Fdbus实例教程
Fdbus简介
Fdbus 全称 Fast Distributed Bus（高速分布式总线），提供IPC+RPC功能。适用于多种OS：
- Linux
- QNX
- AnroidOS
- Window
Fdbus本质是Socket，IPC基于Unix domain socket，RPC基于TCP。使用Google Protobuf进行序列化和反序列化。
利用它，可以实现同域间的IPC通信，比如应用和OS间。也可以实现跨域、跨设备间通信，比如不同设备间数据传输，比如host/gust间的数据传输。
Fdbus的一些特点
- 支持多种通信模式，比如点对点、注册/发布、广播等等。
- 支持服务动态发现，自带心跳检测、重连，上线通知、离线检测等功能。
- 支持一定程度的安全策略配置，token、证书、访问鉴权等等。
- 支持Log调试，可以通过调试工具抓取在Fdbus上传输的内容。
其作者jeremy_cz（膜拜大神）对于FDBus的介绍非常详细。本文就不介绍了。关于FDBUS的内容，可以阅读作者的《Fast Distributed Bus - FDBus：高速分布式总线以及中间件开发框架》
Fdbus实例教程
基于Fdbus在一台Linux上，写一个C/S通信的Hellworld(例子）。
PC OS：Ubutun 20.04
编译Fdbus
- 编译protobuf
git clone https://github.com/protocolbuffers/protobuf.git
git submodule update --init --recursive
mkdir -p build
cd build
# 这里把/usr作为了安装目录
cmake -DCMAKE_INSTALL_PREFIX=/usr -DBUILD_SHARED_LIBS=1 ../cmake
make -j4
make install
- 编译fdbus
git clone https://gitee.com/jeremyczhen/fdbus.git
cd fdbus
mkdir -p build/install
cd build
cmake -DCMAKE_INSTALL_PREFIX=install -Dfdbus_LOG_TO_STDOUT ../cmake
make -j4
编译成功后，会在build目录下生成大概以下文件，其中name_server是FDBUS用来管理服务名的进程，一会跑test需要运行它（具体请查看Fdbus作者jeremy_cz的博客）。编译生成内容大概如下
CMakeCache.txt
CMakeFiles
cmake_install.cmake
cmake_uninstall.cmake
fdbclienttest
fdbservertest
fdbxclient
fdbxserver
host_server
libfdbus-clib.so
libfdbus.so
logsvc
logviewer
lsclt
lsdp
lsevt
lshost
lssvc
Makefile
name_server
ntfcenter
HellWorld
这里直接在fdbus/example中新建了HelloWorld目录，目录结构（主要为了方便，直接借用fdbus源码的cmake。使用其他方式也可以，只要引用fdbus的lib和头文件即可。）
HelloWorld
-- HelloClient.cpp
-- HelloServer.cpp
-- HelloWorld.pb.h
-- HelloWorld.pb.cc
-- HelloWorld.proto
其中HelloWorld.pb.cc和HelloWorld.pb.h，是通过HelloWorld.proto生成的。生成命令
protoc --proto_path=. --cpp_out=. HelloWorld.proto
- HelloWorld.proto
syntax = "proto2";
message HelloWorld
{
required string name = 1;
}
- HelloServer.cpp
#define FDB_LOG_TAG "HELLO_SERVER"
#include <fdbus/fdbus.h>
#include "HelloWorld.pb.h"
#include <fdbus/CFdbProtoMsgBuilder.h>
#include <fdbus/cJSON/cJSON.h>
#include <fdbus/CFdbCJsonMsgBuilder.h>
using namespace ipc::fdbus;
// FDBUS提供的功能线程
static CBaseWorker main_worker;
static const int METHOD_ID = 1;
class HelloServer : public CBaseServer
{
public:
HelloServer(const char*name, CBaseWorker* work = 0)
: CBaseServer(name, work)
{
// Empty
}
protected:
void onOnline(const CFdbOnlineInfo &info)
{
std::cout << "connected to the client" << std::endl;
}
void onOffline(const CFdbOnlineInfo &info)
{
std::cout << "disconnected from client" << std::endl;
}
/* called when client calls invoke() */
void onInvoke(CBaseJob::Ptr &msg_ref)
{
auto msg = castToMessage<CBaseMessage *>(msg_ref);
static int32_t elapse_time = 0;
switch (msg->code())
{
case METHOD_ID:
{
HelloWorld client;
CFdbProtoMsgParser parser(client);
if (!msg->deserialize(parser))
{
return;
}
std::cout << "Client name " << client.name() << std::endl;
/* fill in protocol buffer and reply to client */
HelloWorld server;
server.set_name("Linduo");
CFdbProtoMsgBuilder builder(server);
msg->reply(msg_ref, builder);
}
break;
default:
break;
}
}
};
int main(int argc, char*argv[])
{
/* start fdbus context thread */
FDB_CONTEXT->start();
fdbLogAppendLineEnd(true);
FDB_CONTEXT->registerNsWatchdogListener([](const tNsWatchdogList &dropped_list)
{
for (auto it = dropped_list.begin(); it != dropped_list.end(); ++it)
{
printf("Error!!! Endpoint drops - name: %s, pid: %d\n",
it->mClientName.c_str(), it->mPid);
}
});
CBaseWorker *worker_ptr = &main_worker;
/* start worker thread */
worker_ptr->start();
/* create servers and bind the address: svc://service_name */
for (int i = 1; i < argc; ++i)
{
std::string server_name = argv[i];
std::string url(FDB_URL_SVC);
url += server_name;
server_name += "_server";
auto server = new HelloServer(server_name.c_str(), worker_ptr);
server->enableWatchdog(true);
server->enableUDP(true);
server->setExportableLevel(FDB_EXPORTABLE_SITE);
server->bind(url.c_str());
}
// 将主线程变为WorkThread
CBaseWorker background_worker;
background_worker.start(FDB_WORKER_EXE_IN_PLACE);
}
- HelloClient.cpp
#define FDB_LOG_TAG "HELLO_SERVER"
#include <fdbus/fdbus.h>
#include "HelloWorld.pb.h"
#include <fdbus/CFdbProtoMsgBuilder.h>
#include <fdbus/cJSON/cJSON.h>
#include <fdbus/CFdbCJsonMsgBuilder.h>
using namespace ipc::fdbus;
// FDBUS提供的功能线程
static CBaseWorker main_worker;
static const int METHOD_ID = 1;
class HelloServer : public CBaseServer
{
public:
HelloServer(const char*name, CBaseWorker* work = 0)
: CBaseServer(name, work)
{
// Empty
}
protected:
void onOnline(const CFdbOnlineInfo &info)
{
std::cout << "connected to the client" << std::endl;
}
void onOffline(const CFdbOnlineInfo &info)
{
std::cout << "disconnected from client" << std::endl;
}
/* called when client calls invoke() */
void onInvoke(CBaseJob::Ptr &msg_ref)
{
auto msg = castToMessage<CBaseMessage *>(msg_ref);
static int32_t elapse_time = 0;
switch (msg->code())
{
case METHOD_ID:
{
HelloWorld client;
CFdbProtoMsgParser parser(client);
if (!msg->deserialize(parser))
{
return;
}
std::cout << "Client name " << client.name() << std::endl;
/* fill in protocol buffer and reply to client */
HelloWorld server;
server.set_name("Linduo");
CFdbProtoMsgBuilder builder(server);
msg->reply(msg_ref, builder);
}
break;
default:
break;
}
}
};
int main(int argc, char*argv[])
{
/* start fdbus context thread */
FDB_CONTEXT->start();
fdbLogAppendLineEnd(true);
FDB_CONTEXT->registerNsWatchdogListener([](const tNsWatchdogList &dropped_list)
{
for (auto it = dropped_list.begin(); it != dropped_list.end(); ++it)
{
printf("Error!!! Endpoint drops - name: %s, pid: %d\n",
it->mClientName.c_str(), it->mPid);
}
});
CBaseWorker *worker_ptr = &main_worker;
/* start worker thread */
worker_ptr->start();
/* create servers and bind the address: svc://service_name */
for (int i = 1; i < argc; ++i)
{
std::string server_name = argv[i];
std::string url(FDB_URL_SVC);
url += server_name;
server_name += "_server";
auto server = new HelloServer(server_name.c_str(), worker_ptr);
server->enableWatchdog(true);
server->enableUDP(true);
server->setExportableLevel(FDB_EXPORTABLE_SITE);
server->bind(url.c_str());
}
// 将主线程变为WorkThread
CBaseWorker background_worker;
background_worker.start(FDB_WORKER_EXE_IN_PLACE);
}
- 编译部分：加到了dbus/cmake/pb-example/example.cmake中，在cmake中编译上面的cpp
add_executable(helloworldclient
${PACKAGE_SOURCE_ROOT}/example/HelloWorld/HelloClient.cpp
${PACKAGE_SOURCE_ROOT}/example/HelloWorld/HelloWorld.pb.cc
${PACKAGE_SOURCE_ROOT}/example/HelloWorld/HelloWorld.pb.h
)
add_executable(helloworldserver
${PACKAGE_SOURCE_ROOT}/example/HelloWorld/HelloServer.cpp
${PACKAGE_SOURCE_ROOT}/example/HelloWorld/HelloWorld.pb.cc
${PACKAGE_SOURCE_ROOT}/example/HelloWorld/HelloWorld.pb.h
)
- 在fdbus/cmake/CMakeLists.txt中引入了这个cmake，并且加入了C++14的Flag。
if (MSVC)
add_definitions("-D__WIN32__")
elseif(fdbus_ANDROID)
add_definitions("-D__LINUX__")
else()
if(CMAKE_COMPILER_IS_GNUCXX)
set(CMAKE_CXX_FLAGS "-std=gnu++14 -Wall -Wl,--copy-dt-needed-entries ${CMAKE_CXX_FLAGS}")
endif()
#add_compile_options(-g -O0)
add_definitions("-D__LINUX__")
endif()
include(pb-example/example.cmake)
- 重新运行cmake，然后make。编译出helloworldclient和helloworldserver两个文件。
cmake -DCMAKE_INSTALL_PREFIX=install -Dfdbus_LOG_TO_STDOUT ../cmake
make -j4
运行HelloWorld
- 开三个终端，分别运行，无先后顺序。Server/Client运行无需先后顺序，这点也是Fdbus的有点。大概原理是，通过服务动态绑定，当网络中的Server上线时，Client会自动连接该Service。
# 开3个终端，分别运行。其中name_server(用来实现服务动态绑定)
./name_server
./helloworldserver my
./helloworldclient my
执行成功后：
helloworldserver会输出从客户端收到的内容。
connected to the client
Client name Adver
helloworldclient会输出从服务端收到的内容。
connected to the server
Server name Linduo
PS：name_server在服务端和客户端连接时，不是必须得。如果两端指定了IPC端口，可以不使用name_server连接。但是不使用name_server时，就需要控制好连接时序。所以一般来讲，应用时都是启动一个name_server。
