陳鵬輝(承飛) 大淘寶技術 2023-07-26 16:20 發表于浙江
本文從開發者的角度深入解析了基于netty的通信子產品, 并通過簡易擴充實作微服務化通信工具雛形, 适合于想要了解netty通信架構的使用案例, 想了解中間件通信子產品設計, 以及微服務通信底層架構的同學。希望此文能給大家帶來通信子產品架構靈感。
概述
網絡通信是很常見的需求,
對于傳統web網頁工具短連接配接場景,浏覽器和伺服器互動,常見為浏覽器通過http協定請求Tomcat伺服器;
對于長連接配接場景, 比如即時通訊,或中間件等實時性要求高的場景,一般采用tcp協定的長連接配接進行全雙工實時通信;
對于java開發者來說,使用原生socket進行tcp開發,效率是比較低的,穩定性可靠性等也不好保障,一般選擇網絡通信架構netty加快開發效率。
對于上層應用來說,netty的标準使用方式依然比較繁瑣,未能很好的适配一些業務使用場景,比如rocketMq根據netty包裝了一層業務架構:通信子產品remoting。
該子產品可用性高,穩定性好,易擴充,經過了中間件産品長期高并發的品質驗證, 值得信任,并廣泛用于其他點對點(指定ip)通信場景,如dleger(raft的java實作)。
有相關通信需求的同學也都可以參考該通信子產品,相信有很多的靈感,或直接使用該通信子產品,帶來開發效率的提升。
本文從一個普通java開發者的視角,去解析該通信子產品
- 如何用 - 常見使用方式
- 實作原理 - 資料流轉鍊路
- 設計關鍵點 - 為什麼要如此設計
- 子產品更新 - 實作簡易的微服務化通信工具
本文代碼版本:
<parent>
<groupId>org.apache.rocketmq</groupId>
<artifactId>rocketmq-remoting</artifactId>
<version>5.0.1-PREVIEW-SNAPSHOT</version>
</parent>
如何用
編寫簡單易懂的測試demo,實作server client的互動流程。
簡單示例 協定code 為寫死 0 1 5 9,輸入測試資訊,輸出使用sysout。
▐啟動server 注冊服務監聽
import com.alibaba.fastjson.JSON;
import io.netty.channel.ChannelHandlerContext;
import org.apache.rocketmq.remoting.RemotingServer;
import org.apache.rocketmq.remoting.netty.NettyRemotingServer;
import org.apache.rocketmq.remoting.netty.NettyRequestProcessor;
import org.apache.rocketmq.remoting.netty.NettyServerConfig;
import org.apache.rocketmq.remoting.protocol.RemotingCommand;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
public class Server {
public static void main(String[] args) throws Exception {
NettyServerConfig nettyServerConfig = new NettyServerConfig();
// 配置端口
nettyServerConfig.setListenPort(8888);
// 配置線程數 netty workGroup 線程池 處理io等低耗時
nettyServerConfig.setServerSelectorThreads(2);
// 配置線程數 netty eventGroup 線程池 處理自定義hander/長耗時等
nettyServerConfig.setServerWorkerThreads(8);
NettyRemotingServer remotingServer = new NettyRemotingServer(nettyServerConfig, null);
// 支援共用或獨立的業務處理線程池
ExecutorService poolA = new ThreadPoolExecutor(4, 4, 0, TimeUnit.SECONDS, new ArrayBlockingQueue<>(1024));
ExecutorService poolB = new ThreadPoolExecutor(4, 4, 0, TimeUnit.SECONDS, new ArrayBlockingQueue<>(1024));
// 業務處理器
NettyRequestProcessor processA = new NettyRequestProcessor() {
@Override
public RemotingCommand processRequest(ChannelHandlerContext ctx, RemotingCommand request) throws Exception {
System.out.println("received from client, remark:" + request.getRemark() + ", coe:" + request.getCode());
RemotingCommand response = RemotingCommand.createResponseCommand(0, "server");
switch (request.getCode()) {
case 0:
response.setBody(new String("hello sync 0").getBytes());
case 1:
response.setBody(new String("hello sync 1").getBytes());
default:
break;
}
return response;
}
@Override
public boolean rejectRequest() {
return false;
}
};
// 業務處理器
NettyRequestProcessor processB = new NettyRequestProcessor(){
@Override
public RemotingCommand processRequest(ChannelHandlerContext ctx, RemotingCommand request) throws Exception {
System.out.println("received from client, remark:" + request.getRemark() + ", coe:" + request.getCode());
RemotingCommand response = RemotingCommand.createResponseCommand(0, "server");
switch (request.getCode()) {
case 9:
response.setBody(new String("hello sync 9").getBytes());
default:
break;
}
return response;
}
@Override
public boolean rejectRequest() {
return false;
}
};
// 注冊 協定 - 對應的處理器, 類似web url 路由到對應的class
remotingServer.registerProcessor(0, processA, poolA);
remotingServer.registerProcessor(1, processA, poolA);
remotingServer.registerProcessor(9, processB, poolB);
remotingServer.start();
System.out.println("start ok " + JSON.toJSONString(nettyServerConfig));
System.in.read();
}
}
▐啟動client 發起調用
import io.netty.channel.ChannelHandlerContext;
import org.apache.rocketmq.remoting.InvokeCallback;
import org.apache.rocketmq.remoting.netty.NettyClientConfig;
import org.apache.rocketmq.remoting.netty.NettyRemotingClient;
import org.apache.rocketmq.remoting.netty.NettyRequestProcessor;
import org.apache.rocketmq.remoting.netty.ResponseFuture;
import org.apache.rocketmq.remoting.protocol.RemotingCommand;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
public class Client {
public static void main(String[] args) throws Exception {
NettyClientConfig nettyServerConfig = new NettyClientConfig();
// 配置線程數 netty eventGroup 線程池 處理自定義hander/耗時長等
nettyServerConfig.setClientWorkerThreads(8);
NettyRemotingClient remotingClient = new NettyRemotingClient(nettyServerConfig, null);
// 支援共用或獨立的業務處理線程池
ExecutorService poolA = new ThreadPoolExecutor(4, 4, 0, TimeUnit.SECONDS, new ArrayBlockingQueue<>(1024));
// 監聽服務端發過來的請求
remotingClient.registerProcessor(5, new NettyRequestProcessor() {
@Override
public RemotingCommand processRequest(ChannelHandlerContext ctx, RemotingCommand request) throws Exception {
System.out.println("receive from server : " + request.getCode());
return null;
}
@Override
public boolean rejectRequest() {
return false;
}
}, poolA);
remotingClient.start();
// 主動發起遠端調用
{
// 同步調用
RemotingCommand request = RemotingCommand.createRequestCommand(0, null);
request.setRemark("sync");
RemotingCommand response = remotingClient.invokeSync("127.0.0.1:8888", request, 30 * 1000L);
System.out.println("call sync ok remark:" + response.getRemark() + " body:" + new String(response.getBody()));
}
{
// 異步調用
RemotingCommand request = RemotingCommand.createRequestCommand(1, null);
request.setRemark("async");
remotingClient.invokeAsync("127.0.0.1:8888", request, 30 * 1000L, new InvokeCallback() {
@Override
public void operationComplete(ResponseFuture responseFuture) {
RemotingCommand response = responseFuture.getResponseCommand();
System.out.println("call async ok remark:" + response.getRemark() + " body:" + new String(response.getBody()));
}
});
}
{
// 單向調用
RemotingCommand request = RemotingCommand.createRequestCommand(9, null);
request.setRemark("oneway");
remotingClient.invokeOneway("127.0.0.1:8888", request, 30 * 1000L);
System.out.println("call oneway ok ");
}
System.in.read();
}
}
該點對點調用,是需要手動指定目标伺服器的ip和端口的,不同于hsf擁有注冊中心進行協調撮合提供目标ip。
▐日志輸出
Connected to the target VM, address: '127.0.0.1:57381', transport: 'socket'
start ok {"listenPort":8888,"serverAsyncSemaphoreValue":64,"serverCallbackExecutorThreads":0,"serverChannelMaxIdleTimeSeconds":120,"serverOnewaySemaphoreValue":256,"serverPooledByteBufAllocatorEnable":true,"serverSelectorThreads":2,"serverSocketRcvBufSize":65535,"serverSocketSndBufSize":65535,"serverWorkerThreads":8,"useEpollNativeSelector":false}
received from client, remark:sync, coe:0
received from client, remark:async, coe:1
received from client, remark:oneway, coe:9
Connected to the target VM, address: '127.0.0.1:57385', transport: 'socket'
call sync ok remark:server body:hello sync 1
call oneway ok
call async ok remark:server body:hello sync 1
實作原理
關于netty如何封裝java基礎nio socket不做展開。
這裡分析通信子產品是如何封裝netty,擴充調用協定規範的部分,重點描述其中關鍵的設計要點。
▐ server 啟動 監聽請求
作為服務端,需綁定端口,監聽請求,這裡采用标準netty服務端模式。
remotingServer.start();
@Override
public void start() {
...
ServerBootstrap childHandler =
this.serverBootstrap.group(this.eventLoopGroupBoss, this.eventLoopGroupSelector)
.channel(useEpoll() ? EpollServerSocketChannel.class : NioServerSocketChannel.class)
.option(ChannelOption.SO_BACKLOG, 1024)
.option(ChannelOption.SO_REUSEADDR, true)
.option(ChannelOption.SO_KEEPALIVE, false)
.childOption(ChannelOption.TCP_NODELAY, true)
.childOption(ChannelOption.SO_SNDBUF, nettyServerConfig.getServerSocketSndBufSize())
.childOption(ChannelOption.SO_RCVBUF, nettyServerConfig.getServerSocketRcvBufSize())
.localAddress(new InetSocketAddress(this.nettyServerConfig.getListenPort()))
.childHandler(new ChannelInitializer<SocketChannel>() {
@Override
public void initChannel(SocketChannel ch) throws Exception {
ch.pipeline()
.addLast(defaultEventExecutorGroup, HANDSHAKE_HANDLER_NAME, handshakeHandler)
.addLast(defaultEventExecutorGroup,
encoder,
new NettyDecoder(),
new IdleStateHandler(0, 0, nettyServerConfig.getServerChannelMaxIdleTimeSeconds()),
connectionManageHandler,
serverHandler
);
}
});
...
ChannelFuture sync = this.serverBootstrap.bind().sync();
InetSocketAddress addr = (InetSocketAddress) sync.channel().localAddress();
...
}
關注涉及幾個線程池的地方:
- bossGroup -> eventLoopGroupBoss 固定線程數1
- workerGroup -> eventLoopGroupSelector 若linux采用epoll實作 否則使用nio實作, 線程數可配置
- eventGroup -> defaultEventExecutorGroup 普通實作的 handler 工作線程池, 線程數可配置
另外就是傳統藝能:心跳, 解碼器 NettyEncoder,編碼器 NettyDecoder,連接配接管理器 connectionManageHandler,和最終的業務處理器 serverHandler
▐ server 注冊業務處理器
業務線程池配置
請求協定code關聯業務處理器
// 支援共用或獨立的業務處理線程池
ExecutorService poolA = new ThreadPoolExecutor(4, 4, 0, TimeUnit.SECONDS, new ArrayBlockingQueue<>(1024));
ExecutorService poolB = new ThreadPoolExecutor(4, 4, 0, TimeUnit.SECONDS, new ArrayBlockingQueue<>(1024));
// 業務處理器
NettyRequestProcessor processA = new NettyRequestProcessor() {
@Override
public RemotingCommand processRequest(ChannelHandlerContext ctx, RemotingCommand request) throws Exception {
System.out.println("received from client, remark:" + request.getRemark() + ", coe:" + request.getCode());
RemotingCommand response = RemotingCommand.createResponseCommand(0, "server");
switch (request.getCode()) {
case 0:
response.setBody(new String("hello sync 0").getBytes());
case 1:
response.setBody(new String("hello sync 1").getBytes());
default:
break;
}
return response;
}
@Override
public boolean rejectRequest() {
return false;
}
};
// 業務處理器
NettyRequestProcessor processB = new NettyRequestProcessor(){
@Override
public RemotingCommand processRequest(ChannelHandlerContext ctx, RemotingCommand request) throws Exception {
System.out.println("received from client, remark:" + request.getRemark() + ", coe:" + request.getCode());
RemotingCommand response = RemotingCommand.createResponseCommand(0, "server");
switch (request.getCode()) {
case 9:
response.setBody(new String("hello sync 9").getBytes());
default:
break;
}
return response;
}
@Override
public boolean rejectRequest() {
return false;
}
};
// 注冊 協定 - 對應的處理器, 類似web url 路由到對應的class
remotingServer.registerProcessor(0, processA, poolA);
remotingServer.registerProcessor(1, processA, poolA);
remotingServer.registerProcessor(9, processB, poolB);
不同業務獨立線程池的必要性
在複雜業務場景中,比如商品管理鍊路,訂單交易鍊路,将所有的請求堆積在一個線程池中,快請求和慢請求公用一個賽道,無法避免資源配置設定不均問題
通信子產品設計為可手動配置每個業務的處理線程池
注冊路由和線程池關系
@Override
public void registerProcessor(int requestCode, NettyRequestProcessor processor, ExecutorService executor) {
ExecutorService executorThis = executor;
if (null == executor) {
executorThis = this.publicExecutor;
}
Pair<NettyRequestProcessor, ExecutorService> pair = new Pair<NettyRequestProcessor, ExecutorService>(processor, executorThis);
this.processorTable.put(requestCode, pair);
}
建立 code - processor - pool 的三者映射關系,在後續收到請求後,可查找注冊關系進行路由喚起processor
▐ client 啟動 發起請求
NettyRemotingClient remotingClient = new NettyRemotingClient(nettyServerConfig, null);
remotingClient.start();
// 主動發起遠端調用
{
// 同步調用
RemotingCommand request = RemotingCommand.createRequestCommand(0, null);
request.setRemark("sync");
RemotingCommand response = remotingClient.invokeSync("127.0.0.1:8888", request, 30 * 1000L);
System.out.println("call sync ok remark:" + response.getRemark() + " body:" + new String(response.getBody()));
}
{
// 異步調用
RemotingCommand request = RemotingCommand.createRequestCommand(1, null);
request.setRemark("async");
remotingClient.invokeAsync("127.0.0.1:8888", request, 30 * 1000L, new InvokeCallback() {
@Override
public void operationComplete(ResponseFuture responseFuture) {
RemotingCommand response = responseFuture.getResponseCommand();
System.out.println("call async ok remark:" + response.getRemark() + " body:" + new String(response.getBody()));
}
});
}
{
// 單向調用
RemotingCommand request = RemotingCommand.createRequestCommand(9, null);
request.setRemark("oneway");
remotingClient.invokeOneway("127.0.0.1:8888", request, 30 * 1000L);
System.out.println("call oneway ok ");
}
啟動用戶端client後,即處于長連接配接狀态,雙向通信及時性有保障
三種調用模式
作為通信元件,需要适配多種調用場景,同步異步調用已是基本操作,oneway用于不關心是否傳回的場景。
試想一下,在全雙工雙向異步通信的背景下,如何能像http一樣實作同步調用,發出一個請求,收到一個請求後怎麼跟前面發出的請求關聯起來,又如何實作異步等待轉為同步響應。
- 同步調用
發起請求
public RemotingCommand invokeSyncImpl(final Channel channel, final RemotingCommand request, final long timeoutMillis)
throws InterruptedException, RemotingSendRequestException, RemotingTimeoutException {
// 唯一id
final int opaque = request.getOpaque();
...
final ResponseFuture responseFuture = new ResponseFuture(channel, opaque, timeoutMillis, null, null);
// 把目前請求記錄到待響應table中
this.responseTable.put(opaque, responseFuture);
final SocketAddress addr = channel.remoteAddress();
channel.writeAndFlush(request).addListener(new ChannelFutureListener() {
@Override
public void operationComplete(ChannelFuture f) throws Exception {
if (f.isSuccess()) {
//标記為寫入成功
responseFuture.setSendRequestOK(true);
return;
} else {
responseFuture.setSendRequestOK(false);
}
// 寫入異常結果 并喚起wait的線程
responseTable.remove(opaque);
responseFuture.setCause(f.cause());
responseFuture.putResponse(null);
public void putResponse(final RemotingCommand responseCommand) {
this.responseCommand = responseCommand;
this.countDownLatch.countDown();
}
log.warn("send a request command to channel <" + addr + "> failed.");
}
});
// 同步等待結果
RemotingCommand responseCommand = responseFuture.waitResponse(timeoutMillis);
public RemotingCommand waitResponse(final long timeoutMillis) throws InterruptedException {
this.countDownLatch.await(timeoutMillis, TimeUnit.MILLISECONDS);
return this.responseCommand;
}
...
}
關鍵設計點:每一個請求request,都配置設定了一個 client唯一自增的id (request.getOpaque(); requestId.getAndIncrement())。
把id和上下文存儲到請求待響應table中:發送請求後(寫入channel),線程等待結果響應 responseFuture.waitResponse,利用countDownLatch等待結果。
- 異步調用
發起請求
public void invokeAsyncImpl(final Channel channel, final RemotingCommand request, final long timeoutMillis,final InvokeCallback invokeCallback)
// 唯一id
final int opaque = request.getOpaque();
...
final ResponseFuture responseFuture = new ResponseFuture(channel, opaque, timeoutMillis - costTime, invokeCallback, once);
// 把目前請求記錄到待響應table中
this.responseTable.put(opaque, responseFuture);
...
channel.writeAndFlush(request).addListener(new ChannelFutureListener() {
@Override
public void operationComplete(ChannelFuture f) throws Exception {
if (f.isSuccess()) {
//标記為寫入成功
responseFuture.setSendRequestOK(true);
return;
}
requestFail(opaque);
log.warn("send a request command to channel <{}> failed.", RemotingHelper.parseChannelRemoteAddr(channel));
}
});
...
}
關鍵設計點:每一個請求request,都配置設定了一個 client唯一自增的id (request.getOpaque(); requestId.getAndIncrement())。
把id和上下文存儲到請求待響應table中:發送請求後,将callback傳遞給responseFuture,等待callback被調用。
- 單向調用oneway
發起請求
public void invokeOnewayImpl(final Channel channel, final RemotingCommand request, final long timeoutMillis)throws InterruptedException, RemotingTooMuchRequestException, RemotingTimeoutException, RemotingSendRequestException {
request.markOnewayRPC();
...
boolean acquired = this.semaphoreOneway.tryAcquire(timeoutMillis, TimeUnit.MILLISECONDS);
final SemaphoreReleaseOnlyOnce once = new SemaphoreReleaseOnlyOnce(this.semaphoreOneway);
channel.writeAndFlush(request).addListener(new ChannelFutureListener() {
@Override
public void operationComplete(ChannelFuture f) throws Exception {
once.release();
if (!f.isSuccess()) {
log.warn("send a request command to channel <" + channel.remoteAddress() + "> failed.");
}
}
});
...
}
無需監聽結果
關鍵設計點:使用信号量Semaphore控制并發數
是通道瞬間并發度,不同于流控qps
oneway模式:不同于同步調用 異步調用 這裡不關心傳回值 是以無需記錄id到待響應table
▐ server受理請求 路由
監聽請求
class NettyServerHandler extends SimpleChannelInboundHandler<RemotingCommand> {
@Override
protected void channelRead0(ChannelHandlerContext ctx, RemotingCommand msg) throws Exception {
processMessageReceived(ctx, msg);
}
}
public void processMessageReceived(ChannelHandlerContext ctx, RemotingCommand msg) throws Exception {
final RemotingCommand cmd = msg;
if (cmd != null) {
switch (cmd.getType()) {
// 來自client的請求
case REQUEST_COMMAND:
processRequestCommand(ctx, cmd);
break;
// 來自client的響應
case RESPONSE_COMMAND:
processResponseCommand(ctx, cmd);
break;
default:
break;
}
}
}
public void processRequestCommand(final ChannelHandlerContext ctx, final RemotingCommand cmd) {
// 路由關系 線程池配置 查詢
final Pair<NettyRequestProcessor, ExecutorService> matched = this.processorTable.get(cmd.getCode());
final Pair<NettyRequestProcessor, ExecutorService> pair = null == matched ? this.defaultRequestProcessor : matched;
final int opaque = cmd.getOpaque();
...
Runnable run = new Runnable() {
@Override
public void run() {
...
final RemotingResponseCallback callback = new RemotingResponseCallback() {
@Override
public void callback(RemotingCommand response) {
...
// 非oneway模式 才需要回寫response
if (!cmd.isOnewayRPC()) {
...
ctx.writeAndFlush(response);
...
}
}
};
...
// 使用指定的業務處理器processor處理業務
NettyRequestProcessor processor = pair.getObject1();
RemotingCommand response = processor.processRequest(ctx, cmd);
callback.callback(response);
...
}
};
...
// 包裝為線程任務 放到配置的線程池中執行
final RequestTask requestTask = new RequestTask(run, ctx.channel(), cmd);
pair.getObject2().submit(requestTask);
...
}
關鍵設計點
抽象複用:
client 和 server的 網絡通信讀子產品是高度一緻的,是以抽象出來共有的部分,複用代碼,繼承結構:
是一個很标準的抽象複用案例, 但需注意在兩個角色(client server)中同一份代碼是有不一樣的解讀鍊路
路由實作:
利用code - processor - pool 的三者映射關系友善的拿到對應業務的處理器及其獨立的線程池,進行任務投遞
設計理念類似觀察者模式,添加觀察者-業務處理器(這裡僅單個觀察者),當事件來了(socket消息讀取)後,通知到所有觀察者進行具體業務處理。
▐ client 監聽響應
- 監聽 同步調用結果
class NettyClientHandler extends SimpleChannelInboundHandler<RemotingCommand> { @Override protected void channelRead0(ChannelHandlerContext ctx, RemotingCommand msg) throws Exception {
processMessageReceived(ctx, msg);
}
}
public void processMessageReceived(ChannelHandlerContext ctx, RemotingCommand msg) throws Exception {
final RemotingCommand cmd = msg;
if (cmd != null) {
switch (cmd.getType()) {
// 來自server的請求
case REQUEST_COMMAND:
processRequestCommand(ctx, cmd);
break;
// 來自server的響應
case RESPONSE_COMMAND:
processResponseCommand(ctx, cmd);
break;
default:
break;
}
}
}
public void processResponseCommand(ChannelHandlerContext ctx, RemotingCommand cmd) {
final int opaque = cmd.getOpaque();
// 從待響應table中找到響應對應的請求
final ResponseFuture responseFuture = responseTable.get(opaque);
if (responseFuture != null) {
responseFuture.setResponseCommand(cmd);
responseTable.remove(opaque);
if (responseFuture.getInvokeCallback() != null) {
// 異步調用 回調callback
executeInvokeCallback(responseFuture);
} else {
// 同步調用
// 寫入正常結果 并喚起wait的線程
responseFuture.putResponse(cmd);
public void putResponse(final RemotingCommand responseCommand) {
this.responseCommand = responseCommand;
this.countDownLatch.countDown();
}
responseFuture.release();
}
} else {
log.warn("receive response, but not matched any request, " + RemotingHelper.parseChannelRemoteAddr(ctx.channel()));
log.warn(cmd.toString());
}
}
關鍵設計點
異步協調 && 同步等待 && 喚起機制
讀取到來自server響應資料的線程 -> 通過待響應table查找目前響應歸屬的請求 -> 操作其countDownLatch定向喚起等待結果的請求線程
同步結果喚起條件:寫入異常 || 等待逾時 || 讀取到來自server的對應id的響應
// 同步等待結果
RemotingCommand responseCommand = responseFuture.waitResponse(timeoutMillis);
- 監聽 異步調用結果
class NettyClientHandler extends SimpleChannelInboundHandler<RemotingCommand> {
@Override
protected void channelRead0(ChannelHandlerContext ctx, RemotingCommand msg) throws Exception {
processMessageReceived(ctx, msg);
}
}
public void processMessageReceived(ChannelHandlerContext ctx, RemotingCommand msg) throws Exception {
final RemotingCommand cmd = msg;
if (cmd != null) {
switch (cmd.getType()) {
// 來自server的請求
case REQUEST_COMMAND:
processRequestCommand(ctx, cmd);
break;
// 來自server的響應
case RESPONSE_COMMAND:
processResponseCommand(ctx, cmd);
break;
default:
break;
}
}
}
public void processResponseCommand(ChannelHandlerContext ctx, RemotingCommand cmd) {
final int opaque = cmd.getOpaque();
// 從待響應table中找到響應對應的請求
final ResponseFuture responseFuture = responseTable.get(opaque);
if (responseFuture != null) {
responseFuture.setResponseCommand(cmd);
responseTable.remove(opaque);
if (responseFuture.getInvokeCallback() != null) {
// 異步調用
executeInvokeCallback(responseFuture);
} else {
// 同步調用
// 寫入結果 并喚起wait的線程
responseFuture.putResponse(cmd);
public void putResponse(final RemotingCommand responseCommand) {
this.responseCommand = responseCommand;
this.countDownLatch.countDown();
}
responseFuture.release();
}
} else {
log.warn("receive response, but not matched any request, " + RemotingHelper.parseChannelRemoteAddr(ctx.channel()));
log.warn(cmd.toString());
}
}
private void executeInvokeCallback(final ResponseFuture responseFuture) {
ExecutorService executor = this.getCallbackExecutor();
...
executor.submit(new Runnable() {
@Override
public void run() {
try {
responseFuture.executeInvokeCallback();
} catch (Throwable e) {
log.warn("execute callback in executor exception, and callback throw", e);
} finally {
responseFuture.release();
}
}
});
...
}
關鍵設計點
- 異步協調 && callback機制
讀取到來自server響應資料的線程 -> 通過待響應table查找目前響應歸屬的請求 -> 回調callback
異步結果回調callback條件:寫入異常 || 等待逾時 || 讀取到來自server的對應id的響應
另外callback執行采用了cas機制限制僅執行一次
子產品更新-微服務化通信工具
why?
從業務視角開發來看,通信子產品依然是比較基礎的,對于普通開發者,希望能夠像hsf一樣,簡單的定制協定service,契合java接口實作多态機制,不希望每次都去根據code或其他url之類的手動去分發路由,顯得過于原始。
how?
參考hsf系列的遠端調用方式,使用動态代理規範化協定傳輸,使用泛化反射機制便捷調用。
封裝程度跟靈活程度往往是成反比的,注意不要過度設計,盡可能保留原始通信子產品的靈活。
▐ 使用方式
- 定義接口 和 實作
public interface ServiceHello {
String sayHello(String a, String b);
Integer sayHelloInteger(Integer a, Integer b);
}
import com.uext.remote.rf.service.ServiceHello;
public class ServiceHelloImpl implements ServiceHello {
@Override
public String sayHello(String a, String b) {
return "hello " + a + " " + b;
}
@Override
public Integer sayHelloInteger(Integer a, Integer b) {
return 1000 + a + b;
}
}
同hsf,接口interface可打包後提供給消費者,實作類隐藏于提供者代碼中
- 啟動provider 注冊服務監聽
import com.alibaba.fastjson.JSON;
import com.uext.remote.rf.provider.ServiceHelloImpl;
import com.uext.remote.rf.provider.ServiceWorldImpl;
import com.uext.remote.rf.service.ServiceHello;
import com.uext.remote.rf.service.ServiceWorld;
public class TestServer {
public static void main(String[] args) throws Exception {
ApiProviderBean apiProviderBean = new ApiProviderBean();
apiProviderBean.setPort(8888);
apiProviderBean.init();
apiProviderBean.register(ServiceHello.class, new ServiceHelloImpl());
apiProviderBean.register(ServiceWorld.class, new ServiceWorldImpl());
System.out.println("start ok " + JSON.toJSONString(apiProviderBean));
System.in.read();
}
}
啟動服務端,注冊一些需要暴露的服務,通過接口和接口的實作類的執行個體進行綁定
- 啟動consumer 發起調用
import com.uext.remote.rf.service.ServiceHello;
import com.uext.remote.rf.service.ServiceWorld;
import org.apache.rocketmq.remoting.netty.NettyClientConfig;
import org.apache.rocketmq.remoting.netty.NettyRemotingClient;
public class TestClient {
public static void main(String[] args) throws Exception {
// 初始化一個連接配接用戶端
NettyClientConfig nettyServerConfig = new NettyClientConfig();
NettyRemotingClient remotingClient = new NettyRemotingClient(nettyServerConfig, null);
remotingClient.start();
ApiConsumerBean apiConsumerBean = new ApiConsumerBean();
apiConsumerBean.setRemotingClient(remotingClient);
apiConsumerBean.setInterfac(ServiceHello.class);
apiConsumerBean.setTimeOut(30000L);
apiConsumerBean.setAddr("127.0.0.1:8888");
ServiceHello serviceHello = apiConsumerBean.getProxy();
ApiConsumerBean apiConsumerBean2 = new ApiConsumerBean();
apiConsumerBean2.setRemotingClient(remotingClient);
apiConsumerBean2.setInterfac(ServiceWorld.class);
apiConsumerBean2.setTimeOut(30000L);
apiConsumerBean2.setAddr("127.0.0.1:8888");
ServiceWorld serviceWorld = apiConsumerBean2.getProxy();
System.out.println(serviceHello.sayHello("a", "b"));
System.out.println(serviceHello.sayHelloInteger(1, 2));
serviceWorld.sayWorld("aa", "bb");
System.in.read();
}
}
初始化一個長連接配接用戶端, 擷取接口遠端實作執行個體, 發起調用。
- 日志輸出
Connected to the target VM, address: '127.0.0.1:49830', transport: 'socket'
start ok {"index":{"com.uext.remote.hsf.service.ServiceWorld":{"public abstract void com.uext.remote.hsf.service.ServiceWorld.sayWorld(java.lang.String,java.lang.String)":{}},"com.uext.remote.hsf.service.ServiceHello":{"public abstract java.lang.Integer com.uext.remote.hsf.service.ServiceHello.sayHelloInteger(java.lang.Integer,java.lang.Integer)":{},"public abstract java.lang.String com.uext.remote.hsf.service.ServiceHello.sayHello(java.lang.String,java.lang.String)":{}}},"port":8888,"remotingServer":{"callbackExecutor":{"activeCount":0,"completedTaskCount":0,"corePoolSize":4,"largestPoolSize":0,"maximumPoolSize":4,"poolSize":0,"queue":[],"rejectedExecutionHandler":{},"shutdown":false,"taskCount":0,"terminated":false,"terminating":false,"threadFactory":{}},"rPCHooks":[]}}
world aa bb
Connected to the target VM, address: '127.0.0.1:53211', transport: 'socket'
hello a b
1003
▐ 實作方式
- 請求頭 參數協定
import lombok.Data;
import org.apache.rocketmq.remoting.CommandCustomHeader;
import org.apache.rocketmq.remoting.exception.RemotingCommandException;
@Data
public class CommonHeader implements CommandCustomHeader{
/**
* com.uext.remote.hsf.service.ServiceHello
*/
String interfaceName;
/**
* public abstract java.lang.String com.uext.remote.hsf.service.ServiceHello.sayHello(java.lang.String,java.lang.String)
*/
String methodName;
String argsJsonJson;
@Override
public void checkFields() throws RemotingCommandException {
}
}
使用接口interface package url 和 方法 method的作為識别碼,用以路由選擇。
其中動态參數問題,需要考慮如何解決解碼為方法參數對應的不同類型,本文采用簡易實作(json)。
- provider實作代碼
import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.TypeReference;
import io.netty.channel.ChannelHandlerContext;
import lombok.Data;
import org.apache.rocketmq.remoting.netty.*;
import org.apache.rocketmq.remoting.protocol.RemotingCommand;
import java.lang.reflect.Method;
import java.lang.reflect.Parameter;
import java.util.*;
@Data
public class ApiProviderBean {
private int port = 8888;
// 長連接配接執行個體
private NettyRemotingServer remotingServer;
public void init() throws Exception {
NettyServerConfig nettyServerConfig = new NettyServerConfig();
nettyServerConfig.setListenPort(port);
remotingServer = new NettyRemotingServer(nettyServerConfig, null);
remotingServer.registerProcessor(0, new NettyRequestProcessor() {
@Override
public RemotingCommand processRequest(ChannelHandlerContext ctx, RemotingCommand request) throws Exception {
// 請求資料解析
CommonHeader commonHeader = (CommonHeader) request.decodeCommandCustomHeader(CommonHeader.class);
// 路由查找
Map<String/*method*/, Call> map = index.get(commonHeader.getInterfaceName());
Call call = Objects.requireNonNull(map, "interface not exists " + commonHeader.getInterfaceName()).get(commonHeader.getMethodName());
if(call == null){
throw new RuntimeException("method not exists " + commonHeader.getMethodName());
}
// 參數解碼 todo 優化解碼編碼
Parameter[] ts = call.method.getParameters();
List<Object> args = new ArrayList<>();
List<String> argsJson = JSON.parseObject(commonHeader.argsJsonJson, new TypeReference<List<String>>(){});
for (int i = 0; i < argsJson.size(); i++) {
// 根據method規範 逐一反序列化
args.add(JSON.parseObject(argsJson.get(i), ts[i].getType()));
}
// 反射調用
Object res = call.method.invoke(call.instance, args.toArray(new Object[0]));
// 結果編碼 回傳 todo 優化解碼編碼
RemotingCommand response = RemotingCommand.createResponseCommand(0, null);
if(res != null) {
response.setBody(JSON.toJSONBytes(res));
}
return response;
}
@Override
public boolean rejectRequest() {
return false;
}
}, null);
remotingServer.start();
}
private static class Call{
Object instance;
Method method;
}
private Map<String/*interface*/, Map<String/*method*/, Call>> index = new HashMap<>();
/**
* @param interfac 接口 協定
* @param impl 實作類的執行個體
*/
public synchronized <T> void register(Class<T> interfac, T impl){
// 建立 接口-實作類-方法 路由關系
String iname = interfac.getName();
Map<String/*method*/, Call> map = index.get(iname);
if(map == null){
map = new LinkedHashMap<>();
index.put(iname, map);
}
for (Method declaredMethod : interfac.getDeclaredMethods()) {
Call call = new Call();
call.instance = impl;
call.method = declaredMethod;
map.put(declaredMethod.toString(), call);
}
}
}
關鍵在于 注冊協定(interface)和實作類, 維護映射路由關系。
收到channel請求的資料後,解碼,根據映射路由關系進行反射調用拿到結果,編碼結果,回寫到channel
由于通道code 定義為int,但為了靈活配置接口及實作,不想寫死,是以丢失了自定義不同業務線程池的特性,如果有需要可以重構通道code為string,然後把相關路由協定序列化到通道code中。
- consumer實作代碼
import com.alibaba.fastjson.JSON;
import lombok.Data;
import org.apache.rocketmq.remoting.netty.NettyRemotingClient;
import org.apache.rocketmq.remoting.protocol.RemotingCommand;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.List;
@Data
public class ApiConsumerBean implements InvocationHandler {
/**
* 逾時時間
*/
private Long timeOut = 3000L;
/**
* 目标 ip:port
*/
private String addr = "127.0.0.1:8888";
/**
* 實作類
*/
private Class<?> interfac;
/**
* 長連接配接執行個體
*/
private NettyRemotingClient remotingClient;
/**
* 擷取協定 代理執行個體
*/
public <T> T getProxy() throws IllegalArgumentException {
return (T) Proxy.newProxyInstance(Thread.currentThread().getContextClassLoader(), new Class[]{interfac}, this);
}
/**
* 規範編碼協定
*/
@Override
public Object invoke(Object target, Method method, Object[] args) throws Throwable {
if (Object.class.equals(method.getDeclaringClass())) {
return method.invoke(this, args);
}
// 協定編碼入參
CommonHeader header = new CommonHeader();
header.setInterfaceName(interfac.getName());
header.setMethodName(method.toString());
// todo 優化解碼編碼
List<String> argJson = new ArrayList<>();
for (Object arg : args) {
argJson.add(JSON.toJSONString(arg));
}
header.setArgsJsonJson(JSON.toJSONString(argJson));
// 定義通道code 0 為 遠端使用
RemotingCommand request = RemotingCommand.createRequestCommand(0, header);
Object res = null;
if(method.getReturnType() != null) {
RemotingCommand response = remotingClient.invokeSync(addr, request, timeOut);
// 協定解碼結果 todo 優化解碼編碼
if(response.getBody() != null && response.getBody().length > 0) {
res = JSON.parseObject(new String(response.getBody(), StandardCharsets.UTF_8), method.getReturnType());
}
}else{
remotingClient.invokeOneway(addr, request, timeOut);
}
return res;
}
}
關鍵在于 委托接口(interface)的調用實作, 動态代理為: 根據協定編碼, 包裝request之後寫入channel
同步等待, 是以采用了同步調用模式
收到channel響應的結果後, 解碼, 傳回結果
其中無傳回值的接口, 不關心響應結果, 可使用oneway方式調用
▐ 更進一步 注冊中心 ip自動選擇
引入注冊中心 zk 或 namesrv,通過中心化協調,讓某一些consumer自動選擇某一台provider,并同時可以支援配置中心化下放,實作服務治理,越來越像微服務(dubbo)架構了哈。
當然,在跟多業務場景中,是無法引入其他中間件的,能少依賴就少依賴,降低複雜度。
在内網環境中,絕大部分項目采用Axxx一站式釋出部署,配套Nxxxxxxx叢集雲資源管理,是支援按應用名動态擷取目前叢集ip清單的。
curl http://xxxxx.xxxx
{
"num": 164,
"result": [
{
"dns_ip": "13.23.xx.xxx",
"state": "working_online"
},
...
],
"start": 0,
"total": 164
}
那麼我們是否可以依賴該 ip清單,用來做本地hash ip自動選擇呢?
當然可以,配合可用性心跳探測,每台機器節點自己維護一份可用性提供者消費者清單緩存,通過一緻性hash等算法選擇機器比對機器。
那麼就得到了一個簡易版的低依賴,去中心化,高可用的微服務通信架構。
團隊介紹
大淘寶技術開放平台,是淘寶天貓與外部生态互聯互通的重要開放途徑,通過開放的産品技術把一系列基礎服務像水、電、煤一樣輸送給我們的商家、開發者、社群媒體以及其他合作夥伴,推動行業的定制、創新、進化,并最終促成新商業文明生态圈。
我們是一支技術能力雄厚,有着光榮曆史傳統的技術團隊。在曆年雙十一戰場上,團隊都表現着優異的成績。這裡承載着每秒百萬級的業務處理,90%的訂單通過訂單推送服務實時地推送到商家的ERP系統完成電商作業,通過奇門開放的ERP-WMS場景已經成為倉儲行業标準。随着新零售業務的持續探索與快速發展,我們渴求各路高手加入,參與核心系統架構設計、性能調優,開放模式創新等富有技術挑戰的工作。