kqlog

header-only, easy to use, C++ logging library minimum C++17

Setup

clone the repo with --recursive, it will clone: kqlog, fmt, magic_enum, Catch2.

Platforms

• Linux: clang 15.0.7
• Windows: clang 15.0.7

Features

---

• Header only
• Allows user defined log types(/levels)
• Log filtering
• Log color
• Custom formtting for log pattern
• Rich formatting, by fmt
• Thread safe
• Backup
• xml for .npp log files (in progress)

Pattern flags

flag	meaning	example
%V	The log itself	"your text"
%T	Event type	"Debug" / "Info" / "YourEvent"
%Y	Year	"2023"
%M	Month 01-12	"06"
%m	Month full name	"June"
%b	Month abbriviated name	"Jun"
%D	Day 01-31	"23"
%d	Day full name	"Friday"
%B	Day abbriviated name	"Fri"
%H	Hours 00-23	"18"
%N	Minutes 00-59	"42"
%S	Seconds 00-59	"36"
%t	Thread id	"1234"
%L	Caller's source line	"123"
%F	Caller's function name	"my_func"
%s	Caller's source file	"my_func_impl.cpp"
%%	The % sign	"%"
%K	Black color
%R	Red color
%G	Green color
%y	Yellow color
%E	Blue color
%g	Magenta color
%C	Cyan oclor
%W	White color

Usage example

---

Custom log file

by default the logger will output into ./logs.txt (filename="logs.txt", directory="./") you can change it by providing a filename and directory in the constructor e.g

kq::logger logger("myfile.txt", "myDirectory/myOutputDirectory/");

Make sure to include any / in your directory

---

Declare a logger with your own custom enum

enum class myTypes { /* your types here */ };
kq::logger<myTypes> loggers;

if no template argument is provided, kq::default_symbols is used as a default, containing: (macros)

1. KQDEBUG
2. KQINFO
3. KQWARNING
4. KQERROR
5. KQCRITICAL

---

How to log with your logger

call .out() with an enum type and a format string with all it's argument wrapped in {} e.g

logger.out( KQINFO, { "{} is a nice {}", "Today", "day" } );
output: `[2023-02-27 06:38:11] [INFO] [main@07] Today is a nice day`

---

Custom pattern

by default the logger will have the following pattern:

[{%Y}-{%M}-{%D} {%H}:{%N}:{%S}] [{%T}] [{%F}@{%L}] {%V}

see Pattern Flags for reference you can change this pattern with .set_pattern() and provide a string containing the new pattern to reset to the default pattern call the function with no arguments

---

Rainbow

kq::logger Logger("logs.txt", "output/");
    for(int i = 0; i < 10; ++i)
    {
        Logger.set_pattern("{%R}[{%Y}-{%M}-{%D}{%y} {%H}:{%N}:{%S}] {%G}[{%T}] {%E}[{%F}@{%L}] {%V}\n");
        Logger.out(KQINFO, {"{%C} {0:5} {%g}START", i + 10});
        Logger.set_pattern("{%y}[{%Y}-{%M}-{%D}{%G} {%H}:{%N}:{%S}] {%C}[{%T}] [{%F}@{%L}] {%V}\n");
        Logger.out(KQDEBUG, {"{%g} {0:5} {%R}CONTINUE", i + 10});
        Logger.set_pattern("{%G}[{%Y}-{%M}-{%D}{%C} {%H}:{%N}:{%S}] {%E}[{%T}] [{%F}@{%L}] {%V}\n");
        Logger.out(KQCRITICAL, {"{%R} {0:5} {%E}END", i + 10});
    }

---

How to filter your console output

the .set_filter() function takes as parameters:
a vector containing values from the enum of choice
a bool which if true, will only print the values found in the vector, if false, will only print the values NOT found in the vector
(basically filter in/out)
example:

    kq::logger logger;
    // logger.set_filter(.....)
    logger.out( KQINFO,     { "Some info message\n" } );
    logger.out( KQDEBUG,    { "Some debug message\n" } );
    logger.out( KQCRITICAL, { "Some critical message\n" } );

with .set_filter({KQINFO}, true), we get the folloiwng console output:

[2023-03-01 20:32:43] [INFO] [main@08] Some info message

with .set_filter({KQINFO}, false), we get the following console output:

[2023-03-01 20:33:35] [DEBUG] [main@09] Some debug message
[2023-03-01 20:33:35] [CRITICAL] [main@10] Some critical message

the file output does not experience any changes

---

Backup

simply call .backup() it will create backup/ in the directory specified at construction
and will make a copy of the log file with the following pattern name:
{year}-{month}-{day}_{hour}:{min}:{sec}-{filename}

---

Other

this project was made by me and norctus
we took inspiration from other loggers like spdlog and plog
but we've added our on twist and took a more flexible and different approach on our logger