LaunchDarkly Node.js Server-Side Observability Plugin

NB: APIs are subject to change until a 1.x version is released.

Install

Install the package

# npm
npm i @launchdarkly/observability-node

# yarn
yarn add @launchdarkly/observability-node

Update your application to instantiate the observability plugin when you initialize the LaunchDarkly SDK.

import { init } from '@launchdarkly/node-server-sdk'
import { Observability } from '@launchdarkly/observability-node'

const client = init(
  'sdk-key',
  {
    plugins: [
      new Observability(),
    ],
  },
)

Manual instrumentation with LDObserve

The Observability plugin automatically captures flag evaluations, logs, and traces. Use the LDObserve singleton when you want to record custom metrics, logs, errors, or spans so they are correlated with your LaunchDarkly data.

import { LDObserve } from '@launchdarkly/observability-node'

// Record custom metrics (counters, gauges, histograms, etc.)
LDObserve.recordCount({ name: 'api_calls', value: 1 })
LDObserve.recordHistogram({ name: 'response_time_ms', value: 150 })

// Record logs and errors
LDObserve.recordLog('User performed action', 'info', undefined, undefined, { user_id: '12345' })
LDObserve.recordError(new Error('Payment failed'), undefined, undefined, { component: 'checkout' })

// Create spans tied to request context (e.g. in Express)
app.get('/order', (req, res) => {
  LDObserve.runWithHeaders('handle-order', req.headers, (span) => {
    // Your handler logic; span is linked to the request trace
    res.json({ orderId: '123' })
  })
})

Getting started

Refer to the SDK documentation for instructions on getting started with using the SDK.

Verifying SDK build provenance with the SLSA framework

LaunchDarkly uses the SLSA framework (Supply-chain Levels for Software Artifacts) to help developers make their supply chain more secure by ensuring the authenticity and build integrity of our published SDK packages. To learn more, see the provenance guide.

About LaunchDarkly

• LaunchDarkly Observability provies a way to collect and send errors, logs, traces to LaunchDarkly. Correlate latency or exceptions with your releases to safely ship code.
• LaunchDarkly is a continuous delivery platform that provides feature flags as a service and allows developers to iterate quickly and safely. We allow you to easily flag your features and manage them from the LaunchDarkly dashboard. With LaunchDarkly, you can:
  • Roll out a new feature to a subset of your users (like a group of users who opt-in to a beta tester group), gathering feedback and bug reports from real-world use cases.
  • Gradually roll out a feature to an increasing percentage of users, and track the effect that the feature has on key metrics (for instance, how likely is a user to complete a purchase if they have feature A versus feature B?).
  • Turn off a feature that you realize is causing performance problems in production, without needing to re-deploy, or even restart the application with a changed configuration file.
  • Grant access to certain features based on user attributes, like payment plan (eg: users on the ‘gold’ plan get access to more features than users in the ‘silver’ plan).
  • Disable parts of your application to facilitate maintenance, without taking everything offline.
• LaunchDarkly provides feature flag SDKs for a wide variety of languages and technologies. Read our documentation for a complete list.
• Explore LaunchDarkly
  • launchdarkly.com for more information
  • docs.launchdarkly.com for our documentation and SDK reference guides
  • apidocs.launchdarkly.com for our API documentation
  • blog.launchdarkly.com for the latest product updates