Spring Cloud OpenFeign

Feign supports two timeout parameters:

• connectTimeout: Prevents blocking the caller due to long server processing time during connection establishment.
• readTimeout: Triggered when returning the response takes too long after the connection is established.

The spring-cloud-build module includes a docs profile that uses [Antora] to build asciidoc sources from modules/ROOT/. To generate the documentation site, run the following command:

./mvnw -pl docs -P docs antora:antora

To build the source, you need JDK 17 installed. The project uses Maven for build activities. You can use the included Maven wrapper (./mvnw) or your own Maven installation (version 3.3.3 or better).

If using your own Maven installation, you may need to add the -P spring profile to resolve Spring milestone and snapshot repositories if your local settings.xml does not already contain them.

$ ./mvnw install

If Spring Cloud CircuitBreaker is enabled (spring.cloud.openfeign.circuitbreaker.enabled=true), you can define a fallback class or a fallbackFactory in the @FeignClient annotation. The fallback class must implement the Feign client interface and be declared as a Spring bean (e.g., using @Component).

Use fallbackFactory if you need access to the Throwable cause that triggered the fallback.

@FeignClient(name = "test", url = "http://localhost:${server.port}/", fallback = Fallback.class)
protected interface TestClientWithFallback {
    @GetMapping("/hello")
    Hello getHello();
}

@Component
static class Fallback implements TestClientWithFallback {
    @Override
    public Hello getHello() {
        return new Hello("Fallback response");
    }
}

To use Feign, add the spring-cloud-starter-openfeign starter to your project dependencies. You must also enable Feign clients in your Spring Boot application using the @EnableFeignClients annotation.

@SpringBootApplication
@EnableFeignClients
public class Application {

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }

}