mirror of
https://github.com/open-telemetry/opentelemetry-go.git
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6b4acf47b8
* Rename distributedcontext package to correlation Correlation is the name we agreed upon. * Move trace propagators to api/trace The trace propagators tests had to be moved to a testtrace subpackage to avoid import cycles between api/trace and internal/trace. Needed to shut up golint about stutter in trace.TraceContext - TraceContext is a name of a W3C spec, so this stutter is expected. It's certainly still better than golint's suggestion of having trace.Context. * Rename api/propagators to api/propagation This package will not contain any propagators in the long run, just the interface definitions. Co-authored-by: Joshua MacDonald <jmacd@users.noreply.github.com>
205 lines
4.9 KiB
Go
205 lines
4.9 KiB
Go
// Copyright 2019, OpenTelemetry Authors
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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 trace
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import (
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"context"
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"fmt"
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"strings"
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"go.opentelemetry.io/otel/api/core"
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"go.opentelemetry.io/otel/api/correlation"
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"go.opentelemetry.io/otel/api/propagation"
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)
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const (
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B3SingleHeader = "X-B3"
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B3DebugFlagHeader = "X-B3-Flags"
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B3TraceIDHeader = "X-B3-TraceId"
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B3SpanIDHeader = "X-B3-SpanId"
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B3SampledHeader = "X-B3-Sampled"
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B3ParentSpanIDHeader = "X-B3-ParentSpanId"
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)
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// B3 propagator serializes core.SpanContext to/from B3 Headers.
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// This propagator supports both version of B3 headers,
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// 1. Single Header :
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// X-B3: {TraceId}-{SpanId}-{SamplingState}-{ParentSpanId}
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// 2. Multiple Headers:
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// X-B3-TraceId: {TraceId}
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// X-B3-ParentSpanId: {ParentSpanId}
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// X-B3-SpanId: {SpanId}
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// X-B3-Sampled: {SamplingState}
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// X-B3-Flags: {DebugFlag}
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//
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// If SingleHeader is set to true then X-B3 header is used to inject and extract. Otherwise,
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// separate headers are used to inject and extract.
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type B3 struct {
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SingleHeader bool
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}
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var _ propagation.TextFormat = B3{}
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func (b3 B3) Inject(ctx context.Context, supplier propagation.Supplier) {
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sc := SpanFromContext(ctx).SpanContext()
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if sc.IsValid() {
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if b3.SingleHeader {
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sampled := sc.TraceFlags & core.TraceFlagsSampled
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supplier.Set(B3SingleHeader,
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fmt.Sprintf("%s-%.16x-%.1d", sc.TraceIDString(), sc.SpanID, sampled))
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} else {
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supplier.Set(B3TraceIDHeader, sc.TraceIDString())
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supplier.Set(B3SpanIDHeader,
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fmt.Sprintf("%.16x", sc.SpanID))
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var sampled string
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if sc.IsSampled() {
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sampled = "1"
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} else {
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sampled = "0"
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}
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supplier.Set(B3SampledHeader, sampled)
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}
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}
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}
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// Extract retrieves B3 Headers from the supplier
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func (b3 B3) Extract(ctx context.Context, supplier propagation.Supplier) (core.SpanContext, correlation.Map) {
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if b3.SingleHeader {
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return b3.extractSingleHeader(supplier), correlation.NewEmptyMap()
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}
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return b3.extract(supplier), correlation.NewEmptyMap()
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}
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func (b3 B3) GetAllKeys() []string {
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if b3.SingleHeader {
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return []string{B3SingleHeader}
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}
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return []string{B3TraceIDHeader, B3SpanIDHeader, B3SampledHeader}
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}
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func (b3 B3) extract(supplier propagation.Supplier) core.SpanContext {
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tid, err := core.TraceIDFromHex(supplier.Get(B3TraceIDHeader))
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if err != nil {
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return core.EmptySpanContext()
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}
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sid, err := core.SpanIDFromHex(supplier.Get(B3SpanIDHeader))
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if err != nil {
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return core.EmptySpanContext()
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}
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sampled, ok := b3.extractSampledState(supplier.Get(B3SampledHeader))
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if !ok {
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return core.EmptySpanContext()
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}
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debug, ok := b3.extracDebugFlag(supplier.Get(B3DebugFlagHeader))
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if !ok {
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return core.EmptySpanContext()
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}
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if debug == core.TraceFlagsSampled {
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sampled = core.TraceFlagsSampled
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}
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sc := core.SpanContext{
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TraceID: tid,
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SpanID: sid,
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TraceFlags: sampled,
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}
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if !sc.IsValid() {
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return core.EmptySpanContext()
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}
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return sc
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}
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func (b3 B3) extractSingleHeader(supplier propagation.Supplier) core.SpanContext {
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h := supplier.Get(B3SingleHeader)
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if h == "" || h == "0" {
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core.EmptySpanContext()
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}
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sc := core.SpanContext{}
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parts := strings.Split(h, "-")
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l := len(parts)
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if l > 4 {
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return core.EmptySpanContext()
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}
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if l < 2 {
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return core.EmptySpanContext()
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}
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var err error
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sc.TraceID, err = core.TraceIDFromHex(parts[0])
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if err != nil {
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return core.EmptySpanContext()
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}
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sc.SpanID, err = core.SpanIDFromHex(parts[1])
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if err != nil {
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return core.EmptySpanContext()
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}
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if l > 2 {
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var ok bool
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sc.TraceFlags, ok = b3.extractSampledState(parts[2])
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if !ok {
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return core.EmptySpanContext()
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}
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}
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if l == 4 {
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_, err = core.SpanIDFromHex(parts[3])
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if err != nil {
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return core.EmptySpanContext()
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}
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}
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if !sc.IsValid() {
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return core.EmptySpanContext()
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}
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return sc
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}
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// extractSampledState parses the value of the X-B3-Sampled b3Header.
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func (b3 B3) extractSampledState(sampled string) (flag byte, ok bool) {
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switch sampled {
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case "", "0":
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return 0, true
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case "1":
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return core.TraceFlagsSampled, true
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case "true":
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if !b3.SingleHeader {
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return core.TraceFlagsSampled, true
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}
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case "d":
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if b3.SingleHeader {
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return core.TraceFlagsSampled, true
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}
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}
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return 0, false
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}
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// extracDebugFlag parses the value of the X-B3-Sampled b3Header.
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func (b3 B3) extracDebugFlag(debug string) (flag byte, ok bool) {
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switch debug {
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case "", "0":
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return 0, true
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case "1":
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return core.TraceFlagsSampled, true
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}
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return 0, false
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}
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