server: update instance metadata in separate job

Previously, the deliver and inbox queue jobs would also take care of
updating the instance metadata. On a low resource server like mine,
the deliver queue is often the "critical path" and handling this
there is not a good idea.

Instead, this is handled in a separate job and with a slight delay,
to not interfere with bulk delivery jobs.

packages/backend/src/queue/index.ts

@@ -310,6 +310,22 @@ export function webhookDeliver(webhook: Webhook, type: typeof webhookEventTypes[
 	});
 }
 
+export function createUpdateInstanceJob(host: string) {
+	return systemQueue.add(
+		'updateInstance',
+		{ host },
+		{
+			delay: 5 * MINUTE,
+			// The docs say that trying to add a job with an ID that already exists will
+			// not actually add the job. This is useful to not duplicate jobs when parallel
+			// jobs request an update.
+			jobId: host,
+			removeOnComplete: true,
+			removeOnFail: 10,
+		}
+	);
+}
+
 export default function() {
 	deliverQueue.process(config.deliverJobConcurrency, processDeliver);
 	inboxQueue.process(config.inboxJobConcurrency, processInbox);

packages/backend/src/queue/processors/system/index.ts

@@ -3,12 +3,14 @@ import { tickCharts } from './tick-charts.js';
 import { resyncCharts } from './resync-charts.js';
 import { cleanCharts } from './clean-charts.js';
 import { checkExpired } from './check-expired.js';
+import { updateInstance } from './update-instance.js';
 
 const jobs = {
 	tickCharts,
 	resyncCharts,
 	cleanCharts,
 	checkExpired,
+	updateInstance,
 } as Record<string, Bull.ProcessCallbackFunction<Record<string, unknown>> | Bull.ProcessPromiseFunction<Record<string, unknown>>>;
 
 export default function(dbQueue: Bull.Queue<Record<string, unknown>>) {

packages/backend/src/queue/processors/system/update-instance.ts

@@ -0,0 +1,8 @@
+import Bull from 'bull';
+import { fetchInstanceMetadata } from '@/services/fetch-instance-metadata.js';
+
+export async function updateInstance(job: Bull.Job<Record<string, unknown>>, done: any): Promise<void> {
+	await fetchInstanceMetadata({ host: job.data.host }, true);
+
+	done();
+}

packages/backend/src/services/fetch-instance-metadata.ts

@@ -7,6 +7,7 @@ import { getJson, getHtml, getAgentByUrl } from '@/misc/fetch.js';
 import { Instance } from '@/models/entities/instance.js';
 import { Instances } from '@/models/index.js';
 import { getFetchInstanceMetadataLock } from '@/misc/app-lock.js';
+import { createUpdateInstanceJob } from '@/queue/index.js';
 import Logger from './logger.js';
 
 const logger = new Logger('metadata');
@@ -16,8 +17,14 @@ export async function fetchInstanceMetadata(instance: Instance, force = false):
 
 	if (!force) {
 		const _instance = await Instances.findOneBy({ host: instance.host });
-		const now = Date.now();
-		if (_instance && _instance.infoUpdatedAt && (now - _instance.infoUpdatedAt.getTime() < DAY)) {
+		if (_instance && _instance.infoUpdatedAt) {
+			const threshold = Date.now() - _instance.infoUpdatedAt.getTime();
+			if (threshold > DAY) {
+				// queue a job to deal with it later
+				createUpdateInstanceJob(instance.host);
+			}
+			// if the instance is already known and force is not specified,
+			// never update the data in the same thread
 			unlock();
 			return;
 		}