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feat: b3 single header support (#1560)
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mwear authored Oct 9, 2020
1 parent 9f72a15 commit e62c481
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Showing 12 changed files with 1,128 additions and 678 deletions.
3 changes: 3 additions & 0 deletions packages/opentelemetry-api/src/index.ts
Original file line number Diff line number Diff line change
Expand Up @@ -61,6 +61,9 @@ export {
INVALID_SPANID,
INVALID_TRACEID,
INVALID_SPAN_CONTEXT,
isSpanContextValid,
isValidTraceId,
isValidSpanId,
} from './trace/spancontext-utils';

export {
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Original file line number Diff line number Diff line change
@@ -0,0 +1,144 @@
/*
* 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.
*/

import {
Context,
GetterFunction,
TextMapPropagator,
SetterFunction,
TraceFlags,
isValidSpanId,
isValidTraceId,
isSpanContextValid,
getParentSpanContext,
setExtractedSpanContext,
} from '@opentelemetry/api';
import { B3_DEBUG_FLAG_KEY } from './b3-common';

/* b3 multi-header keys */
export const X_B3_TRACE_ID = 'x-b3-traceid';
export const X_B3_SPAN_ID = 'x-b3-spanid';
export const X_B3_SAMPLED = 'x-b3-sampled';
export const X_B3_PARENT_SPAN_ID = 'x-b3-parentspanid';
export const X_B3_FLAGS = 'x-b3-flags';

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: TraceFlags | undefined): boolean {
return sampled === TraceFlags.SAMPLED || sampled === TraceFlags.NONE;
}

export function parseHeader(header: unknown) {
return Array.isArray(header) ? header[0] : header;
}

function getHeaderValue(carrier: unknown, getter: GetterFunction, key: string) {
const header = getter(carrier, key);
return parseHeader(header);
}

function getTraceId(carrier: unknown, getter: GetterFunction): string {
const traceId = getHeaderValue(carrier, getter, X_B3_TRACE_ID);
if (typeof traceId === 'string') {
return traceId.padStart(32, '0');
}
return '';
}

function getSpanId(carrier: unknown, getter: GetterFunction): string {
const spanId = getHeaderValue(carrier, getter, X_B3_SPAN_ID);
if (typeof spanId === 'string') {
return spanId;
}
return '';
}

function getDebug(
carrier: unknown,
getter: GetterFunction
): string | undefined {
const debug = getHeaderValue(carrier, getter, X_B3_FLAGS);
return debug === '1' ? '1' : undefined;
}

function getTraceFlags(
carrier: unknown,
getter: GetterFunction
): TraceFlags | undefined {
const traceFlags = getHeaderValue(carrier, getter, X_B3_SAMPLED);
const debug = getDebug(carrier, getter);
if (debug === '1' || VALID_SAMPLED_VALUES.has(traceFlags)) {
return TraceFlags.SAMPLED;
}
if (traceFlags === undefined || VALID_UNSAMPLED_VALUES.has(traceFlags)) {
return 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
*/
export class B3MultiPropagator implements TextMapPropagator {
inject(context: Context, carrier: unknown, setter: SetterFunction) {
const spanContext = getParentSpanContext(context);
if (!spanContext || !isSpanContextValid(spanContext)) return;

const debug = context.getValue(B3_DEBUG_FLAG_KEY);
setter(carrier, X_B3_TRACE_ID, spanContext.traceId);
setter(carrier, 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(carrier, 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(
carrier,
X_B3_SAMPLED,
(TraceFlags.SAMPLED & spanContext.traceFlags) === TraceFlags.SAMPLED
? '1'
: '0'
);
}
}

extract(context: Context, carrier: unknown, getter: GetterFunction): Context {
const traceId = getTraceId(carrier, getter);
const spanId = getSpanId(carrier, getter);
const traceFlags = getTraceFlags(carrier, getter) as TraceFlags;
const debug = getDebug(carrier, getter);

if (
isValidTraceId(traceId) &&
isValidSpanId(spanId) &&
isValidSampledValue(traceFlags)
) {
context = context.setValue(B3_DEBUG_FLAG_KEY, debug);
return setExtractedSpanContext(context, {
traceId,
spanId,
isRemote: true,
traceFlags,
});
}
return context;
}
}
182 changes: 34 additions & 148 deletions packages/opentelemetry-core/src/context/propagation/B3Propagator.ts
Original file line number Diff line number Diff line change
Expand Up @@ -19,168 +19,54 @@ import {
GetterFunction,
TextMapPropagator,
SetterFunction,
TraceFlags,
getParentSpanContext,
setExtractedSpanContext,
} from '@opentelemetry/api';
import { B3SinglePropagator, B3_CONTEXT_HEADER } from './B3SinglePropagator';
import { B3MultiPropagator } from './B3MultiPropagator';

import { createContextKey } from '@opentelemetry/context-base';

export const X_B3_TRACE_ID = 'x-b3-traceid';
export const X_B3_SPAN_ID = 'x-b3-spanid';
export const X_B3_SAMPLED = 'x-b3-sampled';
export const X_B3_PARENT_SPAN_ID = 'x-b3-parentspanid';
export const X_B3_FLAGS = 'x-b3-flags';
export const PARENT_SPAN_ID_KEY = createContextKey(
'OpenTelemetry Context Key B3 Parent Span Id'
);
export const DEBUG_FLAG_KEY = createContextKey(
'OpenTelemetry Context Key B3 Debug Flag'
);
const VALID_TRACEID_REGEX = /^([0-9a-f]{16}){1,2}$/i;
const VALID_SPANID_REGEX = /^[0-9a-f]{16}$/i;
const INVALID_ID_REGEX = /^0+$/i;
const VALID_SAMPLED_VALUES = new Set([true, 'true', 'True', '1', 1]);
const VALID_UNSAMPLED_VALUES = new Set([false, 'false', 'False', '0', 0]);

function isValidTraceId(traceId: string): boolean {
return VALID_TRACEID_REGEX.test(traceId) && !INVALID_ID_REGEX.test(traceId);
}

function isValidSpanId(spanId: string): boolean {
return VALID_SPANID_REGEX.test(spanId) && !INVALID_ID_REGEX.test(spanId);
}

function isValidParentSpanID(spanId: string | undefined): boolean {
return spanId === undefined || isValidSpanId(spanId);
}

function isValidSampledValue(sampled: TraceFlags | undefined): boolean {
return sampled === TraceFlags.SAMPLED || sampled === TraceFlags.NONE;
}

function parseHeader(header: unknown) {
return Array.isArray(header) ? header[0] : header;
}

function getHeaderValue(carrier: unknown, getter: GetterFunction, key: string) {
const header = getter(carrier, key);
return parseHeader(header);
}

function getTraceId(carrier: unknown, getter: GetterFunction): string {
const traceId = getHeaderValue(carrier, getter, X_B3_TRACE_ID);
if (typeof traceId === 'string') {
return traceId.padStart(32, '0');
}
return '';
/** Enumeraion of B3 inject encodings */
export enum B3InjectEncoding {
SINGLE_HEADER,
MULTI_HEADER,
}

function getSpanId(carrier: unknown, getter: GetterFunction): string {
const spanId = getHeaderValue(carrier, getter, X_B3_SPAN_ID);
if (typeof spanId === 'string') {
return spanId;
}
return '';
}

function getParentSpanId(
carrier: unknown,
getter: GetterFunction
): string | undefined {
const spanId = getHeaderValue(carrier, getter, X_B3_PARENT_SPAN_ID);
if (typeof spanId === 'string') {
return spanId;
}
return;
}

function getDebug(
carrier: unknown,
getter: GetterFunction
): string | undefined {
const debug = getHeaderValue(carrier, getter, X_B3_FLAGS);
return debug === '1' ? '1' : undefined;
}

function getTraceFlags(
carrier: unknown,
getter: GetterFunction
): TraceFlags | undefined {
const traceFlags = getHeaderValue(carrier, getter, X_B3_SAMPLED);
const debug = getDebug(carrier, getter);
if (debug === '1' || VALID_SAMPLED_VALUES.has(traceFlags)) {
return TraceFlags.SAMPLED;
}
if (traceFlags === undefined || VALID_UNSAMPLED_VALUES.has(traceFlags)) {
return TraceFlags.NONE;
}
// This indicates to isValidSampledValue that this is not valid
return;
/** Configuration for the B3Propagator */
export interface B3PropagatorConfig {
injectEncoding?: B3InjectEncoding;
}

/**
* Propagator for the B3 HTTP header format.
* 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 implements TextMapPropagator {
inject(context: Context, carrier: unknown, setter: SetterFunction) {
const spanContext = getParentSpanContext(context);
if (!spanContext) return;
const parentSpanId = context.getValue(PARENT_SPAN_ID_KEY) as
| undefined
| string;
if (
isValidTraceId(spanContext.traceId) &&
isValidSpanId(spanContext.spanId) &&
isValidParentSpanID(parentSpanId)
) {
const debug = context.getValue(DEBUG_FLAG_KEY);
setter(carrier, X_B3_TRACE_ID, spanContext.traceId);
setter(carrier, X_B3_SPAN_ID, spanContext.spanId);
if (parentSpanId) {
setter(carrier, X_B3_PARENT_SPAN_ID, parentSpanId);
}
// According to the B3 spec, if the debug flag is set,
// the sampled flag shouldn't be propagated as well.
if (debug === '1') {
setter(carrier, 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(
carrier,
X_B3_SAMPLED,
(TraceFlags.SAMPLED & spanContext.traceFlags) === TraceFlags.SAMPLED
? '1'
: '0'
);
}
private readonly _b3MultiPropagator: B3MultiPropagator = new B3MultiPropagator();
private readonly _b3SinglePropagator: B3SinglePropagator = new B3SinglePropagator();
private readonly _inject: (
context: Context,
carrier: unknown,
setter: SetterFunction
) => void;

constructor(config: B3PropagatorConfig = {}) {
if (config.injectEncoding === B3InjectEncoding.MULTI_HEADER) {
this._inject = this._b3MultiPropagator.inject;
} else {
this._inject = this._b3SinglePropagator.inject;
}
}

extract(context: Context, carrier: unknown, getter: GetterFunction): Context {
const traceId = getTraceId(carrier, getter);
const spanId = getSpanId(carrier, getter);
const parentSpanId = getParentSpanId(carrier, getter);
const traceFlags = getTraceFlags(carrier, getter) as TraceFlags;
const debug = getDebug(carrier, getter);
inject(context: Context, carrier: unknown, setter: SetterFunction) {
this._inject(context, carrier, setter);
}

if (
isValidTraceId(traceId) &&
isValidSpanId(spanId) &&
isValidParentSpanID(parentSpanId) &&
isValidSampledValue(traceFlags)
) {
context = context.setValue(PARENT_SPAN_ID_KEY, parentSpanId);
context = context.setValue(DEBUG_FLAG_KEY, debug);
return setExtractedSpanContext(context, {
traceId,
spanId,
isRemote: true,
traceFlags,
});
extract(context: Context, carrier: unknown, getter: GetterFunction): Context {
if (getter(carrier, B3_CONTEXT_HEADER)) {
return this._b3SinglePropagator.extract(context, carrier, getter);
} else {
return this._b3MultiPropagator.extract(context, carrier, getter);
}
return context;
}
}
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