Summary

This section introduces a new module for a NestJS application to connect to Redis using ioredis and provides two ways to connect and communicate with Redis.

Abstract

This section is part of a larger guide on NestJS and introduces a new module that uses ioredis to enable a NestJS application to connect to Redis. The module provides two ways to connect and communicate with Redis: a standard ioredis connection and the NestJS Redis transporter. The needed packages are installed, and a config instance is introduced that provides all the needed ioredis settings. A service is provided that extends ioredis and acts as a "raw" Redis client for packages that can't work with Redis Transporter. The NestJS Transporter is also set up for "high" level redis access. The new redis module is imported at the app.module.ts file. The application now connects to Redis, and services can use it for Redis operations. Test suites that use this redis module should close the connection by calling redisService.onModuleDestroy or app.close(). Useful links are provided for further reference.

Bullet points

A new module is introduced that uses ioredis to enable a NestJS application to connect to Redis.
The module provides two ways to connect and communicate with Redis: a standard ioredis connection and the NestJS Redis transporter.
The needed packages are installed, and a config instance is introduced that provides all the needed ioredis settings.
A service is provided that extends ioredis and acts as a "raw" Redis client for packages that can't work with Redis Transporter.
The NestJS Transporter is set up for "high" level redis access.
The new redis module is imported at the app.module.ts file.
The application now connects to Redis, and services can use it for Redis operations.
Test suites that use this redis module should close the connection by calling redisService.onModuleDestroy or app.close().
Useful links are provided for further reference.

NestJS - Redis

In this section, we’ll introduce a new module that uses ioredis and enables our NestJS application to connect to Redis.

This section is part of a larger guide. You can follow it from the beginning or just complete the only prerequisite step (getting started).

At this point, you should have a fully operational NestJS project to follow the upcoming steps.

Our new Redis module will provide two ways to connect and communicate with Redis. The first one is a standard ioredis connection and the second one is by configuring the standard NestJS Redis transporter (uses ioredis internally).

Let’s start by installing the needed packages:

npm i @nestjs/microservices ioredis @nestjs/config

We’ll first introduce a config instance that provides all the needed ioredis settings.

By default, it will connect to redis://@localhost:6379/0 and by providing the appropriate env variables (REDIS_HOST, REDIS_PORT, REDIS_USERNAME, REDIS_PASSWORD, REDIS_DB) the application can connect to any Redis server.

We’ll provide a service that will extend ioredis and will act as a “raw” Redis client for packages that can’t work with Redis Transporter (e.g. connect-redis).

It basically just setups the connection, logs incoming events and provides ioredis interface methods to be used by other services in the application.

Now that we have the ioredis client ready, we can also set up the NestJS Transporter for our “high” level redis access:

Don’t forget to import your new redis module at your app.module.ts :

@Module({
  imports: [RedisModule]
})
export class AppModule {}

Now your application connects to Redis and your services can use it for Redis operations (e.g. caching values).

Hint: test suites that use this redis module should close the connection by calling redisService.onModuleDestroy (or app.close() that destroys all modules). Example:

afterAll(async () => {
  service.onModuleDestroy();
});

or

afterAll(async () => {
  await app.close();
});

Useful Links: