initial commit

src/MutexLock.ts

@@ -0,0 +1,51 @@
+import type { MutexOptions } from "./types";
+import redis from "redis";
+
+type RedisClient = redis.RedisClientType<
+	redis.RedisDefaultModules & redis.RedisModules,
+	redis.RedisFunctions,
+	redis.RedisScripts
+>;
+
+export class MutexLock {
+	redisClient: RedisClient;
+	mutexOptions: MutexOptions;
+
+	constructor(redisClient: RedisClient, options: MutexOptions) {
+		this.mutexOptions = options;
+		this.redisClient = redisClient;
+	}
+
+	static async create(options: MutexOptions) {
+		const redisClient = await redis
+			.createClient({
+				url: `redis://${options.redis.host}:${options.redis.port}`,
+			})
+			.connect();
+
+		return new MutexLock(redisClient, options);
+	}
+
+	async obtainLock(lockName: string) {
+		const lockIdentifier = `mutexlock:${lockName}`;
+		const releaseFunc = async () => {
+			await this.redisClient.del(lockIdentifier);
+		};
+		
+		while (true) {
+			const acquired = await this.redisClient.set(lockIdentifier, "1", {
+				NX: true
+			});
+			
+			if (acquired) {
+				await this.redisClient.expire(
+					lockIdentifier, 
+					this.mutexOptions.mutex?.ttl || 60
+				);
+				return releaseFunc;
+			}
+			await new Promise(resolve => 
+				setTimeout(resolve, this.mutexOptions.mutex?.checkInterval || 100)
+			);
+		}
+	}}

src/types.ts

@@ -0,0 +1,10 @@
+export type MutexOptions = {
+  redis: {
+    host: string;
+    port: number;
+  };
+  mutex?: {
+    checkInterval?: number;
+    ttl: number;
+  };
+};