Shut down gracefully

Call close() before your process exits to flush pending metrics:

process.on('SIGTERM', async () => {
  await openfuse.close({ timeoutMs: 3000 })
  process.exit(0)
})

The timeoutMs option (default: 5000) limits how long the final metrics flush can take. If your platform gives you 10 seconds for shutdown, set this to 3000-5000ms to leave room for other cleanup.

Instance ID auto-detection

The SDK generates a unique instance ID for metrics deduplication. It detects your platform automatically:

Platform	Source
AWS Lambda	`AWS_LAMBDA_LOG_STREAM_NAME`
ECS	`ECS_CONTAINER_METADATA_URI_V4`
Kubernetes	`KUBERNETES_SERVICE_HOST` + pod name from `/etc/hostname`
Google Cloud Run	`K_SERVICE` + `K_REVISION`
Google Cloud Run Jobs	`CLOUD_RUN_JOB` + `CLOUD_RUN_EXECUTION` + `CLOUD_RUN_TASK_INDEX`
Azure Container Apps	`CONTAINER_APP_NAME` + `CONTAINER_APP_REVISION` + `CONTAINER_APP_REPLICA_NAME`
Azure App Service	`WEBSITE_INSTANCE_ID`
Azure Functions	`WEBSITE_INSTANCE_ID`
Fly.io	`FLY_ALLOC_ID`
Railway	`RAILWAY_REPLICA_ID`
Render	`RENDER_INSTANCE_ID`
Heroku	`DYNO`
Fallback	`hostname-pid-random`

Set a custom instance ID

const openfuse = new OpenfuseCloud({
  system: 'payments',
  clientId: 'YOUR_CLIENT_ID',
  clientSecret: 'YOUR_CLIENT_SECRET',
  instanceId: 'worker-3',
})

Read the resolved instance ID with openfuse.instanceId.

Tune metrics

Default metrics settings come from the server. Override locally:

Setting	Default	When to change
`windowSizeMs`	`10000`	Increase for low-traffic breakers. Decrease for real-time dashboards.
`flushIntervalMs`	`15000`	Decrease for faster metrics visibility. Increase to reduce API calls.
`maxLatencySamples`	`1000`	Increase for more accurate percentiles under high throughput.
`enabled`	`true`	Set to `false` in test environments.

const openfuse = new OpenfuseCloud({
  system: 'payments',
  clientId: 'YOUR_CLIENT_ID',
  clientSecret: 'YOUR_CLIENT_SECRET',
  metrics: {
    flushIntervalMs: 30_000,
  },
})

Use a singleton

Create one client per process. The SDK manages internal caches, timers, and connections that shouldn't be duplicated.

lib/openfuse.ts

import { OpenfuseCloud } from '@openfuseio/sdk'

export const openfuse = new OpenfuseCloud({
  system: 'payments',
  clientId: 'YOUR_CLIENT_ID',
  clientSecret: 'YOUR_CLIENT_SECRET',
})

openfuse.init()

// Pre-create breaker handles for reuse
export const stripeBreaker = openfuse.breaker('stripe-get-customer')
export const emailBreaker = openfuse.breaker('twilio-send-email')

routes/customers.ts

import { stripeBreaker } from '../lib/openfuse.js'

// Use the pre-created handle directly
const customer = await stripeBreaker.protect(
  (signal) => stripe.customers.retrieve(customerId, { signal }),
  { fallback: () => cachedCustomer },
)

Zero dependencies

The SDK has zero runtime dependencies. It uses built-in Node.js APIs for HTTP, crypto, and timers.

Production