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Use Azure Event Grid in Spring

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This article shows you how to use Azure Event Grid to send an event to a topic and use Service Bus Queue as an Event Handler to receive in a Spring Boot application.

The Azure Event Grid service is a highly scalable, fully managed Pub Sub message distribution service that offers flexible message consumption patterns using the MQTT and HTTP protocols.

Prerequisites

Subscribe to custom topic

Use the following steps to create an event subscription to tell the Event Grid to send events to the Service Bus Queue:

  1. In the Azure portal, navigate to your Event Grid Topic instance.
  2. Select Event Subscriptions on the toolbar.
  3. On the Create Event Subscription page, enter a name value for the event subscription.
  4. For Endpoint Type, select Service Bus Queue.
  5. Choose Select an endpoint and then select the Service Bus Queue instance you created earlier.

Send an event by Azure Event Grid and receive by Azure Service Bus Queue

With an Azure Event Grid resource, you can send an event using Spring Cloud Azure Event Grid. With an Azure Service Bus Queue resource as an event handler, you can receive the event using Spring Cloud Azure Stream Binder for Service Bus.

To install the Spring Cloud Azure Event Grid Starter module and the Spring Cloud Azure Stream Binder Service Bus module, add the following dependencies to your pom.xml file:

  • The Spring Cloud Azure Bill of Materials (BOM):

    <dependencyManagement>
  <dependencies>
    <dependency>
      <groupId>com.azure.spring</groupId>
      <artifactId>spring-cloud-azure-dependencies</artifactId>
      <version>5.18.0</version>
      <type>pom</type>
      <scope>import</scope>
    </dependency>
  </dependencies>
</dependencyManagement>

    Note

    If you're using Spring Boot 2.x, be sure to set the spring-cloud-azure-dependencies version to 4.19.0. This Bill of Material (BOM) should be configured in the <dependencyManagement> section of your pom.xml file. This ensures that all Spring Cloud Azure dependencies are using the same version. For more information about the version used for this BOM, see Which Version of Spring Cloud Azure Should I Use.

  • The Spring Cloud Azure Event Grid Starter artifact:

    <dependency>
  <groupId>com.azure.spring</groupId>
  <artifactId>spring-cloud-azure-starter-eventgrid</artifactId>
</dependency>

  • The Spring Cloud Azure Stream Binder Service Bus artifact:

    <dependency>
  <groupId>com.azure.spring</groupId>
  <artifactId>spring-cloud-azure-stream-binder-servicebus</artifactId>
</dependency>

Code the application

Use the following steps to configure your application to send an event by using Event Grid and receive by using Service Bus Queue.

  1. Configure Azure Event Grid and Service Bus credentials in the application.yaml configuration file, as shown in the following example:

    spring:
  cloud:
    azure:
      eventgrid:
        endpoint: ${AZURE_EVENTGRID_ENDPOINT}
        key: ${AZURE_EVENTGRID_KEY}
      servicebus:
        connection-string: ${AZURE_SERVICEBUS_CONNECTION_STRING}
    function:
      definition: consume
    stream:
      bindings:
        consume-in-0:
          destination: ${AZURE_SERVICEBUS_QUEUE_NAME}
      servicebus:
        bindings:
          consume-in-0:
            consumer:
              auto-complete: false

  2. Edit the startup class file to show the following content. This code generates completions.

    import com.azure.core.util.BinaryData;
import com.azure.messaging.eventgrid.EventGridEvent;
import com.azure.messaging.eventgrid.EventGridPublisherClient;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.messaging.Message;

import java.util.List;
import java.util.function.Consumer;

@SpringBootApplication
public class EventGridSampleApplication implements CommandLineRunner {

    private static final Logger LOGGER = LoggerFactory.getLogger(EventGridSampleApplication.class);

    @Autowired
    EventGridPublisherClient<EventGridEvent> client;

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

    @Bean
    public Consumer<Message<String>> consume() {
        return message -> {
            List<EventGridEvent> eventData = EventGridEvent.fromString(message.getPayload());
            eventData.forEach(event -> {
                LOGGER.info("New event received: '{}'", event.getData());
            });
        };
    }

    @Override
    public void run(String... args) throws Exception {
        String str = "FirstName: John, LastName: James";
        EventGridEvent event = new EventGridEvent("A user is created", "User.Created.Text", BinaryData.fromObject(str), "0.1");

        client.sendEvent(event);
        LOGGER.info("New event published: '{}'", event.getData());
    }
}

  3. Start the application. After launch, the application produces logs similar to the following example:

    New event published: '"FirstName: John, LastName: James"'
...
New event received: '"FirstName: John, LastName: James"'

Deploy to Azure Spring Apps

Now that you have the Spring Boot application running locally, it's time to move it to production. Azure Spring Apps makes it easy to deploy Spring Boot applications to Azure without any code changes. The service manages the infrastructure of Spring applications so developers can focus on their code. Azure Spring Apps provides lifecycle management using comprehensive monitoring and diagnostics, configuration management, service discovery, CI/CD integration, blue-green deployments, and more. To deploy your application to Azure Spring Apps, see Deploy your first application to Azure Spring Apps.

Next steps

To learn more about Spring and Azure, continue to the Spring on Azure documentation center.

Azure for Spring developers Spring Cloud Azure Event Grid samples