mirror of
https://github.com/rclone/rclone.git
synced 2024-12-27 01:19:12 +01:00
124 lines
3.6 KiB
Go
124 lines
3.6 KiB
Go
// Copyright 2018, OpenCensus 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 b3 contains a propagation.HTTPFormat implementation
|
|
// for B3 propagation. See https://github.com/openzipkin/b3-propagation
|
|
// for more details.
|
|
package b3 // import "go.opencensus.io/plugin/ochttp/propagation/b3"
|
|
|
|
import (
|
|
"encoding/hex"
|
|
"net/http"
|
|
|
|
"go.opencensus.io/trace"
|
|
"go.opencensus.io/trace/propagation"
|
|
)
|
|
|
|
// B3 headers that OpenCensus understands.
|
|
const (
|
|
TraceIDHeader = "X-B3-TraceId"
|
|
SpanIDHeader = "X-B3-SpanId"
|
|
SampledHeader = "X-B3-Sampled"
|
|
)
|
|
|
|
// HTTPFormat implements propagation.HTTPFormat to propagate
|
|
// traces in HTTP headers in B3 propagation format.
|
|
// HTTPFormat skips the X-B3-ParentId and X-B3-Flags headers
|
|
// because there are additional fields not represented in the
|
|
// OpenCensus span context. Spans created from the incoming
|
|
// header will be the direct children of the client-side span.
|
|
// Similarly, receiver of the outgoing spans should use client-side
|
|
// span created by OpenCensus as the parent.
|
|
type HTTPFormat struct{}
|
|
|
|
var _ propagation.HTTPFormat = (*HTTPFormat)(nil)
|
|
|
|
// SpanContextFromRequest extracts a B3 span context from incoming requests.
|
|
func (f *HTTPFormat) SpanContextFromRequest(req *http.Request) (sc trace.SpanContext, ok bool) {
|
|
tid, ok := ParseTraceID(req.Header.Get(TraceIDHeader))
|
|
if !ok {
|
|
return trace.SpanContext{}, false
|
|
}
|
|
sid, ok := ParseSpanID(req.Header.Get(SpanIDHeader))
|
|
if !ok {
|
|
return trace.SpanContext{}, false
|
|
}
|
|
sampled, _ := ParseSampled(req.Header.Get(SampledHeader))
|
|
return trace.SpanContext{
|
|
TraceID: tid,
|
|
SpanID: sid,
|
|
TraceOptions: sampled,
|
|
}, true
|
|
}
|
|
|
|
// ParseTraceID parses the value of the X-B3-TraceId header.
|
|
func ParseTraceID(tid string) (trace.TraceID, bool) {
|
|
if tid == "" {
|
|
return trace.TraceID{}, false
|
|
}
|
|
b, err := hex.DecodeString(tid)
|
|
if err != nil {
|
|
return trace.TraceID{}, false
|
|
}
|
|
var traceID trace.TraceID
|
|
if len(b) <= 8 {
|
|
// The lower 64-bits.
|
|
start := 8 + (8 - len(b))
|
|
copy(traceID[start:], b)
|
|
} else {
|
|
start := 16 - len(b)
|
|
copy(traceID[start:], b)
|
|
}
|
|
|
|
return traceID, true
|
|
}
|
|
|
|
// ParseSpanID parses the value of the X-B3-SpanId or X-B3-ParentSpanId headers.
|
|
func ParseSpanID(sid string) (spanID trace.SpanID, ok bool) {
|
|
if sid == "" {
|
|
return trace.SpanID{}, false
|
|
}
|
|
b, err := hex.DecodeString(sid)
|
|
if err != nil {
|
|
return trace.SpanID{}, false
|
|
}
|
|
start := 8 - len(b)
|
|
copy(spanID[start:], b)
|
|
return spanID, true
|
|
}
|
|
|
|
// ParseSampled parses the value of the X-B3-Sampled header.
|
|
func ParseSampled(sampled string) (trace.TraceOptions, bool) {
|
|
switch sampled {
|
|
case "true", "1":
|
|
return trace.TraceOptions(1), true
|
|
default:
|
|
return trace.TraceOptions(0), false
|
|
}
|
|
}
|
|
|
|
// SpanContextToRequest modifies the given request to include B3 headers.
|
|
func (f *HTTPFormat) SpanContextToRequest(sc trace.SpanContext, req *http.Request) {
|
|
req.Header.Set(TraceIDHeader, hex.EncodeToString(sc.TraceID[:]))
|
|
req.Header.Set(SpanIDHeader, hex.EncodeToString(sc.SpanID[:]))
|
|
|
|
var sampled string
|
|
if sc.IsSampled() {
|
|
sampled = "1"
|
|
} else {
|
|
sampled = "0"
|
|
}
|
|
req.Header.Set(SampledHeader, sampled)
|
|
}
|