原文转自:http://www.tanjp.com/archives/176 (即时修正和更新)
文件日志异步读写
我们都知道普通的读写文件打开文件都是同步的,比如C的fopen, fclose, fread等。并且磁盘的访问速度远远的低于内存,所以操作系统要阻塞等待磁盘设备准备好才进行读写。如果采用同步,那么上次业务逻辑将会阻塞挂起,等待磁盘把数据准备好,再通知操作系统上报到应用层。高性能的服务器,提高并发,读写文件都会采用异步的模式。
C或C++提高文件读写的接口(FILE, fopen, fclose, fwrite),都是非线程安全的。而我们之前已经知道一个Actor内的行为能确保不可能被多个线程执行,也就是说把日志文件的写入,封装在一个Actor里面(无需使用锁),并且通过调度机制就能实现高并发的文件日志异步写入。文件日志系统,主要用于记录各种日志信息到磁盘文件,所以只需要写入操作。
Actor模式实现高并发的异步文件日志系统
利用Actor的特性,同一个Actor里面的行为,不需要加锁,也就是说Actor可以很方便地封装同步操作。
1、实现一个同步的文件日志写入类型 SyncFileLog。
2、用Actor包装SyncFileLog,得到类型ActorFileLog。
3、实现ActorLog类型,该类型包含了单独的调度器(Scheduler)和舞台(Stage),和管理所有ActorFileLog。
4、ActorLog类型接收信件,创建N个FileLogActor对象,每个FileLogActor对象负责一个单独的文件句柄写入。
这样就实现了基于Actor模式高并发写入多个文件的日志系统。ActorLog对象的设计如下图:
首先,实现一个同步的文件日志写入类型 SyncFileLog,也就是说,这些接口如果直接调用阻塞业务层逻辑。
有以下接口(实现细节有几百行,暂时不粘贴,之后再把源码上传):图文代码请参照以上笔记
class SyncFileLog
{
public:
// 配置文件日志
// @ps_dir, 所在目录。
// @ps_name, 文件名称,不包括路径和后缀。
// @ps_suffix, 后缀名。
// @pn_divide_size, 划分文件的大小。
// @pb_create_dir_everyday, 是否每天划分目录。
// @return 配置成功返回true,否则返回false。
bool config(const std::string & ps_dir, const std::string & ps_name,
const std::string & ps_suffix, uint32 pn_divide_size, bool pb_create_dir_everyday = false);
// @ps_data, 待写入的字符串日志数据。
// @return 写入成功返回true, 否则返回false。
bool write(const std::string & ps_data);
// 关闭文件。
void close();
};
然后,用Actor包装同步的文件日志写入类型SyncFileLog,得到类型ActorFileLog。代码如下:
class ActorFileLog : public Actor
{
public:
explicit ActorFileLog(Stage * pp_stage, uint32 pn_actorid);
~ActorFileLog();
void init() override;
private:
void op_config(Mail * pp_mail);
void op_write(Mail * pp_mail);
void op_close(Mail * pp_mail);
private:
SyncFileLog * mp_filelog;
};
ActorFileLog::ActorFileLog(Stage * pp_stage, uint32 pn_actorid)
: Actor(pp_stage, pn_actorid), mp_filelog(new SyncFileLog()){}
ActorFileLog::~ActorFileLog() { SAFE_DELETE(mp_filelog);}
void ActorFileLog::init()
{
set_operation(ActorLog::kMSIdConfig, std::bind(&ActorFileLog::op_config, this, std::placeholders::_1));
set_operation(ActorLog::kMSIdWrite, std::bind(&ActorFileLog::op_write, this, std::placeholders::_1));
set_operation(ActorLog::kMSIdClose, std::bind(&ActorFileLog::op_close, this, std::placeholders::_1));
}
void ActorFileLog::op_config(Mail * pp_mail)
{
ActorLog::ConfigAttachment * zp_attachment = static_cast< ActorLog::ConfigAttachment* >(pp_mail->attachment);
if (!zp_attachment)
{
return; //static_cast attachment error
}
ActorLog::ConfigAttachment & zo_attachment = *zp_attachment;
const std::string & zs_dir = std::get<0>(zo_attachment);
const std::string & zs_name = std::get<1>(zo_attachment);
const std::string & zs_suffix = std::get<2>(zo_attachment);
uint32 zn_divide_size = std::get<3>(zo_attachment);
bool zb_create_dir_everyday = std::get<4>(zo_attachment);
bool zb_ok = mp_filelog->config(zs_dir, zs_name, zs_suffix, zn_divide_size, zb_create_dir_everyday);
if (!zb_ok) { //失败处理 }
SAFE_DELETE(zp_attachment); //销毁附件
}
void ActorFileLog::op_write(Mail * pp_mail)
{
ActorLog::WriteAttachment * zp_attachment = static_cast<ActorLog::WriteAttachment*>(pp_mail->attachment);
if (!zp_attachment)
{
return; //static_cast attachment error
}
std::string & zs_data = *zp_attachment;
bool zb_ok = mp_filelog->write(zs_data);
if (!zb_ok) { //失败处理 }
SAFE_DELETE(zp_attachment); //销毁附件
}
void ActorFileLog::op_close(Mail * pp_mail)
{
this->close();
mp_filelog->close();
}
最后,实现ActorLog类型,该类型包含了单独的调度器(Scheduler)和舞台(Stage),和管理所有ActorFileLog。
class ActorLog : public Actor
{
friend class ActorFileLog;
typedef std::tuple<std::string, std::string, std::string, uint32, bool> ConfigAttachment;
typedef std::string WriteAttachment;
static const uint32 kMSIdConfig = LOG_MAIL_SUBJECT(1);
static const uint32 kMSIdWrite = LOG_MAIL_SUBJECT(2);
static const uint32 kMSIdClose = LOG_MAIL_SUBJECT(3);
public:
static const uint32 kActorId = LOG_ACTOR_ID;
static bool post_config(ActorPtr & pp_sender, uint32 pn_logid,
const std::string & ps_dir, const std::string & ps_name,
const std::string & ps_suffix, uint32 pn_divide_size, bool pb_create_dir_everyday);
static bool post_write(ActorPtr & pp_sender, uint32 pn_logid, const std::string & ps_data);
static bool post_close(ActorPtr & pp_sender);
public:
explicit ActorLog(Stage * pp_stage);
~ActorLog();
void init() override;
// pp_data, 传入uint32类型, 表示日志调度分配的CPU核数。
bool set_special(void * pp_data) override;
private:
void op_config(Mail * pp_mail);
void op_write(Mail * pp_mail);
void op_close(Mail * pp_mail);
private:
Scheduler * mp_schd;
Stage * mp_stage;
};
bool ActorLog::post_config(ActorPtr & pp_sender, uint32 pn_logid,
const std::string & ps_dir, const std::string & ps_name,
const std::string & ps_suffix, uint32 pn_divide_size, bool pb_create_dir_everyday)
{
ConfigAttachment * zp_attachment = new ConfigAttachment(ps_dir, ps_name, ps_suffix, pn_divide_size, pb_create_dir_everyday);
bool zb_ok = pp_sender->post(kActorId, kMSIdConfig, pn_logid, zp_attachment);
if (!zb_ok) {SAFE_DELETE(zp_attachment);}
return zb_ok;
}
bool ActorLog::post_write(ActorPtr & pp_sender, uint32 pn_logid, const std::string & ps_data)
{
WriteAttachment * zp_attachment = new WriteAttachment(ps_data);
bool zb_ok = pp_sender->post(kActorId, kMSIdWrite, pn_logid, zp_attachment);
if (!zb_ok){ SAFE_DELETE(zp_attachment); }
return zb_ok;
}
bool ActorLog::post_close(ActorPtr & pp_sender)
{
return pp_sender->post(kActorId, kMSIdClose, 0, 0);
}
ActorLog::ActorLog(Stage * pp_stage) : Actor(pp_stage, kActorId), mp_schd(0), mp_stage(0){}
ActorLog::~ActorLog()
{
SAFE_DELETE(mp_stage);
SAFE_DELETE(mp_schd);
}
void ActorLog::init()
{
set_operation(kMSIdConfig, std::bind(&ActorLog::op_config, this, std::placeholders::_1));
set_operation(kMSIdWrite, std::bind(&ActorLog::op_write, this, std::placeholders::_1));
set_operation(kMSIdClose, std::bind(&ActorLog::op_close, this, std::placeholders::_1));
}
bool ActorLog::set_special(void * pp_data)
{
if (mp_schd || mp_stage){ return false;/*can not repeat set_special*/ }
uint32 * zp_data = static_cast<uint32*>(pp_data);
if (!zp_data){ return false;/*static_cast cpu count error*/ }
uint32 zn_cpu_count = *zp_data;
mp_schd = new Scheduler(zn_cpu_count, enST_DEFAULT, false);
bool zb_ok = mp_schd->start();
if (!zb_ok)
{
SAFE_DELETE(mp_schd);
return false; //scheduler start failed
}
mp_stage = new Stage(mp_schd);
return zb_ok;
}
void ActorLog::op_config(Mail * pp_mail)
{
ConfigAttachment * zp_attachment = static_cast< ConfigAttachment* >(pp_mail->attachment);
if (!zp_attachment){return;/*static_cast attachment*/}
if (!mp_schd || !mp_stage)
{
SAFE_DELETE(zp_attachment); //销毁附件
return;//please call function set_specia
}
uint32 zn_logid = pp_mail->content;
ActorPtr zp_actor = ActorPtr(new ActorFileLog(mp_stage, zn_logid));
zp_actor->init();
bool zb_ok = mp_stage->add_actor(zp_actor);
if (!zb_ok)
{
SAFE_DELETE(zp_attachment); //销毁附件
return;//add actor failed
}
zb_ok = zp_actor->post(zn_logid, pp_mail->subject, 0, zp_attachment);
if (!zb_ok)
{
SAFE_DELETE(zp_attachment); //销毁附件
ExTrack::error(TI_LIBLOG, ss.str());//actor post self failed
}
}
void ActorLog::op_write(Mail * pp_mail)
{
WriteAttachment * zp_attachment = static_cast<WriteAttachment*>(pp_mail->attachment);
if (!zp_attachment)
{
return;//static_cast attachment error
}
if (!mp_schd || !mp_stage)
{
SAFE_DELETE(zp_attachment); //销毁附件
return;//please call function set_special
}
uint32 zn_logid = pp_mail->content;
ActorPtr zp_actor = mp_stage->get(zn_logid);
if (!zp_actor)
{
SAFE_DELETE(zp_attachment); //销毁附件
return;//get actor failed
}
bool zb_ok = zp_actor->post(zn_logid, pp_mail->subject, 0, zp_attachment);
if (!zb_ok)
{
SAFE_DELETE(zp_attachment); //销毁附件
ExTrack::error(TI_LIBLOG, ss.str());//actor post self failed
}
}
void ActorLog::op_close(Mail * pp_mail)
{
if (!mp_schd || !mp_stage)
{
return;//please call function set_special
}
this->close();
std::vector<uint32> zc_ids = mp_stage->get_ids();
uint32 zn_actorid = 0;
for (auto it = zc_ids.begin(); it != zc_ids.end(); ++it)
{
zn_actorid = *it;
ActorPtr & zp_actor = mp_stage->get(zn_actorid);
zp_actor->post(zn_actorid, kMSIdClose, 0, 0);
}
mp_stage->wait_for_destroyed();
mp_schd->stop();
}
测试示例
void main(int argc, char* argv[])
{
std::cout << std::endl << "begin" << std::endl;
Scheduler schd(0, enST_STEALING, true);
schd.start();
{
Stage stage(&schd);
{ //创建Actor
ActorPtr zp_actor = ActorPtr(new ActorLog(&stage));
zp_actor->init();
uint32 zn_core_num = 3;
zp_actor->set_special(&zn_core_num);
stage.add_actor(zp_actor);
}{
// 开始投递信件
ActorPtr zp_actor = stage.get(ActorLog::kActorId);
ActorLog::post_config(zp_actor, 11, "./logs/", "11_test", ".txt", 1024 * 1024, true);
ActorLog::post_config(zp_actor, 12, "./logs/", "12_test", ".txt", 1024 * 1024, true);
ActorLog::post_config(zp_actor, 21, "./logs_all/", "21_test", ".txt", 1024 * 1024, false);
ActorLog::post_config(zp_actor, 22, "./logs_all/", "22_test", ".txt", 1024 * 1024, false);
}{ // 写入数据到多个日志文件
ActorPtr zp_actor = stage.get(ActorLog::kActorId);
auto f = [&](uint32 n) {
std::string s1("abc ");
if (n > 0){ s1.assign((n % 100) + 1, 'A' + (n % 26));}
s1.append("\n");
ActorLog::post_write(zp_actor, 11, s1);
ActorLog::post_write(zp_actor, 12, s1);
std::string s2("123 ");
if (n > 0){s2.assign((n % 100) + 1, 'a' + (n % 26));}
s2.append("\n");
ActorLog::post_write(zp_actor, 21, s2);
ActorLog::post_write(zp_actor, 22, s2);
};
for (uint32 i = 0; i < 100000; ++i)
{
f(i);
}
}{ // 投递关闭信件
ActorPtr zp_actor = stage.get(ActorLog::kActorId);
ActorLog::post_close(zp_actor);
}
// 等待所有操作完成并销毁
stage.wait_for_destroyed();
}
schd.stop();
std::cout << std::endl << "end" << std::endl;
}