Redis

You can use Redis inside your AdonisJS applications using the @adonisjs/redis package. The package is a thin wrapper on top of ioredis with better DX around Pub/Sub and automatic management of multiple redis connections.

Installation

Install and configure the package using the following command :

node ace add @adonisjs/redis

Installs the @adonisjs/redis package using the detected package manager.

Registers the following service provider inside the adonisrc.ts file.

{
  providers: [
    // ...other providers
    () => import('@adonisjs/redis/redis_provider')
  ]
}

Create config/redis.ts file. This file contains the connection configuration for your redis server.
Define following environment variables and their validation rules.
```
REDIS_HOST=127.0.0.1
REDIS_PORT=6379
REDIS_PASSWORD=
```

Configuration

The configuration for the Redis package is stored inside the config/redis.ts file.

Configuring clusters

The @adonisjs/redis package will create a cluster connection if you define an array of hosts inside the connection config. For example:

const redisConfig = defineConfig({
  connections: {
    main: {
      clusters: [
        { host: '127.0.0.1', port: 6380 },
        { host: '127.0.0.1', port: 6381 },
      ],
      clusterOptions: {
        scaleReads: 'slave',
        slotsRefreshTimeout: 10 * 1000,
      },
    },
  },
})

Configuring sentinels

You can configure a redis connection to use sentinels by defining an array of sentinel nodes within the connection config. For example:

const redisConfig = defineConfig({
  connections: {
    main: {
      sentinels: [
        { host: 'localhost', port: 26379 },
        { host: 'localhost', port: 26380 },
      ],
      name: 'mymaster',
    },
  },
})

Usage

You can run redis commands using the redis service exported by the package. The redis service is a singleton object configured using the configuration you have defined inside the config/redis.ts file.

Consult the ioredis documentation to view the list of available methods. Since we are a wrapper on top of IORedis, the commands API is identical.

import redis from '@adonisjs/redis/services/main'

await redis.set('username', 'virk')
const username = await redis.get('username')

Switching between connections

Commands executed using the redis service are invoked against the default connection defined inside the config file. However, you can execute commands on a specific connection by first getting an instance of it.

The .connection() method creates and caches a connection instance for the process's lifetime.

import redis from '@adonisjs/redis/services/main'

// Get connection instance
const redisMain = redis.connection('main')

await redisMain.set('username', 'virk')
const username = await redisMain.get('username')

Quitting connections

The connections are long-lived, and you will get the same instance every time you call the .connection() method. You can quit the connection using the quit method. Use the disconnect method to end the connection forcefully.

import redis from '@adonisjs/redis/services/main'

await redis.quit('main') // Quit the main connection
await redis.disconnect('main') // Force quit the main connection

import redis from '@adonisjs/redis/services/main'

const redisMain = redis.connection('main')
redisMain.quit() // Quit using connection instance
redisMain.disconnect() // Force quit using connection instance

Error handling

Redis connections can fail anytime during the lifecycle of your application. Therefore it is essential to capture the errors and have a retry strategy.

By default, AdonisJS will log the redis connection errors using the application logger and retry a connection ten times before closing it permanently. The retry strategy is defined for every connection within the config/redis.ts file.

config/redis.ts

{
  main: {
    host: env.get('REDIS_HOST'),
    port: env.get('REDIS_PORT'),
    password: env.get('REDIS_PASSWORD', ''),
    retryStrategy(times) {
      return times > 10 ? null : times * 50
    },
  },
}

You can disable the default error reporter using the .doNotLogErrors method. Doing so will remove the error event listener from the redis connection.

import redis from '@adonisjs/redis/services/main'

/**
 * Disable default error reporter
 */
redis.doNotLogErrors()

redis.on('connection', (connection) => {
  /**
   * Make sure always to have an error listener defined.
   * Otherwise, the app will crash
   */
  connection.on('error', (error) => {
    console.log(error)
  })
})

Pub/Sub

Redis needs multiple connections to publish and subscribe to channels. The subscriber connection cannot perform operations other than subscribing to new channels/patterns and unsubscribing.

When using the @adonisjs/redis package, you do not have to create a subscriber connection manually; we will handle that for you. When you call the subscribe method for the first time, we will automatically create a new subscriber connection.

import redis from '@adonisjs/redis/services/main'

redis.subscribe('user:add', function (message) {
  console.log(message)
})

API differences between IORedis and AdonisJS

When using ioredis, you must use two different APIs to subscribe to a channel and listen for new messages. However, with the AdonisJS wrapper, the subscribe method takes care of both.

With IORedis

redis.on('message', (channel, messages) => {
  console.log(message)
})

redis.subscribe('user:add', (error, count) => {
  if (error) {
    console.log(error)
  }
})

With AdonisJS

redis.subscribe('user:add', (message) => {
  console.log(message)
},
{
  onError(error) {
    console.log(error)
  },
  onSubscription(count) {
    console.log(count)
  },
})

Publishing messages

You can publish messages using the publish method. The method accepts the channel name as the first parameter and the data to publish as the second parameter.

redis.publish(
  'user:add',
  JSON.stringify({
    id: 1,
    username: 'virk',
  })
)

Subscribing to patterns

You can subscribe to patterns using the psubscribe method. Similar to the subscribe method, it will create a subscriber connection (if one does not exist).

redis.psubscribe('user:*', (channel, message) => {
  console.log(channel)
  console.log(message)
})

redis.publish(
  'user:add',
  JSON.stringify({
    id: 1,
    username: 'virk',
  })
)

Unsubscribing

You can unsubscribe from channels or patterns using the unsubscribe and punsubscribe methods.

await redis.unsubscribe('user:add')
await redis.punsubscribe('user:*add*')

Using Lua scripts

You can register Lua Scripts as commands with the redis service, and they will be applied to all the connections.

Transforming arguments and replies

You can define the arguments transformer and the reply transformer using the redis.Command property. The API is identical to the IORedis API.

Argument transformer

import redis from '@adonisjs/redis/services/main'

redis.Command.setArgumentTransformer('hmset', (args) => {
  if (args.length === 2) {
    if (args[1] instanceof Map) {
      // utils is an internal module of ioredis
      return [args[0], ...utils.convertMapToArray(args[1])]
    }
    if (typeof args[1] === 'object' && args[1] !== null) {
      return [args[0], ...utils.convertObjectToArray(args[1])]
    }
  }
  return args
})

Reply transformer

import redis from '@adonisjs/redis/services/main'

redis.Command.setReplyTransformer('hgetall', (result) => {
  if (Array.isArray(result)) {
    const obj = {}
    for (let i = 0; i < result.length; i += 2) {
      obj[result[i]] = result[i + 1]
    }
    return obj
  }
  return result
})

Events

Following is the list of events emitted by a Redis connection instance.

connect / subscriber:connect

The event is emitted when a connection is made. The subscriber:connect event is emitted when a subscriber connection is made.

import redis from '@adonisjs/redis/services/main'

redis.on('connection', (connection) => {
  connection.on('connect', () => {})
  connection.on('subscriber:connect', () => {})
})

wait

Emitted when the connection is in wait mode because the lazyConnect option is set inside the config. After executing the first command, the connection will be moved from the wait state.

import redis from '@adonisjs/redis/services/main'

redis.on('connection', (connection) => {
  connection.on('wait', () => {})
})

ready / subscriber:ready

The event will be emitted immediately after the connect event unless you have enabled the enableReadyCheck flag inside the config. In that case, we will wait for the Redis server to report it is ready to accept commands.

import redis from '@adonisjs/redis/services/main'

redis.on('connection', (connection) => {
  connection.on('ready', () => {})
  connection.on('subscriber:ready', () => {})
})

error / subscriber:error

The event is emitted when unable to connect to the redis server. See error handling to learn how AdonisJS handles connection errors.

import redis from '@adonisjs/redis/services/main'

redis.on('connection', (connection) => {
  connection.on('error', () => {})
  connection.on('subscriber:error', () => {})
})

close / subscriber:close

The event is emitted when a connection is closed. IORedis might retry establishing a connection after emitting the close event, depending upon the retry strategy.

import redis from '@adonisjs/redis/services/main'

redis.on('connection', (connection) => {
  connection.on('close', () => {})
  connection.on('subscriber:close', () => {})
})

reconnecting / subscriber:reconnecting

The event is emitted when trying to reconnect to the redis server after the close event.

import redis from '@adonisjs/redis/services/main'

redis.on('connection', (connection) => {
  connection.on('reconnecting', ({ waitTime }) => {
    console.log(waitTime)
  })
  connection.on('subscriber:reconnecting', ({ waitTime }) => {
    console.log(waitTime)
  })
})

end / subscriber:end

The event is emitted when the connection has been closed, and no further reconnections will be made. It should be the end of the connection lifecycle.

import redis from '@adonisjs/redis/services/main'

redis.on('connection', (connection) => {
  connection.on('end', () => {})
  connection.on('subscriber:end', () => {})
})

node:added

The event is emitted when connected to a new cluster node (Applicable to cluster instances only).

import redis from '@adonisjs/redis/services/main'

redis.on('connection', (connection) => {
  connection.on('node:added', () => {})
})

node:removed

The event is emitted when a cluster node is removed (Applicable to cluster instances only).

import redis from '@adonisjs/redis/services/main'

redis.on('connection', (connection) => {
  connection.on('node:removed', () => {})
})

node:error

The event is emitted when unable to connect to a cluster node (Applicable to cluster instances only).

import redis from '@adonisjs/redis/services/main'

redis.on('connection', (connection) => {
  connection.on('node:error', ({ error, address }) => {
    console.log(error, address)
  })
})

subscription:ready / psubscription:ready

The event is emitted when a subscription on a given channel or a pattern has been established.

import redis from '@adonisjs/redis/services/main'

redis.on('connection', (connection) => {
  connection.on('subscription:ready', ({ count }) => {
    console.log(count)
  })
  connection.on('psubscription:ready', ({ count }) => {
    console.log(count)
  })
})

subscription:error / psubscription:error

The event is emitted when unable to subscribe to a channel or a pattern.

import redis from '@adonisjs/redis/services/main'

redis.on('connection', (connection) => {
  connection.on('subscription:error', () => {})
  connection.on('psubscription:error', () => {})
})