@opentelemetry/propagator-b3
Version:
OpenTelemetry B3 propagator provides context propagation for systems that are using the B3 header format
52 lines • 1.9 kB
JavaScript
/*
* Copyright The OpenTelemetry Authors
* SPDX-License-Identifier: Apache-2.0
*/
import { isTracingSuppressed } from '@opentelemetry/core';
import { B3MultiPropagator } from './B3MultiPropagator';
import { B3SinglePropagator } from './B3SinglePropagator';
import { B3_CONTEXT_HEADER } from './constants';
import { B3InjectEncoding } from './types';
/**
* Propagator that extracts B3 context in both single and multi-header variants,
* with configurable injection format defaulting to B3 single-header. Due to
* the asymmetry in injection and extraction formats this is not suitable to
* be implemented as a composite propagator.
* Based on: https://github.com/openzipkin/b3-propagation
*/
export class B3Propagator {
_b3MultiPropagator = new B3MultiPropagator();
_b3SinglePropagator = new B3SinglePropagator();
_inject;
_fields;
constructor(config = {}) {
if (config.injectEncoding === B3InjectEncoding.MULTI_HEADER) {
this._inject = this._b3MultiPropagator.inject;
this._fields = this._b3MultiPropagator.fields();
}
else {
this._inject = this._b3SinglePropagator.inject;
this._fields = this._b3SinglePropagator.fields();
}
}
inject(context, carrier, setter) {
if (isTracingSuppressed(context)) {
return;
}
this._inject(context, carrier, setter);
}
extract(context, carrier, getter) {
const header = getter.get(carrier, B3_CONTEXT_HEADER);
const b3Context = Array.isArray(header) ? header[0] : header;
if (b3Context) {
return this._b3SinglePropagator.extract(context, carrier, getter);
}
else {
return this._b3MultiPropagator.extract(context, carrier, getter);
}
}
fields() {
return this._fields;
}
}
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