Introduction:

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 724h 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724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.

  • [x] 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.

  • [x] 生命周期自动化管理, 接口简洁易用.

  • [x] 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).

  • [x] 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.

  • [x] 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)

  • [x] 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.

  • [x] 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

  • [x] 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
    支持虚拟设备 支持用户进行特殊导出等处理, 并保存有日志现场信息.

  • [x] 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

  1. [20190514 16:47:20.536][ALARM] [15868]channel [0] start.
  3. [20190514 16:47:20.548][DEBUG] [15868] fn-log\tests\simple_test.cpp:<40> main log init success
  4. [20190514 16:47:20.548][DEBUG] [15868] fn-log\tests\simple_test.cpp:<42> main now time:1557823640;
  5. [20190514 16:47:20.548][DEBUG] [15868] fn-log\tests\simple_test.cpp:<44> main hex text:
  6.     [
  7.     [0x7FF67B00B4B4:  f  n  l  o  g  . 
  8.     [0x7FF67B00B4B4: 66 6E 6C 6F 67 00 
  9.     ]
  11. [20190514 16:47:20.548][ALARM] [15868] fn-log\tests\simple_test.cpp:<46> main finish

Fast Use Example With Out Yaml File

  1. #include "fn_log.h"
  3. int main(int argc, char* argv[])
  4. {
  5.     int ret = FNLog::FastStartDefaultLogger();
  6.     if (ret != 0)
  7.     {
  8.         return ret;
  9.     }
  11.     LogAlarm() << "log init success";
  13.     LogDebug() << "now time:" << time(nullptr) << ";";
  14.     LOGD("now time:" << time(nullptr) << ";");
  15.     LogDebugPack(0, 0, "now time:", time(nullptr), ";");
  17.     LogAlarm() << "finish";
  19.     return 0;
  20. }

Fast Use Example With Yaml File

yaml file

  1. # 配表文件  
  3.  hot_update: true
  4. # 0通道为多线程带文件和屏显输出
  5.  - channel: 0  
  6.     priority: trace
  7.     category: 0
  8.     category_extend: 0
  9.     -device: 0
  10.         disable: false
  11.         out_type: file
  12.         priority: trace
  13.         category: 0
  14.         category_extend: 0
  15.         path: "./log/"
  16.         file: "$PNAME_$YEAR$MON$DAY"
  17.         rollback: 4
  18.         limit_size: 1000 m #only support M byte
  19.     -device: 1
  20.         disable: false
  21.         out_type: screen
  22.         category: 0
  23.         category_extend: 0
  24.  # 1通道为多线程不挂任何输出端
  25.  - channel: 1
  27.  # 2通道为单线程同步写文件
  28.  - channel: 2
  29.     sync_write: 1 #only support single thread
  30.     -device: 0
  31.         disable: false
  32.         out_type: file
  34.  # 3通道为单线程无输出端
  35.  - channel: 3
  36.     sync_write: 1 #only support single thread

code

  1. #include "fn_log.h"
  3. int main(int argc, char* argv[])
  4. {
  5.     int ret = FNLog::LoadAndStartDefaultLogger("./log.yaml");
  6.     if (ret != 0)
  7.     {
  8.         return ret;
  9.     }
  11.     int limit_second = 50;
  12.     while (limit_second > 0)
  13.         {
  14.             LogDebug() << "default channel.";
  15.             LogDebugStream(1, 0) << "channel:1, category:0.";
  16.             LogDebugStream(2, 0) << "channel:2, category:0.";
  17.             LogDebugStream(3, 0) << "channel:3, category:0.";
  18.             std::this_thread::sleep_for(std::chrono::milliseconds(1000));
  19.             limit_second--;
  20.         }
  23.     LogAlarm() << "finish";
  24.     return 0;
  25. }

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

    1. mkdir build
    2. cd build
    3. cmake ..
    4. make
    5. cd ../bin
    6. ./buffer_test
    7. ./buffer_correct_test
    8. ./load_config_test
    9. ./simple_test
    10. ./stress_udp_test
    11. ./stress_test
    12. ./multi-thread_test
    13. ./multi-thread_write_file_test

    Yaml Manual

    Global Option:

  • [x] hot_update

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

  • [x] shm_key

    option: hex number default: 0 desc: fn-log will used the number to create at shm memory , if already has shm memory will load it and run continue.

  • [x] logger_name

    option: default: desc: logger name

  • [x] logger_desc

    option: default: desc: logger desc

Channel Option: (channel.)

  • [x] sync

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

  • [x] priority

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

  • [x] 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.)

  • [x] disable

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

  • [x] out_type

    option: null, file, udp, screen, virtual default: null desc: as the option name. only one virtual device per one channel.

  • [x] priority

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

  • [x] category

  • [x] category_extend

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

  • [x] udp_addr

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

  • [x] path

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

  • [x] 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

  • [x] rollback

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

  • [x] 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).

  • [x] stuff_up

    option: default: false desc: in out_type:file valid. desc: rollback files when they are out limit size.

  1. stress_test_2019.log
  2. stress_test_2019.log.1
  3. stress_test_2019.log.2
  4. stress_test_2019.log.3

About The Author

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