grpclb

grpclb

grpc load balancer integrated with etcd for Node.js

Install

npm i grpclb

Usage

Server side

import { register } from 'grpclb';

const revoke = await register({
  server, // your grpc server instance
  etcdKV: { key, value }, // leave you to decide how to serialize service name, host, port into KV
  ttl: 10, // default 10 in seconds
  etcdHosts: hosts, // etcd hosts, or you can set as env var ETCD_HOSTS
});

// then you can revoke
// by direct call the revoke handler
revoke();

// or by shutting down the grpc server
server.tryShutdown(() => {});

Client side

• client-side load balancing with round-robin strategy

We can't register custom service resolver util the c library exposes the api.

So we can implement client-side load-balancing on the other way: javascript Proxy

import { createGrpcProxy } from 'grpclb';

proxy = await createGrpcProxy({
  etcdHosts: hosts, // etcd hosts, or you can set as env var ETCD_HOSTS
  target: pkgDef.helloworld, // your gRPC object, MUST be the package definition object
  parseKV, // how to extract service name, host, port from etcd key and value
});

// Every time you access the service object, you get the new servant address.
proxy.Greeter;

// The service was already initialized and
// you can just call the service method to send request
proxy.Greeter.sayHello({ name }, (error, response) => {});

Changelog

1.2.0 (2019-07-31)

Features

• allow parseKV return undefined (84ae325)

1.1.1 (2019-07-31)

Build System

• generator declaration file (594b845)