index has CLI interface, is clustered

index.js

@@ -0,0 +1,32 @@
+const cluster = require('cluster');
+const program = require('commander');
+const os = require('os');
+
+const App = require('./src/app');
+
+const DEFAULT_PORT = 4000;
+
+program
+  .version(require('./package.json').version)
+  .option('-p, --port <n>', 'Port', parseInt)
+  .parse(process.argv);
+
+if (cluster.isMaster) {
+  // Spin up two processes per CPU
+  const processCount = os.cpus().length * 2;
+
+  console.log(`Master process spinning up ${processCount} children`);
+
+  for (let i = 0; i < processCount; i++) {
+    cluster.fork();
+  }
+
+  cluster.on('exit', (worker, code, signal) => {
+    console.log(`Process ${worker.pid} died`);
+  });
+} else {
+  const app = new App(program.port || DEFAULT_PORT);
+  app.start().then(() => {
+    console.log(`Process ${process.pid} is running`);
+  });
+}