HttpTraceContext.ts

/*!
 * 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
 *
 * https://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.
 */

import{SpanContext,HttpTextFormat,TraceFlags}from'@opentelemetry/types';
import{TraceState}from'../../trace/TraceState';

exportconstTRACE_PARENT_HEADER='traceparent';
exportconstTRACE_STATE_HEADER='tracestate';
constVALID_TRACE_PARENT_REGEX=/^[\da-f]{2}-[\da-f]{32}-[\da-f]{16}-[\da-f]{2}$/;
constVALID_TRACEID_REGEX=/^[0-9a-f]{32}$/i;
constVALID_SPANID_REGEX=/^[0-9a-f]{16}$/i;
constINVALID_ID_REGEX=/^0+$/i;
constVERSION='00';

functionparse(traceParent: string): SpanContext|null{
constmatch=traceParent.match(VALID_TRACE_PARENT_REGEX);
if(!match)returnnull;
constparts=traceParent.split('-');
const[version,traceId,spanId,option]=parts;
// tslint:disable-next-line:ban Needed to parse hexadecimal.
consttraceFlags=parseInt(option,16);

if(
!isValidVersion(version)||
!isValidTraceId(traceId)||
!isValidSpanId(spanId)
){
returnnull;
}

return{ traceId, spanId, traceFlags };
}

functionisValidVersion(version: string): boolean{
returnversion===VERSION;
}

functionisValidTraceId(traceId: string): boolean{
returnVALID_TRACEID_REGEX.test(traceId)&&!INVALID_ID_REGEX.test(traceId);
}

functionisValidSpanId(spanId: string): boolean{
returnVALID_SPANID_REGEX.test(spanId)&&!INVALID_ID_REGEX.test(spanId);
}

/**
 * Propagates {@link SpanContext} through Trace Context format propagation.
 *
 * Based on the Trace Context specification:
 * https://www.w3.org/TR/trace-context/
 */
exportclassHttpTraceContextimplementsHttpTextFormat{
inject(
spanContext: SpanContext,
format: string,
carrier: {[key: string]: unknown}
){
consttraceParent=`${VERSION}-${spanContext.traceId}-${
spanContext.spanId
}-0${Number(spanContext.traceFlags||TraceFlags.UNSAMPLED).toString(16)}`;

carrier[TRACE_PARENT_HEADER]=traceParent;
if(spanContext.traceState){
carrier[TRACE_STATE_HEADER]=spanContext.traceState.serialize();
}
}

extract(
format: string,
carrier: {[key: string]: unknown}
): SpanContext|null{
consttraceParentHeader=carrier[TRACE_PARENT_HEADER];
if(!traceParentHeader)returnnull;
consttraceParent=Array.isArray(traceParentHeader)
 ? traceParentHeader[0]
 : traceParentHeader;
constspanContext=parse(traceParent);
if(!spanContext)returnnull;

consttraceStateHeader=carrier[TRACE_STATE_HEADER];
if(traceStateHeader){
// If more than one `tracestate` header is found, we merge them into a
// single header.
conststate=Array.isArray(traceStateHeader)
 ? traceStateHeader.join(',')
 : traceStateHeader;
spanContext.traceState=newTraceState(stateasstring);
}
returnspanContext;
}
}