Change threading model (#7)

* Change threading model to use cluster

* increase thread pool size

* Default thread pool size to 2

* default thread pool size 4

bin/squirrel.js

@@ -2,6 +2,8 @@
 
 "use strict";
 
+process.env.UV_THREADPOOL_SIZE = process.env.UV_THREADPOOL_SIZE || 4;
+
 var nomnom = require("nomnom")
   .options({
     config: {
@@ -43,5 +45,25 @@ case !opts.config:
   return nomnom.print(nomnom.getUsage());
 
 default:
-  return require("../lib/cacher")(opts);
+  return run(opts);
+}
+
+function run(opts) {
+  var cluster = require('cluster'),
+    numCPUs = require('os').cpus().length;
+
+  var numworkers = process.env.WORKER_COUNT || numCPUs; 
+  if (cluster.isMaster) {
+    // Fork workers.
+    for (var i = 0; i < numworkers; i++) {
+      cluster.fork();
+    }
+
+    cluster.on('exit', (worker, code, signal) => {
+      console.log(`worker ${worker.process.pid} died`);
+    });
+  } else {
+    console.log("Starting worker");
+    require("../lib/cacher")(opts);
+  }
 }

lib/cacher.js

@@ -1,10 +1,6 @@
 #!/usr/bin/env node
 "use strict";
 
-// increase the libuv threadpool size to 1.5x the number of logical CPUs.
-process.env.UV_THREADPOOL_SIZE = process.env.UV_THREADPOOL_SIZE || 
-  Math.ceil(Math.max(4, require('os').cpus().length * 1.5));
-
 var path = require("path"),
   debug = require("debug"),
   rabbit = require('rabbit.js'),