@opentelemetry/propagator-b3
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OpenTelemetry B3 propagator provides context propagation for systems that are using the B3 header format
121 lines • 4.73 kB
JavaScript
;
/*
* Copyright The 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.
*/
Object.defineProperty(exports, "__esModule", { value: true });
exports.B3MultiPropagator = void 0;
const api_1 = require("@opentelemetry/api");
const core_1 = require("@opentelemetry/core");
const common_1 = require("./common");
const constants_1 = require("./constants");
const VALID_SAMPLED_VALUES = new Set([true, 'true', 'True', '1', 1]);
const VALID_UNSAMPLED_VALUES = new Set([false, 'false', 'False', '0', 0]);
function isValidSampledValue(sampled) {
return sampled === api_1.TraceFlags.SAMPLED || sampled === api_1.TraceFlags.NONE;
}
function parseHeader(header) {
return Array.isArray(header) ? header[0] : header;
}
function getHeaderValue(carrier, getter, key) {
const header = getter.get(carrier, key);
return parseHeader(header);
}
function getTraceId(carrier, getter) {
const traceId = getHeaderValue(carrier, getter, constants_1.X_B3_TRACE_ID);
if (typeof traceId === 'string') {
return traceId.padStart(32, '0');
}
return '';
}
function getSpanId(carrier, getter) {
const spanId = getHeaderValue(carrier, getter, constants_1.X_B3_SPAN_ID);
if (typeof spanId === 'string') {
return spanId;
}
return '';
}
function getDebug(carrier, getter) {
const debug = getHeaderValue(carrier, getter, constants_1.X_B3_FLAGS);
return debug === '1' ? '1' : undefined;
}
function getTraceFlags(carrier, getter) {
const traceFlags = getHeaderValue(carrier, getter, constants_1.X_B3_SAMPLED);
const debug = getDebug(carrier, getter);
if (debug === '1' || VALID_SAMPLED_VALUES.has(traceFlags)) {
return api_1.TraceFlags.SAMPLED;
}
if (traceFlags === undefined || VALID_UNSAMPLED_VALUES.has(traceFlags)) {
return api_1.TraceFlags.NONE;
}
// This indicates to isValidSampledValue that this is not valid
return;
}
/**
* Propagator for the B3 multiple-header HTTP format.
* Based on: https://github.com/openzipkin/b3-propagation
*/
class B3MultiPropagator {
inject(context, carrier, setter) {
const spanContext = api_1.trace.getSpanContext(context);
if (!spanContext ||
!(0, api_1.isSpanContextValid)(spanContext) ||
(0, core_1.isTracingSuppressed)(context))
return;
const debug = context.getValue(common_1.B3_DEBUG_FLAG_KEY);
setter.set(carrier, constants_1.X_B3_TRACE_ID, spanContext.traceId);
setter.set(carrier, constants_1.X_B3_SPAN_ID, spanContext.spanId);
// According to the B3 spec, if the debug flag is set,
// the sampled flag shouldn't be propagated as well.
if (debug === '1') {
setter.set(carrier, constants_1.X_B3_FLAGS, debug);
}
else if (spanContext.traceFlags !== undefined) {
// We set the header only if there is an existing sampling decision.
// Otherwise we will omit it => Absent.
setter.set(carrier, constants_1.X_B3_SAMPLED, (api_1.TraceFlags.SAMPLED & spanContext.traceFlags) === api_1.TraceFlags.SAMPLED
? '1'
: '0');
}
}
extract(context, carrier, getter) {
const traceId = getTraceId(carrier, getter);
const spanId = getSpanId(carrier, getter);
const traceFlags = getTraceFlags(carrier, getter);
const debug = getDebug(carrier, getter);
if ((0, api_1.isValidTraceId)(traceId) &&
(0, api_1.isValidSpanId)(spanId) &&
isValidSampledValue(traceFlags)) {
context = context.setValue(common_1.B3_DEBUG_FLAG_KEY, debug);
return api_1.trace.setSpanContext(context, {
traceId,
spanId,
isRemote: true,
traceFlags,
});
}
return context;
}
fields() {
return [
constants_1.X_B3_TRACE_ID,
constants_1.X_B3_SPAN_ID,
constants_1.X_B3_FLAGS,
constants_1.X_B3_SAMPLED,
constants_1.X_B3_PARENT_SPAN_ID,
];
}
}
exports.B3MultiPropagator = B3MultiPropagator;
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