nacos配置动态刷新及监听到变化触发一些方法

2023-09-21 07:21

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介绍

在使用spring 时，动态更新配置是常见的，属性值更新，但是需要开启支持刷新功能，一个是spring.cloud.nacos.config.isRefreshEnabled=true; 这个值一般是默认的，可以在nacosConfigProperties这个类中看到。还要在扩展配置中开启refresh = true

spring    cloud:      nacos:        config:          server-addr: ${nacos-ip}          extension-configs[0]:            data-id: ${spring.application.name}.yml            group: base        # 这个地方必须开启，否则不会自动刷新            refresh: true

2 使用

2.1 新建配置类

import lombok.Data;import org.springframework.boot.context.properties.ConfigurationProperties;import org.springframework.context.annotation.Configuration;@Data@Configuration@ConfigurationProperties(prefix = "apply.demo")public class DemoConfig {        private String config;}

2.2 新建测试访问类

import com.purgeteam.dynamic.config.starter.event.ActionConfigEvent;import lombok.extern.slf4j.Slf4j;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.context.ApplicationListener;import org.springframework.web.bind.annotation.GetMapping;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RestController;import java.util.HashMap;import java.util.Map;@RestController@Slf4j@RequestMapping("/api/test2")public class Test2Controller {//    @Autowired    private DemoConfig demoConfig;    @GetMapping(value = "dd")    public String test4(String params){        log.info("dsds" + params);        System.out.println(demoConfig.getConfig());        System.out.println(SpringUtil.getApplicationContext().getBean("testController"));        // 保存数据        return demoConfig.getConfig();    }}

2.3 yml配置

apply:  demo:    config: 2225dssww

测试结果：配置中心值改变，对应的属性值也改变

------这里好像没用加@RefreshScope注解

3. 监听到变化触发方法

在监听到配置值变化后，需要触发一些方法，需要实现ApplicationListener 接口，重写onApplicationEvent方法

3.1 触发代码

import com.purgeteam.dynamic.config.starter.event.ActionConfigEvent;import lombok.extern.slf4j.Slf4j;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.context.ApplicationListener;import org.springframework.web.bind.annotation.GetMapping;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RestController;import java.util.HashMap;import java.util.Map;@RestController@Slf4j@RequestMapping("/api/test2")public class Test2Controller implements ApplicationListener {//    @Autowired    private DemoConfig demoConfig;    @GetMapping(value = "dd")    public String test4(String params){        log.info("dsds" + params);        System.out.println(demoConfig.getConfig());        System.out.println(SpringUtil.getApplicationContext().getBean("testController"));        // 保存数据        return demoConfig.getConfig();    }// 这个方法会在属性变化后调用，这里可以根据某个值变化去处理其他逻辑    @Override    public void onApplicationEvent(ActionConfigEvent actionConfigEvent) {// 获取变化的key        Map propertyMap = actionConfigEvent.getPropertyMap();// 取出变化的key的map        HashMap hashMap = propertyMap.get("spring.profiles1.active1");// 变化后的值        Object after = hashMap.get("after");// 变化前的值        Object after = hashMap.get("before");// 打印属性值        log.info("====env========={}",this.demoConfig.getConfig());    }}

4. 执行流程分析

处理属性变化绑定值类org.springframework.cloud.context.properties.ConfigurationPropertiesRebinder#onApplicationEvent

自己可以打断点，看方法走向。

获取服务端配置最后是一个string，在com.alibaba.nacos.client.config.impl.ClientWorker.LongPollingRunnable#run这个方法中

String[] ct = ClientWorker.this.getServerConfig(dataId, group, tenant, 3000L);

4.1 服务启动注册配置监听

com.alibaba.cloud.nacos.refresh.NacosContextRefresher#onApplicationEvent这里会调用注册方法com.alibaba.cloud.nacos.refresh.NacosContextRefresher#registerNacosListenersForApplications

// 注册监听方法private void registerNacosListenersForApplications() {// 全局开启刷新，默认是true        if (isRefreshEnabled()) {            for (NacosPropertySource propertySource : NacosPropertySourceRepository                    .getAll()) {            // 判断单个配置文件是否支持刷新，就是refresh = true，开启了就会注册监听，有变化就会及时通知                if (!propertySource.isRefreshable()) {                    continue;                }                String dataId = propertySource.getDataId();                // 调用注册方法                registerNacosListener(propertySource.getGroup(), dataId);            }        }    }

private void registerNacosListener(final String groupKey, final String dataKey) {        String key = NacosPropertySourceRepository.getMapKey(dataKey, groupKey);        // 创建监听        Listener listener = listenerMap.computeIfAbsent(key,                lst -> new AbstractSharedListener() {                    @Override                    public void innerReceive(String dataId, String group,String configInfo) {                        refreshCountIncrement();                        nacosRefreshHistory.addRefreshRecord(dataId, group, configInfo);                        // todo feature: support single refresh for listening                        applicationContext.publishEvent(    new RefreshEvent(this, null, "Refresh Nacos config"));                        if (log.isDebugEnabled()) {log.debug(String.format(        "Refresh Nacos config group=%s,dataId=%s,configInfo=%s",        group, dataId, configInfo));                        }                    }                });        try {        // 这里是最重要的，将监听添加到，config里，注册上            configService.addListener(dataKey, groupKey, listener);        }        catch (NacosException e) {            log.warn(String.format(                    "register fail for nacos listener ,dataId=[%s],group=[%s]", dataKey,                    groupKey), e);        }    }

4.2 配置改变刷新配置属性

调用到org.springframework.cloud.context.refresh.ContextRefresher#refreshEnvironment

// 返回变化的keypublic synchronized Set refreshEnvironment() {// 以前的配置的值        Map before = this.extract(this.context.getEnvironment().getPropertySources());        this.addConfigFilesToEnvironment();// 改变后的key        Set keys = this.changes(before, this.extract(this.context.getEnvironment().getPropertySources())).keySet();// 发布环境变化时间，spring内部事件        this.context.publishEvent(new EnvironmentChangeEvent(this.context, keys));// 返回变化的key        return keys;    }

求出以前和现在变化的key

private Map changes(Map before, Map after) {        Map result = new HashMap();        Iterator var4 = before.keySet().iterator();        String key;        while(var4.hasNext()) {            key = (String)var4.next();            if (!after.containsKey(key)) {                result.put(key, (Object)null);            } else if (!this.equal(before.get(key), after.get(key))) {                result.put(key, after.get(key));            }        }        var4 = after.keySet().iterator();        while(var4.hasNext()) {            key = (String)var4.next();            if (!before.containsKey(key)) {                result.put(key, after.get(key));            }        }        return result;    }

环境变化事件处理

org.springframework.cloud.context.properties.ConfigurationPropertiesRebinder#onApplicationEvent

public void onApplicationEvent(EnvironmentChangeEvent event) {        if (this.applicationContext.equals(event.getSource()) || event.getKeys().equals(event.getSource())) {// 重新绑定值            this.rebind();        }    }

这里会看到需要绑定的配置类

开始绑定

这里绑定值后，虽然经过了销毁和初始化，发现，地址没有变，里面的值变了

刷新后还会调用这个方法org.springframework.cloud.context.refresh.ContextRefresher#refresh

发布一个RefreshScopeRefreshedEvent事件

com.purgeteam.dynamic.config.starter.event.DynamicConfigApplicationListener#onApplicationEvent

public void onApplicationEvent(RefreshEvent event) {        ConfigurableEnvironment beforeEnv = (ConfigurableEnvironment)this.context.getEnvironment();        MutablePropertySources propertySources = beforeEnv.getPropertySources();        MutablePropertySources beforeSources = new MutablePropertySources(propertySources);        Set refresh = this.refresh.refresh();        Map contrast = this.propertyUtil.contrast(beforeSources, propertySources);// 发布一个配置变化事件        this.context.publishEvent(new ActionConfigEvent(this, "Refresh config", contrast));        log.info("[ActionApplicationListener] The update is successful {}", refresh);    }

调用到自己的方法

public void onApplicationEvent(ActionConfigEvent actionConfigEvent) {        Map propertyMap = actionConfigEvent.getPropertyMap();        HashMap hashMap = propertyMap.get("spring.profiles1.active1");        Object after = hashMap.get("after");// 触发其他逻辑        log.info("====env========={}",this.demoConfig.getConfig());    }