LockR

...a NestJS Redis lock. Distributed lock, single Redis node.

(for now)

Requirements

• this works on the assumption that your application already is using Redis
• this particular implementation uses ioredis

Installation

• install through npm or yarn

npm i @stephanson/lockr --save
#OR
yarn add @stephanson/lockr

Configuration

• you can configure through module options
• or any mechanism that is recognized by @nestjs/config/ConfigService
  • example: dotenv files
  • a current list of the values used by the ConfigService:
    • LOCKR_DEFAULT_EXPIRATION_TIME_UNIT : 'seconds' | 'milliseconds'
    • LOCKR_DEFAULT_EXPIRATION_DURATION_AT_MOST: number
    • LOCKR_DEFAULT_RETRY_TIME_UNIT: 'seconds' | 'milliseconds'
    • LOCKR_DEFAULT_RETRY_INTERVAL: number
    • LOCKR_DEFAULT_RETRY_MAX_COUNT: number
• you can mix and match whatever approach works for you best
• when using the decorator or the service, the precedence of the values is the following:
  1. the actual input, if exists
  2. the configured module options, if exists
  3. the source for ConfigService
• if none of them can provide a value, an error will be thrown by the ConfigService
• the exceptions are
  • the RetryPreferences where the assumption is that the retry behavior is not desired.
  • the lock name prefix parameter, which, if not supplied is defaulted to lock
    • a lock will have the format: <prefix ?? lock>:<user-defined-name>

Usage

Contributions and future

• there are several topics i would like to address in the future
  • adding testcontainers and writing actual tests within the library
  • adding a nestjs specific implementation for redlock (the distributed, multi node redis version of the algorithm)