azure-eventgrid-java

# Azure Event Grid SDK for Java Build event-driven applications using the Azure Event Grid SDK for Java. ## Installation ```xml <dependency> <groupId>com.azure</groupId> <artifactId>azure-messaging-eventgrid</artifactId> <version>4.27.0</version> </dependency> ``` ## Client Creation ### EventGridPublisherClient ```java import com.azure.messaging.eventgrid.EventGridPublisherClient; import com.azure.messaging.eventgrid.EventGridPublisherClientBuilder; import com.azure.core.credential.AzureKeyCredential; // With API Key EventGridPublisherClient<EventGridEvent> client = new EventGridPublisherClientBuilder() .endpoint("<topic-endpoint>") .credential(new AzureKeyCredential("<access-key>")) .buildEventGridEventPublisherClient(); // For CloudEvents EventGridPublisherClient<CloudEvent> cloudClient = new EventGridPublisherClientBuilder() .endpoint("<topic-endpoint>") .credential(new AzureKeyCredential("<access-key>")) .buildCloudEventPublisherClient(); ``` ### With DefaultAzureCredential ```java import com.azure.identity.DefaultAzureCredentialBuilder; EventGridPublisherClient<EventGridEvent> client = new EventGridPublisherClientBuilder() .endpoint("<topic-endpoint>") .credential(new DefaultAzureCredentialBuilder().build()) .buildEventGridEventPublisherClient(); ``` ### Async Client ```java import com.azure.messaging.eventgrid.EventGridPublisherAsyncClient; EventGridPublisherAsyncClient<EventGridEvent> asyncClient = new EventGridPublisherClientBuilder() .endpoint("<topic-endpoint>") .credential(new AzureKeyCredential("<access-key>")) .buildEventGridEventPublisherAsyncClient(); ``` ## Event Types | Type | Description | |------|-------------| | `EventGridEvent` | Azure Event Grid native schema | | `CloudEvent` | CNCF CloudEvents 1.0 specification | | `BinaryData` | Custom schema events | ## Core Patterns ### Publish EventGridEvent ```java import com.azure.messaging.eventgrid.EventGridEvent; import com.azure.core.util.BinaryData; EventGridEvent event = new EventGridEvent( "resource/path", // subject "MyApp.Events.OrderCreated", // eventType BinaryData.fromObject(new OrderData("order-123", 99.99)), // data "1.0" // dataVersion ); client.sendEvent(event); ``` ### Publish Multiple Events ```java List<EventGridEvent> events = Arrays.asList( new EventGridEvent("orders/1", "Order.Created", BinaryData.fromObject(order1), "1.0"), new EventGridEvent("orders/2", "Order.Created", BinaryData.fromObject(order2), "1.0") ); client.sendEvents(events); ``` ### Publish CloudEvent ```java import com.azure.core.models.CloudEvent; import com.azure.core.models.CloudEventDataFormat; CloudEvent cloudEvent = new CloudEvent( "/myapp/orders", // source "order.created", // type BinaryData.fromObject(orderData), // data CloudEventDataFormat.JSON // dataFormat ); cloudEvent.setSubject("orders/12345"); cloudEvent.setId(UUID.randomUUID().toString()); cloudClient.sendEvent(cloudEvent); ``` ### Publish CloudEvents Batch ```java List<CloudEvent> cloudEvents = Arrays.asList( new CloudEvent("/app", "event.type1", BinaryData.fromString("data1"), CloudEventDataFormat.JSON), new CloudEvent("/app", "event.type2", BinaryData.fromString("data2"), CloudEventDataFormat.JSON) ); cloudClient.sendEvents(cloudEvents); ``` ### Async Publishing ```java asyncClient.sendEvent(event) .subscribe( unused -> System.out.println("Event sent successfully"), error -> System.err.println("Error: " + error.getMessage()) ); // With multiple events asyncClient.sendEvents(events) .doOnSuccess(unused -> System.out.println("All events sent")) .doOnError(error -> System.err.println("Failed: " + error)) .block(); // Block if needed ``` ### Custom Event Data Class ```java public class OrderData { private String orderId; private double amount; private String customerId; public OrderData(String orderId, double amount) { this.orderId = orderId; this.amount = amount; } // Getters and setters } // Usage OrderData order = new OrderData("ORD-123", 150.00); EventGridEvent event = new EventGridEvent( "orders/" + order.getOrderId(), "MyApp.Order.Created", BinaryData.fromObject(order), "1.0" ); ``` ## Receiving Events ### Parse EventGridEvent ```java import com.azure.messaging.eventgrid.EventGridEvent; // From JSON string (e.g., webhook payload) String jsonPayload = "[{\"id\": \"...\", ...}]"; List<EventGridEvent> events = EventGridEvent.fromString(jsonPayload); for (EventGridEvent event : events) { System.out.println("Event Type: " + event.getEventType()); System.out.println("Subject: " + event.getSubject()); System.out.println("Event Time: " + event.getEventTime()); // Get data BinaryData data = event.getData(); OrderData orderData = data.toObject(OrderData.class); } ``` ### Parse CloudEvent ```java import com.azure.core.models.CloudEvent; String cloudEventJson = "[{\"specversion\": \"1.0\", ...}]"; List<CloudEvent> cloudEvents = CloudEvent.fromString(cloudEventJson); for (CloudEvent event : cloudEvents) { System.out.println("Type: " + event.getType()); System.out.println("Source: " + event.getSource()); System.out.println("ID: " + event.getId()); MyEventData data = event.getData().toObject(MyEventData.class); } ``` ### Handle System Events ```java import com.azure.messaging.eventgrid.systemevents.*; for (EventGridEvent event : events) { if (event.getEventType().equals("Microsoft.Storage.BlobCreated")) { StorageBlobCreatedEventData blobData = event.getData().toObject(StorageBlobCreatedEventData.class); System.out.println("Blob URL: " + blobData.getUrl()); } } ``` ## Event Grid Namespaces (MQTT/Pull) ### Receive from Namespace Topic ```java import com.azure.messaging.eventgrid.namespaces.EventGridReceiverClient; import com.azure.messaging.eventgrid.namespaces.EventGridReceiverClientBuilder; import com.azure.messaging.eventgrid.namespaces.models.*; EventGridReceiverClient receiverClient = new EventGridReceiverClientBuilder() .endpoint("<namespace-endpoint>") .credential(new AzureKeyCredential("<key>")) .topicName("my-topic") .subscriptionName("my-subscription") .buildClient(); // Receive events ReceiveResult result = receiverClient.receive(10, Duration.ofSeconds(30)); for (ReceiveDetails detail : result.getValue()) { CloudEvent event = detail.getEvent(); System.out.println("Event: " + event.getType()); // Acknowledge the event receiverClient.acknowledge(Arrays.asList(detail.getBrokerProperties().getLockToken())); } ``` ### Reject or Release Events ```java // Reject (don't retry) receiverClient.reject(Arrays.asList(lockToken)); // Release (retry later) receiverClient.release(Arrays.asList(lockToken)); // Release with delay receiverClient.release(Arrays.asList(lockToken), new ReleaseOptions().setDelay(ReleaseDelay.BY_60_SECONDS)); ``` ## Error Handling ```java import com.azure.core.exception.HttpResponseException; try { client.sendEvent(event); } catch (HttpResponseException e) { System.out.println("Status: " + e.getResponse().getStatusCode()); System.out.println("Error: " + e.getMessage()); } ``` ## Environment Variables ```bash EVENT_GRID_TOPIC_ENDPOINT=https://<topic-name>.<region>.eventgrid.azure.net/api/events EVENT_GRID_ACCESS_KEY=<your-access-key> ``` ## Best Practices 1. **Batch Events**: Send multiple events in one call when possible 2. **Idempotency**: Include unique event IDs for deduplication 3. **Schema Validation**: Use strongly-typed event data classes 4. **Retry Logic**: Built-in, but consider dead-letter for failures 5. **Event Size**: Keep events under 1MB (64KB for basic tier) ## Trigger Phrases - "Event Grid Java" - "publish events Azure" - "CloudEvent SDK" - "event-driven messaging" - "pub/sub Azure" - "webhook events" ## When to Use Build event-driven applications with Azure Event Grid SDK for Java. Use when publishing events, implementing pub/sub patterns, or integrating with Azure services via events. Covers: Azure Event Grid SDK for Java, Client Creation, EventGridPublisherClient, With DefaultAzureCredential, Async Client.