@opencensus/propagation-b3
Version:
Opencensus propagation package for B3 format.
90 lines • 3.26 kB
JavaScript
;
/**
* 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.
*/
Object.defineProperty(exports, "__esModule", { value: true });
exports.B3Format = exports.NOT_SAMPLED_VALUE = exports.SAMPLED_VALUE = exports.X_B3_SAMPLED = exports.X_B3_PARENT_SPAN_ID = exports.X_B3_SPAN_ID = exports.X_B3_TRACE_ID = void 0;
const crypto = require("crypto");
const uuid = require("uuid");
const validators_1 = require("./validators");
exports.X_B3_TRACE_ID = 'x-b3-traceid';
exports.X_B3_SPAN_ID = 'x-b3-spanid';
exports.X_B3_PARENT_SPAN_ID = 'x-b3-parentspanid';
exports.X_B3_SAMPLED = 'x-b3-sampled';
exports.SAMPLED_VALUE = 0x1;
exports.NOT_SAMPLED_VALUE = 0x0;
/** Propagates span context through B3 Format propagation. */
class B3Format {
/**
* Gets the trace context from a request headers. If there is no trace context
* in the headers, null is returned.
* @param getter
*/
extract(getter) {
const traceId = this.parseHeader(getter.getHeader(exports.X_B3_TRACE_ID));
const spanId = this.parseHeader(getter.getHeader(exports.X_B3_SPAN_ID));
const opt = this.parseHeader(getter.getHeader(exports.X_B3_SAMPLED));
if (traceId && spanId) {
return {
traceId,
spanId,
options: isNaN(Number(opt)) ? exports.NOT_SAMPLED_VALUE : Number(opt),
};
}
return null;
}
/**
* Adds a trace context in a request headers.
* @param setter
* @param spanContext
*/
inject(setter, spanContext) {
if (!spanContext ||
!validators_1.isValidTraceId(spanContext.traceId) ||
!validators_1.isValidSpanId(spanContext.spanId)) {
return;
}
setter.setHeader(exports.X_B3_TRACE_ID, spanContext.traceId);
setter.setHeader(exports.X_B3_SPAN_ID, spanContext.spanId);
if (((spanContext.options || exports.NOT_SAMPLED_VALUE) & exports.SAMPLED_VALUE) !== 0) {
setter.setHeader(exports.X_B3_SAMPLED, `${exports.SAMPLED_VALUE}`);
}
else {
setter.setHeader(exports.X_B3_SAMPLED, `${exports.NOT_SAMPLED_VALUE}`);
}
}
/**
* Generate SpanContexts
*/
generate() {
return {
traceId: uuid
.v4()
.split('-')
.join(''),
spanId: crypto.randomBytes(8).toString('hex'),
options: exports.SAMPLED_VALUE,
};
}
/** Converts a headers type to a string. */
parseHeader(str) {
if (Array.isArray(str)) {
return str[0];
}
return str;
}
}
exports.B3Format = B3Format;
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