Registry / aws / eureka-js-client

eureka-js-client

library4.5.0jsnpmunverified

A JavaScript client for Netflix OSS Eureka service registry (v4.5.0, actively maintained). Enables Node.js services to register, heartbeat, and discover instances from Eureka servers. Supports YAML configuration, environment-specific overrides (EUREKA_ENV, NODE_ENV), custom request middleware for auth, and delta registry updates. Key differentiator: full Eureka client implementation with instance management, unlike lighter discovery-only libraries.

aws http-networking devops

npm install eureka-js-client

github ↗package ↗

INSTALL

IMPORT

SIG · EUREKA-JS-CLIENT

eureka-js-client

awsjavascriptv4.5.0

harness data pending

Install & Compatibility

Where this runs

No compatibility data collected yet for this library.

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

Eureka

✓ const { Eureka } = require('eureka-js-client');

✗ const Eureka = require('eureka-js-client');

Client exports Eureka as a named export, not default. Misleading README shows both styles; use named import.

Eureka

✓ import { Eureka } from 'eureka-js-client';

✗ import Eureka from 'eureka-js-client';

ESM named import is correct. Default import works due to module interop but TypeScript may flag it.

Eureka

✓ const Eureka = require('eureka-js-client').Eureka;

CommonJS require of named export. This is explicit and avoids confusion.

Instantiate and start a Eureka client with minimal configuration, then fetch instances by app ID and stop after 10 seconds.

const { Eureka } = require('eureka-js-client'); const client = new Eureka({ instance: { app: 'my-service', hostName: 'localhost', ipAddr: '127.0.0.1', port: 8080, vipAddress: 'my-service.vip', dataCenterInfo: { name: 'MyOwn' }, }, eureka: { host: '192.168.99.100', port: 8761, servicePath: '/eureka/apps/', }, }); client.start((err) => { if (err) { console.error('Failed to start Eureka client:', err); } else { console.log('Eureka client started and registered'); const instances = client.getInstancesByAppId('other-service'); console.log('Instances:', instances); setTimeout(() => client.stop(), 10000); } });

Debug

Known issues

gotchaConstructor options overwrite YAML config but merge behavior is not documented; missing fields from options may fallback to YAML defaults, causing silent misconfiguration.

fix

Always explicitly set all required options in constructor if using YAML fallback; avoid relying on partial overrides.

affects: >=4.0.0

breakingIn v4.0.0, default export changed to named export. Code using `const Eureka = require('eureka-js-client')` will get the whole module, not the constructor.

fix

Use destructured require: `const { Eureka } = require('eureka-js-client')`.

affects: >=4.0.0

deprecatedThe `request` library used internally is deprecated and unmaintained since 2020, with known security vulnerabilities.

fix

Use requestMiddleware to patch auth/headers; consider forking or switching to a maintained client like `@netflix/eureka-js-client`.

affects: >=4.4.1

gotchaEUREKA_ENV env var takes precedence over NODE_ENV but many users expect NODE_ENV to be the sole configuration driver.

fix

Set EUREKA_ENV explicitly to control environment config file selection, or ensure NODE_ENV is set if EUREKA_ENV is absent.

affects: >=4.5.0

Errors

Common errors & fixes

TypeError: Eureka is not a constructor

Using default import or incorrect require pattern that imports the whole module object.

fix

Use const { Eureka } = require('eureka-js-client'); or import { Eureka } from 'eureka-js-client';

Error: listen EADDRINUSE: address already in use :::8080

Port conflict when multiple instances run on same host without unique ports.

fix

Configure each instance with a different port in the instance configuration or bind to port 0 for dynamic assignment.

Error: Failed to fetch registry: ECONNREFUSED

Eureka server is not running or unreachable at configured host/port.

fix

Verify Eureka server is up and accessible; check eureka.host and eureka.port configuration.

Upgrade

Version history

4.5.0latest on npm

Audit

Dependencies

No dependency data recorded yet.

Agent activity

17 hits · last 30 days

node

OpenAI (training)

Resources

githubhttps://github.com/jquatier/eureka-js-client ↗

packagehttps://www.npmjs.com/package/eureka-js-client ↗