core: pm2 cluster management

packages/hydrooj/src/init.ts

@@ -1,17 +1,16 @@
-import cluster from 'cluster';
-
 const versionNum = +process.version.replace(/v/gim, '').split('.')[0];
 if (versionNum < 10) throw new Error('NodeJS >=10.4 required');
-else if (versionNum < 14 && cluster.isMaster) {
+else if (versionNum < 14 && process.env.NODE_APP_INSTANCE === '0') {
     console.warn('NodeJS version <14, startup performance will be impacted.');
 }
+
+console.log('Process', process.pid, 'running as', process.env.NODE_APP_INSTANCE === '0' ? 'master' : 'worker');
 if (!global.Hydro) {
     global.Hydro = {
         version: {
             node: process.version,
             hydrooj: require('hydrooj/package.json').version,
         },
-        stat: { reqCount: 0 },
         handler: {},
         // @ts-ignore
         service: {},