Spring Cloud OpenFeign: Ribbon and Hystrix based declarative service call

SpringBoot actual electricity supplier item mall (20k + star) Address: github.com/macrozheng/...

Summary

Spring Cloud OpenFeign service call is declarative tool that integrates Ribbon and Hystrix, have load balancing and fault tolerance service, we will detail its usage.

Feign Profile

Feign service call is declarative tools, we only need to create an interface with annotations and ways to configure it, you can achieve a call to a service interface, simplifying the development of direct use to call RestTemplate amount of service interfaces. Feign with pluggable annotation support, while supporting Feign annotations, JAX-RS annotations and SpringMvc comment. When using Feign, Spring Cloud integrates Ribbon and Eureka to provide load balancing service calls and service-based Hystrix fault tolerance protection.

Create a feign-service module

Here we create a feign-service module to demonstrate the common features feign.

Add its dependencies in pom.xml

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-openfeign</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>
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In the configuration application.yml

server:
  port: 8701
spring:
  application:
    name: feign-service
eureka:
  client:
    register-with-eureka: true
    fetch-registry: true
    service-url:
      defaultZone: http://localhost:8001/eureka/
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Add @EnableFeignClients comment on the start of classes to enable Feign client functionality

@EnableFeignClients
@EnableDiscoveryClient
@SpringBootApplication
public class FeignServiceApplication {

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

}
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Add UserService interface to complete the interface is bound to user-service services

We implemented a Feign client by @FeignClient notes, the value of which is user-service interface calls that this is a client of the user-service services. We can recall at user-service in UserController, simply change it to interface to retain the original SpringMvc comment.

/**
 * Created by macro on 2019/9/5.
 */
@FeignClient(value = "user-service")
public interface UserService {
    @PostMapping("/user/create")
    CommonResult create(@RequestBody User user);

    @GetMapping("/user/{id}")
    CommonResult<User> getUser(@PathVariable Long id);

    @GetMapping("/user/getByUsername")
    CommonResult<User> getByUsername(@RequestParam String username);

    @PostMapping("/user/update")
    CommonResult update(@RequestBody User user);

    @PostMapping("/user/delete/{id}")
    CommonResult delete(@PathVariable Long id);
}
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Add UserFeignController call UserService achieve service call

/**
 * Created by macro on 2019/8/29.
 */
@RestController
@RequestMapping("/user")
public class UserFeignController {
    @Autowired
    private UserService userService;

    @GetMapping("/{id}")
    public CommonResult getUser(@PathVariable Long id) {
        return userService.getUser(id);
    }

    @GetMapping("/getByUsername")
    public CommonResult getByUsername(@RequestParam String username) {
        return userService.getByUsername(username);
    }

    @PostMapping("/create")
    public CommonResult create(@RequestBody User user) {
        return userService.create(user);
    }

    @PostMapping("/update")
    public CommonResult update(@RequestBody User user) {
        return userService.update(user);
    }

    @PostMapping("/delete/{id}")
    public CommonResult delete(@PathVariable Long id) {
        return userService.delete(id);
    }
}
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Load balancing feature presentation

• Start eureka-service, two user-service, feign-service service, after starting the registry is shown below:

• Multiple calls to http: // localhost: 8701 / user / 1 test run can be found alternately print the following information in 8201 and 8202 of the user-service service:

2019-10-04 15:15:34.829  INFO 9236 --- [nio-8201-exec-5] c.macro.cloud.controller.UserController  : 根据id获取用户信息，用户名称为：macro
2019-10-04 15:15:35.492  INFO 9236 --- [io-8201-exec-10] c.macro.cloud.controller.UserController  : 根据id获取用户信息，用户名称为：macro
2019-10-04 15:15:35.825  INFO 9236 --- [nio-8201-exec-9] c.macro.cloud.controller.UserController  : 根据id获取用户信息，用户名称为：macro
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Feign in service degradation

Feign in service degradation is easy to use, only need to add the interfaces as defined by the client Feign a class can implement downgrade service, let's implement a class for the service degradation UserService add an interface.

Add Service downgraded implementation class UserFallbackService

Note that it implements the UserService interfaces, and each interface implemented method were implemented logic service degradation.

/**
 * Created by macro on 2019/9/5.
 */
@Component
public class UserFallbackService implements UserService {
    @Override
    public CommonResult create(User user) {
        User defaultUser = new User(-1L, "defaultUser", "123456");
        return new CommonResult<>(defaultUser);
    }

    @Override
    public CommonResult<User> getUser(Long id) {
        User defaultUser = new User(-1L, "defaultUser", "123456");
        return new CommonResult<>(defaultUser);
    }

    @Override
    public CommonResult<User> getByUsername(String username) {
        User defaultUser = new User(-1L, "defaultUser", "123456");
        return new CommonResult<>(defaultUser);
    }

    @Override
    public CommonResult update(User user) {
        return new CommonResult("调用失败，服务被降级",500);
    }

    @Override
    public CommonResult delete(Long id) {
        return new CommonResult("调用失败，服务被降级",500);
    }
}
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UserService modify the interface, arranged to downgrade the service class UserFallbackService

Modify the parameters @FeignClient annotations, and can set fallback to UserFallbackService.class.

@FeignClient(value = "user-service",fallback = UserFallbackService.class)
public interface UserService {
}
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Modify application.yml, open Hystrix function

feign:
  hystrix:
    enabled: true #在Feign中开启Hystrix
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Service downgraded Demo

• Close both user-service service, restart feign-service;

• Call http: // localhost: 8701 / user / 1 for testing can be found returned service degradation information.

Log Print function

Feign provides a log printing capabilities, we can adjust the log level by configuring to understand the details of Feign in Http request.

Log Level

• NONE: default, does not show any log;
• BASIC: Only requests recording method, URL, and the response status code execution time;
• HEADERS: BASIC addition to the information defined in the header information as well as request and response;
• FULL: HEADERS defined in addition to the information, as well as text and metadata requests and responses.

Open a more detailed log by configuring

Let's Feign print the java configuration is the most detailed Http request log information.

/**
 * Created by macro on 2019/9/5.
 */
@Configuration
public class FeignConfig {
    @Bean
    Logger.Level feignLoggerLevel() {
        return Logger.Level.FULL;
    }
}
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In application.yml need to open Feign configure client log

UserService configuration of log level debug.

logging:
  level:
    com.macro.cloud.service.UserService: debug
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View Log

Call http: // localhost: 8701 / user / 1 for testing, you can see the following log.

2019-10-04 15:44:03.248 DEBUG 5204 --- [-user-service-2] com.macro.cloud.service.UserService      : [UserService#getUser] ---> GET http://user-service/user/1 HTTP/1.1
2019-10-04 15:44:03.248 DEBUG 5204 --- [-user-service-2] com.macro.cloud.service.UserService      : [UserService#getUser] ---> END HTTP (0-byte body)
2019-10-04 15:44:03.257 DEBUG 5204 --- [-user-service-2] com.macro.cloud.service.UserService      : [UserService#getUser] <--- HTTP/1.1 200 (9ms)
2019-10-04 15:44:03.257 DEBUG 5204 --- [-user-service-2] com.macro.cloud.service.UserService      : [UserService#getUser] content-type: application/json;charset=UTF-8
2019-10-04 15:44:03.258 DEBUG 5204 --- [-user-service-2] com.macro.cloud.service.UserService      : [UserService#getUser] date: Fri, 04 Oct 2019 07:44:03 GMT
2019-10-04 15:44:03.258 DEBUG 5204 --- [-user-service-2] com.macro.cloud.service.UserService      : [UserService#getUser] transfer-encoding: chunked
2019-10-04 15:44:03.258 DEBUG 5204 --- [-user-service-2] com.macro.cloud.service.UserService      : [UserService#getUser] 
2019-10-04 15:44:03.258 DEBUG 5204 --- [-user-service-2] com.macro.cloud.service.UserService      : [UserService#getUser] {"data":{"id":1,"username":"macro","password":"123456"},"message":"操作成功","code":200}
2019-10-04 15:44:03.258 DEBUG 5204 --- [-user-service-2] com.macro.cloud.service.UserService      : [UserService#getUser] <--- END HTTP (92-byte body)
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Feign common configuration

Feign own configuration

feign:
  hystrix:
    enabled: true #在Feign中开启Hystrix
  compression:
    request:
      enabled: false #是否对请求进行GZIP压缩
      mime-types: text/xml,application/xml,application/json #指定压缩的请求数据类型
      min-request-size: 2048 #超过该大小的请求会被压缩
    response:
      enabled: false #是否对响应进行GZIP压缩
logging:
  level: #修改日志级别
    com.macro.cloud.service.UserService: debug
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Ribbon in the configuration Feign

Feign configuration can be used directly in the Ribbon Ribbon configuration, specifically refer to Spring Cloud Ribbon: load balancing service call .

Hystrix configuration of Feign

Feign configuration can be used directly in Hystrix Hystrix configuration, specifically refer to Spring Cloud Hystrix: Service fault tolerance protection .

To use the module

springcloud-learning
├── eureka-server -- eureka注册中心
├── user-service -- 提供User对象CRUD接口的服务
└── feign-service -- feign服务调用测试服务
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Project Source Address

github.com/macrozheng/…

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