Examples for 8.8

Author: samerbuna

8.8/cluster.js

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+const cluster = require('cluster');
+const os = require('os');
+
+if (cluster.isMaster) {
+  const cpus = os.cpus().length;
+  for (let i = 0; i<cpus; i++) {
+    cluster.fork();
+  }
+  console.log(`Master PID: ${process.pid}`);
+
+  cluster.on('exit', (worker, code, signal) => {
+    if (code !== 0 && !worker.exitedAfterDisconnect) {
+      console.log(`Worker ${worker.id} crashed. ` +
+                  'Starting a new worker...');
+      cluster.fork();
+    }
+  });
+
+  process.on('SIGUSR2', () => {
+    const workers = Object.values(cluster.workers);
+
+    const restartWorker = (workerIndex) => {
+      const worker = workers[workerIndex];
+      if (!worker) return;
+
+      worker.on('exit', () => {
+        if (!worker.exitedAfterDisconnect) return;
+        console.log(`Exited process ${worker.process.pid}`);
+        cluster.fork().on('listening', () => {
+          restartWorker(workerIndex + 1);
+        });
+      });
+
+      worker.disconnect();
+    };
+
+    restartWorker(0);
+  });
+
+} else {
+  require('./server');
+}

8.8/server.js

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+const http = require('http');
+const pid = process.pid;
+
+http.createServer((req, res) => {
+  for (let i=0; i<1e7; i++); // simulate CPU work
+  res.end(`Handled by process ${pid}`);
+}).listen(8080, () => {
+  console.log(`Started process ${pid}`);
+});
+
+// setTimeout(() => {
+//   process.exit(1) // death by random timeout
+// }, Math.random() * 10000);