Thrift 基础(C++ rpc )

一、thrift简介

thrift是Facebook开源的一套rpc框架，目前被许多公司使用
我理解的特点

1. 使用IDL语言生成多语言的实现代码，程序员只需要实现自己的业务逻辑
2. 支持序列化和反序列化操作，底层封装协议，传输模块
3. 以同步rpc调用为主，使用libevent evhttp支持http形式的异步调用
4. rpc服务端线程安全，客户端大多数非线程安全
5. 相比protocol buffer效率差些，protocol buffer不支持rpc，需要自己实现rpc扩展，目前有grpc可以使用

由于thrift支持序列化和反序列化，并且支持rpc调用，其代码风格较好并且使用方便，对效率要求不算太高的业务，以及需要rpc的场景，可以选择thrift作为基础库

层次图：

二、编译(thrift for c++ && centos7)

1、官网获取源码包 thrift-0.11.0.tar.gz 解压

tar zxvf thrift-0.11.0.tar.gz

2、安装依赖

yum -y install automake libtool flex bison pkgconfig gcc-c++ boost-devel libevent-devel zlib-devel python-devel ruby-devel openssl-devel

3、编译boost
使用boost_1_63_0.tar.gz

./bootstrap.sh
./b2

4、编译thrift
源码根目录运行

./configure && make
sudo make install

5、验证安装

thrift -version
显示 Thrift version 0.11.0

三、编写使用IDL编写.thrift文件

这里给出一个thrift的IDL基本语法列表，详细用法可以去官网查找

namespace cpp thrift.Test
//typedef 用法
typedef i32 MyInt32;
typedef string MyString;
typedef i32 UserId;
//struct 结构定义
struct TypedefTestStruct
{
	1: MyInt32 field_MyInt32;
	2: MyString field_MyString;
	3: i32 field_Int32;
	4: string filed_string;
}
//enum 枚举定义
enum Numberz
{
	ONE = 1,
	TWO,
	THREE,
	FIVE = 5,
	SIX,
	EIGHT = 8
}
//const 用法
const Numberz myNumberz = Numberz.ONE;
struct Bonk
{
	1: string message,
	2: i32 type
}
//类型嵌套
struct Xtruct
{
	1: string string_thing,
	2: i8 byte_thing,
	3: i32 i32_thing,
	4: i64 i64_thing
}
struct Xtruct2
{
	1: i8 byte_thing,
	2: Xtruct struct_thing,
	3: i32 i32_thing
}
//支持map list set类型分别对应C++中的 map = stl::map list = stl::vector set = stl::set
typedef map<string, Bonk> MapType
struct Insanity
{
	1: map<Numberz, UserId> userMap;
	2: list<Xtruct> xtructs;
}
struct CrazyNesting
{
	1: string string_field,
	2: optional set<Insanity> set_field;
	3: required list<map<set<i32>, map<i32,set<list<map<Insanity,string>>>>>> list_field,
	4: binary binary_field
}
//union用法
union SomeUnion
{
	1: map<NumberZ, UserId> map_thing,
	2: string string_thing,
	3: i32 i32_thing,
	4: Xtruct3 xtruct_thing,
	5: Insanity insanity_thing
}
//exception 异常
exception Xception
{
	1: i32 errorCode,
	2: string message
}
exception Xception2
{	
	1: i32 errorCode,
	2: Xtruct struct_thing
}
// empty struct
struct EmptyStruct{}
struct OneField
{
	1: EmptyStruct field;
}
//service 定义的一组rpc服务,一般是抽象出来的接口调用
service ThriftTest
{
	void testVoid(),
	string testString(1: string thing),
	bool testBool(1: bool thing),
	i8 testByte(1: i8 thing),
	i32 testI32(1: i32 thing),
	i64 testI64(1: i64 thing),
	Xtruct testStruct(1: Xtruct thing),
	Xtruct2 testNest(1: Xtruct2 thing),
	map<string, string> testStringMap(1: map<string, string> thing),
	set<i32> testSet(1: set<i32> thing),
	list<i32> testList(1: list<i32> thing),
	Numberz testEnum(1: Numberz thing),
	map<i32, map<i32,i32>> testMapMap(1: i32 hello),
	map<UserId, map<Numberz,Insanity>> testInsanity(1: Insanity argument),
	Xtruct testMulti(1: i8 arg0, 2: i32 arg1, 3: i64 arg2, 4: map<i16, string> arg3, 5: Numberz arg4, 6: UserId arg5),
	void testException(1: string arg) throws(1: Xception err1),
	Xtruct testMultiException(1: string arg0, 2: string arg1) throws(1: Xception err1, 2: Xception2 err2),
	oneway void testOneway(1:i32 secondsToSleep)
}

四、使用thrift文件生成C++代码

1、生成同步调用的C++代码

thrift -r --gen cpp xxx.thrift

2、生成异步调用的C++代码(同时同步调用的代码也被生成)

thrift --gen cpp:cob_style xxx.thrift 

五、thrfit同步调用

1、StressTest.thrift文件

namespace cpp test.stress
service Service {
  void echoVoid(),
  i8 echoByte(1: i8 arg),
  i32 echoI32(1: i32 arg),
  i64 echoI64(1: i64 arg),
  string echoString(1: string arg),
  list<i8>  echoList(1: list<i8> arg),
  set<i8>  echoSet(1: set<i8> arg),
  map<i8, i8>  echoMap(1: map<i8, i8> arg),
}

2、使用thrift -r --gen cpp StressTest.thrift 生成代码
gen-cpp目录有

StressTest_types.h StressTest_types.cpp StressTest_constants.h StressTest_constants.cpp Service.h Service.cpp Service_server.skeleton.cpp 

生成
StressTest_types.h StressTest_constants.h 为相关类型定义文件
Service_server.skeleton为服务端需要的实现文件

3、代码实现
服务端:

#include <thrift/concurrency/ThreadManager.h>
#include <thrift/concurrency/PlatformThreadFactory.h>
#include <thrift/concurrency/Thread.h>
#include <thrift/protocol/TBinaryProtocol.h>
#include <thrift/server/TSimpleServer.h>
#include <thrift/server/TNonblockingServer.h>
#include <thrift/transport/TServerSocket.h>
#include <thrift/transport/TNonblockingServerSocket.h>
#include <thrift/transport/TNonblockingServerTransport.h>
#include <thrift/transport/TBufferTransports.h>
#include "Service.h"
using namespace ::apache::thrift;
using namespace ::apache::thrift::protocol;
using namespace ::apache::thrift::transport;
using namespace ::apache::thrift::server;
using namespace  ::test::stress;
class ServiceHandler : virtual public ServiceIf {
 public:
  ServiceHandler() {
  }
  void echoVoid() {
    // Your implementation goes here
    printf("echoVoid
");
  }
  int8_t echoByte(const int8_t arg) {
    printf("echoByte %c
", arg);
	return arg;
  }
  int32_t echoI32(const int32_t arg) {
    printf("echoI32
");
	return arg;
  }
  int64_t echoI64(const int64_t arg) {
    printf("echoI64
");
	return arg;
  }
  void echoString(std::string& _return, const std::string& arg) {
    printf("echoString
");
  }
  void echoList(std::vector<int8_t> & _return, const std::vector<int8_t> & arg) {
    printf("echoList
");
  }
  void echoSet(std::set<int8_t> & _return, const std::set<int8_t> & arg) {
    printf("echoSet
");
  }
  void echoMap(std::map<int8_t, int8_t> & _return, const std::map<int8_t, int8_t> & arg) {
    printf("echoMap
");
  }
};

int main(int argc, char **argv) {
  int port = 9090;
  stdcxx::shared_ptr<ServiceHandler> handler(new ServiceHandler());
  stdcxx::shared_ptr<TProcessor> processor(new ServiceProcessor(handler));
  stdcxx::shared_ptr<TProtocolFactory> protocolFactory(new TBinaryProtocolFactory());
  stdcxx::shared_ptr<TNonblockingServerTransport> serverTransport(new TNonblockingServerSocket(port));
  stdcxx::shared_ptr<PlatformThreadFactory> threadFactory = std::shared_ptr<PlatformThreadFactory>(new PlatformThreadFactory());
  stdcxx::shared_ptr<ThreadManager> threadManager = ThreadManager::newSimpleThreadManager(10);

  threadManager->threadFactory(threadFactory);
  threadManager->start();

  stdcxx::shared_ptr<TNonblockingServer> server(new TNonblockingServer(processor, protocolFactory, serverTransport, threadManager));

  server->serve();
  
  return 0;
}

我们需要实现ServiceHandler继承ServiceIf的相关接口，ServiceHandler是负责相关rpc调用业务的功能实现，
thrift服务器模型基本模型有四种、SimpleServer ThreadedServer ThreadPoolServer NoBlockingServer
SimpleServer 简单的单线程模型
ThreadedServer 一个线程一个连接
ThreadPoolServer 线程池
NoBlockingServer 基于libevent的IO复用模型 libevent在linux平台是基于epoll的reactor模型
还有一个异步Server模型TEvhttpServer 基于libevent的evhttp
这里服务端使用了非阻塞epoll实现的thrift服务端模型

客户端:

#include <iostream>
#include <string>
#include <thrift/transport/TTransportUtils.h>
#include <thrift/transport/TSocket.h>
#include <thrift/protocol/TBinaryProtocol.h>
#include "Service.h"

using namespace  ::test::stress;
using namespace apache::thrift;
using namespace apache::thrift::protocol;
using namespace apache::thrift::transport;

int main()
{
	::apache::thrift::stdcxx::shared_ptr<TSocket> socket(new TSocket("localhost", 9090));
	::apache::thrift::stdcxx::shared_ptr<TTransport> transport(new TFramedTransport(socket));
	::apache::thrift::stdcxx::shared_ptr<TProtocol> protocol(new TBinaryProtocol(transport));
	ServiceClient client(protocol);
	transport->open();
	std::cout << "client echoByte byte=" << client.echoByte('A') << std::endl;
	std::cout << "send_echoByte('B')" << std::endl;
	client.send_echoByte('B');
	std::cout << "send_echoByte('C')" << std::endl;
	client.send_echoByte('C');
	std::cout << "recv_echoByte()" << client.recv_echoByte() << std::endl;
	std::cout << "recv_echoByte()" << client.recv_echoByte() << std::endl;
	transport->close();
	return 0;
}

客户端使用则比较简单，Service.h定义了相关接口，ServiceClient则是rpc客户类
TTransport new TFramedTransport(socket) 这里创建基于socket的传输层
TProtocol 协议层，序列化后的数据存储方式，这里以TBinaryProtocol 二进制存储

六、thrift异步调用

1、thrift文件同同步调用一致
2、使用thrift --gen cpp:cob_style StressTest.thrift 生成代码

StressTest_types.h StressTest_types.cpp StressTest_constants.h StressTest_constants.cpp Service.h Service.cpp Service_server.skeleton.cpp Service_async_server.skeleton.cpp

Service_server.skeleton.cpp 同步代码用不到
Service_async_server.skeleton.cpp则为http的异步实现
服务端：

#include <thrift/protocol/TBinaryProtocol.h>
#include <thrift/async/TAsyncProtocolProcessor.h>
#include <thrift/async/TEvhttpServer.h>
#include <event.h>
#include <evhttp.h>
#include <iostream>
#include "Service.h"

using namespace ::apache::thrift;
using namespace ::apache::thrift::protocol;
using namespace ::apache::thrift::transport;
using namespace ::apache::thrift::async;

using namespace  ::test::stress;

class ServiceHandler : virtual public ServiceIf {
public:
	ServiceHandler() {
	}

	void echoVoid() {
		printf("echoVoid
");
	}

	int8_t echoByte(const int8_t arg) {
		printf("echoByte %c
", arg);
		return arg;
	}

	int32_t echoI32(const int32_t arg) {
		printf("echoI32
");
		return arg;
	}

	int64_t echoI64(const int64_t arg) {
		printf("echoI64
");
		return arg;
	}

	void echoString(std::string& _return, const std::string& arg) {
		printf("echoString %s
", arg.c_str());
		_return = arg;
	}

	void echoList(std::vector<int8_t> & _return, const std::vector<int8_t> & arg) {
		printf("echoList
");
	}

	void echoSet(std::set<int8_t> & _return, const std::set<int8_t> & arg) {
		printf("echoSet
");
	}

	void echoMap(std::map<int8_t, int8_t> & _return, const std::map<int8_t, int8_t> & arg) {
		printf("echoMap
");
	}

};

class ServiceAsyncHandler : public ServiceCobSvIf {
 public:
  ServiceAsyncHandler() {
    syncHandler_ = std::auto_ptr<ServiceHandler>(new ServiceHandler);
    // Your initialization goes here
  }
  virtual ~ServiceAsyncHandler(){}

  void echoVoid(::apache::thrift::stdcxx::function<void()> cob) {
    syncHandler_->echoVoid();
    return cob();
  }

  void echoByte(::apache::thrift::stdcxx::function<void(int8_t const& _return)> cob, const int8_t arg) {
    int8_t _return = 0;
    _return = syncHandler_->echoByte(arg);
    return cob(_return);
  }

  void echoI32(::apache::thrift::stdcxx::function<void(int32_t const& _return)> cob, const int32_t arg) {
    int32_t _return = 0;
    _return = syncHandler_->echoI32(arg);
    return cob(_return);
  }

  void echoI64(::apache::thrift::stdcxx::function<void(int64_t const& _return)> cob, const int64_t arg) {
    int64_t _return = 0;
    _return = syncHandler_->echoI64(arg);
    return cob(_return);
  }

  void echoString(::apache::thrift::stdcxx::function<void(std::string const& _return)> cob, const std::string& arg) {
    std::string _return;
    syncHandler_->echoString(_return, arg);
    return cob(_return);
  }

  void echoList(::apache::thrift::stdcxx::function<void(std::vector<int8_t>  const& _return)> cob, const std::vector<int8_t> & arg) {
    std::vector<int8_t>  _return;
    syncHandler_->echoList(_return, arg);
    return cob(_return);
  }

  void echoSet(::apache::thrift::stdcxx::function<void(std::set<int8_t>  const& _return)> cob, const std::set<int8_t> & arg) {
    std::set<int8_t>  _return;
    syncHandler_->echoSet(_return, arg);
    return cob(_return);
  }

  void echoMap(::apache::thrift::stdcxx::function<void(std::map<int8_t, int8_t>  const& _return)> cob, const std::map<int8_t, int8_t> & arg) {
    std::map<int8_t, int8_t>  _return;
    syncHandler_->echoMap(_return, arg);
    return cob(_return);
  }
  
 protected:
  std::auto_ptr<ServiceHandler> syncHandler_;
};

int main()
{
	::apache::thrift::stdcxx::shared_ptr<ServiceAsyncProcessor> asynProcessor(new ServiceAsyncProcessor(
							::apache::thrift::stdcxx::shared_ptr<ServiceCobSvIf>(new ServiceAsyncHandler())));

	::apache::thrift::stdcxx::shared_ptr<TAsyncProtocolProcessor> asynProtocolProcessor(new TAsyncProtocolProcessor(asynProcessor,
							::apache::thrift::stdcxx::shared_ptr<TProtocolFactory>(new TBinaryProtocolFactory())));

	TEvhttpServer server(asynProtocolProcessor, 9999);
	server.serve();
	
	return 0;
}

这里实现ServiceHandler的相关业务接口即可实现rpc服务端的相关功能

客户端：

#include "Service.h"
#include <string>
#include <iostream>
#include <unistd.h>
#include <thrift/concurrency/ThreadManager.h>
#include <thrift/concurrency/PlatformThreadFactory.h>
#include <thrift/concurrency/Thread.h>
#include <thrift/async/TAsyncChannel.h>
#include <thrift/async/TEvhttpClientChannel.h>
#include <thrift/transport/TSocket.h>
#include <thrift/transport/TTransportUtils.h>
#include <thrift/transport/TBufferTransports.h>
#include <thrift/protocol/TBinaryProtocol.h>
#include <thrift/protocol/TProtocol.h>
#include <event.h>

using namespace  ::apache::thrift;
using namespace  ::apache::thrift::transport;
using namespace  ::apache::thrift::protocol;
using namespace  ::apache::thrift::async;
using namespace  ::apache::thrift::concurrency;
using namespace  ::test::stress;

class MyClient : public ServiceCobClient
{
public:
	MyClient(stdcxx::shared_ptr<TAsyncChannel> channel, TProtocolFactory* protocolFactory)
		: ServiceCobClient(channel, protocolFactory)
	{

	}
	virtual ~MyClient(){}

	virtual void completed__(bool success)
	{
		if (success)
		{
			std::cout << "completed" << std::endl;
		}
		else
		{
			std::cout << "completed failed" << std::endl;
		}
	}

	void my_send_byte()
	{
		std::cout << "begin my_send_byte" << std::endl;
		stdcxx::function<void(ServiceCobClient*)> cob = stdcxx::bind(&MyClient::recv_byte_callback, this, stdcxx::placeholders::_1);
		echoByte(cob, 'A');
		std::cout << "end my_send_byte" << std::endl;
	}

	void my_send_string()
	{
		std::cout << "begin my_send_string" << std::endl;
		stdcxx::function<void(ServiceCobClient*)> cob = stdcxx::bind(&MyClient::recv_string_callback, this, stdcxx::placeholders::_1);
		echoString(cob, "test asynclient");
		std::cout << "end my_send_string" << std::endl;
	}

	void recv_byte_callback(ServiceCobClient* client)
	{
		std::cout << "recv_byte_callback" << std::endl;
	    _res_byte = recv_echoByte();
		std::cout << "_res_byte =" << _res_byte << std::endl;
	}

	void recv_string_callback(ServiceCobClient* client)
	{
		std::cout << "recv_string_callback" << std::endl;
		recv_echoString(_res_string);
		std::cout << "_res_string=" << _res_string << std::endl;
	}
private:
	char _res_byte;
	std::string _res_string;
};

class ClientThread : public Runnable
{
public:
	ClientThread(event_base* base, std::string & host, int port)
		: _base(base), _host(host), _port(port)
	{
	}
	virtual ~ClientThread(){}
	virtual void run()
	{
		stdcxx::shared_ptr<TAsyncChannel>  channel1(new TEvhttpClientChannel(_host, "/", _host.c_str(), _port, _base));
		stdcxx::shared_ptr<TAsyncChannel>  channel2(new TEvhttpClientChannel(_host, "/", _host.c_str(), _port, _base));

		MyClient client1(channel1, new TBinaryProtocolFactory());
		MyClient client2(channel2, new TBinaryProtocolFactory());

		client1.my_send_byte();
		client1.my_send_string();

		client2.my_send_byte();
		client2.my_send_string();

		while (1)
		{
			client1.my_send_byte();
			sleep(1);
		}
	}
protected:
private:
	event_base* _base;
	std::string _host;
	int _port;
};

int main()
{
	std::string host = "192.168.119.129";
	int port = 9999;

	event_base* base = event_base_new();

	stdcxx::shared_ptr<PlatformThreadFactory> threadFactory = std::shared_ptr<PlatformThreadFactory>(new PlatformThreadFactory());
	stdcxx::shared_ptr<ThreadManager> threadManager = ThreadManager::newSimpleThreadManager(10);

	threadManager->threadFactory(threadFactory);
	threadManager->start();

	stdcxx::shared_ptr<Thread> thread = threadFactory->newThread(std::shared_ptr<ClientThread>(new ClientThread(base, host, port)));
	thread->start();

	event_base_dispatch(base);
	event_base_free(base);

	return 0;
}

客户端则实现了MyClient，MyClient继承公共的rpc服务接口，提供了异步回调的recv_byte_callback，recv_string_callback函数， ClientThread的线程函数的实现则对MyClient异步客户端进了测试

七、简单总结

通过这两天的学习，简单总结一下这个库
1、thrift的C++代码实现很漂亮，很规范，适合学习阅读
2、thrift可以满足很多基本的rpc调用场景
3、本文只是简单写了thrift的用法，想深入了解这个库的，其内部实现还是需要花时间好好研究

作者 [@karllen][3]
2018 年 09月 15日
QQ群: 347769318