@dcl/tracer-component

Creates trace spans over an execution, providing context to the code being run so it can be traced and the W3C Trace Context (traceparent / tracestate) propagated.

Installation

npm install @dcl/tracer-component

Usage

Import the component, initialize it and wrap your traceable code into a trace span:

import { createTracerComponent } from '@dcl/tracer-component'

const tracer = createTracerComponent()
tracer.span('my span', () => {
  // Do some work here
})

While inside the span, the traced code is able to access the trace context. This is especially useful for adding traced logs:

const tracer = createTracerComponent()
tracer.span('my span', () => {
  console.log(`[${tracer.getTraceString()}] Starting some work`)
  // Do some work here
  console.log(`[${tracer.getTraceString()}] Finishing some work`)
})

The logs output a trace alongside the message using the traceparent format (version-traceId-parentId-flags):

  [00-7970d1a8361cc811ee59dc3ee1c8134e-0000000000000000-00] Starting some work
  [00-7970d1a8361cc811ee59dc3ee1c8134e-0000000000000000-00] Finishing some work

The traceId is unique throughout the span execution and makes it easy to track which run of the span a log belongs to. The parentId identifies the span the current span was created from, making it possible to follow the chain of spans. See the W3C Trace Context spec for the meaning of the version and flags values.