dubbo-远程服务暴露
DubboBootstrapApplicationListener
继承体系图
源码解析
public class DubboBootstrapApplicationListener extends OneTimeExecutionApplicationContextEventListener
implements Ordered {
/**
* The bean name of {@link DubboBootstrapApplicationListener}
*
* @since 2.7.6
*/
public static final String BEAN_NAME = "dubboBootstrapApplicationListener";
private final DubboBootstrap dubboBootstrap;
public DubboBootstrapApplicationListener() {
this.dubboBootstrap = DubboBootstrap.getInstance();
}
/**
* 在Spring容器初始化完成后执行某个方法 防止onApplicationEvent方法被执行两次
*/
@Override
public void onApplicationContextEvent(ApplicationContextEvent event) {
if (event instanceof ContextRefreshedEvent) {
onContextRefreshedEvent((ContextRefreshedEvent) event);
} else if (event instanceof ContextClosedEvent) {
onContextClosedEvent((ContextClosedEvent) event);
}
}
/**
* ContextRefreshedEvent 事件会在Spring容器初始化完成会触发该事件
*/
private void onContextRefreshedEvent(ContextRefreshedEvent event) {
dubboBootstrap.start();
}
/**
* close是spring容器真正销毁了才会触发
*/
private void onContextClosedEvent(ContextClosedEvent event) {
dubboBootstrap.stop();
}
@Override
public int getOrder() {
return LOWEST_PRECEDENCE;
}
}DubboBootstrap#start()
start()方法
/**
* Start the bootstrap
*/
public DubboBootstrap start() {
// 只初始化一次
if (started.compareAndSet(false, true)) {
ready.set(false);
initialize();
if (logger.isInfoEnabled()) {
logger.info(NAME + " is starting...");
}
// 导入dubbo服务
exportServices();
// Not only provider register
if (!isOnlyRegisterProvider() || hasExportedServices()) {
// 2. export MetadataService
exportMetadataService();
//3. Register the local ServiceInstance if required
registerServiceInstance();
}
referServices();
if (asyncExportingFutures.size() > 0) {
new Thread(() -> {
try {
this.awaitFinish();
} catch (Exception e) {
logger.warn(NAME + " exportAsync occurred an exception.");
}
ready.set(true);
if (logger.isInfoEnabled()) {
logger.info(NAME + " is ready.");
}
}).start();
} else {
ready.set(true);
if (logger.isInfoEnabled()) {
logger.info(NAME + " is ready.");
}
}
if (logger.isInfoEnabled()) {
logger.info(NAME + " has started.");
}
}
return this;
}- initialize方法
在start方法中，也会调用initialize方法，之前提到过，服务端启动的时候，dubbo在start方法中调用initialize方法做初始化，而客户端启动的时候会跳过initialize方法。
-
exportServices方法
initialize方法之后调用exportServices方法，该方法用于暴露服务，服务端使用
private void exportServices() { //创建的每个ServiceConfig对象都添加到configManager，下面获取所有的ServiceConfig对象并遍历 configManager.getServices().forEach(sc -> { // TODO, compatible with ServiceConfig.export() ServiceConfig serviceConfig = (ServiceConfig) sc; serviceConfig.setBootstrap(this); if (exportAsync) { 异步暴露，使用线程池暴露服务 ExecutorService executor = executorRepository.getServiceExporterExecutor(); Future future = executor.submit(() -> { //暴露服务 sc.export(); //;//记录所有暴露的服务 exportedServices.add(sc); }); asyncExportingFutures.add(future); } else { sc.export(); exportedServices.add(sc); } }); }public synchronized void export() { if (this.shouldExport()) { if (this.bootstrap == null) { this.bootstrap = DubboBootstrap.getInstance(); this.bootstrap.initialize(); } this.checkAndUpdateSubConfigs(); this.serviceMetadata.setVersion(this.getVersion()); this.serviceMetadata.setGroup(this.getGroup()); this.serviceMetadata.setDefaultGroup(this.getGroup()); this.serviceMetadata.setServiceType(this.getInterfaceClass()); this.serviceMetadata.setServiceInterfaceName(this.getInterface()); this.serviceMetadata.setTarget(this.getRef()); if (this.shouldDelay()) { DELAY_EXPORT_EXECUTOR.schedule(this::doExport, (long)this.getDelay(), TimeUnit.MILLISECONDS); } else { this.doExport(); } this.exported(); } } - hasExportedServices方法
hasExportedServices()检查是否配置元数据中心的url，如果配置了，返回true。
- exportMetadataService
exportMetadataService方法用于暴露本地元数据服务
private void exportMetadataService() { metadataServiceExporters .stream() .filter(this::supports) .forEach(MetadataServiceExporter::export); } - registerServiceInstance方法
registerServiceInstance用于将dubbo实例注册到专用于服务发现的注册中心。
- referServices方法
referServices方法用于处理ReferenceConfig对象，但是这里有个问题。
ServiceConfig
继承体系图
doExportUrlsFor1Protocol()方法
private void doExportUrlsFor1Protocol(ProtocolConfig protocolConfig, List registryURLs) {
String name = protocolConfig.getName();
if (StringUtils.isEmpty(name)) {
name = "dubbo";
}
Map map = new HashMap();
map.put("side", "provider");
appendRuntimeParameters(map);
AbstractConfig.appendParameters(map, this.getMetrics());
AbstractConfig.appendParameters(map, this.getApplication());
AbstractConfig.appendParameters(map, this.getModule());
AbstractConfig.appendParameters(map, this.provider);
AbstractConfig.appendParameters(map, protocolConfig);
AbstractConfig.appendParameters(map, this);
MetadataReportConfig metadataReportConfig = this.getMetadataReportConfig();
if (metadataReportConfig != null && metadataReportConfig.isValid()) {
map.putIfAbsent("metadata-type", "remote");
}
String scope;
Iterator var10;
if (CollectionUtils.isNotEmpty(this.getMethods())) {
Iterator var6 = this.getMethods().iterator();
label172:
while(true) {
MethodConfig method;
List arguments;
do {
if (!var6.hasNext()) {
break label172;
}
method = (MethodConfig)var6.next();
AbstractConfig.appendParameters(map, method, method.getName());
String retryKey = method.getName() + ".retry";
if (map.containsKey(retryKey)) {
scope = (String)map.remove(retryKey);
if ("false".equals(scope)) {
map.put(method.getName() + ".retries", "0");
}
}
arguments = method.getArguments();
} while(!CollectionUtils.isNotEmpty(arguments));
var10 = arguments.iterator();
while(true) {
ArgumentConfig argument;
Method[] methods;
do {
while(true) {
if (!var10.hasNext()) {
continue label172;
}
argument = (ArgumentConfig)var10.next();
if (argument.getType() != null && argument.getType().length() > 0) {
methods = this.interfaceClass.getMethods();
break;
}
if (argument.getIndex() == -1) {
throw new IllegalArgumentException("Argument config must set index or type attribute.eg: URL地址
dubbo://10.0.73.222:20880/com.jd.dubbo.EchoService?anyhost=true&application=echo-provider&bind.ip=10.0.73.222&bind.port=20880&deprecated=false&dubbo=2.0.2&dynamic=true&generic=false&interface=com.jd.dubbo.EchoService&metadata-type=remote&methods=echo,hello&pid=74193&release=2.7.8&side=provider&timeout=1000×tamp=1628125664210