Use Auth0 Actions to Send User Info to Apache Kafka When They Register
Tags: programming, tutorial, security
Published: 2022-02-15 15:30:28

#### Learn how to integrate Auth0 with Apache Kafka using Actions. You’ll do this by writing an Action that pushes information from new user registrations to a Kafka cluster.

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In this post, you’ll learn how to integrate Auth0 with [Apache Kafka](https://kafka.apache.org/) using Actions. You’ll do this by writing an Action that pushes information from new user registrations to a Kafka cluster. By doing this, you open a number of analytics and user experience possibilities, including:

*   Processing sign-up events (with [Apache Flink](https://flink.apache.org/) or [Spark](https://spark.apache.org/)) to notify your business and sales team when a new user signs up for an account.
*   Trigger processes such as sending a welcome email or Slack message in response to a user signing up.
*   Using a [Kafka connector](https://docs.snowflake.com/en/user-guide/kafka-connector-overview.html) to move the user data gathered from the sign-up process to a database or data warehouse to feed reporting and analytics applications.
*   Feeding new user data to your CRM application.

![Kafka](https://images.ctfassets.net/23aumh6u8s0i/47eyPrCR712YD4KWSRvG80/8150b144cf5cbb5747096d3f3af8bea4/Uploaded_from_Send_Auth0_Events_to_Kafka_for_Realtime_Processing_)

## Why Apache Kafka?

Apache Kafka is a distributed messaging platform that receives data as events in real-time from sources such as sensors, mobile devices, databases, applications, and services (including Auth0) and makes that data available to target systems. It supports both publish/subscribe and distributed queue scenarios. Kafka gives you the flexibility to perform both stream processing and batch processing with your data. Kafka’s replication feature and durability allow you to use it as a persistent hub for your data.

## Auth0 Actions

Auth0 Actions are serverless Node.js functions that are triggered by certain events that take place when signing up for an Auth0 user account or authenticating with Auth0. Using Actions, you can customize and extend Auth0’s capabilities with your custom logic that you can add to events such as login, registration, changing passwords, and more. Auth0 Actions are stateless, so you’ll need an external store if you use them to collect data. Check [this article](https://auth0.com/docs/customize/actions/actions-overview) to learn more about Actions.

In this post, we will write an Auth0 Action which will be triggered by the Post User Registration flow, which happens after a user has completed signing up for an account.

## Create a Kafka Cluster

Because Auth0 Actions are stateless, we need a Kafka service that does not require stateful connections. We will use [Upstash’s Kafka service](https://upstash.com/kafka), which has a REST API and is designed for serverless environments and a free plan suitable for this project.

If you don’t already have an Upstash account, [sign up for one](https://console.upstash.com/login). The process is very quick, especially if you sign up using an Amazon, GitHub, or Google account. You’ll be taken to the [Upstash console](https://console.upstash.com/) immediately afterward:

![Cluster](https://images.ctfassets.net/23aumh6u8s0i/7i8OxJQwxFJZYOAKZGvS1f/d89275afb1698cc4f7c498eb100fb12d/Uploaded_from_Send_Auth0_Events_to_Kafka_for_Realtime_Processing_)

Select **Kafka** in the menu bar at the top of the page. You’ll be taken here:

![Cluster](https://images.ctfassets.net/23aumh6u8s0i/4shEb8jySPGei6xBcZ0DPK/6e056b1ae7fa8e0a9a60f7f67d047506/Uploaded_from_Send_Auth0_Events_to_Kafka_for_Realtime_Processing_)

In order to use Kafka, you need a cluster, which is a set of one or more servers running Apache Kafka. Click the **Create Cluster** button. This form will appear:

![Cluster](https://images.ctfassets.net/23aumh6u8s0i/6LZJRtkgqpHLUPxpdoesuj/08d7a77dc2da2ef54e57f3dea316eaf7/Uploaded_from_Send_Auth0_Events_to_Kafka_for_Realtime_Processing_)

Provide the following information for each of its fields:

*   **Name:** Pick a name that will make it easy to recognize, such as “Auth0 Actions Test.”
*   **Region:** Select the region closest to you.
*   **Type:** Select **Single Zone**

Click the **Create** button to continue. You’ll see the form’s second page:

![Create](https://images.ctfassets.net/23aumh6u8s0i/130Z4nzMY3elKtmElpZz4o/d25551d11ae2615697e6b724199cac47/Uploaded_from_Send_Auth0_Events_to_Kafka_for_Realtime_Processing_)

You need to provide a name for a _topic,_ which is how Kafka organizes events. If you think of events as being like files, topics are like directories. Enter the topic name **user-events-topic** into the **Name** field and click the **Send Request** button.

Upstash will create the cluster and immediately take you to its **Details** page:

![Details](https://images.ctfassets.net/23aumh6u8s0i/1iU7Q3GmamqgUbJQGVOOeF/fbf5724310a40936c0937a0e3d4baeca/Uploaded_from_Send_Auth0_Events_to_Kafka_for_Realtime_Processing_)

Scroll down to the **REST API** section, where you’ll see controls to copy the values for `UPSTASH_KAFKA_REST_URL`, `UPSTASH_KAFKA_REST_USERNAME`, and `UPSTASH_KAFKA_REST_PASSWORD`, which you will use in the next step.

![REST API](https://images.ctfassets.net/23aumh6u8s0i/3FEKvlN77iwUh0V8RBQ6aC/265f34f90d4d38ad09f64b5662a7dc79/Uploaded_from_Send_Auth0_Events_to_Kafka_for_Realtime_Processing_)

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