cloudcms-server/launchpad/launchers/cluster.js

Cloud CMS Application Server Module

const cluster = require("cluster");
const { Server } = require("socket.io");
const { setupMaster, setupWorker } = require("@socket.io/sticky");
const { createAdapter, setupPrimary } = require("@socket.io/cluster-adapter");

module.exports = function(config) {
    
    var r = {};
    
    r.startCluster = function(httpServer, callback)
    {
        // setup sticky sessions
        setupMaster(httpServer, {
            //loadBalancingMethod: "least-connection"
            loadBalancingMethod: "round-robin"
        });

        // setup connections between the workers
        setupPrimary();

        // needed for packets containing buffers
        // cluster.setupPrimary({
        //     serialization: "advanced"
        // });

        return callback();
    };
    
    r.afterStartCluster = function(httpServer, callback)
    {
        var startupCount = 0;
    
        var numCPUs = require("os").cpus().length;
        if (process.env.FORCE_SINGLE_CPU) {
            numCPUs = 1;
        }
    
        var workers = [];
        for (let i = 0; i < numCPUs; i++)
        {
            var workerEnv = {};
            if (i === 0) {
                workerEnv["CLUSTER_REPORT"] = true;
            }
            
            var worker = cluster.fork(workerEnv);
            
            worker.on('message', function (msg, c) {
                //console.log("Worker message: " + msg + ", c: " + c);
                if (msg === "worker-startup") {
                    startupCount++;
                }
            });
            
            worker.on('error', function(err) {
                console.log("Worker.on(error) - " + JSON.stringify(err));
            });
            
            workers.push(worker);
        }
        
        cluster.on("error", function(err) {
            console.log("Cluster.on(error) - " + JSON.stringify(err));
        });
        
        cluster.on("exit", (worker) => {
            console.log(`Worker ${worker.process.pid} died`);
            //cluster.fork();
        });
        
        // wait for workers to start
        var waitFn = function() {
            setTimeout(function() {
                if (startupCount >= numCPUs) {
                    return callback(null, workers);
                }
                else
                {
                    waitFn();
                }
            }, 25);
        };
        waitFn();
    };
    
    r.afterStartServer = function(app, httpServer, callback)
    {
        // worker
    
        const io = new Server(httpServer);
        httpServer.io = io;
        
        // use the cluster adapter
        io.adapter(createAdapter());
    
        // setup connection with the primary process
        setupWorker(io);
        
        // on connect
        io.on("connection", (socket) => {
            // TODO
    
            // always catch err
            socket.on("error", function(err) {
                console.log("Caught socket error");
                console.log(err.stack);
            });
        });

        return callback();
    };
    
    return r;
}