版权声明:署名,允许他人基于本文进行创作,且必须基于与原先许可协议相同的许可协议分发本文 (Creative Commons)
处理请求,判断请求是否已经被损坏
void handleRequest(final ExchangeChannel channel, Request req) throws RemotingException {
Response res = new Response(req.getId(), req.getVersion());
if (req.isBroken()) {
Object data = req.getData();
String msg;
if (data == null) {
msg = null;
} else if (data instanceof Throwable) {
msg = StringUtils.toString((Throwable) data);
} else {
msg = data.toString();
}
res.setErrorMessage("Fail to decode request due to: " + msg);
res.setStatus(Response.BAD_REQUEST);
channel.send(res);
return;
}
// find handler by message class.
Object msg = req.getData();
try {
// handle data.
CompletableFuture<Object> future = handler.reply(channel, msg);
if (future.isDone()) {
res.setStatus(Response.OK);
res.setResult(future.get());
channel.send(res);
return;
}
future.whenComplete((result, t) -> {
try {
if (t == null) {
res.setStatus(Response.OK);
res.setResult(result);
} else {
res.setStatus(Response.SERVICE_ERROR);
res.setErrorMessage(StringUtils.toString(t));
}
channel.send(res);
} catch (RemotingException e) {
logger.warn("Send result to consumer failed, channel is " + channel + ", msg is " + e);
} finally {
// HeaderExchangeChannel.removeChannelIfDisconnected(channel);
}
});
} catch (Throwable e) {
res.setStatus(Response.SERVICE_ERROR);
res.setErrorMessage(StringUtils.toString(e));
channel.send(res);
}
}
处理请求
class DubboProtocol extends AbstractProtocol
public CompletableFuture<Object> reply(ExchangeChannel channel, Object message) throws RemotingException {
if (!(message instanceof Invocation)) {
throw new RemotingException(channel, "Unsupported request: "
+ (message == null ? null : (message.getClass().getName() + ": " + message))
+ ", channel: consumer: " + channel.getRemoteAddress() + " --> provider: " + channel.getLocalAddress());
}
Invocation inv = (Invocation) message;
Invoker<?> invoker = getInvoker(channel, inv);
// need to consider backward-compatibility if it's a callback
if (Boolean.TRUE.toString().equals(inv.getAttachments().get(IS_CALLBACK_SERVICE_INVOKE))) {
String methodsStr = invoker.getUrl().getParameters().get("methods");
boolean hasMethod = false;
if (methodsStr == null || !methodsStr.contains(",")) {
hasMethod = inv.getMethodName().equals(methodsStr);
} else {
String[] methods = methodsStr.split(",");
for (String method : methods) {
if (inv.getMethodName().equals(method)) {
hasMethod = true;
break;
}
}
}
if (!hasMethod) {
logger.warn(new IllegalStateException("The methodName " + inv.getMethodName()
+ " not found in callback service interface ,invoke will be ignored."
+ " please update the api interface. url is:"
+ invoker.getUrl()) + " ,invocation is :" + inv);
return null;
}
}
RpcContext rpcContext = RpcContext.getContext();
rpcContext.setRemoteAddress(channel.getRemoteAddress());
Result result = invoker.invoke(inv);
if (result instanceof AsyncRpcResult) {
return ((AsyncRpcResult) result).getResultFuture().thenApply(r -> (Object) r);
} else {
return CompletableFuture.completedFuture(result);
}
}
获取暴露的invoker代理
Invoker<?> getInvoker(Channel channel, Invocation inv) throws RemotingException {
boolean isCallBackServiceInvoke = false;
boolean isStubServiceInvoke = false;
int port = channel.getLocalAddress().getPort();
String path = inv.getAttachments().get(Constants.PATH_KEY);
// if it's callback service on client side
isStubServiceInvoke = Boolean.TRUE.toString().equals(inv.getAttachments().get(Constants.STUB_EVENT_KEY));
if (isStubServiceInvoke) {
port = channel.getRemoteAddress().getPort();
}
//callback
isCallBackServiceInvoke = isClientSide(channel) && !isStubServiceInvoke;
if (isCallBackServiceInvoke) {
path += "." + inv.getAttachments().get(Constants.CALLBACK_SERVICE_KEY);
inv.getAttachments().put(IS_CALLBACK_SERVICE_INVOKE, Boolean.TRUE.toString());
}
String serviceKey = serviceKey(port, path, inv.getAttachments().get(Constants.VERSION_KEY), inv.getAttachments().get(Constants.GROUP_KEY));
DubboExporter<?> exporter = (DubboExporter<?>) exporterMap.get(serviceKey);
if (exporter == null) {
throw new RemotingException(channel, "Not found exported service: " + serviceKey + " in " + exporterMap.keySet() + ", may be version or group mismatch " +
", channel: consumer: " + channel.getRemoteAddress() + " --> provider: " + channel.getLocalAddress() + ", message:" + inv);
}
return exporter.getInvoker();
}
执行过滤器EchoFilter,ClassLoaderFilter,GenericFilter,ContextFilter,TraceFilter,TimeoutFilter,MonitorFilter,ExceptionFilter
class ProtocolFilterWrapper implements Protocol
public Result invoke(Invocation invocation) throws RpcException {
Result result = filter.invoke(next, invocation);
if (result instanceof AsyncRpcResult) {
AsyncRpcResult asyncResult = (AsyncRpcResult) result;
asyncResult.thenApplyWithContext(r -> filter.onResponse(r, invoker, invocation));
return asyncResult;
} else {
return filter.onResponse(result, invoker, invocation);
}
}
执行invoker包装代理类
class InvokerDelegate<T> extends InvokerWrapper<T>
public Result invoke(Invocation invocation) throws RpcException {
return invoker.invoke(invocation);
}
class DelegateProviderMetaDataInvoker<T>
public Result invoke(Invocation invocation) throws RpcException {
return invoker.invoke(invocation);
}
执行动态代理类
public Result invoke(Invocation invocation) throws RpcException {
RpcContext rpcContext = RpcContext.getContext();
try {
Object obj = doInvoke(proxy, invocation.getMethodName(), invocation.getParameterTypes(), invocation.getArguments());
if (RpcUtils.isReturnTypeFuture(invocation)) {
return new AsyncRpcResult((CompletableFuture<Object>) obj);
} else if (rpcContext.isAsyncStarted()) { // ignore obj in case of RpcContext.startAsync()? always rely on user to write back.
return new AsyncRpcResult(((AsyncContextImpl)(rpcContext.getAsyncContext())).getInternalFuture());
} else {
return new RpcResult(obj);
}
} catch (InvocationTargetException e) {
// TODO async throw exception before async thread write back, should stop asyncContext
if (rpcContext.isAsyncStarted() && !rpcContext.stopAsync()) {
logger.error("Provider async started, but got an exception from the original method, cannot write the exception back to consumer because an async result may have returned the new thread.", e);
}
return new RpcResult(e.getTargetException());
} catch (Throwable e) {
throw new RpcException("Failed to invoke remote proxy method " + invocation.getMethodName() + " to " + getUrl() + ", cause: " + e.getMessage(), e);
}
}
protected Object doInvoke(T proxy, String methodName,
Class<?>[] parameterTypes,
Object[] arguments) throws Throwable {
return wrapper.invokeMethod(proxy, methodName, parameterTypes, arguments);
}
请求处理完成后把结果发送给消费端
class HeaderExchangeChannel implements ExchangeChannel
public void send(Object message) throws RemotingException {
send(message, false);
}
@Override
public void send(Object message, boolean sent) throws RemotingException {
if (closed) {
throw new RemotingException(this.getLocalAddress(), null, "Failed to send message " + message + ", cause: The channel " + this + " is closed!");
}
if (message instanceof Request
|| message instanceof Response
|| message instanceof String) {
channel.send(message, sent);
} else {
Request request = new Request();
request.setVersion(Version.getProtocolVersion());
request.setTwoWay(false);
request.setData(message);
channel.send(request, sent);
}
}
写入通道
class NettyChannel extends AbstractChannel
public void send(Object message, boolean sent) throws RemotingException {
super.send(message, sent);
boolean success = true;
int timeout = 0;
try {
ChannelFuture future = channel.writeAndFlush(message);
if (sent) {
timeout = getUrl().getPositiveParameter(Constants.TIMEOUT_KEY, Constants.DEFAULT_TIMEOUT);
success = future.await(timeout);
}
Throwable cause = future.cause();
if (cause != null) {
throw cause;
}
} catch (Throwable e) {
throw new RemotingException(this, "Failed to send message " + message + " to " + getRemoteAddress() + ", cause: " + e.getMessage(), e);
}
if (!success) {
throw new RemotingException(this, "Failed to send message " + message + " to " + getRemoteAddress()
+ "in timeout(" + timeout + "ms) limit");
}
}
触发各个处理器的发送事件
class NettyServerHandler extends ChannelDuplexHandler
public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) throws Exception {
super.write(ctx, msg, promise);
NettyChannel channel = NettyChannel.getOrAddChannel(ctx.channel(), url, handler);
try {
handler.sent(channel, msg);
} finally {
NettyChannel.removeChannelIfDisconnected(ctx.channel());
}
}
消费端接收响应,依次经过NettyClient的父类AbstractPeer,MultiMessageHandler,HeartbeatHandler,AllChannelHandler
class NettyClientHandler extends ChannelDuplexHandler
public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
NettyChannel channel = NettyChannel.getOrAddChannel(ctx.channel(), url, handler);
try {
handler.received(channel, msg);
} finally {
NettyChannel.removeChannelIfDisconnected(ctx.channel());
}
}
针对响应解码
class DecodeHandler extends AbstractChannelHandlerDelegate
if (message instanceof Response) {
decode(((Response) message).getResult());
}
public void decode() throws Exception {
if (!hasDecoded && channel != null && inputStream != null) {
try {
decode(channel, inputStream);
} catch (Throwable e) {
if (log.isWarnEnabled()) {
log.warn("Decode rpc result failed: " + e.getMessage(), e);
}
response.setStatus(Response.CLIENT_ERROR);
response.setErrorMessage(StringUtils.toString(e));
} finally {
hasDecoded = true;
}
}
}
解析具体结果
public Object decode(Channel channel, InputStream input) throws IOException {
ObjectInput in = CodecSupport.getSerialization(channel.getUrl(), serializationType)
.deserialize(channel.getUrl(), input);
byte flag = in.readByte();
switch (flag) {
case DubboCodec.RESPONSE_NULL_VALUE:
break;
case DubboCodec.RESPONSE_VALUE:
handleValue(in);
break;
case DubboCodec.RESPONSE_WITH_EXCEPTION:
handleException(in);
break;
case DubboCodec.RESPONSE_NULL_VALUE_WITH_ATTACHMENTS:
handleAttachment(in);
break;
case DubboCodec.RESPONSE_VALUE_WITH_ATTACHMENTS:
handleValue(in);
handleAttachment(in);
break;
case DubboCodec.RESPONSE_WITH_EXCEPTION_WITH_ATTACHMENTS:
handleException(in);
handleAttachment(in);
break;
default:
throw new IOException("Unknown result flag, expect '0' '1' '2', get " + flag);
}
if (in instanceof Cleanable) {
((Cleanable) in).cleanup();
}
return this;
}
private void handleValue(ObjectInput in) throws IOException {
try {
Type[] returnTypes = RpcUtils.getReturnTypes(invocation);
Object value = null;
if (ArrayUtils.isEmpty(returnTypes)) {
value = in.readObject();
} else if (returnTypes.length == 1) {
value = in.readObject((Class<?>) returnTypes[0]);
} else {
value = in.readObject((Class<?>) returnTypes[0], returnTypes[1]);
}
setValue(value);
} catch (ClassNotFoundException e) {
rethrow(e);
}
}
处理响应,唤醒等待,返回结果
class HeaderExchangeHandler implements ChannelHandlerDelegate
if (message instanceof Response) {
handleResponse(channel, (Response) message);
}
static void handleResponse(Channel channel, Response response) throws RemotingException {
if (response != null && !response.isHeartbeat()) {
DefaultFuture.received(channel, response);
}
}