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Microservices for Java Developers, 2nd Edition
book

Microservices for Java Developers, 2nd Edition

by Rafael Benevides, Christian Posta
June 2019
Intermediate to advanced content levelIntermediate to advanced
117 pages
2h 28m
English
O'Reilly Media, Inc.
Content preview from Microservices for Java Developers, 2nd Edition

Chapter 4. API Gateway with Apache Camel

Now that you know how to build microservices, you could continue building more and more. However, as the number of microservices grows, the complexity for the client who is consuming these APIs also grows.

Real applications could have dozens or even hundreds of microservices. A simple process like buying a book from an online store like Amazon can cause a client (your web browser or your mobile app) to use several other microservices. A client that has direct access to the microservice would have to locate and invoke them and handle any failures they caused itself. So, usually a better approach is to hide those services behind a new service layer. This aggregator service layer is known as an API gateway.

Another advantage of using an API gateway is that you can add cross-cutting concerns like authorization and data transformation in this layer. Services that use non-internet-friendly protocols can also benefit from the usage of an API gateway. However, keep in mind that it usually isn’t recommended to have a single API gateway for all the microservices in your application. If you (wrongly) decided to take that approach, it would act just like a monolithic bus, violating microservice independence by coupling all the microservices. Adding business logic to an API gateway is a mistake and should be avoided.

Apache Camel

Apache Camel is an open source integration framework that is well suited to implementing API gateways. The framework implements ...

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Publisher Resources

ISBN: 9781492038290