feat: support reusePort on server listen (#115)

closes eggjs/egg#5365


<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **New Features**
* Added reusePort support to allow multiple sockets to listen on the
same port where supported.

* **Improvements**
  * Improved agent startup error handling and clearer debug logs.
* CI now tests Node.js 24; package metadata and project links updated;
version bumped.

* **Tests**
* Added unit/integration and cluster tests exercising reusePort and
related startup flows.

* **Documentation**
  * README updated with reusePort details.

* **Other**
  * .gitignore updated.

<sub>✏️ Tip: You can customize this high-level summary in your review
settings.</sub>
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---------

Signed-off-by: MK (fengmk2) <[email protected]>
Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>
Co-authored-by: Copilot <[email protected]>

Author: 3 people

.github/workflows/nodejs.yml

@@ -12,6 +12,6 @@ jobs:
     uses: node-modules/github-actions/.github/workflows/node-test.yml@master
     with:
       os: 'ubuntu-latest, macos-latest'
-      version: '14, 16, 18, 20, 22'
+      version: '14, 16, 18, 20, 22, 24'
     secrets:
       CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}

.gitignore

@@ -9,3 +9,4 @@ run
 .nyc_output
 package-lock.json
 .package-lock.json
+pnpm-lock.yaml

README.md

@@ -8,8 +8,8 @@
 
 [npm-image]: https://img.shields.io/npm/v/egg-cluster.svg?style=flat-square
 [npm-url]: https://npmjs.org/package/egg-cluster
-[codecov-image]: https://codecov.io/github/eggjs/egg-cluster/coverage.svg?branch=master
-[codecov-url]: https://codecov.io/github/eggjs/egg-cluster?branch=master
+[codecov-image]: https://codecov.io/github/eggjs/cluster/coverage.svg?branch=master
+[codecov-url]: https://codecov.io/github/eggjs/cluster?branch=master
 [snyk-image]: https://snyk.io/test/npm/egg-cluster/badge.svg?style=flat-square
 [snyk-url]: https://snyk.io/test/npm/egg-cluster
 [download-image]: https://img.shields.io/npm/dm/egg-cluster.svg?style=flat-square
@@ -53,12 +53,13 @@ startCluster(options, () => {
 | workers      | `Number`  | numbers of app workers                   |
 | sticky       | `Boolean` | sticky mode server                       |
 | port         | `Number`  | port                                     |
+| reusePort   | `Boolean` | (Required Node.js >= 22.12.0) allows multiple sockets on the same host to bind to the same port. Incoming connections are distributed by the operating system to listening sockets. This option is available only on some platforms, such as Linux 3.9+, DragonFlyBSD 3.6+, FreeBSD 12.0+, Solaris 11.4, and AIX 7.2.5+. **Default:** `false` |
 | debugPort    | `Number`  | the debug port only listen on http protocol |
 | https        | `Object`  | start a https server, note: `key` / `cert` / `ca` should be full path to file |
 | require      | `Array\|String` | will inject into worker/agent process |
 | pidFile      | `String`  | will save master pid to this file |
 | startMode    | `String`  | default is 'process', use 'worker_threads' to start the app & agent worker by worker_threads |
-| ports        | `Array`   | startup port of each app worker, such as: [7001, 7002, 7003], only effects when the startMode is 'worker_threads' |
+| ports        | `Array`   | startup port of each app worker, such as: [7001, 7002, 7003], only effects when the `startMode` is `'worker_threads'` and `reusePort` is `false` |
 | env        | `String`   | custom env, default is process.env.EGG_SERVER_ENV |
 
 ## Env

lib/agent_worker.js

@@ -24,7 +24,7 @@ if (options.startMode === 'worker_threads') {
   AgentWorker = require('./utils/mode/impl/process/agent').AgentWorker;
 }
 
-const debug = require('util').debuglog('egg-cluster');
+const debug = require('util').debuglog('egg-cluster:agent_worker');
 const ConsoleLogger = require('egg-logger').EggConsoleLogger;
 const consoleLogger = new ConsoleLogger({ level: process.env.EGG_AGENT_WORKER_LOGGER_LEVEL });
 

lib/app_worker.js

@@ -16,9 +16,11 @@ if (options.startMode === 'worker_threads') {
   AppWorker = require('./utils/mode/impl/process/app').AppWorker;
 }
 
+const os = require('os');
 const fs = require('fs');
-const debug = require('util').debuglog('egg-cluster');
+const debug = require('util').debuglog('egg-cluster:app_worker');
 const ConsoleLogger = require('egg-logger').EggConsoleLogger;
+
 const consoleLogger = new ConsoleLogger({
   level: process.env.EGG_APP_WORKER_LOGGER_LEVEL,
 });
@@ -38,6 +40,18 @@ const port = options.port = options.port || listenConfig.port;
 const debugPort = options.debugPort;
 const protocol = (httpsOptions.key && httpsOptions.cert) ? 'https' : 'http';
 
+// https://nodejs.org/api/net.html#serverlistenoptions-callback
+// https://github.com/nodejs/node/blob/main/node.gypi#L310
+// https://docs.python.org/3/library/sys.html#sys.platform
+// This option is available only on some platforms, such as Linux 3.9+, DragonFlyBSD 3.6+, FreeBSD 12.0+, Solaris 11.4, and AIX 7.2.5+.
+const supportedPlatforms = [ 'linux', 'freebsd', 'sunos', 'aix' ];
+let reusePort = options.reusePort = options.reusePort || listenConfig.reusePort;
+if (reusePort && !supportedPlatforms.includes(os.platform())) {
+  reusePort = false;
+  options.reusePort = false;
+  debug('platform %s is not supported currently, set reusePort to false', os.platform());
+}
+
 AppWorker.send({
   to: 'master',
   action: 'realport',
@@ -121,21 +135,36 @@ function startServer(err) {
         exitProcess();
         return;
       }
-      const args = [ port ];
-      if (listenConfig.hostname) args.push(listenConfig.hostname);
-      debug('listen options %s', args);
-      server.listen(...args);
+      if (reusePort) {
+        // https://nodejs.org/api/net.html#serverlistenoptions-callback
+        const listenOptions = { port, reusePort };
+        if (listenConfig.hostname) {
+          listenOptions.host = listenConfig.hostname;
+        }
+        debug('listen options %j', listenOptions);
+        server.listen(listenOptions);
+      } else {
+        const args = [ port ];
+        if (listenConfig.hostname) {
+          args.push(listenConfig.hostname);
+        }
+        debug('listen options %s', args);
+        server.listen(...args);
+      }
     }
     if (debugPortServer) {
       debug('listen on debug port: %s', debugPort);
       debugPortServer.listen(debugPort);
     }
   }
 
-  AppWorker.send({
-    to: 'master',
-    action: 'listening',
-    data: server.address() || { port },
+  server.once('listening', () => {
+    AppWorker.send({
+      to: 'master',
+      action: 'listening',
+      data: server.address() || { port },
+      reusePort,
+    });
   });
 }
 

lib/master.js

@@ -34,6 +34,7 @@ class Master extends EventEmitter {
    *  - {Object} [plugins] - customized plugins, for unittest
    *  - {Number} [workers] numbers of app workers, default to `os.cpus().length`
    *  - {Number} [port] listening port, default to 7001(http) or 8443(https)
+   *  - {Boolean} [reusePort] setting `reusePort` to `true` allows multiple sockets on the same host to bind to the same port. Incoming connections are distributed by the operating system to listening sockets. This option is available only on some platforms, such as Linux 3.9+, DragonFlyBSD 3.6+, FreeBSD 12.0+, Solaris 11.4, and AIX 7.2.5+. **Default:** `false`.
    *  - {Number} [debugPort] listening a debug port on http protocol
    *  - {Object} [https] https options, { key, cert, ca }, full path
    *  - {Array|String} [require] will inject into worker/agent process

lib/utils/mode/impl/process/app.js

@@ -41,8 +41,15 @@ class AppWorker extends BaseAppWorker {
     process.on(event, callback);
   }
 
-  static send(data) {
-    process.send(data);
+  static send(message) {
+    if (message && message.action === 'listening' && message.reusePort) {
+      // cluster won't get `listening` event when reusePort is true, use cluster `message` event instead
+      // rewrite message.action to 'reuse-port-listening'
+      message.action = 'reuse-port-listening';
+      cluster.worker.send(message);
+      return;
+    }
+    process.send(message);
   }
 
   static kill() {
@@ -124,6 +131,25 @@ class AppUtils extends BaseAppUtils {
     });
     cluster.on('listening', (worker, address) => {
       const appWorker = new AppWorker(worker);
+      this.logger.info('[master] app_worker#%s:%s listening on %j', appWorker.id, appWorker.workerId, address);
+      this.messenger.send({
+        action: 'app-start',
+        data: {
+          workerId: appWorker.workerId,
+          address,
+        },
+        to: 'master',
+        from: 'app',
+      });
+    });
+    // handle 'reuse-port-listening' message: { action: 'reuse-port-listening', data: { port: 3000 } }
+    cluster.on('message', (worker, message) => {
+      if (!message || message.action !== 'reuse-port-listening') {
+        return;
+      }
+      const address = message.data;
+      const appWorker = new AppWorker(worker);
+      this.logger.info('[master] app_worker#%s:%s reuse-port listening on %j', appWorker.id, appWorker.workerId, address);
       this.messenger.send({
         action: 'app-start',
         data: {

lib/utils/mode/impl/worker_threads/app.js

@@ -71,15 +71,14 @@ class AppWorker extends BaseAppWorker {
 }
 
 class AppUtils extends BaseAppUtils {
-  #workers = [];
+  #appWorkers = [];
 
   #forkSingle(appPath, options, id) {
     // start app worker
     const worker = new workerThreads.Worker(appPath, options);
-    this.#workers.push(worker);
-
     // wrap app worker
     const appWorker = new AppWorker(worker, id);
+    this.#appWorkers.push(appWorker);
     this.emit('worker_forked', appWorker);
     appWorker.disableRefork = true;
     worker.on('message', msg => {
@@ -129,23 +128,40 @@ class AppUtils extends BaseAppUtils {
         to: 'master',
         from: 'app',
       });
-
     });
 
     // handle worker exit
     worker.on('exit', async code => {
+      this.log('[master] app_worker#%s (tid:%s) exit with code: %s', appWorker.id, appWorker.workerId, code);
+      // remove worker from workers array
+      const idx = this.#appWorkers.indexOf(appWorker);
+      if (idx !== -1) {
+        this.#appWorkers.splice(idx, 1);
+      }
+      // remove all listeners to avoid memory leak
+      worker.removeAllListeners();
+
       appWorker.state = 'dead';
-      this.messenger.send({
-        action: 'app-exit',
-        data: {
-          workerId: appWorker.workerId,
-          code,
-        },
-        to: 'master',
-        from: 'app',
-      });
+      try {
+        this.messenger.send({
+          action: 'app-exit',
+          data: {
+            workerId: appWorker.workerId,
+            code,
+          },
+          to: 'master',
+          from: 'app',
+        });
+      } catch (err) {
+        this.log('[master][warning] app_worker#%s (tid:%s) send "app-exit" message error: %s',
+          appWorker.id, appWorker.workerId, err);
+      }
 
+      if (appWorker.disableRefork) {
+        return;
+      }
       // refork app worker
+      this.log('[master] app_worker#%s (tid:%s) refork after 1s', appWorker.id, appWorker.workerId);
       await sleep(1000);
       this.#forkSingle(appPath, options, id);
     });
@@ -155,26 +171,38 @@ class AppUtils extends BaseAppUtils {
     this.startTime = Date.now();
     this.startSuccessCount = 0;
 
-    const ports = this.options.ports;
-    if (!ports.length) {
-      ports.push(this.options.port);
+    if (this.options.reusePort) {
+      if (!this.options.port) {
+        throw new Error('options.port must be specified when reusePort is enabled');
+      }
+      for (let i = 0; i < this.options.workers; i++) {
+        const argv = [ JSON.stringify(this.options) ];
+        const appWorkerId = i + 1;
+        this.#forkSingle(this.getAppWorkerFile(), { argv }, appWorkerId);
+      }
+    } else {
+      const ports = this.options.ports;
+      if (!ports.length) {
+        ports.push(this.options.port);
+      }
+      this.options.workers = ports.length;
+      let i = 0;
+      do {
+        const options = Object.assign({}, this.options, { port: ports[i] });
+        const argv = [ JSON.stringify(options) ];
+        this.#forkSingle(this.getAppWorkerFile(), { argv }, ++i);
+      } while (i < ports.length);
     }
-    this.options.workers = ports.length;
-    let i = 0;
-    do {
-      const options = Object.assign({}, this.options, { port: ports[i] });
-      const argv = [ JSON.stringify(options) ];
-      this.#forkSingle(this.getAppWorkerFile(), { argv }, ++i);
-    } while (i < ports.length);
 
     return this;
   }
 
   async kill() {
-    for (const worker of this.#workers) {
-      this.log(`[master] kill app worker#${worker.id} (worker_threads) by worker.terminate()`);
-      worker.removeAllListeners();
-      worker.terminate();
+    for (const appWorker of this.#appWorkers) {
+      this.log('[master] kill app_worker#%s (tid:%s) (worker_threads) by worker.terminate()', appWorker.id, appWorker.workerId);
+      appWorker.disableRefork = true;
+      appWorker.instance.removeAllListeners();
+      appWorker.instance.terminate();
     }
   }
 }

lib/utils/options.js

@@ -12,6 +12,7 @@ module.exports = function(options) {
     framework: '',
     baseDir: process.cwd(),
     port: options.https ? 8443 : null,
+    reusePort: false,
     workers: null,
     plugins: null,
     https: false,

package.json

@@ -1,22 +1,22 @@
 {
   "name": "egg-cluster",
-  "version": "2.4.0",
+  "version": "2.5.0-beta.3",
   "description": "cluster manager for egg",
   "main": "index.js",
   "scripts": {
     "lint": "eslint .",
     "test": "npm run lint -- --fix && npm run test-local",
     "test-local": "egg-bin test --ts false",
     "cov": "egg-bin cov --prerequire --timeout 100000 --ts false",
-    "ci": "npm run lint && npm run cov"
+    "ci": "npm run lint && node test/reuseport_cluster.js && npm run cov"
   },
   "files": [
     "index.js",
     "lib"
   ],
   "repository": {
     "type": "git",
-    "url": "git+https://github.com/eggjs/egg-cluster.git"
+    "url": "git+https://github.com/eggjs/cluster.git"
   },
   "keywords": [
     "egg",
@@ -26,9 +26,9 @@
   "author": "dead-horse <[email protected]>",
   "license": "MIT",
   "bugs": {
-    "url": "https://github.com/eggjs/egg-cluster/issues"
+    "url": "https://github.com/eggjs/cluster/issues"
   },
-  "homepage": "https://github.com/eggjs/egg-cluster#readme",
+  "homepage": "https://github.com/eggjs/cluster#readme",
   "dependencies": {
     "await-event": "^2.1.0",
     "cfork": "^1.7.1",