartSpanOptions
for _, opt := range opts {
opt.Apply(&os)
}
if len(os.Tags) > 0 {
t := make(map[string]string)
for k, v := range os.Tags {
t[k] = fmt.Sprint(v)
}
o = append(o, zipkin.Tags(t))
}
for _, ref := range os.References {
switch ref.Type {
case opentracing.ChildOfRef:
sp := ref.ReferencedContext.(spanContext)
o = append(o, zipkin.Parent(
sp.SpanContext,
))
}
}
}
sp := z.zip.StartSpan(operationName, o...)
return Span{tr: z, span: sp}
}
func (z *zipkinTracer) Extract(format interface{}, carrier interface{}) (opentracing.SpanContext, error) {
if x, ok := z.extractors[format]; ok {
return x.extract(carrier)
}
return nil, opentracing.ErrUnsupportedFormat
}
func (z *zipkinTracer) Inject(ctx opentracing.SpanContext, format interface{}, carrier interface{}) error {
c, ok := ctx.(spanContext)
if !ok {
return opentracing.ErrInvalidSpanContext
}
if x, ok := z.injectors[format]; ok {
return x.inject(c, carrier)
}
return opentracing.ErrUnsupportedFormat
}
type Tracer struct {
opentracing.Tracer
reporter.Reporter
}
func (Tracer) Name() string {
return Name
}
func Init(service string, opts map[string]interface{}) (*Tracer, error) {
c, err := Load(opts)
if err != nil {
return nil, err
}
if c.Reporter.URL == "" {
return nil, errors.New("zipkin: missing url")
}
r := http.NewReporter(c.Reporter.URL)
endpoint, err := zipkin.NewEndpoint(service, "")
if err != nil {
return nil, err
}
sampler, err := getSampler(c.Sampler)
if err != nil {
return nil, err
}
tr, err := zipkin.NewTracer(r,
zipkin.WithLocalEndpoint(endpoint),
zipkin.WithSampler(sampler),
)
if err != nil {
return nil, err
}
return &Tracer{Tracer: NewTracer(tr), Reporter: r}, nil
}
func getSampler(s config.Sampler) (zipkin.Sampler, error) {
if s.Name == "" {
return zipkin.AlwaysSample, nil
}
switch s.Name {
case "boundary":
return zipkin.NewBoundarySampler(s.Rate, s.Salt)
case "count":
return zipkin.NewCountingSampler(s.Rate)
case "mod":
return zipkin.NewModuloSampler(s.Mod), nil
}
return nil, fmt.Errorf("zipkin: unknown sampler %s", s.Name)
}