DiskCache fix when using clustering.

backend/src/api/disk-cache.ts

@@ -1,5 +1,6 @@
+const config = require('../../mempool-config.json');
 import * as fs from 'fs';
-import * as cluster from 'cluster';
+import * as process from 'process';
 import memPool from './mempool';
 import blocks from './blocks';
 
@@ -7,15 +8,17 @@ class DiskCache {
   static FILE_NAME = './cache.json';
 
   constructor() {
-    process.on('SIGINT', () => {
+    if (process.env.workerId === '0' || !config.CLUSTER_NUM_CORES || config.CLUSTER_NUM_CORES === 1) {
-      this.saveCacheToDisk();
+      process.on('SIGINT', () => {
-      process.exit(2);
+        this.saveCacheToDisk();
-    });
+        process.exit(2);
+      });
 
-    process.on('SIGTERM', () => {
+      process.on('SIGTERM', () => {
-      this.saveCacheToDisk();
+        this.saveCacheToDisk();
-      process.exit(2);
+        process.exit(2);
-    });
+      });
+    }
   }
 
   saveCacheToDisk() {

backend/src/index.ts

@@ -37,12 +37,19 @@ class Server {
 
       const numCPUs = config.CLUSTER_NUM_CORES;
       for (let i = 0; i < numCPUs; i++) {
-        cluster.fork();
+        const env = { workerId: i };
+        const worker = cluster.fork(env);
+        worker.process['env'] = env;
       }
 
       cluster.on('exit', (worker, code, signal) => {
-        console.log(`Mempool Worker #${worker.process.pid} died. Restarting in 10 seconds...`, signal || code);
+        const workerId = worker.process['env'].workerId;
-        setTimeout(() => { cluster.fork(); }, 10000);
+        console.log(`Mempool Worker PID #${worker.process.pid} workerId: ${workerId} died. Restarting in 10 seconds...`, signal || code);
+        setTimeout(() => {
+          const env = { workerId: workerId };
+          const newWorker = cluster.fork(env);
+          newWorker.process['env'] = env;
+        }, 10000);
       });
     } else {
       this.startServer(true);