From c1e98eefa7fe93431ac312ecc0d90314db2c49b1 Mon Sep 17 00:00:00 2001
From: Ben Lubar <ben.lubar+github@gmail.com>
Date: Mon, 23 Jul 2018 11:21:36 -0500
Subject: [PATCH] Allow single-host clusters to not send pubsub and socket.io
 messages through the database. (#6659)

* Allow single-host clusters to not send pubsub and socket.io messages through the database.

* Fix lint errors.
---
 install/package.json   |  1 +
 loader.js              |  9 +++++++++
 src/pubsub.js          | 16 +++++++++++++++-
 src/socket.io/index.js |  8 +++++++-
 4 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/install/package.json b/install/package.json
index 94ab028d33..e09864dc4d 100644
--- a/install/package.json
+++ b/install/package.json
@@ -95,6 +95,7 @@
         "serve-favicon": "^2.4.5",
         "sitemap": "^1.13.0",
         "socket.io": "2.1.1",
+        "socket.io-adapter-cluster": "^1.0.1",
         "socket.io-adapter-mongo": "^2.0.1",
         "socket.io-client": "2.1.1",
         "socket.io-redis": "5.2.0",
diff --git a/loader.js b/loader.js
index 3071a6f8d5..9150c868c8 100644
--- a/loader.js
+++ b/loader.js
@@ -36,6 +36,10 @@ Loader.init = function (callback) {
 		};
 	}
 
+	if (nconf.get('singleHostCluster')) {
+		require('socket.io-adapter-cluster/master')();
+	}
+
 	process.on('SIGHUP', Loader.restart);
 	process.on('SIGUSR2', Loader.reload);
 	process.on('SIGTERM', Loader.stop);
@@ -88,6 +92,11 @@ Loader.addWorkerEvents = function (worker) {
 				console.log('[cluster] Reloading...');
 				Loader.reload();
 				break;
+			case 'pubsub':
+				workers.forEach(function (w) {
+					w.send(message);
+				});
+				break;
 			}
 		}
 	});
diff --git a/src/pubsub.js b/src/pubsub.js
index 6b6f12d171..82c4a1b57b 100644
--- a/src/pubsub.js
+++ b/src/pubsub.js
@@ -1,5 +1,6 @@
 'use strict';
 
+var EventEmitter = require('events');
 var nconf = require('nconf');
 
 var real;
@@ -12,9 +13,22 @@ function get() {
 	var pubsub;
 
 	if (nconf.get('isCluster') === 'false') {
-		var EventEmitter = require('events');
 		pubsub = new EventEmitter();
 		pubsub.publish = pubsub.emit.bind(pubsub);
+	} else if (nconf.get('singleHostCluster')) {
+		pubsub = new EventEmitter();
+		pubsub.publish = function (event, data) {
+			process.send({
+				action: 'pubsub',
+				event: event,
+				data: data,
+			});
+		};
+		process.on('message', function (message) {
+			if (message && typeof message === 'object' && message.action === 'pubsub') {
+				pubsub.emit(message.event, message.data);
+			}
+		});
 	} else if (nconf.get('redis')) {
 		pubsub = require('./database/redis/pubsub');
 	} else if (nconf.get('mongo')) {
diff --git a/src/socket.io/index.js b/src/socket.io/index.js
index 884a7e432c..bf7d7cdd7d 100644
--- a/src/socket.io/index.js
+++ b/src/socket.io/index.js
@@ -27,7 +27,13 @@ Sockets.init = function (server) {
 		path: nconf.get('relative_path') + '/socket.io',
 	});
 
-	io.adapter(nconf.get('redis') ? require('../database/redis').socketAdapter() : db.socketAdapter());
+	if (nconf.get('singleHostCluster')) {
+		io.adapter(require('socket.io-adapter-cluster')());
+	} else if (nconf.get('redis')) {
+		io.adapter(require('../database/redis').socketAdapter());
+	} else {
+		io.adapter(db.socketAdapter());
+	}
 
 	io.use(socketioWildcard);
 	io.use(authorize);