Event Driven Microservices Architecture

Event-driven architecture (EDA) is a software design pattern that enables an organization to detect “events” or important business moments (such as a transaction, site visit, shopping cart abandonment, etc) and act on them in real-time or near real-time.

Event-driven architecture is often referred to as “asynchronous” communication. This means that the sender and recipient don’t have to wait for each other to move on to their next task. Systems are not dependent on that one message.

An event-driven data management system is mainly practiced to drive microservices. As part of this system, one microservice broadcasts an event when anything notable happens, and then other microservices subscribe to it. This is done through an intermediary event broker, to satisfy the rising expectations of modern companies and make microservices more secure.

A microservice can modify its business entities after receiving an event, which causes fresh events to be published. This design pattern applies to programs written in any language and for any platform.

Benefits of Event Driven Architecture:

• Responsiveness. Since everything happens as soon as possible and nobody is waiting on anyone else, event-driven architecture provides the fastest possible response time.
• Scalability. Since you don’t have to consider what’s happening downstream, you can add service instances to scale. Topic routing and filtering can divide up services quickly and easily – as in command query responsibility segregation.
• Agility. If you want to add another service, you can just have it subscribe to an event and have it generate new events of its own. The existing services don’t know or care that this has happened, so there’s no impact on them.
• Highly scalable and distributed.

When to use this Architecture:

• Multiple subsystems must process the same events.
• Real-time processing with minimum time lag.
• Complex event processing, such as pattern matching or aggregation over time windows.
• High volume and high velocity of data, such as IoT.

Challenges:

• Guaranteed delivery. In some systems, especially in IoT scenarios, it’s crucial to guarantee that events are delivered.
• Processing events in order or exactly once. Each consumer type typically runs in multiple instances, for resiliency and scalability.

Key tools to enable the pub/sub and event driven architecture:

• Google Cloud Platform Dataflow
• IBM Event Streams
• AWS Kinesis
• Keen
• Solace
• Apache kafka
• Active MQ
• Pulsar

Patterns for Event Driven Microservices Architecture:

The following patterns are utilized in the event-driven manner of developing microservices:

• Event Stream
• Event Sourcing
• Polyglot Persistence
• Command Query Responsibility Separation(CQRS)

Conclusion:

In this article, we have discussed event-driven microservices and how to build your microservices using event-driven approaches. In an Event-driven architecture, the publisher publishes an event, and a consumer subscribes to it. These events help the services to communicate in a decoupled manner.