traceparent


This is a basic implementation of the traceparent header part of the W3C trace context spec.

Installation

``
npm install traceparent
`

Example Usage

`js
const crypto = require('crypto')
const TraceParent = require('traceparent')

const version = Buffer.alloc(1).toString('hex')
const traceId = crypto.randomBytes(16).toString('hex')
const id = crypto.randomBytes(8).toString('hex')
const flags = '01'

const header = ${version}-${traceId}-${id}-${flags}

const parent = TraceParent.fromString(header)
`

API

$3

Construct a new TraceParent instance from an existing buffer. The contents are binary data that corresponds to the structure of the [W3C traceparent header][traceparent] format, with separators removed.

$3

Reconstruct a TraceParent instance from a formatted [W3C traceparent header][traceparent] string.

$3

Resume from a parent context, if given, or start a new context. Accepts another TraceParent instance, a [W3C traceparent header][traceparent] string, or a Span or Transaction instance from elastic-apm-node.

Requires a settings object with a transactionSampleRate value from 0.0 to 1.0 to generate a sampling decision for the context. This will only be applied when starting a _new_ context. When continuing an existing context, the sampling decision will be propagated into all child contexts.

$3

Returns true if this TraceParent is sampled.

$3

The traceId property will propagate through all children in the tree to link them all together.

$3

The id property is used to uniquely identify a given TraceParent instance within the tree.

$3

The parentId property links this context to its direct parent in the tree.

$3

The flags property is used to store metadata such as the sampling decision.

$3

The version property corresponds to the version segment of the [W3C traceparent header][traceparent].

$3

Create a new TraceParent instance that is a child of this one.

$3

Formats the TraceParent` instance as a [W3C traceparent header][traceparent].

$3

Return the parent ID, if there is none, generate one. This is useful in browser instrumentation to produce a starting span around a browser request which was not instrumented prior to page load.

License

MIT

[traceparent]: https://github.com/w3c/trace-context/blob/master/spec/20-http_header_format.md