I have an application with eureka, ribbon and feign. I have a feign RequestInterceptor, but the problem is that I need to know which is the host where I'm making the call. So far, with my current code I just can get the path with the RequestTemplate, but not the host.
Any idea?
I'm new to this as well, but I believe I've just learned something relevant to your question.
In the service you're creating, each instance can be given some unique identifier tied to a property included in its instance profile. Some .properties examples below:
application.properties (shared properties between instances)
spring.application.name=its-a-service
eureka.client.service-url.defaultZone=http://localhost:8761/eureka
application-instance1.properties
server.port=5678
instance.uid=some-unique-property
application-instance2.properties
server.port=8765
instance.uid=other-unique-property
This service, as an extremely contrived example will show, can send out #Value annotated attributes to be consumed by the Ribbon app:
#SpringBootApplication
#EnableDiscoveryClient
#RestController
public class ItsAServiceApplication {
#Value("${server.port}")
private int port;
#Value("${instance.uid}")
private String instanceIdentifier;
public static void main(String[] args) {
SpringApplication.run(ItsAServiceApplication.class, args);
}
#RequestMapping
public String identifyMe() {
return "Instance: " + instanceIdentifier + ". Running on port: " + port + ".";
}
}
And just to complete the example, the Ribbon app that might consume these properties could look like this:
#SpringBootApplication
#EnableDiscoveryClient
#RestController
public class ServiceIdentifierAppApplication {
#Autowired
private RestTemplate restTemplate;
public static void main(String[] args) {
SpringApplication.run(ServiceIdentifierAppApplication.class, args);
}
#GetMapping
public String identifyMe() {
return restTemplate.getForEntity("http://its-a-service", String.class).getBody();
}
#Bean
#LoadBalanced
public RestTemplate restTemplate() {
return new RestTemplate();
}
}
Results:
Reloading the rest template created by the services
As I said earlier, I'm pretty new to this and have just been learning myself. Hopefully this has given you an idea for how you might send these properties! I would imagine creating a dynamic property identifier through Spring Cloud Config would be ideal here.
Related
I'm newbie to Spring Cloud. Following the example of Start Guide. I'm stuck at Zuul example.
With a request to zuul, my client app not receive any request from zuul and get 405(Method not allowed) to my browser.
But test without zuul, the client app can response success.
Simple code as this:
Zuul Server:
#EnableZuulProxy
#SpringBootApplication
public class MyZuulApp {
public static void main(String[] args) {
SpringApplication.run(MyZuulApp.class, args);
}
#Bean
public SimpleFilter simpleFilter() {
return new SimpleFilter();
}
}
Configuration:
##Zuul routes. Here for /student path, we are routing to localhost:8090 with extra path after that.
zuul.routes.book_app.url=http://localhost:8090
#zuul.routes.book_app=/book_app/**
##Ribbon is auto integrated with Zuul and for this exercise we are not using that.
ribbon.eureka.enabled=false
##Will start the gateway server #8080
server.port=8083
logging.level.org.springframework.web=DEBUG
Client App:
#RestController
#SpringBootApplication
public class BookApp {
#RequestMapping(value = "/available")
public String available() {
System.out.println("get abailable - ");
return "Spring in Action";
}
#RequestMapping(value = "/checked-out")
public String checkedOut() {
return "Spring Boot in Action";
}
public static void main(String[] args) {
SpringApplication.run(BookApp.class, args);
}
}
Configuration:
spring.application.name=book_app
server.port=8090
logging.level.org.springframework.web=DEBUG
Full code has organized at Github.
See my-zuul and book-app for that situation.
Thanks
I downloaded your code and run locally and it worked as expected.
Your Zuul application.properties
zuul.routes.book_app.url=http://localhost:8090
server.port=8083
Since your book application name is book_app.Zuul will proxy request to /book_app.So you have to send requests like this: http://localhost:8083/book_app/checked-out/.
I have two services registered with eureka. Service C calls service A. Service C is feign client. I want implement feign client manually. But I catch an exception:
com.netflix.client.ClientException: Load balancer does not have
available server for client: service-test-a
Application class:
#EnableEurekaClient
#SpringBootApplication
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}
Feign interface:
#Component
public interface FeignService {
#RequestLine("GET /")
public String getServiceA();
}
Feign config:
#Configuration
#Import(FeignClientsConfiguration.class)
public class MyConfig {
}
Controller:
#RestController
public class Controller {
private FeignService feignService;
#Autowired
public void Controller() {
feignService = Feign.builder()
.client(RibbonClient.create())
.target(FeignService.class, "http://service-test-a");
}
#RequestMapping(value = "/build", method = RequestMethod.GET)
public String getServiceC() {
return feignService.getServiceA();
}
}
What am I doing wrong?
AFAIK, there is no easy way of using OpenFeign with eureka. There is no guide or example for that. Also I guess that it may require some additional implementations and configuration.
Instead, please try to use Spring Cloud Feign. It provides full integration with eureka and ribbon without any additional implementation. You can use Spring Cloud Feign with just a few changes in your above code.
Please refer to Spring Cloud Feign
Trying to use Feign Client with Eureka and Ribbon-
Have a service registered using Eureka with name-test-service.
Was able to use Ribbon and Eureka successfully as follows-
#Autowired
private LoadBalancerClient loadBalancer;
public void getEmployee() throws RestClientException, IOException {
ServiceInstance serviceInstance=loadBalancer.choose("test-service");
String baseUrl=serviceInstance.getUri().toString();
baseUrl=baseUrl+"/test";
RestTemplate restTemplate = new RestTemplate();
ResponseEntity<String> response=null;
try{
response=restTemplate.exchange(baseUrl,
HttpMethod.GET, getHeaders(),String.class);
}
This works correctly including load balancing.
Now tried to replace RestTemplate with Feign as follows-
#FeignClient(name="test-service")
public interface RemoteCallService {
#RequestMapping(method=RequestMethod.GET, value="/test")
public String resp();
}
And making the call with feign as follows-
#Autowired
private RemoteCallService loadBalancer;
public void getEmployee() throws RestClientException, IOException {
String data=loadBalancer.resp();
}
But this is not working. The Feign URL is not getting formed correctly.
On debugging the FeignClient has the following values-
HardCodedTarget(type=RemoteCallService, name=test-service, url=http://test-service)
Can anyone tell what am i missing.
Thanks
According to the samples here (actually - timestamp task), I have implemented a small task class:
#SpringBootApplication
#EnableTask
#EnableConfigurationProperties({ RestProcessorTaskProperties.class })
public class RestProcessorTaskApplication {
public static void main(String[] args) {
SpringApplication.run(RestProcessorTaskApplication.class, args);
}
#Autowired
private RestProcessorTaskProperties config;
// some fields and beans
#Bean
public CommandLineRunner run(RestTemplate restTemplate) {
return args -> {
// doing some stuff
};
}
}
and then I've created Properties class (in the same package)
#ConfigurationProperties("RestProcessor")
public class RestProcessorTaskProperties {
private String host = "http://myhost:port";
public String getHost() {
return host;
}
public void setHost(String host) {
this.host = host;
}
}
But after I've registered task on my local Spring Cloud Data Server, I see numerous parameters, that, I suppose, was added automatically. I those mean parameters like:
abandon-when-percentage-full java.lang.Integer
abandoned-usage-tracking java.lang.Boolean
acceptors java.lang.Integer
access-to-underlying-connection-allowed java.lang.Boolean
and others...
Is it possible somehow to hide (or remove) them, so that when launching task I could configure only those parameters, that was added by me (single host property in my example above)?
By default Spring Cloud Data Flow will show you all the available properties for a boot application. However, you can create a whitelist of properties that you wish to show.
Here is a link to the Spring Cloud Data Flow reference doc that will discuss how to do this: http://docs.spring.io/spring-cloud-dataflow/docs/current/reference/htmlsingle/#spring-cloud-dataflow-stream-app-whitelisting.
And here is link to the timestamp starter app that has an example of this: https://github.com/spring-cloud/spring-cloud-task-app-starters/tree/master/spring-cloud-starter-task-timestamp
I have following service:
#FeignClient(name = "person", fallback = FeignHystrixFallback.class)
public interface PersonService {
#RequestMapping(value = "/find", method = RequestMethod.GET)
Person findPerson(#RequestParam("name") String name);
}
How to change the default timeout and thread pool size?
There are other people that have run into this issue and have posted questions and have answers. The most relevant is this post:
Feign builder timeouts not working
If you are wanting to manage the configuration of Feign you would want to check out the Feign documentation looking at the "configuration" attribute of the #FeignClient annotation.
Set custom configuration for this interface
#FeignClient(name="person", configuration = FeignConfig.class)
and make configuration
public class FeignConfig {
public static final int FIVE_SECONDS = 5000;
#Bean
public Request.Options options() {
return new Request.Options(FIVE_SECONDS, FIVE_SECONDS);
}
}