openvidu/backend/src/services/mutex.service.ts

109 lines
3.4 KiB
TypeScript

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';
import { MeetLock } from '../helpers/redis.helper.js';
export type RedisLock = Lock;
@injectable()
export class MutexService {
protected redlockWithoutRetry: Redlock;
protected readonly TTL_MS = ms('1m');
constructor(
@inject(RedisService) protected redisService: RedisService,
@inject(LoggerService) protected logger: LoggerService
) {
// Create a Redlock instance with no retry strategy
this.redlockWithoutRetry = this.redisService.createRedlock(0);
}
/**
* Acquires a lock for the specified resource.
* @param key The resource to acquire a lock for.
* @param ttl The time-to-live (TTL) for the lock in milliseconds. Defaults to the TTL value of the MutexService.
* @returns A Promise that resolves to the acquired Lock object.
*/
async acquire(key: string, ttl: number = this.TTL_MS): Promise<Lock | null> {
const registryKey = MeetLock.getRegistryLock(key);
try {
this.logger.debug(`Requesting lock: ${key}`);
const lock = await this.redlockWithoutRetry.acquire([key], ttl);
// Store Lock data in Redis registry for support HA and release lock
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);
return null;
}
}
/**
* Releases a lock on a resource.
*
* @param key - The resource to release the lock on.
* @returns A Promise that resolves when the lock is released.
*/
async release(key: string): Promise<void> {
const registryKey = MeetLock.getRegistryLock(key);
const lock = await this.getLockData(key);
if (!lock) {
return;
}
if (lock) {
this.logger.debug(`Releasing lock for resource: ${key}`);
try {
await lock.release();
} catch (error) {
this.logger.error(`Error releasing lock for key ${key}:`, error);
} finally {
await this.redisService.delete(registryKey);
}
}
}
/**
* Retrieves the lock data for a given resource.
*
* This method first attempts to retrieve the lock 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 the method returns `null`.
*
* @param key - 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(key: string): Promise<Lock | null> {
const registryKey = MeetLock.getRegistryLock(key);
try {
this.logger.debug(`Getting lock data in Redis for resource: ${key}`);
// 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: ${key}.`);
return null;
}
const { resources, value, expiration } = JSON.parse(redisLockData);
return new Lock(this.redlockWithoutRetry, resources, value, [], expiration);
} catch (error) {
this.logger.error(`Cannot release lock. Lock not found for resource: ${key}.`);
return null;
}
}
}