Introduction:

OS	GCC	CLANG
OSX
Linux

fn-log is an open source C++ lightweight & cross platform log library. It's an iteration from log4z.
It provides in a C++ application log and trace debug function for 7*24h service program.
Support 64/32 of windows/linux/mac/android/iOS.
fn-log是一款开源的轻量级高性能的跨平台日志库, 从log4z迭代而来, 主要针对7*24小时服务器程序的日志输出与跟踪调试,
支持64/32位的windows/linux/mac/android/iOS等操作系统.

Feature:

MIT开源授权授权的限制非常小.
跨平台支持linux & windows & mac, 仅头文件实现.

通过merge_header.sh脚本可以合并为单个头文件实现.
生命周期自动化管理, 接口简洁易用.
高性能的线程安全实现.

std::atomic实现的lockfree方案, 跨平台并且极低的竞争代价, 多线程下有比单线程更好的性能表现(mutex实现多线程下性能会大幅损失)
文件写入可以达到300万行以上/秒, 不执行文件写入动作则可达到800万行/秒(完整的序列化和通道队列和处理流程).
高性能的流程设计和高性能的序列化实现.

基础类型通过lut表进行序列化, 流程热点均有压测调优
文件写入可以达到300万行以上/秒, 不执行flush刷入动作(完整的序列化和通道队列)可达到800万行/秒.
完备的线程安全实现所有入口流程都做出了线程安全保证

多线程下任意线程开始构造和启停, 任意线程读写日志, 任意线程修改CFG配置(原子动作)
基于SHARED MEMORY的宕机恢复方案 参见测试用例test_shm.cpp

宕机后fn-log会自动使用shm上的数据进行重建和继续完成未写入的日志.
兼容yaml的配置解析器支持热更新

支持延迟热更新和实时热更新
CHANNEL-DEVICE M:N组合方式的多管道-多输出端设计.

简洁的形式提供极强的扩展性, 可以满足大型项目的多种交叉输出和分流输出的复杂需求.
可以针对不同的channel以及不同的device进行独立设置等级/内容过滤机制等.
提供各种形式的device输出机制, 已实现的包括写文件, 写屏幕, 写UDP等.
可以同时支持同步输出和异步输出
常规日志功能支持

支持日志文件回滚
支持屏显日志染色输出
支持LOG4Z风格的流式输入
支持C++ stream风格的流式输入
支持模版参数包形式的类型安全的动参输入
支持C风格的FORMAT输入

Example

Log Format

[20190514 16:47:20.536][ALARM] [15868]channel [0] start.

[20190514 16:47:20.548][DEBUG] [15868] fn-log\tests\simple_test.cpp:<40> main log init success
[20190514 16:47:20.548][DEBUG] [15868] fn-log\tests\simple_test.cpp:<42> main now time:1557823640;
[20190514 16:47:20.548][DEBUG] [15868] fn-log\tests\simple_test.cpp:<44> main hex text:
	[
	[0x7FF67B00B4B4:  f  n  l  o  g  . 
	[0x7FF67B00B4B4: 66 6E 6C 6F 67 00 
	]
	
[20190514 16:47:20.548][ALARM] [15868] fn-log\tests\simple_test.cpp:<46> main finish

Fast Use Example With Out Yaml File

#include "fn_log.h"

int main(int argc, char* argv[])
{
    int ret = FNLog::FastStartDefaultLogger();
    if (ret != 0)
    {
        return ret;
    }

    LogAlarm() << "log init success";

    LogDebug() << "now time:" << time(nullptr) << ";";
    LOGD("now time:" << time(nullptr) << ";");
    LogDebugPack(0, 0, "now time:", time(nullptr), ";");
    
    LogAlarm() << "finish";

    return 0;
}

Fast Use Example With Yaml File

yaml file

# 配表文件  

 hot_update: true
# 0通道为多线程带文件和屏显输出
 - channel: 0  
    priority: trace
    category: 0
    category_extend: 0
    -device: 0
        disable: false
        out_type: file
        priority: trace
        category: 0
        category_extend: 0
        path: "./log/"
        file: "$PNAME_$YEAR$MON$DAY"
        rollback: 4
        limit_size: 1000 m #only support M byte
    -device: 1
        disable: false
        out_type: screen
        category: 0
        category_extend: 0
 # 1通道为多线程不挂任何输出端
 - channel: 1

 # 2通道为单线程同步写文件
 - channel: 2
    sync_write: 1 #only support single thread
    -device: 0
        disable: false
        out_type: file

 # 3通道为单线程无输出端
 - channel: 3
    sync_write: 1 #only support single thread

code

#include "fn_log.h"

int main(int argc, char* argv[])
{
    int ret = FNLog::LoadAndStartDefaultLogger("./log.yaml");
    if (ret != 0)
    {
        return ret;
    }
    
    int limit_second = 50;
    while (limit_second > 0)
    {
        LogDebug() << "default channel.";
        LogDebugStream(1, 0) << "channel:1, category:0.";
        LogDebugStream(2, 0) << "channel:2, category:0.";
        LogDebugStream(3, 0) << "channel:3, category:0.";
        std::this_thread::sleep_for(std::chrono::milliseconds(1000));
        limit_second--;
    }


    LogAlarm() << "finish";
    return 0;
}

How To Use

multi header file

cp src/include/*.h to dst project.

single header file

cp fn_log.h.only to dst project and remove suffix ".only"

the file fn_log.h.only merge from src/include/*.h

Supported Compilers

GCC >= 4.8
MSVC >= VS2015
CLANG >= 3.3

How To Test

mkdir build
cd build
cmake ..
make
cd ../bin
./buffer_test
./buffer_correct_test
./load_config_test
./simple_test
./stress_udp_test
./stress_test
./multi-thread_test
./multi-thread_write_file_test

Yaml Manual

Global Option:

hot_update

option: true false
default: false
desc: moniter yaml file modify and update logger option.

Channel Option: (channel.)

sync

option: async sync default: async
desc: async mod will open thread to async write log
desc: sync mod all operator in master thread
priority

option: trace debug info warn error alarm fatal
default: trace
desc: log will discard when log priority less than filter priority.
category
category_extend

option:
default: 0, invalid value.
desc: log will reserve when category in set [category, category+category_extend], and other not.
desc: mark content category to filter or write diff device

Device Option: (channel.device.)

disable

option: true, false
default: true
desc: the device will ignore in proc log when this option is disable state.
out_type

option: null, file, udp, screen
default: null
desc: as the option name.
priority

option: trace debug info warn error alarm fatal
default: trace
desc: log will not process when log priority less than filter priority.
category
category_extend

option:
default: 0, invalid value.
desc: log will process when category in set [category, category+category_extend], and other not.
udp_addr

option:
default:
desc: in out_type:udp valid.
desc: example format 127.0.0.1_8080
path

option:
default: "./"
desc: in out_type:file valid.
desc: out file path.
file

option:
default: "$PNAME_$YEAR$MON$DAY_$PID."
desc: in out_type:file valid.
desc: diy out file name. support escape string: $PNAME $PID $YEAR $MON $DAY $HOUR $MIN $SEC
rollback

option: default: 0
desc: in out_type:file valid.
desc: 0 is no rollback op, and other number is rollback file count.
limit_size

option: default: 0
desc: in out_type:file valid.
desc: 0 is no limit, and other number is rollback file limit size (M byte).
```
stress_test_2019.log
stress_test_2019.log.1
stress_test_2019.log.2
stress_test_2019.log.3
```

About The Author

Author: YaweiZhang
Mail: yawei.zhang@foxmail.com
QQGROUP: 524700770
GitHub: https://github.com/zsummer/fn-log

fysu / fn-log