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spring-bootwebclientspring-webfluxreactive

Spring boot reactive WebClient calling legacy endpoint

In a Spring Boot (2.2.2.RELEASE) application, I have reactive endpoints (returning Mono or Flux), each of them is using reactive WebClient for calling another service. This "other" service is legacy (non-reactive) one.

Here is my question:

  • Is there a benefit of using Webflux (reactive WebClient) if my reactive endpoint is calling this non-reactive endpoint which does blocking stuff?

  • Is my reactive endpoint still reactive?

Solution

  • If we're talking about HTTP endpoints, we can call them with blocking or non-blocking (asynchronous) clients, but not fully reactive.

    If your "new" application is reactive, you have to use non-blocking client (WebClient in your case), otherwise you will block NIO-threads and loose all the advantages of the reactive approach. The fact that the “other” application is blocking doesn't matter, you can still get a less resource-intensive "new" application.