Spring Cloud Consul 动态配置

Spring Cloud Consul 动态配置

简介

如同 Nacos 一样 Consul 也支持配置存储，并且也提供了配置自动更新的机制。

项目搭建

创建 Spring Cloud 项目，然后按照如下配置引入依赖包

ext {
    set('springCloudVersion', "2022.0.0-M5")
}

dependencies {
    implementation 'org.springframework.boot:spring-boot-starter-web'
    implementation 'org.springframework.cloud:spring-cloud-starter-consul-config'
    implementation 'org.springframework.cloud:spring-cloud-starter-consul-discovery'
    implementation('org.springframework.cloud:spring-cloud-starter-bootstrap')
    compileOnly 'org.projectlombok:lombok'
    developmentOnly 'org.springframework.boot:spring-boot-devtools'
    annotationProcessor 'org.springframework.boot:spring-boot-configuration-processor'
    annotationProcessor 'org.projectlombok:lombok'
    testImplementation 'org.springframework.boot:spring-boot-starter-test'
}

dependencyManagement {
    imports {
        mavenBom "org.springframework.cloud:spring-cloud-dependencies:${springCloudVersion}"
    }
}

编辑 Spring 配置文件 application.yaml：

spring:
  application:
    name: <name>
  cloud:
    consul:
      host: ${CONSUL_HOST:localhost}
      port: ${CONSUL_PORT:8500}
      discovery:
        prefer-ip-address: true
        tags: version=1.0
        instance-id: ${spring.application.name}:${spring.cloud.client.hostname}:${spring.cloud.client.ip-address}:${server.port}
        healthCheckInterval: 15s

server:
  port: 8080
  error:
    include-message: always
    include-exception: true
  servlet:
    encoding:
      charset: UTF-8

编辑引入配置文件 bootstrap.yaml：

spring:
  cloud:
    consul:
      config:
        enabled: true
        defaultContext: <name>
        profileSeparator: '-'
        prefixes: config
        format: properties
        watch:
          enabled: true

注：此处支持的 format 有 yaml, properties, key_value, files 可以根据实际情况进行选用。

编辑 Spring 主类并添加如下注解：

import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.scheduling.annotation.EnableScheduling;

@EnableDiscoveryClient
@EnableScheduling
@SpringBootApplication
public class DynApplication {
}

编辑 Spring 配置类

import lombok.Getter;
import lombok.Setter;
import lombok.extern.slf4j.Slf4j;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.cloud.context.config.annotation.RefreshScope;
import org.springframework.context.annotation.Configuration;

@Slf4j
@Getter
@Setter
@RefreshScope
@Configuration
@ConfigurationProperties(prefix = "my")
public class MyProperties {

    private String prop;

}

编辑调试接口类：

import com.example.dyn.conf.MyProperties;
import jakarta.annotation.Resource;
import org.springframework.http.HttpEntity;
import org.springframework.web.bind.annotation.*;

@RestController
@RequestMapping("/demo")
public class DemoController {

    @Value("http://${spring.cloud.consul.host}:${spring.cloud.consul.port}/v1/kv/${spring.cloud.consul.config.prefixes}/${spring.cloud.consul.config.defaultContext}-${spring.profiles.active}/data")
    String consulUrl;
    
    @Resource
    MyProperties myProperties;

    @GetMapping
    public HttpEntity<String> get() {
        return new HttpEntity<>(myProperties.getProp());
    }

    @PutMapping
    public HttpEntity<String> put(@RequestParam String prop) {
        RestTemplate restTemplate = new RestTemplate();
        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.APPLICATION_FORM_URLENCODED);
        MultiValueMap<String, String> content = new LinkedMultiValueMap<>();
        content.put("my.prop", Collections.singletonList(prop));
        HttpEntity<MultiValueMap<String, String>> entity = new HttpEntity<>(content, headers);
        ResponseEntity<Object> response = restTemplate.exchange(consulUrl, HttpMethod.PUT, entity, Object.class);
        if (response.getStatusCode().is2xxSuccessful()) {
            return new HttpEntity<>(prop);
        } else {
            throw new ResponseStatusException(HttpStatus.BAD_REQUEST, "consul set error");
        }
    }
    
}

启动程序即可

流程测试

如需手动编辑可以访问 consul webUI 的 Key/Value 选项中编辑配置向相关配置：

配置目录如下:

config/<name>/data

配置内容如下：

my.prop=demo-1

也可以通过 REST API 进行编辑，请求样例如下：

request

### 写入配置项
PUT http://localhost:8080/demo?prop=edit

### 获取配置项
GET http://localhost:8080/demo

### 使用 Consul HTTP 接口读取配置项
GET http://localhost:8500/v1/kv/config/dyn-default/data

### 使用 Consul HTTP 接口编辑配置项
PUT http://localhost:8500/v1/kv/config/dyn-default/data
Content-Type: application/x-www-form-urlencoded

my.prop=idea-http

注：配置项的空间上限是 512 kb。

配置变更监听

在配置变更的时候可以采用如下的监听器，针对变更的配置完成业务逻辑。

import lombok.extern.slf4j.Slf4j;
import org.springframework.cloud.endpoint.event.RefreshEvent;
import org.springframework.context.ApplicationListener;
import org.springframework.stereotype.Component;

@Slf4j
@Component
public class CustomRefreshEventListener implements ApplicationListener<RefreshEvent> {

    @Override
    public void onApplicationEvent(RefreshEvent event) {
        log.error("checked");
    }

}

参考资料

Spring Cloud Consul 官方文档

Consul KV store HTTP 接口手册