OpenCensus is a toolkit for collecting application performance and behavior data.

Usage no npm install needed!

<script type="module">
  import pm2OpencensusCore from 'https://cdn.skypack.dev/@pm2/opencensus-core';


OpenCensus Core Node.js

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OpenCensus for Node.js is an implementation of OpenCensus, a toolkit for collecting application performance and behavior monitoring data. It currently includes 3 apis: stats, tracing and tags.

The library is in alpha stage and the API is subject to change.


Install the opencensus-core package with NPM:

npm install @opencensus/core


Set up a new Stats manager instance.

To enable metrics, we’ll import a few items from OpenCensus Core package.

const { Stats, MeasureUnit, AggregationType } = require('@opencensus/core');

// Create the Stats manager
const stats = new Stats();

// The latency in milliseconds
const mLatencyMs = stats.createMeasureDouble(
  "The latency in milliseconds"

Create Views and Tags:

We now determine how our metrics will be organized by creating Views. We will also create the variable needed to add extra text meta-data to our metrics – methodTagKey, statusTagKey, and errorTagKey.

const methodTagKey = "method";
const statusTagKey = "status";
const errorTagKey = "error";

const latencyView = stats.createView(
  [methodTagKey, statusTagKey, errorTagKey],
  "The distribution of the latencies",
  // Bucket Boundaries:
  // [>=0ms, >=25ms, >=50ms, >=75ms, >=100ms, >=200ms, >=400ms, >=600ms, >=800ms, >=1s, >=2s, >=4s, >=6s]
  [0, 25, 50, 75, 100, 200, 400, 600, 800, 1000, 2000, 4000, 6000]

Recording Metrics:

Now we will record the desired metrics. To do so, we will use stats.record() and pass in measurements.

const [_, startNanoseconds] = process.hrtime();
const tags = {method: "repl", status: "OK"};

  measure: mLatencyMs,
  value: sinceInMilliseconds(startNanoseconds)

function sinceInMilliseconds(startNanoseconds) {
  const [_, endNanoseconds] = process.hrtime();
  return (endNanoseconds - startNanoseconds) / 1e6;

See Quickstart/Metrics for a full example of registering and collecting metrics.

Useful links


Apache License 2.0