// 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" "encoding/hex" "fmt" "regexp" "strconv" "strings" "go.opentelemetry.io/api/trace" "go.opentelemetry.io/api/core" apipropagation "go.opentelemetry.io/api/propagation" ) const ( supportedVersion = 0 maxVersion = 254 traceparentHeader = "traceparent" ) type httpTraceContextPropagator struct{} var _ apipropagation.TextFormatPropagator = httpTraceContextPropagator{} var traceCtxRegExp = regexp.MustCompile("^[0-9a-f]{2}-[a-f0-9]{32}-[a-f0-9]{16}-[a-f0-9]{2}-?") func (hp httpTraceContextPropagator) Inject(ctx context.Context, supplier apipropagation.Supplier) { sc := trace.CurrentSpan(ctx).SpanContext() if sc.IsValid() { h := fmt.Sprintf("%.2x-%.16x%.16x-%.16x-%.2x", supportedVersion, sc.TraceID.High, sc.TraceID.Low, sc.SpanID, sc.TraceFlags&core.TraceFlagsSampled) supplier.Set(traceparentHeader, h) } } func (hp httpTraceContextPropagator) Extract(ctx context.Context, supplier apipropagation.Supplier) core.SpanContext { h := supplier.Get(traceparentHeader) if h == "" { return core.EmptySpanContext() } h = strings.Trim(h, "-") if !traceCtxRegExp.MatchString(h) { return core.EmptySpanContext() } sections := strings.Split(h, "-") if len(sections) < 4 { return core.EmptySpanContext() } if len(sections[0]) != 2 { return core.EmptySpanContext() } ver, err := hex.DecodeString(sections[0]) if err != nil { return core.EmptySpanContext() } version := int(ver[0]) if version > maxVersion { return core.EmptySpanContext() } if version == 0 && len(sections) != 4 { return core.EmptySpanContext() } if len(sections[1]) != 32 { return core.EmptySpanContext() } result, err := strconv.ParseUint(sections[1][0:16], 16, 64) if err != nil { return core.EmptySpanContext() } var sc core.SpanContext sc.TraceID.High = result result, err = strconv.ParseUint(sections[1][16:32], 16, 64) if err != nil { return core.EmptySpanContext() } sc.TraceID.Low = result if len(sections[2]) != 16 { return core.EmptySpanContext() } result, err = strconv.ParseUint(sections[2][0:], 16, 64) if err != nil { return core.EmptySpanContext() } sc.SpanID = result if len(sections[3]) != 2 { return core.EmptySpanContext() } opts, err := hex.DecodeString(sections[3]) if err != nil || len(opts) < 1 || (version == 0 && opts[0] > 2) { return core.EmptySpanContext() } sc.TraceFlags = opts[0] &^ core.TraceFlagsUnused if !sc.IsValid() { return core.EmptySpanContext() } return sc } func (hp httpTraceContextPropagator) GetAllKeys() []string { return []string{traceparentHeader} } // HttpTraceContextPropagator creates a new text format propagator that propagates SpanContext // in W3C TraceContext format. func HttpTraceContextPropagator() apipropagation.TextFormatPropagator { return httpTraceContextPropagator{} }