cluster-rpc

A simple way to wrap node.js modules for use with cluster even though they were designed to be used in a single non-cluster instance.

Install

npm install --save cluster-rpc

Usage

In the master process you will create the real instance of whatever module you're trying to use (for example express-session/session/memory, sqlite3, level) and then you will supply the names of the methods you wish to export to worker processes.

You must pass each worker via addWorker() so that it signals the worker to creates its own rpc-wrapped instance.

master

// You can pick any module with thunk-style callbacks
// For example:
var db = require('level')('./mydb')


// Wrap the instance
var crpc = require('cluster-rpc/master').create({
  instance: db
, methods: [ 'get', 'put' ]
, name: 'foo-level'
});


// You must add each worker
crpc.addWorker(cluster.fork());


crpc.then(function (db) {
  // processes are connected and ready
  // 'db' is the original instance
});

worker

// retrieve the instance
var crpc = require('cluster-rpc/worker').create({
  name: 'foo-level'
});


// all listed methods will be rpc'd
crpc.then(function (db) {
  // db.put, db.get
});

Example

'use strict';

var cluster = require('cluster');
var crpc;


if (cluster.isMaster) {


  crpc = require('cluster-rpc/master').create({
    instance: require('level')('./mydb')
  , methods: [ 'get', 'put' ]
  , name: 'foo-level'
  });
  crpc.addWorker(cluster.fork());
  crpc.then(function () {
    db.put('foo', 'bar');
  });


}
else {


  crpc = require('cluster-rpc/worker').create({
    name: 'foo-level'
  });


}


crpc.then(function (db) {
  setTimeout(function () {
    db.get('foo', function (err, result) {
      console.log("db.get('foo')", result);
    });
  }, 250);
});