Upstash Kafka

This guide goes through the required steps to connect Materialize to an Upstash Kafka cluster.

If you already have an Upstash Kafka cluster, you can skip steps 1 and 2 and directly move on to Create a topic. You can also skip step 3 if you already have an Upstash Kafka cluster up and running, and have created a topic that you want to create a source for.

The process to connect Materialize to Upstash Kafka consists of the following steps:

  1. Create an Upstash Kafka cluster

    If you already have an Upstash Kafka cluster set up, then you can skip this step.

    a. Sign in to the Upstash console

    b. Choose Kafka and then click the Create Cluster button

    c. Enter a cluster name, and specify the rest of the settings based on your needs

    d. Choose Create

    e. Create your first topic by specifying a topic name and the number of partitions

    f. Click Create

    Note: This creation process should take only a few seconds.

  2. Create new credentials

    By default, Upstash provides a default credential that you can use to connect to your cluster. It’s important to note that this default has full access to all topics in your cluster. For a more restricted setup, you can create a new credential with limited access to specific topics. If you want to use the default credential, skip this step.

    a. Navigate to the Upstash console

    b. Choose the Upstash Kafka cluster you just created in Step 1

    c. Click on the Credentials tab

    d. In the Credentials section, choose New Credentials

    e. Specify a name for the credentials

    f. List the topics you want to grant access to

    g. Choose the Permissions you want to grant to the credentials

    h. Click Create

    If you want to create a source in Materialize, you’ll need to grant the Read permission. To create a sink, you’ll need to grant the Read and Write permissions.

    Take note of the credentials you just created, you’ll need them later on. Keep in mind that the credentials contain sensitive information, and you should store them somewhere safe!

  3. Create a topic

    To start using Materialize with Upstash, you need to point it to an existing Upstash Kafka topic you want to read data from.

    If you already have a topic created, you can skip this step.

    Otherwise, you can follow the steps here to create a topic.

    Once you have a topic, you can produce a message to it by clicking on the topic name and then clicking on the Messages tab, and then clicking on the Produce button.

  4. Create a source in Materialize

    a. Open the Upstash console and select your cluster

    b. Click on Details

    c. Copy the URL under Endpoint. This will be your <upstash-broker-url> going forward

    d. From the psql terminal, run the following command. Replace <upstash_kafka> with whatever you want to name your source. The broker URL is what you copied in step c of this subsection. The <topic-name> is the name of the topic you created in Step 3. The <your-username> and <your-password> are from the Create new credentials step.

      CREATE SECRET upstash_username AS '<your-username>';
      CREATE SECRET upstash_password AS '<your-password>';
    
      CREATE CONNECTION <upstash_kafka> TO KAFKA (
          BROKER '<upstash-broker-url>',
          SASL MECHANISMS = 'SCRAM-SHA-256',
          SASL USERNAME = SECRET upstash_username,
          SASL PASSWORD = SECRET upstash_password
      );
    
      CREATE SOURCE <source-name>
        FROM KAFKA CONNECTION upstash_kafka (TOPIC '<topic-name>')
        FORMAT JSON;
    

    e. If the command executes without an error and outputs CREATE SOURCE, it means that you have successfully connected Materialize to your Upstash Kafka cluster.

    Note: The example above walked through creating a source, which is a way of connecting Materialize to an external data source. We created a connection to Upstash Kafka using SASL authentication and credentials securely stored as secrets in Materialize’s secret management system. For input formats, we used JSON, but you can also ingest Kafka messages formatted in e.g. Avro and Protobuf. You can find more details about the various different supported formats and possible configurations in the reference documentation.

  5. Create a sink in Materialize

    A sink is a way to write data from Materialize to an external system like a Kafka cluster.

    To create a sink, from the psql terminal, run the following command:

      CREATE SINK <sink-name>
        FROM <source, table or mview>
        INTO KAFKA CONNECTION <upstash_kafka> (TOPIC '<sink-topic-name>')
        FORMAT JSON
        ENVELOPE DEBEZIUM;
    

    The generated schema will have a Debezium-style diff envelope to capture changes in the input view or source as we defined in the ENVELOPE clause. You can find more details about the various different supported formats and possible configurations here.

    Once you have created the sink, you can go to the Upstash console and click on the topic you defined in the CREATE SINK statement. You will see the messages that were written to the topic. Materialize will produce messages to the topic every time the underlying source, table, or materialized view has new changes.

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