301 lines
9.3 KiB
Go
301 lines
9.3 KiB
Go
// Copyright (c) 2017 Uber Technologies, Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// 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
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package jaeger
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import (
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"bytes"
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"encoding/binary"
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"fmt"
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"io"
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"log"
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"net/url"
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"strings"
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"sync"
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opentracing "github.com/opentracing/opentracing-go"
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)
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// Injector is responsible for injecting SpanContext instances in a manner suitable
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// for propagation via a format-specific "carrier" object. Typically the
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// injection will take place across an RPC boundary, but message queues and
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// other IPC mechanisms are also reasonable places to use an Injector.
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type Injector interface {
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// Inject takes `SpanContext` and injects it into `carrier`. The actual type
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// of `carrier` depends on the `format` passed to `Tracer.Inject()`.
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//
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// Implementations may return opentracing.ErrInvalidCarrier or any other
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// implementation-specific error if injection fails.
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Inject(ctx SpanContext, carrier interface{}) error
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}
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// Extractor is responsible for extracting SpanContext instances from a
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// format-specific "carrier" object. Typically the extraction will take place
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// on the server side of an RPC boundary, but message queues and other IPC
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// mechanisms are also reasonable places to use an Extractor.
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type Extractor interface {
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// Extract decodes a SpanContext instance from the given `carrier`,
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// or (nil, opentracing.ErrSpanContextNotFound) if no context could
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// be found in the `carrier`.
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Extract(carrier interface{}) (SpanContext, error)
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}
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type textMapPropagator struct {
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headerKeys *HeadersConfig
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metrics Metrics
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encodeValue func(string) string
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decodeValue func(string) string
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}
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func newTextMapPropagator(headerKeys *HeadersConfig, metrics Metrics) *textMapPropagator {
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return &textMapPropagator{
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headerKeys: headerKeys,
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metrics: metrics,
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encodeValue: func(val string) string {
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return val
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},
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decodeValue: func(val string) string {
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return val
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},
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}
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}
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func newHTTPHeaderPropagator(headerKeys *HeadersConfig, metrics Metrics) *textMapPropagator {
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return &textMapPropagator{
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headerKeys: headerKeys,
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metrics: metrics,
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encodeValue: func(val string) string {
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return url.QueryEscape(val)
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},
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decodeValue: func(val string) string {
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// ignore decoding errors, cannot do anything about them
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if v, err := url.QueryUnescape(val); err == nil {
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return v
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}
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return val
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},
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}
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}
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type binaryPropagator struct {
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tracer *Tracer
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buffers sync.Pool
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}
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func newBinaryPropagator(tracer *Tracer) *binaryPropagator {
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return &binaryPropagator{
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tracer: tracer,
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buffers: sync.Pool{New: func() interface{} { return &bytes.Buffer{} }},
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}
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}
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func (p *textMapPropagator) Inject(
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sc SpanContext,
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abstractCarrier interface{},
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) error {
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textMapWriter, ok := abstractCarrier.(opentracing.TextMapWriter)
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if !ok {
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return opentracing.ErrInvalidCarrier
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}
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// Do not encode the string with trace context to avoid accidental double-encoding
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// if people are using opentracing < 0.10.0. Our colon-separated representation
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// of the trace context is already safe for HTTP headers.
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textMapWriter.Set(p.headerKeys.TraceContextHeaderName, sc.String())
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for k, v := range sc.baggage {
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safeKey := p.addBaggageKeyPrefix(k)
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safeVal := p.encodeValue(v)
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textMapWriter.Set(safeKey, safeVal)
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}
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return nil
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}
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func (p *textMapPropagator) Extract(abstractCarrier interface{}) (SpanContext, error) {
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textMapReader, ok := abstractCarrier.(opentracing.TextMapReader)
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if !ok {
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return emptyContext, opentracing.ErrInvalidCarrier
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}
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var ctx SpanContext
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var baggage map[string]string
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err := textMapReader.ForeachKey(func(rawKey, value string) error {
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key := strings.ToLower(rawKey) // TODO not necessary for plain TextMap
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if key == p.headerKeys.TraceContextHeaderName {
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var err error
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safeVal := p.decodeValue(value)
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if ctx, err = ContextFromString(safeVal); err != nil {
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return err
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}
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} else if key == p.headerKeys.JaegerDebugHeader {
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ctx.debugID = p.decodeValue(value)
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} else if key == p.headerKeys.JaegerBaggageHeader {
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if baggage == nil {
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baggage = make(map[string]string)
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}
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for k, v := range p.parseCommaSeparatedMap(value) {
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baggage[k] = v
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}
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} else if strings.HasPrefix(key, p.headerKeys.TraceBaggageHeaderPrefix) {
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if baggage == nil {
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baggage = make(map[string]string)
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}
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safeKey := p.removeBaggageKeyPrefix(key)
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safeVal := p.decodeValue(value)
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baggage[safeKey] = safeVal
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}
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return nil
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})
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if err != nil {
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p.metrics.DecodingErrors.Inc(1)
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return emptyContext, err
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}
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if !ctx.traceID.IsValid() && ctx.debugID == "" && len(baggage) == 0 {
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return emptyContext, opentracing.ErrSpanContextNotFound
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}
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ctx.baggage = baggage
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return ctx, nil
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}
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func (p *binaryPropagator) Inject(
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sc SpanContext,
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abstractCarrier interface{},
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) error {
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carrier, ok := abstractCarrier.(io.Writer)
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if !ok {
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return opentracing.ErrInvalidCarrier
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}
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// Handle the tracer context
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if err := binary.Write(carrier, binary.BigEndian, sc.traceID); err != nil {
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return err
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}
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if err := binary.Write(carrier, binary.BigEndian, sc.spanID); err != nil {
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return err
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}
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if err := binary.Write(carrier, binary.BigEndian, sc.parentID); err != nil {
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return err
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}
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if err := binary.Write(carrier, binary.BigEndian, sc.flags); err != nil {
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return err
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}
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// Handle the baggage items
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if err := binary.Write(carrier, binary.BigEndian, int32(len(sc.baggage))); err != nil {
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return err
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}
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for k, v := range sc.baggage {
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if err := binary.Write(carrier, binary.BigEndian, int32(len(k))); err != nil {
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return err
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}
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io.WriteString(carrier, k)
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if err := binary.Write(carrier, binary.BigEndian, int32(len(v))); err != nil {
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return err
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}
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io.WriteString(carrier, v)
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}
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return nil
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}
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func (p *binaryPropagator) Extract(abstractCarrier interface{}) (SpanContext, error) {
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carrier, ok := abstractCarrier.(io.Reader)
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if !ok {
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return emptyContext, opentracing.ErrInvalidCarrier
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}
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var ctx SpanContext
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if err := binary.Read(carrier, binary.BigEndian, &ctx.traceID); err != nil {
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return emptyContext, opentracing.ErrSpanContextCorrupted
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}
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if err := binary.Read(carrier, binary.BigEndian, &ctx.spanID); err != nil {
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return emptyContext, opentracing.ErrSpanContextCorrupted
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}
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if err := binary.Read(carrier, binary.BigEndian, &ctx.parentID); err != nil {
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return emptyContext, opentracing.ErrSpanContextCorrupted
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}
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if err := binary.Read(carrier, binary.BigEndian, &ctx.flags); err != nil {
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return emptyContext, opentracing.ErrSpanContextCorrupted
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}
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// Handle the baggage items
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var numBaggage int32
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if err := binary.Read(carrier, binary.BigEndian, &numBaggage); err != nil {
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return emptyContext, opentracing.ErrSpanContextCorrupted
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}
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if iNumBaggage := int(numBaggage); iNumBaggage > 0 {
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ctx.baggage = make(map[string]string, iNumBaggage)
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buf := p.buffers.Get().(*bytes.Buffer)
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defer p.buffers.Put(buf)
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var keyLen, valLen int32
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for i := 0; i < iNumBaggage; i++ {
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if err := binary.Read(carrier, binary.BigEndian, &keyLen); err != nil {
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return emptyContext, opentracing.ErrSpanContextCorrupted
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}
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buf.Reset()
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buf.Grow(int(keyLen))
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if n, err := io.CopyN(buf, carrier, int64(keyLen)); err != nil || int32(n) != keyLen {
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return emptyContext, opentracing.ErrSpanContextCorrupted
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}
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key := buf.String()
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if err := binary.Read(carrier, binary.BigEndian, &valLen); err != nil {
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return emptyContext, opentracing.ErrSpanContextCorrupted
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}
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buf.Reset()
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buf.Grow(int(valLen))
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if n, err := io.CopyN(buf, carrier, int64(valLen)); err != nil || int32(n) != valLen {
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return emptyContext, opentracing.ErrSpanContextCorrupted
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}
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ctx.baggage[key] = buf.String()
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}
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}
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return ctx, nil
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}
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// Converts a comma separated key value pair list into a map
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// e.g. key1=value1, key2=value2, key3 = value3
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// is converted to map[string]string { "key1" : "value1",
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// "key2" : "value2",
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// "key3" : "value3" }
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func (p *textMapPropagator) parseCommaSeparatedMap(value string) map[string]string {
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baggage := make(map[string]string)
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value, err := url.QueryUnescape(value)
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if err != nil {
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log.Printf("Unable to unescape %s, %v", value, err)
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return baggage
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}
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for _, kvpair := range strings.Split(value, ",") {
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kv := strings.Split(strings.TrimSpace(kvpair), "=")
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if len(kv) == 2 {
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baggage[kv[0]] = kv[1]
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} else {
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log.Printf("Malformed value passed in for %s", p.headerKeys.JaegerBaggageHeader)
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}
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}
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return baggage
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}
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// Converts a baggage item key into an http header format,
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// by prepending TraceBaggageHeaderPrefix and encoding the key string
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func (p *textMapPropagator) addBaggageKeyPrefix(key string) string {
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// TODO encodeBaggageKeyAsHeader add caching and escaping
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return fmt.Sprintf("%v%v", p.headerKeys.TraceBaggageHeaderPrefix, key)
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}
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func (p *textMapPropagator) removeBaggageKeyPrefix(key string) string {
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// TODO decodeBaggageHeaderKey add caching and escaping
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return key[len(p.headerKeys.TraceBaggageHeaderPrefix):]
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}
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