How to subscribe to AWS Event Bus events from client side applications ex: NodeJS app, Angular client or a Mobile client app ?
In December 2020, an email from AWS Marketing has presented the advantages to use the Event-Driven architecture . Following the documentation and the tutorials, soon I stumble into the wall of not finding a way to subscribe to this events from a client side application.
The email states:
4 Reasons to Care About Event-Driven Architectures
Are you looking to scale and build robust applications without delays and dependencies? We break down the basics of event-driven architectures, how they work, and show you ways to get started. Learn how event-driven architectures can help you:
The disappointing part is that there is no example of libraries to be integrated in the client side code to subscribe to those event. Googling does not return any significant result and the only current library for node: @aws-sdk/client-eventbridge-node only expose a send and destroy methods.
There is no way to directly subscribe to an Amazon EventBridge bus, as it doesn't provide publish/subscribe functionality. In order to process events in EventBridge you create event rules that filter and send matching events to targets. You can find all targets available to EventBridge rules on this list: Amazon EventBridge Targets.
One of these targets could be an Amazon SNS topic, which provides pub/sub functionality, i.e. your client application can subscribe to the topic to automatically receive the respective events.
This may sound complicated at first, but the implementation is strictly following the principle of separating concerns. It provides simple building blocks--like Lego pieces--that you can put together in order to create truly loosely coupled architectures.
This diagram shows the functionality in scope of Amazon Event Bridge and how it communicates with other services and applications.
