@opencensus/propagation-stackdriver
Version:
Opencensus propagation package for Stackdriver format.
85 lines • 3.21 kB
JavaScript
;
/**
* Copyright 2015 Google Inc. All Rights Reserved.
*
* 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.generate = exports.inject = exports.extract = exports.serializeSpanContext = exports.parseContextFromHeader = void 0;
/**
* This file implements propagation for the Stackdriver Trace v1 Trace Context
* format.
* Full details at https://cloud.google.com/trace/docs/support.
*/
const crypto = require("crypto");
const hex2dec_1 = require("hex2dec");
const uuid = require("uuid");
const TRACE_CONTEXT_HEADER_NAME = 'x-cloud-trace-context';
function parseContextFromHeader(str) {
if (typeof str !== 'string') {
return null;
}
const matches = str.match(/^([0-9a-fA-F]+)(?:\/([0-9]+))(?:;o=(.*))?/);
if (!matches ||
matches.length !== 4 ||
matches[0] !== str ||
(matches[2] && isNaN(Number(matches[2])))) {
return null;
}
return {
traceId: matches[1],
// strip 0x prefix from hex output from decToHex, and and pad so it's always
// a length-16 hex string
spanId: `0000000000000000${hex2dec_1.decToHex(matches[2]).slice(2)}`.slice(-16),
options: isNaN(Number(matches[3])) ? undefined : Number(matches[3]),
};
}
exports.parseContextFromHeader = parseContextFromHeader;
function serializeSpanContext(spanContext) {
let header = `${spanContext.traceId}/${hex2dec_1.hexToDec(spanContext.spanId)}`;
if (spanContext.options) {
header += `;o=${spanContext.options}`;
}
return header;
}
exports.serializeSpanContext = serializeSpanContext;
function extract(getter) {
return parseContextFromHeader(getter.getHeader(TRACE_CONTEXT_HEADER_NAME));
}
exports.extract = extract;
function inject(setter, spanContext) {
setter.setHeader(TRACE_CONTEXT_HEADER_NAME, serializeSpanContext(spanContext));
}
exports.inject = inject;
const SPAN_ID_RANDOM_BYTES = 8;
// Use the faster crypto.randomFillSync when available (Node 7+) falling back to
// using crypto.randomBytes.
// TODO(ofrobots): Use alternate logic for the browser where crypto and Buffer
// are not available.
const spanIdBuffer = Buffer.alloc(SPAN_ID_RANDOM_BYTES);
const randomFillSync = crypto.randomFillSync;
const randomBytes = crypto.randomBytes;
const spanRandomBuffer = randomFillSync
? () => randomFillSync(spanIdBuffer)
: () => randomBytes(SPAN_ID_RANDOM_BYTES);
function generate() {
return {
traceId: uuid
.v4()
.split('-')
.join(''),
spanId: spanRandomBuffer().toString('hex'),
};
}
exports.generate = generate;
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