Nacos（一）原始碼分析Nacos註冊示例流程
阿新 • • 發佈：2020-12-26
nacos官方地址：https://nacos.io/zh-cn/
大家可以看一下nacos的中文手冊以及官方原始碼，博主就不帶領大家快速入門 了，官方文件中都有而且非常標準，比其他部落格寫的好多了並且還是實時更新的。
先看一下博主給大家畫的流程圖，掌握一下大概的基本流程，好理解，博主給大家講原始碼：
https://www.processon.com/view/link/5f7e895be0b34d0711f65178
nacos最主要的功能就是服務註冊及發現，那它到底是如何實現的呢？博主用的springboot開發的，所以直接就去找nacos的jar包下的spring.factories，這是每個要自動注入的服務jar的必備檔案，我們來看一下
裡面有很多的自動配置類，我們只看一下NacosServiceRegistryAutoConfiguration，該類主要做的是服務註冊的相關事宜，如果大家第一次看原始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自己找的，因為這是阿里巴巴開發的，他們是有java開發規範的，要做到見名知意。
1 /** 2 * @author xiaojing 3 * @author <a href="mailto:[email protected]">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 //這裡才是自動注入的類，我們需要進去看一下 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 }看到這裡，大家可能有點懵，我應該找那個方法呢？大家可以看一下構造器中，引用了父類，當我們看到父類的時候，發現父類實現了ApplicationListener，這個類大家不陌生，系統會自動執行其onApplicationEvent而正好我們的類實現了這個方法，最後我們發現了應該看register() 方法，大家可以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 //看到這兩個引數，大家看過nacos文件就知道這兩個引數要幹啥用了
9 String serviceId = registration.getServiceId();
10 String group = nacosDiscoveryProperties.getGroup();
11 //要傳送的例項物件，具體的屬性，大家可以看看這個方法
12 Instance instance = getNacosInstanceFromRegistration(registration);
13
14 try {
15 //走這裡，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 //是否是臨時的，這個引數預設是臨時例項，這個是臨時或者是否持久很重要，先記住
4 if (instance.isEphemeral()) {
5 //填寫各種心跳資訊，畢竟服務需要往nacos傳送心跳，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傳送心跳
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 //會呼叫nacos服務端的/instance/beat介面
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 //如果找不到服務，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 //該方法封裝好引數後，會呼叫/instance介面
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 //定時執行緒池不會一直迴圈進行呼叫，所以每次執行完之後會繼續新增定時任務進行傳送心跳
47 executorService.schedule(new BeatTask(beatInfo), nextTime, TimeUnit.MILLISECONDS);
48 }
看完傳送心跳的方法，我們該看註冊服務的方法了：serverProxy.registerService(NamingUtils.getGroupedName(serviceName, groupName), groupName, instance);其實就是傳送心跳後，找不到服務時呼叫的/instance介面。
到此，我們的服務就會註冊到nacos服務端中，客戶端的程式碼就是如此，還是挺簡單的，我們下一篇就會帶大家走進服務端的程式碼。
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