From 386d1bbf7462d98c9f4663a5d54f4a5fdd39931f Mon Sep 17 00:00:00 2001
From: Johann150 <johann.galle@protonmail.com>
Date: Fri, 12 May 2023 19:34:08 +0200
Subject: [PATCH] fix: update meta cache between workers

---
 packages/backend/src/boot/master.ts     |  9 +++++++++
 packages/backend/src/misc/fetch-meta.ts | 12 ++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/packages/backend/src/boot/master.ts b/packages/backend/src/boot/master.ts
index a688a8ae6..6f64715f8 100644
--- a/packages/backend/src/boot/master.ts
+++ b/packages/backend/src/boot/master.ts
@@ -168,6 +168,15 @@ function spawnWorker(mode: 'web' | 'queue'): Promise<void> {
 				case 'ready':
 					res();
 					break;
+				case 'metaUpdate':
+					// forward new instance metadata to all workers
+					for (const otherWorker of Object.values(cluster.workers)) {
+						// don't forward the message to the worker that sent it
+						if (worker.id === otherWorker.id) continue;
+
+						otherWorker.send(message);
+					}
+					break;
 			}
 		});
 	});
diff --git a/packages/backend/src/misc/fetch-meta.ts b/packages/backend/src/misc/fetch-meta.ts
index ab8c81eef..da71b1d4b 100644
--- a/packages/backend/src/misc/fetch-meta.ts
+++ b/packages/backend/src/misc/fetch-meta.ts
@@ -1,3 +1,4 @@
+import process from 'node:process';
 import push from 'web-push';
 import { db } from '@/db/postgre.js';
 import { Meta } from '@/models/entities/meta.js';
@@ -17,9 +18,20 @@ export async function setMeta(meta: Meta): Promise<void> {
 
 	cache = meta;
 
+	/*
+	The meta is not included here because another process may have updated
+	the content before the other process receives it.
+	*/
+	process.send!('metaUpdated');
+
 	unlock();
 }
 
+// the primary will forward this message
+process.on('message', async message => {
+	if (message === 'metaUpdated') await getMeta();
+});
+
 /**
  * Performs the primitive database operation to fetch server configuration.
  * If there is no entry yet, inserts a new one.