hawkbit/docs/src/main/resources/documentation/guide/feignclient.md

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Create Feign REST Client

In this guide we describe how to create a Feign Rest Client based on a Spring Boot Application. hawkBit provides REST interfaces for Management API and [DDI API] (https://github.com/eclipse/hawkbit/tree/master/hawkbit-ddi-api). Using this interfaces you can create a feign client with the help of the [feign inheritance support] (http://projects.spring.io/spring-cloud/spring-cloud.html#spring-cloud-feign-inheritance). Our example modules demonstrate how to create Feign client resources. Here you can find the Management API client resources and the DDI client resources. A small simulator application demonstrates how you can interact with the hawkBit via the Management API .

Example Managment API simulator

In the follow code section, you can a see a feign client resource example. The interface extend the orgin api inteface to declare the @FeignClient. The @FeignClientdeclares that a REST client with that interface should be created.

@FeignClient(url = "${hawkbit.url:localhost:8080}/" + MgmtRestConstants.TARGET_V1_REQUEST_MAPPING)
public interface MgmtTargetClientResource extends MgmtTargetRestApi {
}

This interface can be autowired and use as a normal java interface:

public class CreateStartedRolloutExample {

    @Autowired
    private MgmtTargetClientResource targetResource;


    public void run() {
        // create ten targets
        targetResource.createTargets(new TargetBuilder().controllerId("00-FF-AA-0").name("00-FF-AA-0")
                .description("Targets used for rollout example").buildAsList(10));
    }

At hawkbit-example-core-feign-client is a spring configuration to auto configure some beans, which can be reused for a own feign client.

@Configuration
@ConditionalOnClass(Feign.class)
@Import(FeignClientsConfiguration.class)
public class FeignClientConfiguration {

    @Bean
    public ApplicationJsonRequestHeaderInterceptor jsonHeaderInterceptor() {
        return new ApplicationJsonRequestHeaderInterceptor();
    }

    @Bean
    public Contract feignContract() {
        return new IgnoreMultipleConsumersProducersSpringMvcContract();
    }
}