Connect to your cluster using the Spring client

This document describes how to connect to a cluster through a Spring client, and use the Spring producer and consumer to produce and consume messages to and from a topic. The Spring client supports connecting to a Pulsar cluster through either OAuth2 or Token authentication.

Note

This document assumes that you have created a Pulsar cluster and a service account, and have granted the service account produce and consume permissions to the namespace for the target topic.

Prerequisites

See the minimum supported versions required for the underlying libraries for more details.

Connect to your cluster through OAuth2 authentication

To connect a Pulsar cluster through OAuth2 authentication, follow these steps.

Step 1: Get the broker service URL of your cluster

To get the service URL of a Pulsar cluster through the StreamNative Console, follow these steps.

On the left navigation pane, in the Admin area, click Pulsar Clusters.
Select the Details tab, and in the Access Points area, click Copy at the end of the row of the service URL.

Step 2: Get the OAuth2 credential file of your service account

To get an OAuth2 credential file of a service account through the StreamNative Console, follow these steps.

On the left navigation pane, click Service Accounts.
In the row of the service account you want to use, in the Key File column, click the Download icon to download the OAuth2 credential file to your local directory.
The OAuth2 credential file should be something like this:
```
{
  "type": "SN_SERVICE_ACCOUNT",
  "client_id": "CLIENT_ID",
  "client_secret": "CLIENT_SECRET",
  "client_email": "[email protected]",
  "issuer_url": "https://auth.streamnative.cloud"
}
```

Step 3: Connect to your cluster

Configure a YAML file

Set the following configurations in the code of your Spring applications.

spring:
  pulsar:
    client:
      service-url: ${brokerServiceURL}
      auth-plugin-class-name: org.apache.pulsar.client.impl.auth.oauth2.AuthenticationOAuth2
      authentication:
        issuer-url: 'https://auth.streamnative.cloud/'
        private-key: '/YOUR-KEY-FILE-PATH' # TODO Absolute file path of your downloaded key file
        audience: 'urn:sn:pulsar:${orgName}:${instanceName}'

service-url: the broker service URL of your Pulsar cluster.
private-key: your downloaded OAuth2 credential. This parameter supports the following two pattern formats:
- file:///path/to/file: the path to your downloaded OAuth2 credential file.
- data:application/json;base64,<base64-encoded value>: the credential file content encoded into Base64 format.
audience: the Uniform Resource Name (URN), which is a combination of the urn:sn:pulsar, your organization name, and your Pulsar instance name.
- ${orgName}: the name of your organization.
- ${instanceName}: the name of your instance.

Create a Spring consumer to consume messages

You can create and configure a Spring consumer to consume messages using the OAuth2 credential file as follows.

import org.springframework.pulsar.annotation.PulsarListener;

@SpringBootApplication
public class PulsarBootHelloWorld {

    public static void main(String[] args) {
        SpringApplication.run(PulsarBootHelloWorld.class, args);
    }

    @PulsarListener(subscriptionName = "${subscription}", topics = "persistent://${tenant}/${namespace}/${topic}")
    void listen(String message) {
        System.out.println("Message Received: " + message);
    }

}

Create a Spring producer to produce messages

You can create and configure a Spring producer to produce messages using the OAuth2 credential file as follows.

import org.springframework.pulsar.core.PulsarTemplate;

@SpringBootApplication
public class PulsarBootHelloWorld {

    public static void main(String[] args) {
        SpringApplication.run(PulsarBootHelloWorld.class, args);
    }

    @Bean
    ApplicationRunner runner(PulsarTemplate<String> pulsarTemplate) {
        return (args) -> pulsarTemplate.send("persistent://${tenant}/${namespace}/${topic}", "Hello Pulsar World!");
    }

}

For a complete example of how to connect to a cluster through the Spring client, see Spring client examples.

Connect to your cluster through Token authentication

To connect a Pulsar cluster through Token authentication, follow these steps.

Step 1: Get the broker service URL of your cluster

To get the service URL of a Pulsar cluster through the StreamNative Console, follow these steps.

On the left navigation pane, in the Admin area, click Pulsar Clusters.
Select the Details tab, and in the Access Points area, click Copy at the end of the row of the service URL.

Step 2: Get the Token of your service account