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仿RabbitMq简易消息队列基础篇（Muduo库的使用）

news 2025/9/16 2:19:44

@TOC

Muduo库简介

Muduo由陈硕⼤佬开发，是⼀个基于⾮阻塞IO和事件驱动的C++⾼并发TCP⽹络编程库。他是一款基于主从Reactor模型的网络库，其使用的线程模型是one loop per thread, 所谓 one loop per thread 指的是：

一个线程只能有一个事件循环（EventLoop），用于相应计时器和IO时间
一个文件描述符只能由一个线程进行读写，换句话说就是一个TCP连接必须归属某个EventLoop管理

Muduo库常见接口介绍

muduo::net::TcpServer类基础介绍

typedef std::shared_ptr<TcpConnection> TcpConnectionPtr;
typedef std::function<void(const TcpConnectionPtr &)> ConnectionCallback;
typedef std::function<void(const TcpConnectionPtr &,Buffer *,Timestamp)>MessageCallback;
class InetAddress : public muduo::copyable
{
public:InetAddress(StringArg ip, uint16_t port, bool ipv6 = false);
};
class TcpServer : noncopyable
{
public:enum Option{kNoReusePort,kReusePort,};TcpServer(EventLoop *loop,const InetAddress &listenAddr,const string &nameArg,Option option = kNoReusePort);void setThreadNum(int numThreads);void start();/// 当⼀个新连接建⽴成功的时候被调⽤void setConnectionCallback(const ConnectionCallback &cb){connectionCallback_ = cb;}/// 消息的业务处理回调函数---这是收到新连接消息的时候被调⽤的函数void setMessageCallback(const MessageCallback &cb){messageCallback_ = cb;}
};

muduo::net::EventLoop 类基础介绍

class EventLoop : noncopyable
{
public:/// 无限循环。/// 必须在与对象创建相同的线程中调用。void loop();/// 退出循环。/// 如果通过原始指针调用，这不是 100% 线程安全，/// 最好通过 shared_ptr<EventLoop> 调用以保证 100% 安全。void quit();TimerId runAt(Timestamp time, TimerCallback cb);/// 在 @c delay 秒后运行回调。/// 线程安全，可以从其他线程调用。TimerId runAfter(double delay, TimerCallback cb);/// 每隔 @c interval 秒运行一次回调。/// 线程安全，可以从其他线程调用。TimerId runEvery(double interval, TimerCallback cb);/// 取消定时器。/// 线程安全，可以从其他线程调用。void cancel(TimerId timerId);private:std::atomic<bool> quit_;std::unique_ptr<Poller> poller_;mutable MutexLock mutex_;std::vector<Functor> pendingFunctors_ GUARDED_BY(mutex_);
};

muduo::net::TcpConnection 类基础介绍

class TcpConnection : noncopyable,public std::enable_shared_from_this<TcpConnection>
{
public:/// 使用已连接的 sockfd 构造 TcpConnection////// 用户不应创建此对象。TcpConnection(EventLoop *loop,const string &name,int sockfd,const InetAddress &localAddr,const InetAddress &peerAddr);/// 检查连接是否已建立bool connected() const { return state_ == kConnected; }/// 检查连接是否已断开bool disconnected() const { return state_ == kDisconnected; }/// 发送消息（右值引用，C++11）void send(string &&message); // C++11/// 发送消息（指针和长度）void send(const void *message, int len);/// 发送消息（StringPiece）void send(const StringPiece &message);/// 发送消息（Buffer 指针，交换数据）void send(Buffer *message); // this one will swap data/// 关闭连接（非线程安全，不能同时调用）void shutdown(); // NOT thread safe, no simultaneous calling/// 设置上下文void setContext(const boost::any &context){context_ = context;}/// 获取上下文（常量引用）const boost::any &getContext() const{return context_;}/// 获取可变的上下文指针boost::any *getMutableContext(){return &context_;}/// 设置连接回调函数void setConnectionCallback(const ConnectionCallback &cb){connectionCallback_ = cb;}/// 设置消息回调函数void setMessageCallback(const MessageCallback &cb){messageCallback_ = cb;}private:/// 连接状态枚举enum StateE{kDisconnected,kConnecting,kConnected,kDisconnecting};EventLoop *loop_;                             // 事件循环指针ConnectionCallback connectionCallback_;       // 连接回调函数MessageCallback messageCallback_;             // 消息回调函数WriteCompleteCallback writeCompleteCallback_; // 写完成回调函数boost::any context_;                          // 上下文数据
};

muduo::net::TcpClient类基础介绍

class TcpClient : noncopyable
{
public:/// 构造函数，通过服务器地址和客户端名称构造TcpClientTcpClient(EventLoop *loop,const InetAddress &serverAddr,const string &nameArg);/// 析构函数，强制外部析构，以便管理std::unique_ptr成员~TcpClient(); // force out-line dtor, for std::unique_ptr members./// 连接服务器void connect();/// 断开连接void disconnect();/// 停止客户端void stop();/// 获取客户端对应的通信连接Connection对象的接口/// 在调用connect后，有可能连接还没有建立成功TcpConnectionPtr connection() const{MutexLockGuard lock(mutex_);return connection_;}/// 设置连接服务器成功时的回调函数void setConnectionCallback(ConnectionCallback cb){connectionCallback_ = std::move(cb);}/// 设置收到服务器发送的消息时的回调函数void setMessageCallback(MessageCallback cb){messageCallback_ = std::move(cb);}private:EventLoop *loop_;                                // 事件循环指针ConnectionCallback connectionCallback_;          // 连接回调函数MessageCallback messageCallback_;                // 消息回调函数WriteCompleteCallback writeCompleteCallback_;    // 写完成回调函数TcpConnectionPtr connection_ GUARDED_BY(mutex_); // 连接对象，受mutex_保护
};/*
需要注意的是，因为muduo库不管是服务器端还是客户端都是异步操作，
对于客户端来说，如果我们在连接还没有完全建立成功的时候发送数据，这是不被允许的。
因此我们可以使用内置的CountDownLatch类进行同步控制。
*/
class CountDownLatch : noncopyable
{
public:/// 显式构造函数，初始化倒计时计数explicit CountDownLatch(int count);/// 等待倒计时完成void wait(){MutexLockGuard lock(mutex_);while (count_ > 0){condition_.wait();}}/// 倒计时减一void countDown(){MutexLockGuard lock(mutex_);--count_;if (count_ == 0){condition_.notifyAll();}}/// 获取当前倒计时计数int getCount() const;private:mutable MutexLock mutex_;                // 互斥锁，受保护的成员变量Condition condition_ GUARDED_BY(mutex_); // 条件变量，受mutex_保护int count_ GUARDED_BY(mutex_);           // 倒计时计数，受mutex_保护
};

muduo::net::Buffer 类基础介绍

class Buffer : public muduo::copyable
{
public:/// 常量：预留的前置空间大小static const size_t kCheapPrepend = 8;/// 常量：初始缓冲区大小static const size_t kInitialSize = 1024;/// 显式构造函数，初始化缓冲区大小explicit Buffer(size_t initialSize = kInitialSize): buffer_(kCheapPrepend + initialSize),readerIndex_(kCheapPrepend),writerIndex_(kCheapPrepend) {}/// 交换缓冲区内容void swap(Buffer &rhs);/// 可读字节数size_t readableBytes() const;/// 可写字节数size_t writableBytes() const;/// 返回指向可读数据的指针const char *peek() const;/// 查找换行符（CRLF）的指针const char *findEOL() const;/// 从指定位置开始查找换行符（CRLF）的指针const char *findEOL(const char *start) const;/// 从缓冲区中取出指定长度的数据void retrieve(size_t len);/// 从缓冲区中取出一个64位整数void retrieveInt64();/// 从缓冲区中取出一个32位整数void retrieveInt32();/// 从缓冲区中取出一个16位整数void retrieveInt16();/// 从缓冲区中取出一个8位整数void retrieveInt8();/// 将缓冲区中的所有数据取出并转换为字符串string retrieveAllAsString();/// 将缓冲区中指定长度的数据取出并转换为字符串string retrieveAsString(size_t len);/// 向缓冲区追加字符串void append(const StringPiece &str);/// 向缓冲区追加指定数据和长度void append(const char * /*restrict*/ data, size_t len);/// 向缓冲区追加指定数据和长度void append(const void * /*restrict*/ data, size_t len);/// 返回指向可写数据的指针char *beginWrite();/// 返回指向可写数据的常量指针const char *beginWrite() const;/// 更新已写入的长度void hasWritten(size_t len);/// 向缓冲区追加一个64位整数void appendInt64(int64_t x);/// 向缓冲区追加一个32位整数void appendInt32(int32_t x);/// 向缓冲区追加一个16位整数void appendInt16(int16_t x);/// 向缓冲区追加一个8位整数void appendInt8(int8_t x);/// 从缓冲区中读取一个64位整数int64_t readInt64();/// 从缓冲区中读取一个32位整数int32_t readInt32();/// 从缓冲区中读取一个16位整数int16_t readInt16();/// 从缓冲区中读取一个8位整数int8_t readInt8();/// 查看缓冲区中的一个64位整数int64_t peekInt64() const;/// 查看缓冲区中的一个32位整数int32_t peekInt32() const;/// 查看缓冲区中的一个16位整数int16_t peekInt16() const;/// 查看缓冲区中的一个8位整数int8_t peekInt8() const;/// 在缓冲区前面添加一个64位整数void prependInt64(int64_t x);/// 在缓冲区前面添加一个32位整数void prependInt32(int32_t x);/// 在缓冲区前面添加一个16位整数void prependInt16(int16_t x);/// 在缓冲区前面添加一个8位整数void prependInt8(int8_t x);/// 在缓冲区前面添加指定数据和长度void prepend(const void * /*restrict*/ data, size_t len);private:std::vector<char> buffer_; // 缓冲区size_t readerIndex_;       // 读索引size_t writerIndex_;       // 写索引static const char kCRLF[]; // 换行符常量
};

接下来就是通过上面的接口来使用muduo库通过protobuf实现网络通信，这里我们简单写一个计算器

客户端

#include "muduo/proto/dispatcher.h"
#include "muduo/proto/codec.h"
#include "muduo/base/Logging.h"
#include "muduo/base/Mutex.h"
#include "muduo/net/EventLoop.h"
#include "muduo/net/TcpClient.h"
#include "muduo/net/EventLoopThread.h"
#include "muduo/base/CountDownLatch.h"#include "request.pb.h"
#include <memory>
#include <iostream>class Client
{
public:typedef std::shared_ptr<sslx::AddResponse> AddResponsePtr;typedef std::shared_ptr<sslx::SubResponse> SubResponsePtr;typedef std::shared_ptr<sslx::MulResponse> MulResponsePtr;typedef std::shared_ptr<sslx::DivResponse> DivResponsePtr;typedef std::shared_ptr<sslx::ErrorResponse> ErrorResponsePtr;typedef std::shared_ptr<google::protobuf::Message> MessagePtr;Client(const std::string& sip, int port):_latch(1),_client(_loopthread.startLoop(), muduo::net::InetAddress(sip, port), "Client"),_dispatcher(std::bind(&Client::onUnknownMessage, this, std::placeholders::_1, std::placeholders::_2, std::placeholders::_3)),_codec(std::bind(&ProtobufDispatcher::onProtobufMessage, &_dispatcher, std::placeholders::_1, std::placeholders::_2, std::placeholders::_3)){// 注册业务回复处理函数_dispatcher.registerMessageCallback<sslx::AddResponse>(std::bind(&Client::onAdd, this, std::placeholders::_1, std::placeholders::_2, std::placeholders::_3));_dispatcher.registerMessageCallback<sslx::SubResponse>(std::bind(&Client::onSub, this, std::placeholders::_1, std::placeholders::_2, std::placeholders::_3));_dispatcher.registerMessageCallback<sslx::MulResponse>(std::bind(&Client::onMul, this, std::placeholders::_1, std::placeholders::_2, std::placeholders::_3));_dispatcher.registerMessageCallback<sslx::DivResponse>(std::bind(&Client::onDiv, this, std::placeholders::_1, std::placeholders::_2, std::placeholders::_3));_dispatcher.registerMessageCallback<sslx::ErrorResponse>(std::bind(&Client::onError, this, std::placeholders::_1, std::placeholders::_2, std::placeholders::_3));_client.setMessageCallback(std::bind(&ProtobufCodec::onMessage, &_codec, std::placeholders::_1, std::placeholders::_2, std::placeholders::_3));_client.setConnectionCallback(std::bind(&Client::onConnection, this, std::placeholders::_1));Connect();}void Connect(){_client.connect();_latch.wait();}void Add(int num1 , int num2){sslx::AddRequest req;req.set_num1(num1);req.set_num2(num2);send(req);}void Sub(int num1 , int num2){sslx::SubRequest req;req.set_num1(num1);req.set_num2(num2);send(req);}void Mul(int num1 , int num2){sslx::MulRequest req;req.set_num1(num1);req.set_num2(num2);send(req);}void Div(int num1 , int num2){sslx::DivRequest req;req.set_num1(num1);req.set_num2(num2);send(req);}
private:bool send(const google::protobuf::Message& msg){//连接状态正常，再发送，否则就返回falseif(_conn->connected()){_codec.send(_conn, msg);return true;}return false;}void onConnection(const muduo::net::TcpConnectionPtr& conn){if(conn->connected()){_conn = conn;_latch.countDown();}else{_conn.reset();  // 连接关闭时的操作}}void onUnknownMessage(const muduo::net::TcpConnectionPtr& conn, const MessagePtr& msg, muduo::Timestamp){LOG_INFO << "onUnknowMessage" << msg->GetTypeName();conn->shutdown();}void onAdd(const muduo::net::TcpConnectionPtr& conn, const AddResponsePtr& msg, muduo::Timestamp){std::cout << "加法结果 : " << msg->result() << std::endl; }void onSub(const muduo::net::TcpConnectionPtr& conn, const SubResponsePtr& msg, muduo::Timestamp){std::cout << "减法结果 : " << msg->result() << std::endl;}void onMul(const muduo::net::TcpConnectionPtr& conn, const MulResponsePtr& msg, muduo::Timestamp){std::cout << "乘法结果 : " << msg->result() << std::endl;}void onDiv(const muduo::net::TcpConnectionPtr& conn, const DivResponsePtr& msg, muduo::Timestamp){std::cout << "除法结果 : " << msg->result() << std::endl;}void onError(const muduo::net::TcpConnectionPtr& conn, const ErrorResponsePtr& msg, muduo::Timestamp){std::cout << "出现除零错误" << std::endl;}private:muduo::CountDownLatch _latch;  //主要同步主线程和网络线程，确保在连接建立之前不会发送请求muduo::net::EventLoopThread _loopthread; // 提供一个独立的事件循环，用于处理网络事件muduo::net::TcpConnectionPtr _conn;  // 保存当前的TcpConnectionPtr, 用于在连接建立之后发送消息muduo::net::TcpClient _client; // 管理客户端的连接和重连ProtobufDispatcher _dispatcher; // 用于根据消息的类型调用相应的处理函数ProtobufCodec _codec; // 负责Protobuf消息的编解码};int main()
{Client client("127.0.0.1", 8085);client.Add(11, 11);client.Sub(11, 11);sleep(1);return 0; 
}

服务端

#include <muduo/proto/codec.h>
#include "muduo/proto/dispatcher.h"
#include "muduo/base/Logging.h"
#include "muduo/base/Mutex.h"
#include "muduo/net/EventLoop.h"
#include "muduo/net/TcpServer.h"#include "request.pb.h"#include <memory>
#include <string>
#include <iostream>
#include <unordered_map>class Server
{
public:typedef std::shared_ptr<google::protobuf::Message> MessagePtr;typedef std::shared_ptr<sslx::AddRequest> AddRequestPtr;typedef std::shared_ptr<sslx::SubRequest> SubRequestPtr;typedef std::shared_ptr<sslx::MulRequest> MulRequestPtr;typedef std::shared_ptr<sslx::DivRequest> DivRequestPtr;Server(int port):_server(&_baseLoop, muduo::net::InetAddress("0.0.0.0", port), "Server", muduo::net::TcpServer::kReusePort),_dispatcher(std::bind(&Server::onUnknownMessage, this, std::placeholders::_1, std::placeholders::_2, std::placeholders::_3)),_codec(std::bind(&ProtobufDispatcher::onProtobufMessage, &_dispatcher, std::placeholders::_1, std::placeholders::_2, std::placeholders::_3)){_dispatcher.registerMessageCallback<sslx::AddRequest>(std::bind(&Server::onAdd, this, std::placeholders::_1, std::placeholders::_2, std::placeholders::_3));_dispatcher.registerMessageCallback<sslx::SubRequest>(std::bind(&Server::onSub, this, std::placeholders::_1, std::placeholders::_2, std::placeholders::_3));_dispatcher.registerMessageCallback<sslx::MulRequest>(std::bind(&Server::onMul, this, std::placeholders::_1, std::placeholders::_2, std::placeholders::_3));_dispatcher.registerMessageCallback<sslx::DivRequest>(std::bind(&Server::onDiv, this, std::placeholders::_1, std::placeholders::_2, std::placeholders::_3));_server.setMessageCallback(std::bind(&ProtobufCodec::onMessage, &_codec, std::placeholders::_1, std::placeholders::_2, std::placeholders::_3));_server.setConnectionCallback(std::bind(&Server::onConnection, this, std::placeholders::_1));}void start(){_server.start();_baseLoop.loop();}
private:int Add(int num1, int num2){return num1 + num2;}int Sub(int num1, int num2){return num1 - num2;}int Mul(int num1, int num2){return num1 * num2;}int Div(int num1, int num2){if(num2 == 0){return INT_MIN;}return num1 / num2;}void onAdd(const muduo::net::TcpConnectionPtr& conn, const AddRequestPtr& msg, muduo::Timestamp){sslx::AddResponse resp;int ret = Add(msg->num1(), msg->num2());resp.set_result(ret);_codec.send(conn, resp);}void onSub(const muduo::net::TcpConnectionPtr& conn, const SubRequestPtr& msg, muduo::Timestamp){sslx::SubResponse resp;int ret = Sub(msg->num1(), msg->num2());resp.set_result(ret);_codec.send(conn, resp);}void onMul(const muduo::net::TcpConnectionPtr& conn, const MulRequestPtr& msg, muduo::Timestamp){sslx::MulResponse resp;int ret = Mul(msg->num1(), msg->num2());resp.set_result(ret);_codec.send(conn, resp);}void onDiv(const muduo::net::TcpConnectionPtr& conn, const DivRequestPtr& msg, muduo::Timestamp){sslx::DivResponse resp1;sslx::ErrorResponse resp2;int ret = Div(msg->num1(), msg->num2());if(ret ==INT_MIN){resp2.set_msg(std::to_string(ret));_codec.send(conn, resp2);}else{resp1.set_result(ret);_codec.send(conn, resp1);}}void onUnknownMessage(const muduo::net::TcpConnectionPtr& conn, const MessagePtr& message, muduo::Timestamp){LOG_INFO << "onUNknownMessage : " << message->GetTypeName();conn->shutdown();}void onConnection(const muduo::net::TcpConnectionPtr& conn){if(conn->connected()){LOG_INFO << "新连接建立成功";}else{LOG_INFO << "连接已关闭";}}private:muduo::net::EventLoop _baseLoop;muduo::net::TcpServer _server; //服务器对象ProtobufDispatcher _dispatcher; // 请求分发对象 --要向其中注册请求处理函数ProtobufCodec _codec;   // protobuf协议处理器--针对收到的请求数据进行protobuf协议处理};int main()
{Server server(8085);server.start();return 0;
}

这里简单梳理一下网路的流程：在进行初始化的时候，客户端和服务端之间会对_codec和_dispatcher还有事件监控循环线程，在建立连接的时候，异步线程会通过setConnectionCallback的回调函数，onConnection函数中的countDown() 函数唤醒主线程开始进行业务处理，在进行业务处理的时候，会将请求通过send发到缓冲区中，响应报文回来之后会给setMessageCallback函数传递信号，然后由loop线程来接收到响应，调用相关的函数来对结果进行处理。

protobuf

syntax = "proto3";package sslx;message AddRequest
{int32 num1 = 1;int32 num2 = 2;
}message AddResponse
{int32 result = 1;
}message SubRequest
{int32 num1 = 1;int32 num2 = 2;
}message SubResponse
{int32 result = 1;
}message MulRequest
{int32 num1 = 1;int32 num2 = 2;
}message MulResponse
{int32 result = 1;
}message DivRequest
{int32 num1 = 1;int32 num2 = 2;
}message DivResponse
{int32 result = 1;
}message ErrorResponse
{string msg = 1;
}

makefile

all: client server
client: client.cc request.pb.cc mqthird/include/muduo/proto/codec.ccg++ -g -o $@ $^ -std=c++11 -I./mqthird/include -L./mqthird/lib -lmuduo_net -lmuduo_base -lpthread -lprotobuf -lz
server: server.cc request.pb.cc mqthird/include/muduo/proto/codec.ccg++ -g -o $@ $^ -std=c++11 -I./mqthird/include -L./mqthird/lib -lmuduo_net -lmuduo_base -lpthread -lprotobuf -lz
.PHONY:clean
clean:rm -rf server client

gitee

https://gitee.com/pu-mingbo/master.git