Nacos（一）源碼分析Nacos註冊示例流程

nacos官方地址：https://nacos.io/zh-cn/

你們能夠看一下nacos的中文手冊以及官方源碼，博主就不帶領你們快速入門 了，官方文檔中都有並且很是標準，比其餘博客寫的好多了而且仍是實時更新的。

先看一下博主給你們畫的流程圖，掌握一下大概的基本流程，好理解，博主給你們講源碼：

https://www.processon.com/view/link/5f7e895be0b34d0711f65178

nacos最主要的功能就是服務註冊及發現，那它究竟是如何實現的呢？博主用的springboot開發的，因此直接就去找nacos的jar包下的spring.factories，這是每一個要自動注入的服務jar的必備文件，咱們來看一下

 

 

 　　裏面有不少的自動配置類，咱們只看一下NacosServiceRegistryAutoConfiguration，該類主要作的是服務註冊的相關事宜，若是你們第一次看源碼的話不知道該如何下手，最笨的方法就是一個一個看。總會找到的，最好要找名字看起來就像本身找的，由於這是阿里巴巴開發的，他們是有java開發規範的，要作到見名知意。

 1  /**
 2      * @author xiaojing
 3      * @author <a href="mailto:mercyblitz@gmail.com">Mercy</a>
 4      */
 5     @Configuration(proxyBeanMethods = false)
 6     @EnableConfigurationProperties
 7     @ConditionalOnNacosDiscoveryEnabled
 8     @ConditionalOnProperty(value = "spring.cloud.service-registry.auto-registration.enabled",
 9             matchIfMissing = true)
10     @AutoConfigureAfter({ AutoServiceRegistrationConfiguration.class,
11             AutoServiceRegistrationAutoConfiguration.class,
12             NacosDiscoveryAutoConfiguration.class })
13     public class NacosServiceRegistryAutoConfiguration {
14 
15         @Bean
16         public NacosServiceRegistry nacosServiceRegistry(
17                 NacosDiscoveryProperties nacosDiscoveryProperties) {
18             return new NacosServiceRegistry(nacosDiscoveryProperties);
19         }
20 
21         @Bean
22         @ConditionalOnBean(AutoServiceRegistrationProperties.class)
23         public NacosRegistration nacosRegistration(
24                 NacosDiscoveryProperties nacosDiscoveryProperties,
25                 ApplicationContext context) {
26             return new NacosRegistration(nacosDiscoveryProperties, context);
27         }
28 
29         @Bean
30         @ConditionalOnBean(AutoServiceRegistrationProperties.class)
31         public NacosAutoServiceRegistration nacosAutoServiceRegistration(
32                 NacosServiceRegistry registry,
33                 AutoServiceRegistrationProperties autoServiceRegistrationProperties,
34                 NacosRegistration registration) {
35             //這裏纔是自動注入的類，咱們須要進去看一下
36             return new NacosAutoServiceRegistration(registry,
37                     autoServiceRegistrationProperties, registration);
38         }
39 
40     }

 1 public class NacosAutoServiceRegistration
 2         extends AbstractAutoServiceRegistration<Registration> {
 3 
 4     private static final Logger log = LoggerFactory
 5             .getLogger(NacosAutoServiceRegistration.class);
 6 
 7     private NacosRegistration registration;
 8 
 9     public NacosAutoServiceRegistration(ServiceRegistry<Registration> serviceRegistry,
10             AutoServiceRegistrationProperties autoServiceRegistrationProperties,
11             NacosRegistration registration) {
12         super(serviceRegistry, autoServiceRegistrationProperties);
13         this.registration = registration;
14     }
15 
16     @Deprecated
17     public void setPort(int port) {
18         getPort().set(port);
19     }
20 
21     @Override
22     protected NacosRegistration getRegistration() {
23         if (this.registration.getPort() < 0 && this.getPort().get() > 0) {
24             this.registration.setPort(this.getPort().get());
25         }
26         Assert.isTrue(this.registration.getPort() > 0, "service.port has not been set");
27         return this.registration;
28     }
29 
30     @Override
31     protected NacosRegistration getManagementRegistration() {
32         return null;
33     }
34 
35     @Override
36     protected void register() {
37         if (!this.registration.getNacosDiscoveryProperties().isRegisterEnabled()) {
38             log.debug("Registration disabled.");
39             return;
40         }
41         if (this.registration.getPort() < 0) {
42             this.registration.setPort(getPort().get());
43         }
44         super.register();
45     }
46 
47     @Override
48     protected void registerManagement() {
49         if (!this.registration.getNacosDiscoveryProperties().isRegisterEnabled()) {
50             return;
51         }
52         super.registerManagement();
53 
54     }
55 
56     @Override
57     protected Object getConfiguration() {
58         return this.registration.getNacosDiscoveryProperties();
59     }
60 
61     @Override
62     protected boolean isEnabled() {
63         return this.registration.getNacosDiscoveryProperties().isRegisterEnabled();
64     }
65 
66     @Override
67     @SuppressWarnings("deprecation")
68     protected String getAppName() {
69         String appName = registration.getNacosDiscoveryProperties().getService();
70         return StringUtils.isEmpty(appName) ? super.getAppName() : appName;
71     }
72 
73 }

看到這裏，你們可能有點懵，我應該找那個方法呢？你們能夠看一下構造器中，引用了父類，當咱們看到父類的時候，發現父類實現了ApplicationListener，這個類你們不陌生，系統會自動執行其onApplicationEvent而正好咱們的類實現了這個方法，最後咱們發現了應該看register() 方法，你們能夠來看看這個方法的實現

 1 @Override
 2     public void register(Registration registration) {
 3 
 4         if (StringUtils.isEmpty(registration.getServiceId())) {
 5             log.warn("No service to register for nacos client...");
 6             return;
 7         }
 8         //看到這兩個參數，你們看過nacos文檔就知道這兩個參數要幹啥用了
 9         String serviceId = registration.getServiceId();
10         String group = nacosDiscoveryProperties.getGroup();
11         //要發送的實例對象，具體的屬性，你們能夠看看這個方法
12         Instance instance = getNacosInstanceFromRegistration(registration);
13 
14         try {
15         //走這裏，是真正的註冊服務
16             namingService.registerInstance(serviceId, group, instance);
17             log.info("nacos registry, {} {} {}:{} register finished", group, serviceId,
18                     instance.getIp(), instance.getPort());
19         }
20         catch (Exception e) {
21             log.error("nacos registry, {} register failed...{},", serviceId,
22                     registration.toString(), e);
23             // rethrow a RuntimeException if the registration is failed.
24             // issue : https://github.com/alibaba/spring-cloud-alibaba/issues/1132
25             rethrowRuntimeException(e);
26         }
27     }

 1     @Override
 2     public void registerInstance(String serviceName, String groupName, Instance instance) throws NacosException {
 3          //是不是臨時的，這個參數默認是臨時實例，這個是臨時或者是否持久很重要，先記住
 4         if (instance.isEphemeral()) {
 5             //填寫各類心跳信息，畢竟服務須要往nacos發送心跳，nacos才能知道該服務是否還存活
 6             BeatInfo beatInfo = new BeatInfo();
 7             beatInfo.setServiceName(NamingUtils.getGroupedName(serviceName, groupName));
 8             beatInfo.setIp(instance.getIp());
 9             beatInfo.setPort(instance.getPort());
10             beatInfo.setCluster(instance.getClusterName());
11             beatInfo.setWeight(instance.getWeight());
12             beatInfo.setMetadata(instance.getMetadata());
13             beatInfo.setScheduled(false);
14             beatInfo.setPeriod(instance.getInstanceHeartBeatInterval());
15             //看一下客服端是如何發送心跳
16             beatReactor.addBeatInfo(NamingUtils.getGroupedName(serviceName, groupName), beatInfo);
17         }
18         //註冊服務
19         serverProxy.registerService(NamingUtils.getGroupedName(serviceName, groupName), groupName, instance);
20     }

 1         @Override
 2         public void run() {
 3             if (beatInfo.isStopped()) {
 4                 return;
 5             }
 6             long nextTime = beatInfo.getPeriod();
 7             try {
 8                 //會調用nacos服務端的/instance/beat接口
 9                 JSONObject result = serverProxy.sendBeat(beatInfo, BeatReactor.this.lightBeatEnabled);
10                 long interval = result.getIntValue("clientBeatInterval");
11                 boolean lightBeatEnabled = false;
12                 if (result.containsKey(CommonParams.LIGHT_BEAT_ENABLED)) {
13                     lightBeatEnabled = result.getBooleanValue(CommonParams.LIGHT_BEAT_ENABLED);
14                 }
15                 BeatReactor.this.lightBeatEnabled = lightBeatEnabled;
16                 if (interval > 0) {
17                     nextTime = interval;
18                 }
19                 int code = NamingResponseCode.OK;
20                 if (result.containsKey(CommonParams.CODE)) {
21                     code = result.getIntValue(CommonParams.CODE);
22                 }
23                 //若是找不到服務，則進行註冊服務
24                 if (code == NamingResponseCode.RESOURCE_NOT_FOUND) {
25                     Instance instance = new Instance();
26                     instance.setPort(beatInfo.getPort());
27                     instance.setIp(beatInfo.getIp());
28                     instance.setWeight(beatInfo.getWeight());
29                     instance.setMetadata(beatInfo.getMetadata());
30                     instance.setClusterName(beatInfo.getCluster());
31                     instance.setServiceName(beatInfo.getServiceName());
32                     instance.setInstanceId(instance.getInstanceId());
33                     instance.setEphemeral(true);
34                     try {
35                         //該方法封裝好參數後，會調用/instance接口
36                         serverProxy.registerService(beatInfo.getServiceName(),
37                             NamingUtils.getGroupName(beatInfo.getServiceName()), instance);
38                     } catch (Exception ignore) {
39                     }
40                 }
41             } catch (NacosException ne) {
42                 NAMING_LOGGER.error("[CLIENT-BEAT] failed to send beat: {}, code: {}, msg: {}",
43                     JSON.toJSONString(beatInfo), ne.getErrCode(), ne.getErrMsg());
44 
45             }
46             //定時線程池不會一直循環進行調用，因此每次執行完以後會繼續添加定時任務進行發送心跳
47             executorService.schedule(new BeatTask(beatInfo), nextTime, TimeUnit.MILLISECONDS);
48         }

　　看完發送心跳的方法，咱們該看註冊服務的方法了：serverProxy.registerService(NamingUtils.getGroupedName(serviceName, groupName), groupName, instance);其實就是發送心跳後，找不到服務時調用的/instance接口。

　　到此，咱們的服務就會註冊到nacos服務端中，客戶端的代碼就是如此，仍是挺簡單的，咱們下一篇就會帶你們走進服務端的代碼。