@opentelemetry/propagator-b3

What is @opentelemetry/propagator-b3?

The @opentelemetry/propagator-b3 npm package is used for B3 propagation format which is a convention for passing trace context information across service boundaries. It supports both single-header and multi-header encoding. This package is part of the OpenTelemetry project which provides a collection of tools, APIs, and SDKs to instrument, generate, collect, and export telemetry data (metrics, logs, and traces) to help analyze a software's performance and behavior.

What are @opentelemetry/propagator-b3's main functionalities?

B3 Propagation

This feature allows the user to extract and inject B3 propagation headers. The B3Propagator can be set as the global propagator in OpenTelemetry.

const { B3Propagator } = require('@opentelemetry/propagator-b3');
const { propagation } = require('@opentelemetry/api');

// Use the B3Propagator for extracting and injecting
propagation.setGlobalPropagator(new B3Propagator());

B3 Multi-header Propagation

This feature supports the B3 multi-header propagation format, which uses multiple headers to transmit tracing information. It is useful when interacting with systems that expect B3 headers in multiple header format.

const { B3MultiPropagator } = require('@opentelemetry/propagator-b3');
const { propagation } = require('@opentelemetry/api');

// Use the B3MultiPropagator for extracting and injecting with multi-header support
propagation.setGlobalPropagator(new B3MultiPropagator());

Other packages similar to @opentelemetry/propagator-b3

jaeger-client

This package is a Node.js client for Jaeger, a distributed tracing system. It includes Jaeger Tracer which can report tracing information to a Jaeger agent or collector. Jaeger and B3 are both tracing propagation formats, but Jaeger is specific to the Jaeger tracing system, whereas B3 is a more general format used by systems like Zipkin.

zipkin

The Zipkin npm package is a library that interfaces with the Zipkin API for distributed tracing. Similar to B3, Zipkin uses B3 propagation headers for tracing across service boundaries. The Zipkin package provides more comprehensive features for interacting with Zipkin, while @opentelemetry/propagator-b3 focuses on the propagation aspect within the OpenTelemetry ecosystem.

lightstep-tracer

LightStep's tracer library for Node.js is designed to monitor the performance of distributed systems. It uses its own propagation format and is part of the LightStep ecosystem, which is a different distributed tracing solution compared to the B3 propagation used by @opentelemetry/propagator-b3.

README

OpenTelemetry Propagator B3

The OpenTelemetry b3 propagator package provides multiple propagator implementations for systems using the b3 context format. See the b3 specification for complete details.

B3 Formats

Single-Header Format:

b3: {TraceId}-{SpanId}-{SamplingState}-{ParentSpanId}

Multi-Header Format:

X-B3-TraceId: {TraceId}
X-B3-SpanId: {SpanId}
X-B3-ParentSpanId: {ParentSpanId}
X-B3-Sampled: {SamplingState}

• {TraceId}

  • Required
  • Encoded as 32 or 16 lower-hex characters
  • 16 character traceIds will be converted to 32 characters by left-padding with 0s to conform with the OpenTelemetry specification

• {SpanId}

  • Required
  • Encoded as 16 lower-hex characters

• {ParentSpanId}

  • Optional
  • Used to support the Zipkin functionality where the client and server spans that make up an HTTP request share the same id
  • Not propagated by this library

• {SamplingState} - Single-header

  • Optional
  • Valid values
    • 1 - Accept
    • 0 - Deny
    • d - Debug
    • Absent - Defer sampling decision

• {SamplingState} - Multi-header

  • Optional
  • Valid values
    • 1 - Accept
    • 0 - Deny

• {Flags} - Multi-header

  • Optional
  • Debug is encoded as X-B3-Flags: 1. Absent or any other value can be ignored. Debug implies an accept decision, so don't also send the X-B3-Sampled header.

B3 Propagation

The default B3Propagator implements b3 propagation according to the OpenTelemetry specification. It extracts b3 context from multi and single header encodings and injects context using the single-header b3 encoding by default. The inject encoding can be changed to multi-header via configuration. See the examples below.

B3 Single-Header Configuration

const api = require('@opentelemetry/api');
const { B3Propagator } = require('@opentelemetry/propagator-b3');

api.propagation.setGlobalPropagator(new B3Propagator());

B3 Multi-Header Configuration

const api = require('@opentelemetry/api');
const { B3Propagator, B3InjectEncoding } = require('@opentelemetry/propagator-b3');

api.propagation.setGlobalPropagator(
  new B3Propagator({ injectEncoding: B3InjectEncoding.MULTI_HEADER })
);

B3 Single and Multi-Header Configuration

The B3Propagator always extracts both the single and multi-header b3 encodings. If you need to inject both encodings this can accomplished using a composite propagator.

const api = require('@opentelemetry/api');
const { CompositePropagator } = require('@opentelemetry/core');
const { B3Propagator, B3InjectEncoding } = require('@opentelemetry/propagator-b3');
api.propagation.setGlobalPropagator(
  new CompositePropagator({
    propagators: [
      new B3Propagator(),
      new B3Propagator({ injectEncoding: B3InjectEncoding.MULTI_HEADER }),
    ],
  })
);

Useful links

• For more information on OpenTelemetry, visit: https://opentelemetry.io/
• For more about OpenTelemetry JavaScript: https://github.com/open-telemetry/opentelemetry-js
• For help or feedback on this project, join us in GitHub Discussions

License

Apache 2.0 - See LICENSE for more information.

Changelog

0.25.0

:boom: Breaking Change

• opentelemetry-api-metrics, opentelemetry-context-zone-peer-dep, opentelemetry-context-zone, opentelemetry-core, opentelemetry-exporter-collector-grpc, opentelemetry-exporter-collector-proto, opentelemetry-exporter-collector, opentelemetry-exporter-jaeger, opentelemetry-exporter-prometheus, opentelemetry-exporter-zipkin, opentelemetry-instrumentation-fetch, opentelemetry-instrumentation-grpc, opentelemetry-instrumentation-http, opentelemetry-instrumentation-xml-http-request, opentelemetry-instrumentation, opentelemetry-propagator-jaeger, opentelemetry-sdk-metrics-base, opentelemetry-sdk-node, opentelemetry-sdk-trace-base, opentelemetry-sdk-trace-node, opentelemetry-sdk-trace-web, opentelemetry-shim-opentracing
  • #2340 chore: rename sdks to better represent what they are [#2146] (@vmarchaud)

:rocket: (Enhancement)

• opentelemetry-exporter-collector-grpc, opentelemetry-exporter-collector-proto, opentelemetry-exporter-collector, opentelemetry-exporter-zipkin
  • #1775 fix(@opentelemetry/exporter-collector): remove fulfilled promises cor… (@aabmass)
• opentelemetry-exporter-collector
  • #2336 feat: use Blob in sendBeacon to add application/json type (@jufab)

:bug: (Bug Fix)

• opentelemetry-instrumentation-grpc, opentelemetry-instrumentation-http, opentelemetry-instrumentation-jaeger, opentelemetry-exporter-zipkin, opentelemetry-sdk-trace-base
  • #2499 fix: 2389- replaced logger unformatted strings with template literals (@PaurushGarg)
• opentelemetry-instrumentation-fetch
  • #2411 fix(instrumentation-fetch): fetch(string, Request) silently drops request body (@t2t2)
• opentelemetry-sdk-trace-base
  • #2396 fix: respect sampled flag in Span Processors, fix associated tests (@quickgiant)

:books: (Refine Doc)

• Other
  • #2412 docs: fix examples in website_docs/instrumentation.md (@svrnm)
  • #2400 Website docs update 0821 (@svrnm)
• opentelemetry-resources, opentelemetry-semantic-conventions
  • #2399 chore: update doc identifier names in readme (@lonewolf3739)

:house: (Internal)

• opentelemetry-core, opentelemetry-exporter-collector-grpc, opentelemetry-exporter-collector-proto, opentelemetry-instrumentation-http, opentelemetry-sdk-trace-node
  • #2416 chore: hoist dependencies to speed up ci (@dyladan)
• opentelemetry-propagator-b3, opentelemetry-propagator-jaeger, opentelemetry-resources, opentelemetry-sdk-metrics-base
  • #2406 chore: Fix lint warnings in propagator-jaeger, propagator-b3, resources, and sdk-metrics-base packages (@alisabzevari)
• opentelemetry-core
  • #2405 chore: Fix lint warnings in core package (@alisabzevari)
• opentelemetry-resource-detector-aws, opentelemetry-resource-detector-gcp, opentelemetry-sdk-node
  • #2392 refactor: move detectors to opentelemetry-js-contrib repo (@legendecas)
• opentelemetry-exporter-collector-grpc, opentelemetry-exporter-collector-proto, opentelemetry-exporter-collector, opentelemetry-exporter-jaeger, opentelemetry-exporter-zipkin, opentelemetry-instrumentation-fetch, opentelemetry-instrumentation-grpc, opentelemetry-instrumentation-http, opentelemetry-instrumentation-xml-http-request, opentelemetry-sdk-node, opentelemetry-sdk-trace-node, opentelemetry-sdk-trace-web, opentelemetry-shim-opentracing
  • #2402 chore: sort entries in tsconfig (@Flarna)
• opentelemetry-api-metrics, opentelemetry-context-zone-peer-dep
  • #2390 chore: fix Lint warnings in api-metrics and context-zone-peer-dep (@alisabzevari)
• Other
  • #2397 chore: change codeowners to point to team (@dyladan)
  • #2385 chore: move api into dependencies in integration tests (@Flarna)

Committers: 11

• Aaron Abbott (@aabmass)
• Ali Sabzevari (@alisabzevari)
• Clark Jacobsohn (@quickgiant)
• Daniel Dyla (@dyladan)
• Gerhard Stöbich (@Flarna)
• Julien Fabre (@jufab)
• Severin Neumann (@svrnm)
• Srikanth Chekuri (@lonewolf3739)
• Valentin Marchaud (@vmarchaud)
• legendecas (@legendecas)
• t2t2 (@t2t2)