refactoring

Resolve #7779

packages/backend/src/queue/initialize.ts

@@ -0,0 +1,33 @@
+import * as Bull from 'bull';
+import config from '@/config/index';
+
+export function initialize<T>(name: string, limitPerSec = -1) {
+	return new Bull<T>(name, {
+		redis: {
+			port: config.redis.port,
+			host: config.redis.host,
+			password: config.redis.pass,
+			db: config.redis.db || 0,
+		},
+		prefix: config.redis.prefix ? `${config.redis.prefix}:queue` : 'queue',
+		limiter: limitPerSec > 0 ? {
+			max: limitPerSec,
+			duration: 1000
+		} : undefined,
+		settings: {
+			backoffStrategies: {
+				apBackoff
+			}
+		}
+	});
+}
+
+// ref. https://github.com/misskey-dev/misskey/pull/7635#issue-971097019
+function apBackoff(attemptsMade: number, err: Error) {
+	const baseDelay = 60 * 1000;	// 1min
+	const maxBackoff = 8 * 60 * 60 * 1000;	// 8hours
+	let backoff = (Math.pow(2, attemptsMade) - 1) * baseDelay;
+	backoff = Math.min(backoff, maxBackoff);
+	backoff += Math.round(backoff * Math.random() * 0.2);
+	return backoff;
+}