backend: Enhance MutexService with lock registry management and retrieval methods

backend/src/services/mutex.service.ts

@@ -1,7 +1,7 @@
-import Redlock, { Lock } from 'redlock';
-import { RedisService } from './redis.service.js';
-import { inject, injectable } from 'inversify';
 import ms from 'ms';
+import Redlock, { Lock } from 'redlock';
+import { inject, injectable } from 'inversify';
+import { RedisService } from './redis.service.js';
 import { LoggerService } from './logger.service.js';
 
 export type RedisLock = Lock;
@@ -11,6 +11,7 @@ export class MutexService {
 	protected locks: Map<string, Lock>;
 	protected readonly TTL_MS = ms('1m');
 	protected LOCK_KEY_PREFIX = 'ov_meet_lock:';
+	protected LOCK_REGISTRY_PREFIX = 'ov_meet_lock_registry:';
 
 	constructor(
 		@inject(RedisService) protected redisService: RedisService,
@@ -28,12 +29,25 @@ export class MutexService {
 	 * @returns A Promise that resolves to the acquired Lock object.
 	 */
 	async acquire(resource: string, ttl: number = this.TTL_MS): Promise<Lock | null> {
-		const key = this.LOCK_KEY_PREFIX + resource;
+		const key = this.getLockKey(resource);
+		const registryKey = this.getLockRegistryKey(resource);
 
 		try {
 			this.logger.debug(`Acquiring lock for resource: ${resource}`);
 			const lock = await this.redlockWithoutRetry.acquire([key], ttl);
+
+			// Store the lock in memory for easy access (optional)
 			this.locks.set(key, lock);
+			// Store Lock metadata in Redis registry for support HA release
+			await this.redisService.set(
+				registryKey,
+				JSON.stringify({
+					resources: lock.resources,
+					value: lock.value,
+					expiration: lock.expiration
+				}),
+				true
+			);
 			return lock;
 		} catch (error) {
 			this.logger.error('Error acquiring lock:', error);
@@ -48,8 +62,13 @@ export class MutexService {
 	 * @returns A Promise that resolves when the lock is released.
 	 */
 	async release(resource: string): Promise<void> {
-		const key = this.LOCK_KEY_PREFIX + resource;
+		const key = this.getLockKey(resource);
-		const lock = this.locks.get(key);
+
+		const lock = await this.getLockData(resource);
+
+		if (!lock) {
+			return;
+		}
 
 		if (lock) {
 			this.logger.debug(`Releasing lock for resource: ${resource}`);
@@ -60,7 +79,64 @@ export class MutexService {
 				this.logger.error(`Error releasing lock for key ${key}:`, error);
 			} finally {
 				this.locks.delete(key);
+				await this.redisService.delete(this.getLockRegistryKey(resource));
 			}
 		}
 	}
+
+	/**
+	 * Returns the complete key used to acquire the lock in Redis.
+	 */
+	protected getLockKey(resource: string): string {
+		return `${this.LOCK_KEY_PREFIX}${resource}`;
+	}
+
+	/**
+	 * Generates a unique key for the lock registry by combining a predefined prefix
+	 * with the specified resource identifier.
+	 */
+	protected getLockRegistryKey(resource: string): string {
+		return `${this.LOCK_REGISTRY_PREFIX}${resource}`;
+	}
+
+	/**
+	 * Retrieves the lock data for a given resource.
+	 *
+	 * This method first attempts to retrieve the lock from memory. If the lock is not found in memory,
+	 * it then tries to fetch the lock data from Redis. If the lock data is successfully retrieved from Redis,
+	 * it constructs a new `Lock` instance and returns it. If the lock data cannot be found in either memory
+	 * or Redis, the method returns `null`.
+	 *
+	 * @param resource - The identifier of the resource for which the lock data is being retrieved.
+	 * @returns A promise that resolves to the `Lock` instance if found, or `null` if the lock data is not available.
+	 */
+	protected async getLockData(resource: string): Promise<Lock | null> {
+		const key = this.getLockKey(resource);
+		const registryKey = this.getLockRegistryKey(resource);
+
+		// Try to get lock from memory
+		let lock = this.locks.get(key);
+
+		if (lock) {
+			return lock;
+		}
+
+		try {
+			this.logger.debug(`Getting lock data in Redis for resource: ${resource}`);
+			// Try to get lock from Redis
+			const redisLockData = await this.redisService.get(registryKey);
+
+			if (!redisLockData) {
+				this.logger.error(`Cannot release lock. Lock not found for resource: ${resource}.`);
+				return null;
+			}
+
+			const { resources, value, expiration } = JSON.parse(redisLockData);
+			lock = new Lock(this.redlockWithoutRetry, resources, value, [], expiration);
+			return lock;
+		} catch (error) {
+			this.logger.error(`Cannot release lock. Lock not found for resource: ${resource}.`);
+			return null;
+		}
+	}
 }