This time we followed the article to "4 source code analysis --- SOFARPC server exposure" to talk about after being called Client Server service after exposure is how to return the data.
Examples of the article and we still use the same bolt as the agreement is concerned:
public static void main(String[] args) {
ServerConfig serverConfig = new ServerConfig()
.setProtocol("bolt") // 设置一个协议，默认bolt
.setPort(12200) // 设置一个端口，默认12200
.setDaemon(false); // 非守护线程
ProviderConfig<HelloService> providerConfig = new ProviderConfig<HelloService>()
.setInterfaceId(HelloService.class.getName()) // 指定接口
.setRef(new HelloServiceImpl()) // 指定实现
.setServer(serverConfig); // 指定服务端
providerConfig.export(); // 发布服务
}Bolt the following protocol, the server process is invoked when a service is as follows:
BoltServerProcessor-> FilterChain-> ProviderExceptionFilter-> FilterInvoker-> RpcServiceContextFilter-> FilterInvoker-> ProviderBaggageFilter-> FilterInvoker-> ProviderTracerFilter-> ProviderInvoker
BoltServerProcessor # handleRequest
@Override
public void handleRequest(BizContext bizCtx, AsyncContext asyncCtx, SofaRequest request) {
// RPC内置上下文
RpcInternalContext context = RpcInternalContext.getContext();
context.setProviderSide(true);
String appName = request.getTargetAppName();
if (appName == null) {
// 默认全局appName
appName = (String) RpcRuntimeContext.get(RpcRuntimeContext.KEY_APPNAME);
}
// 是否链路异步化中
boolean isAsyncChain = false;
try { // 这个 try-finally 为了保证Context一定被清理
processingCount.incrementAndGet(); // 统计值加1
context.setRemoteAddress(bizCtx.getRemoteHost(), bizCtx.getRemotePort()); // 远程地址
context.setAttachment(RpcConstants.HIDDEN_KEY_ASYNC_CONTEXT, asyncCtx); // 远程返回的通道
if (RpcInternalContext.isAttachmentEnable()) {
InvokeContext boltInvokeCtx = bizCtx.getInvokeContext();
if (boltInvokeCtx != null) {
putToContextIfNotNull(boltInvokeCtx, InvokeContext.BOLT_PROCESS_WAIT_TIME,
context, RpcConstants.INTERNAL_KEY_PROCESS_WAIT_TIME); // rpc线程池等待时间 Long
}
}
if (EventBus.isEnable(ServerReceiveEvent.class)) {
EventBus.post(new ServerReceiveEvent(request));
}
// 开始处理
SofaResponse response = null; // 响应，用于返回
Throwable throwable = null; // 异常，用于记录
ProviderConfig providerConfig = null;
String serviceName = request.getTargetServiceUniqueName();
try { // 这个try-catch 保证一定有Response
invoke:
{
if (!boltServer.isStarted()) { // 服务端已关闭
throwable = new SofaRpcException(RpcErrorType.SERVER_CLOSED, LogCodes.getLog(
LogCodes.WARN_PROVIDER_STOPPED, SystemInfo.getLocalHost() + ":" +
boltServer.serverConfig.getPort()));
response = MessageBuilder.buildSofaErrorResponse(throwable.getMessage());
break invoke;
}
if (bizCtx.isRequestTimeout()) { // 加上丢弃超时的请求的逻辑
throwable = clientTimeoutWhenReceiveRequest(appName, serviceName, bizCtx.getRemoteAddress());
break invoke;
}
// 查找服务
//在server.registerProcessor方法中设置 ProviderProxyInvoker
Invoker invoker = boltServer.findInvoker(serviceName);
if (invoker == null) {
throwable = cannotFoundService(appName, serviceName);
response = MessageBuilder.buildSofaErrorResponse(throwable.getMessage());
break invoke;
}
if (invoker instanceof ProviderProxyInvoker) {
providerConfig = ((ProviderProxyInvoker) invoker).getProviderConfig();
// 找到服务后，打印服务的appName
appName = providerConfig != null ? providerConfig.getAppName() : null;
}
// 查找方法
String methodName = request.getMethodName();
//在server.registerProcessor方法中设置
Method serviceMethod = ReflectCache.getOverloadMethodCache(serviceName, methodName,
request.getMethodArgSigs());
if (serviceMethod == null) {
throwable = cannotFoundServiceMethod(appName, methodName, serviceName);
response = MessageBuilder.buildSofaErrorResponse(throwable.getMessage());
break invoke;
} else {
request.setMethod(serviceMethod);
}
// 真正调用
response = doInvoke(serviceName, invoker, request);
if (bizCtx.isRequestTimeout()) { // 加上丢弃超时的响应的逻辑
throwable = clientTimeoutWhenSendResponse(appName, serviceName, bizCtx.getRemoteAddress());
break invoke;
}
}
} catch (Exception e) {
// 服务端异常，不管是啥异常
LOGGER.errorWithApp(appName, "Server Processor Error!", e);
throwable = e;
response = MessageBuilder.buildSofaErrorResponse(e.getMessage());
}
// Response不为空，代表需要返回给客户端
if (response != null) {
RpcInvokeContext invokeContext = RpcInvokeContext.peekContext();
isAsyncChain = CommonUtils.isTrue(invokeContext != null ?
(Boolean) invokeContext.remove(RemotingConstants.INVOKE_CTX_IS_ASYNC_CHAIN) : null);
// 如果是服务端异步代理模式，特殊处理，因为该模式是在业务代码自主异步返回的
if (!isAsyncChain) {
// 其它正常请求
try { // 这个try-catch 保证一定要记录tracer
asyncCtx.sendResponse(response);
} finally {
if (EventBus.isEnable(ServerSendEvent.class)) {
EventBus.post(new ServerSendEvent(request, response, throwable));
}
}
}
}
} catch (Throwable e) {
// 可能有返回时的异常
if (LOGGER.isErrorEnabled(appName)) {
LOGGER.errorWithApp(appName, e.getMessage(), e);
}
} finally {
processingCount.decrementAndGet();
if (!isAsyncChain) {
if (EventBus.isEnable(ServerEndHandleEvent.class)) {
EventBus.post(new ServerEndHandleEvent());
}
}
RpcInvokeContext.removeContext();
RpcInternalContext.removeAllContext();
}
}This method is mainly to do the following things:
- Set the context parameters
- Get invoker set when the service is exposed from the cache
- Set the method parameter to request
- Call doInvoke return response
- The response back to the client
BoltServerProcessor # doInvoke
We go directly to the doInvoke method, is to see how to generate the response object.
private SofaResponse doInvoke(String serviceName, Invoker invoker, SofaRequest request) throws SofaRpcException {
// 开始调用，先记下当前的ClassLoader
ClassLoader rpcCl = Thread.currentThread().getContextClassLoader();
try {
// 切换线程的ClassLoader到 服务 自己的ClassLoader
ClassLoader serviceCl = ReflectCache.getServiceClassLoader(serviceName);
Thread.currentThread().setContextClassLoader(serviceCl);
return invoker.invoke(request);
} finally {
Thread.currentThread().setContextClassLoader(rpcCl);
}
}Here primarily to obtain a class loader to load the cache and is exposed and services, which prevents a different class is the class loader to load a plurality of times.
Then call the filter chain, and finally into the ProviderInvoker
ProviderInvoker#invoke
@Override
public SofaResponse invoke(SofaRequest request) throws SofaRpcException {
SofaResponse sofaResponse = new SofaResponse();
long startTime = RpcRuntimeContext.now();
try {
// 反射 真正调用业务代码
Method method = request.getMethod();
if (method == null) {
throw new SofaRpcException(RpcErrorType.SERVER_FILTER, "Need decode method first!");
}
Object result = method.invoke(providerConfig.getRef(), request.getMethodArgs());
sofaResponse.setAppResponse(result);
} catch (IllegalArgumentException e) { // 非法参数，可能是实现类和接口类不对应)
sofaResponse.setErrorMsg(e.getMessage());
} catch (IllegalAccessException e) { // 如果此 Method 对象强制执行 Java 语言访问控制，并且底层方法是不可访问的
sofaResponse.setErrorMsg(e.getMessage());
} catch (InvocationTargetException e) { // 业务代码抛出异常
cutCause(e.getCause());
sofaResponse.setAppResponse(e.getCause());
} finally {
if (RpcInternalContext.isAttachmentEnable()) {
long endTime = RpcRuntimeContext.now();
RpcInternalContext.getContext().setAttachment(RpcConstants.INTERNAL_KEY_IMPL_ELAPSE,
endTime - startTime);
}
}
return sofaResponse;
}Finally we have to find the server service method will be invoked by reflection exposed, encapsulated Response class return.
Once again, we return to BoltServerProcessor # handleRequest method
....//忽略其他内容
// Response不为空，代表需要返回给客户端
if (response != null) {
RpcInvokeContext invokeContext = RpcInvokeContext.peekContext();
isAsyncChain = CommonUtils.isTrue(invokeContext != null ?
(Boolean) invokeContext.remove(RemotingConstants.INVOKE_CTX_IS_ASYNC_CHAIN) : null);
// 如果是服务端异步代理模式，特殊处理，因为该模式是在业务代码自主异步返回的
if (!isAsyncChain) {
// 其它正常请求
try { // 这个try-catch 保证一定要记录tracer
asyncCtx.sendResponse(response);
} finally {
if (EventBus.isEnable(ServerSendEvent.class)) {
EventBus.post(new ServerSendEvent(request, response, throwable));
}
}
}
}
....//忽略其他内容Finally, we will use the example of netty response to the client.