Quick start using RedisInsight

Get started with triggers and functions using RedisInsight

Make sure that you have Redis Stack installed and running. Alternatively, you can create a free Redis Cloud account. The triggers and functions preview is available in the fixed subscription plan for the Google Cloud Asia Pacific (Tokyo) and AWS Asia Pacific (Singapore) regions.

Connect to Redis Stack

Open the RedisInsight application, and connect to your database by clicking on its database alias.

Load a library

Click on the triggers and functions icon and then on + Library as shown below.

Add your code to the Library Code section of the right-hand panel and then click Add Library.

You'll see the following when the library was added:

The TFCALL command is used to execute the JavaScript Function. If the command fails, an error will be returned. Click on the >_ CLI button in the lower left-hand corner to open a console window and then run the command shown below.

To update a library you can edit the library code directly in the interface by clicking on the edit (pencil) icon. When you save your changes, the libary will be reloaded.

Uploading an external file

Click on the + Add Library button as before and, instead of adding the code directly into the editor, click on the Upload button, select the file from your file browser, and then click on Add Library. The file needs to contain the header, which contains the engine identifier, the API version, and the library name: #!js api_version=1.0 name=myFirstLibrary.

Creating triggers

Functions within Redis can respond to events using keyspace triggers. While the majority of these events are initiated by command invocations, they also include events that occur when a key expires or is removed from the database.

For the full list of supported events, please refer to the Redis keyspace notifications page.

The following code creates a new keyspace trigger that adds a new field to a new or updated hash with the latest update time.

#!js name=myFirstLibrary api_version=1.0

function addLastUpdatedField(client, data) {
    if(data.event == 'hset') {
        var currentDateTime = Date.now();
        client.call('hset', data.key, 'last_updated', currentDateTime.toString());

// Register the KeySpaceTrigger 'AddLastUpdated' for keys with the prefix 'fellowship'
// with the callback function 'addLastUpdatedField'.
redis.registerKeySpaceTrigger('addLastUpdated', 'fellowship:', addLastUpdatedField);"

Update the existing library as before and then, using the RedisInsight console, add a new hash with the required prefix to trigger the function.

> HSET fellowship:1 name "Frodo Baggins" title "The One Ring Bearer"

Run the HGETALL command to check if the last updated time is added to the example.

> HGETALL fellowship:1
1) "name"
2) "Frodo Baggins"
3) "title"
4) "The One Ring Bearer"
5) "last_updated"
6) "1693238681822"
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