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mirror of https://github.com/open-telemetry/opentelemetry-go.git synced 2024-12-12 10:04:29 +02:00
opentelemetry-go/propagation/http_b3_propagator.go
Gustavo Silva Paiva a6e139e1d4 api(trace): change trace id to byte array. (#226)
* api(trace): change trace id to byte array.

* fix lint errors

* add helper to create trace id from hex and improve stdout exporter.

* remove comma.

* fix lint

* change TraceIDFromHex to be compliant with w3 trace-context

* revert remove of hex16 regex because its used to parse SpanID

* lint

* fix typo
2019-10-22 23:01:33 -07:00

226 lines
5.6 KiB
Go

// Copyright 2019, OpenTelemetry Authors
//
// 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 propagation
import (
"context"
"fmt"
"regexp"
"strconv"
"strings"
"go.opentelemetry.io/api/trace"
"go.opentelemetry.io/api/core"
dctx "go.opentelemetry.io/api/distributedcontext"
apipropagation "go.opentelemetry.io/api/propagation"
)
const (
B3SingleHeader = "X-B3"
B3DebugFlagHeader = "X-B3-Flags"
B3TraceIDHeader = "X-B3-TraceId"
B3SpanIDHeader = "X-B3-SpanId"
B3SampledHeader = "X-B3-Sampled"
B3ParentSpanIDHeader = "X-B3-ParentSpanId"
)
// HTTPB3Propagator that facilitates core.SpanContext
// propagation using B3 Headers.
// This propagator supports both version of B3 headers,
// 1. Single Header :
// X-B3: {TraceId}-{SpanId}-{SamplingState}-{ParentSpanId}
// 2. Multiple Headers:
// X-B3-TraceId: {TraceId}
// X-B3-ParentSpanId: {ParentSpanId}
// X-B3-SpanId: {SpanId}
// X-B3-Sampled: {SamplingState}
// X-B3-Flags: {DebugFlag}
//
// If SingleHeader is set to true then X-B3 header is used to inject and extract. Otherwise,
// separate headers are used to inject and extract.
type HTTPB3Propagator struct {
SingleHeader bool
}
var _ apipropagation.TextFormatPropagator = HTTPB3Propagator{}
var hexStr16ByteRegex = regexp.MustCompile("^[a-f0-9]{16}$")
func (b3 HTTPB3Propagator) Inject(ctx context.Context, supplier apipropagation.Supplier) {
sc := trace.CurrentSpan(ctx).SpanContext()
if sc.IsValid() {
if b3.SingleHeader {
sampled := sc.TraceFlags & core.TraceFlagsSampled
supplier.Set(B3SingleHeader,
fmt.Sprintf("%s-%.16x-%.1d", sc.TraceIDString(), sc.SpanID, sampled))
} else {
supplier.Set(B3TraceIDHeader, sc.TraceIDString())
supplier.Set(B3SpanIDHeader,
fmt.Sprintf("%.16x", sc.SpanID))
var sampled string
if sc.IsSampled() {
sampled = "1"
} else {
sampled = "0"
}
supplier.Set(B3SampledHeader, sampled)
}
}
}
// Extract retrieves B3 Headers from the supplier
func (b3 HTTPB3Propagator) Extract(ctx context.Context, supplier apipropagation.Supplier) (core.SpanContext, dctx.Map) {
if b3.SingleHeader {
return b3.extractSingleHeader(supplier), dctx.NewEmptyMap()
}
return b3.extract(supplier), dctx.NewEmptyMap()
}
func (b3 HTTPB3Propagator) GetAllKeys() []string {
if b3.SingleHeader {
return []string{B3SingleHeader}
}
return []string{B3TraceIDHeader, B3SpanIDHeader, B3SampledHeader}
}
func (b3 HTTPB3Propagator) extract(supplier apipropagation.Supplier) core.SpanContext {
tid, ok := b3.extractTraceID(supplier.Get(B3TraceIDHeader))
if !ok {
return core.EmptySpanContext()
}
sid, ok := b3.extractSpanID(supplier.Get(B3SpanIDHeader))
if !ok {
return core.EmptySpanContext()
}
sampled, ok := b3.extractSampledState(supplier.Get(B3SampledHeader))
if !ok {
return core.EmptySpanContext()
}
debug, ok := b3.extracDebugFlag(supplier.Get(B3DebugFlagHeader))
if !ok {
return core.EmptySpanContext()
}
if debug == core.TraceFlagsSampled {
sampled = core.TraceFlagsSampled
}
sc := core.SpanContext{
TraceID: tid,
SpanID: sid,
TraceFlags: sampled,
}
if !sc.IsValid() {
return core.EmptySpanContext()
}
return sc
}
func (b3 HTTPB3Propagator) extractSingleHeader(supplier apipropagation.Supplier) core.SpanContext {
h := supplier.Get(B3SingleHeader)
if h == "" || h == "0" {
core.EmptySpanContext()
}
sc := core.SpanContext{}
parts := strings.Split(h, "-")
l := len(parts)
if l > 4 {
return core.EmptySpanContext()
}
if l < 2 {
return core.EmptySpanContext()
}
var ok bool
sc.TraceID, ok = b3.extractTraceID(parts[0])
if !ok {
return core.EmptySpanContext()
}
sc.SpanID, ok = b3.extractSpanID(parts[1])
if !ok {
return core.EmptySpanContext()
}
if l > 2 {
sc.TraceFlags, ok = b3.extractSampledState(parts[2])
if !ok {
return core.EmptySpanContext()
}
}
if l == 4 {
_, ok = b3.extractSpanID(parts[3])
if !ok {
return core.EmptySpanContext()
}
}
if !sc.IsValid() {
return core.EmptySpanContext()
}
return sc
}
// extractTraceID parses the value of the X-B3-TraceId b3Header.
func (b3 HTTPB3Propagator) extractTraceID(tid string) (traceID core.TraceID, ok bool) {
traceID, err := core.TraceIDFromHex(tid)
return traceID, err == nil
}
// extractSpanID parses the value of the X-B3-SpanId or X-B3-ParentSpanId headers.
func (b3 HTTPB3Propagator) extractSpanID(sid string) (spanID uint64, ok bool) {
if hexStr16ByteRegex.MatchString(sid) {
spanID, _ = strconv.ParseUint(sid, 16, 64)
ok = true
}
return spanID, ok
}
// extractSampledState parses the value of the X-B3-Sampled b3Header.
func (b3 HTTPB3Propagator) extractSampledState(sampled string) (flag byte, ok bool) {
switch sampled {
case "", "0":
return 0, true
case "1":
return core.TraceFlagsSampled, true
case "true":
if !b3.SingleHeader {
return core.TraceFlagsSampled, true
}
case "d":
if b3.SingleHeader {
return core.TraceFlagsSampled, true
}
}
return 0, false
}
// extracDebugFlag parses the value of the X-B3-Sampled b3Header.
func (b3 HTTPB3Propagator) extracDebugFlag(debug string) (flag byte, ok bool) {
switch debug {
case "", "0":
return 0, true
case "1":
return core.TraceFlagsSampled, true
}
return 0, false
}