Breaking News: Grepper is joining You.com. Read the official announcement!

Dual-Write Problem

Pragya Keshap answered on February 3, 2023 Popularity 3/10 Helpfulness 1/10

answer Dual-Write Problem

Dual-Write Problem

Comment

A dual write occurs when an application has to change data in two different systems, such as when an application needs to persist data in the database and send a Kafka message to notify other systems.

If one of these two operations fails, you might end up with inconsistent data.

@ApplicationScoped
public class OrderService {

    @Inject
    EntityManager entityManager;

    @ConfigProperty(name = "order-event.aggregate.type", defaultValue = "order-event")
    String aggregateType;

    @Transactional
    public Long create(Order order) {
        order.setStatus(OrderStatus.CREATED);
        entityManager.persist(order);
        OutboxEvent outboxEvent = buildOutBoxEvent(order);
        entityManager.persist(outboxEvent);
        entityManager.remove(outboxEvent);
        return order.getId();
    }

    OutboxEvent buildOutBoxEvent(Order order) {
        OutboxEvent outboxEvent = new OutboxEvent();
        outboxEvent.setAggregateType(aggregateType);
        outboxEvent.setAggregateId(Long.toString(order.getId()));
        outboxEvent.setContentType("application/cloudevents+json; charset=UTF-8");
        outboxEvent.setPayload(toCloudEvent(order));
        return outboxEvent;
    }

    String toCloudEvent(Order order) {
        CloudEvent event = CloudEventBuilder.v1().withType("OrderCreatedEvent")
            .withTime(OffsetDateTime.now())
            .withSource(URI.create("ecommerce/order-service"))
            .withDataContentType("application/json")
            .withId(UUID.randomUUID().toString())
            .withData(order.toJson().encode().getBytes())
            .build();
        EventFormat format = EventFormatProvider.getInstance()
            .resolveFormat(JsonFormat.CONTENT_TYPE);
        return new String(format.serialize(event));
    }
}

https://developers.redhat.com/articles/2021/07/30/avoiding-dual-writes-event-driven-applications#provision_a_kafka_cluster_with_openshift_streams_for_apache_kafka

Popularity 3/10 Helpfulness 1/10 Language java

Source: Grepper

Tags: java

Link to this answer
Share Copy Link

Contributed on Feb 03 2023

Pragya Keshap

0 Answers Avg Quality 2/10

Dual-Write Problem

Contents

More Related Answers

Dual-Write Problem

Grepper

Documentation

Social

Legal

Contact

Oops, You will need to install Grepper and log-in to perform this action.