Client remote call Feign

Client remote call

Feign

What is Feign?

Feign is declarative open source Netflix, HTTP client

GitHub: Feign Source

Why Feign?

1. Original code readability is not high
2. Complex URL difficult to maintain ( https://user-center/s?wd={userId}&rsv_spt=1&rsv_iqid=0x93bff3cd000cf3da&issp=1&f=8&rsv_bp=1&rsv_idx=2&ie=utf-8&tn=baiduhome_pg&rsv_enter=1&rsv_sug3=4&rsv_sug1=4&rsv_sug7=100&rsv_t=10c2risCimsUZC0RBruMerdnQRN1gRxFI%2BywuD0L3LwGGNd2dR8XE6x%2FyFOjHnR0oEi0&rsv_sug2=0&inputT=1535&rsv_sug4=1535&rsv_sug=2)
3. Difficult to cope with rapid changes in demand
4. JAVA coding experience and we write quite different

Reconstruction of Example Code

                //替换前 
        ResponseEntity<UserDTO> userEntity = restTemplate.getForEntity(
                "http://user-center/users/{userId}",
                UserDTO.class, userId
        );
        UserDTO userDTO = new UserDTO();
        if (null != userEntity) {
            userDTO = userEntity.getBody();
            log.info("ShareService#findById userDTO: {}", userDTO);
        }

1. Add dependent

        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
        </dependency>

1. Add comment startup class @EnableFeignClients
2. Add Configuration
3. Implement the corresponding micro-client services

/**
 * IUserCenterFeignClient for 定义 user-center feign client
 *
 * @author <a href="mailto:[email protected]">Isaac.Zhang | 若初</a>
 * @since 2019/7/15
 */
@FeignClient(name = "user-center")
public interface IUserCenterFeignClient {

    /**
     * Feign client 会将请求转换为
     * http://user-center/users/{userId}
     *
     * @param userId 用户id
     * @return 返回用户对象
     */
    @GetMapping(path = "/users/{userId}")
    public UserDTO findById(@PathVariable Long userId);
}

1. After replacing the code

        //使用 FeignClient 来替换掉RestTemplate调用
        UserDTO userDTO = this.userCenterFeignClient.findById(userId);

Feign composition

Feign's configuration

Java Code

Supported configuration items

Custom Feign log level

• Level content

Demo

Tip : it is possible to overlap the context of parent-child problems

1. Add client configuration

/**
 * IUserCenterFeignClient for 定义 user-center feign client
 *
 * @author <a href="mailto:[email protected]">Isaac.Zhang | 若初</a>
 * @since 2019/7/15
 */
@FeignClient(name = "user-center",configuration = UserCenterFeignConfiguration.class)
public interface IUserCenterFeignClient {
   ...
}

1. Write java profiles

/**
 * UserCenterFeignConfiguration for 自定义user-center服务请求中，feign的配置信息
 * {@link @Configuration} 不能添加该注解，否则会和ribbon一样，出现上下文重叠问题，造成配置全局共享
 * 如要添加该注解，需要将该类放在主程序启动扫描不到的包下
 *
 * @author <a href="mailto:[email protected]">Isaac.Zhang | 若初</a>
 * @since 2019/7/15
 */
public class UserCenterFeignConfiguration {
    @Bean
    public Logger.Level level() {
        // 配置feign 日志级别，记录请求和响应的header、body以及元数据
        return Logger.Level.FULL;
    }
}

1. Be sure to add the client the full path in the configuration file

   logging:
     level:
      #com.sxzhongf: debug
       com.sxzhongf.sharedcenter.feignclients.IUserCenterFeignClient: debug

2. Print information

2019-07-15 15:06:11.650 DEBUG 20286 --- [nio-8010-exec-1] c.s.s.f.IUserCenterFeignClient           : [IUserCenterFeignClient#findById] <--- HTTP/1.1 200 (402ms)
2019-07-15 15:06:11.651 DEBUG 20286 --- [nio-8010-exec-1] c.s.s.f.IUserCenterFeignClient           : [IUserCenterFeignClient#findById] content-type: application/json;charset=UTF-8
2019-07-15 15:06:11.651 DEBUG 20286 --- [nio-8010-exec-1] c.s.s.f.IUserCenterFeignClient           : [IUserCenterFeignClient#findById] date: Mon, 15 Jul 2019 07:06:11 GMT
2019-07-15 15:06:11.651 DEBUG 20286 --- [nio-8010-exec-1] c.s.s.f.IUserCenterFeignClient           : [IUserCenterFeignClient#findById] transfer-encoding: chunked
2019-07-15 15:06:11.652 DEBUG 20286 --- [nio-8010-exec-1] c.s.s.f.IUserCenterFeignClient           : [IUserCenterFeignClient#findById] 
2019-07-15 15:06:11.652 DEBUG 20286 --- [nio-8010-exec-1] c.s.s.f.IUserCenterFeignClient           : [IUserCenterFeignClient#findById] {"id":1,"wxId":"","wxNickname":"IsaacZhang","roles":"","avatarUrl":"aaa","createTime":"2019-07-11T06:08:18.000+0000","updateTime":"2019-07-11T06:08:18.000+0000","bonus":100}
2019-07-15 15:06:11.652 DEBUG 20286 --- [nio-8010-exec-1] c.s.s.f.IUserCenterFeignClient           : [IUserCenterFeignClient#findById] <--- END HTTP (173-byte body)

Configuration

Supported configuration items

demo

Use the configuration file to define log level

#logging:
  #level:
   #com.sxzhongf: debug
    #com.sxzhongf.sharedcenter.feignclients.IUserCenterFeignClient: debug
feign:
  client:
    config:
      user-center: #单服务配置
        loggerLevel: full
---        
feign:
  client:
    config:
      default: #全局配置日志级别
        loggerLevel: full

Feign of inheritance

• The official is not recommended
• Most companies use?

Architects need to decide according to their own business situation, the need for different coupling micro-business services, or use of redundant code to liberate business coupling.

Feign multi-parameter request

Get

1. use@SpringQueryMap

@FeignClient(name = "user-center")
public interface ITestUserCenterFeignClient {

    @GetMapping("/users/q")
    public UserDTO query(@SpringQueryMap UserDTO userDTO);
}

1. use @RequestParam

@FeignClient(name = "user-center")
public interface ITestUserCenterFeignClient {

    @RequestMapping(value = "/users/q",method = RequestMethod.GET)
    public UserDTO query(@RequestParam("id") Long id,@RequestParam("name") String name);
}

1. Use Mapbuilding, (not recommended)

@FeignClient(name = "user-center")
public interface ITestUserCenterFeignClient {

    @RequestMapping(value = "/users/q",method = RequestMethod.GET)
    public UserDTO query(@RequestParam Map<String,Object> conditions);
}

Note : This method is not recommended. Mainly because of poor readability, and if the parameter is empty when there will be some problems, for example, map.put("username", null);will lead user-centerthe service received username is "", not null.

Post

Service provider method

    @PostMapping("/create")
    public User createUser(@RequestBody User user){
        return null;
    }

The caller service

@FeignClient(name = "user-center")
public interface ITestUserCenterFeignClient {

    @RequestMapping(value = "/users/q",method = RequestMethod.POST)
    public UserDTO query(@RequestBody UserDTO user);
}

Feign out of service registration / Ribbon call

@FeignClient(name = "xxxxx",url = "http://www.baidu.com")
public interface ITestBaiduFeignClient {

    @GetMapping("")
    public String getBaidu();
}

Feign Performance Optimization

Use connection pooling

httpClient

1. Plus dependence

        <!--Feign 性能优化，需要使用连接池，引入依赖-->
        <dependency>
            <groupId>io.github.openfeign</groupId>
            <artifactId>feign-httpclient</artifactId>
        </dependency>

1. Add comment (not required)
2. Change configuration

  httpclient:
    # 为feign启用 apache httpclient 做请求，而不使用默认的urlconection
    enabled: true
    # feign 最大连接数
    max-connections: 200
    # feign 单个路径请求的最大连接数
    max-connections-per-route: 50

okHttp

1. Plus dependence

        <!--Feign 性能优化，需要使用连接池，引入依赖-->
        <dependency>
            <groupId>io.github.openfeign</groupId>
            <artifactId>feign-okhttp</artifactId>
        </dependency>

1. Add comment (not required)
2. Change configuration

  httpclient:
    # 为feign启用 apache httpclient 做请求，而不使用默认的urlconection
    #enabled: true
    # feign 最大连接数
    max-connections: 200
    # feign 单个路径请求的最大连接数
    max-connections-per-route: 50
  okhttp:
    enabled: true

Rational use Feign log

Production environmentsLogger.Level.BASIC

rest Template

RestTemplate VS. Feign