@opentelemetry/sdk-trace-base
TypeScript icon, indicating that this package has built-in type declarations

1.25.1 • Public • Published

OpenTelemetry Tracing SDK

NPM Published Version Apache License

The tracing module contains the foundation for all tracing SDKs of opentelemetry-js.

Used standalone, this module provides methods for manual instrumentation of code, offering full control over span creation for client-side JavaScript (browser) and Node.js.

It does not provide automated instrumentation of known libraries, context propagation for asynchronous invocations or distributed-context out-of-the-box.

For automated instrumentation for Node.js, please see @opentelemetry/sdk-trace-node.

Installation

npm install --save @opentelemetry/api
npm install --save @opentelemetry/sdk-trace-base

Usage

const opentelemetry = require('@opentelemetry/api');
const { BasicTracerProvider } = require('@opentelemetry/sdk-trace-base');

// To start a trace, you first need to initialize the Tracer provider.
// NOTE: The default OpenTelemetry tracer provider does not record any tracing information.
//       Registering a working tracer provider allows the API methods to record traces.
new BasicTracerProvider().register();

// To create a span in a trace, we used the global singleton tracer to start a new span.
const span = opentelemetry.trace.getTracer('default').startSpan('foo');

// Set a span attribute
span.setAttribute('key', 'value');

// We must end the spans so they become available for exporting.
span.end();

Config

Tracing configuration is a merge of user supplied configuration with both the default configuration as specified in config.ts and an environmentally configurable sampling (via OTEL_TRACES_SAMPLER and OTEL_TRACES_SAMPLER_ARG).

Built-in Samplers

Sampler is used to make decisions on Span sampling.

AlwaysOn Sampler

Samples every trace regardless of upstream sampling decisions.

This is used as a default Sampler

const {
  AlwaysOnSampler,
  BasicTracerProvider,
} = require("@opentelemetry/sdk-trace-base");

const tracerProvider = new BasicTracerProvider({
  sampler: new AlwaysOnSampler()
});

AlwaysOff Sampler

Doesn't sample any trace, regardless of upstream sampling decisions.

const {
  AlwaysOffSampler,
  BasicTracerProvider,
} = require("@opentelemetry/sdk-trace-base");

const tracerProvider = new BasicTracerProvider({
  sampler: new AlwaysOffSampler()
});

TraceIdRatioBased Sampler

Samples some percentage of traces, calculated deterministically using the trace ID. Any trace that would be sampled at a given percentage will also be sampled at any higher percentage.

The TraceIDRatioSampler may be used with the ParentBasedSampler to respect the sampled flag of an incoming trace.

const {
  BasicTracerProvider,
  TraceIdRatioBasedSampler,
} = require("@opentelemetry/sdk-trace-base");

const tracerProvider = new BasicTracerProvider({
  // See details of ParentBasedSampler below
  sampler: new ParentBasedSampler({
    // Trace ID Ratio Sampler accepts a positional argument
    // which represents the percentage of traces which should
    // be sampled.
    root: new TraceIdRatioBasedSampler(0.5)
  });
});

ParentBased Sampler

  • This is a composite sampler. ParentBased helps distinguished between the following cases:
    • No parent (root span).
    • Remote parent with sampled flag true
    • Remote parent with sampled flag false
    • Local parent with sampled flag true
    • Local parent with sampled flag false

Required parameters:

  • root(Sampler) - Sampler called for spans with no parent (root spans)

Optional parameters:

  • remoteParentSampled(Sampler) (default: AlwaysOn)
  • remoteParentNotSampled(Sampler) (default: AlwaysOff)
  • localParentSampled(Sampler) (default: AlwaysOn)
  • localParentNotSampled(Sampler) (default: AlwaysOff)
Parent parent.isRemote() parent.isSampled() Invoke sampler
absent n/a n/a root()
present true true remoteParentSampled()
present true false remoteParentNotSampled()
present false true localParentSampled()
present false false localParentNotSampled()
const {
  AlwaysOffSampler,
  BasicTracerProvider,
  ParentBasedSampler,
  TraceIdRatioBasedSampler,
} = require("@opentelemetry/sdk-trace-base");

const tracerProvider = new BasicTracerProvider({
  sampler: new ParentBasedSampler({
    // By default, the ParentBasedSampler will respect the parent span's sampling
    // decision. This is configurable by providing a different sampler to use
    // based on the situation. See configuration details above.
    //
    // This will delegate the sampling decision of all root traces (no parent)
    // to the TraceIdRatioBasedSampler.
    // See details of TraceIdRatioBasedSampler above.
    root: new TraceIdRatioBasedSampler(0.5)
  })
});

Example

See examples/basic-tracer-node for an end-to-end example, including exporting created spans.

Useful links

License

Apache 2.0 - See LICENSE for more information.

Package Sidebar

Install

npm i @opentelemetry/sdk-trace-base

Weekly Downloads

6,146,265

Version

1.25.1

License

Apache-2.0

Unpacked Size

775 kB

Total Files

291

Last publish

Collaborators

  • pichlermarc
  • bogdandrutu
  • dyladan