casual_logger

This logger used when practicing the example programs.
Only write to file, rotate by date.
Not for hard users.

At first, Disclaim

• It differs from the standard Rust log interface.
• Ignore performance for ease of use.

At second, Overall view

Your code:

use casual_logger::{Level, Log, Table, LOGGER};

fn main() {
    let remove_num = if let Ok(mut logger) = LOGGER.lock() {
        // Do not call 'Log::xxxxx()' in this code block.
        //
        // Set file name.
        //
        // All: 'tic-tac-toe-2020-07-12.log.toml'
        // Prefix: 'tic-tac-toe'
        // StartDate: '-2020-07-12' automatically.
        // Suffix: '.log' - To be safe, include a word that
        //         clearly states that you can delete the file.
        // Extention: '.toml'
        //
        // If you don't like the .toml extension, leave the
        // suffix empty and the .log extension.
        logger.set_file_name("tic-tac-toe", ".log", ".toml");

        logger.retention_days = 2;
        // The higher this level, the more will be omitted.
        //
        // |<-- Low Level --------------------- High level -->|
        // |<-- High priority --------------- Low priority -->|
        // |Fatal< Error < Warn < Notice < Info < Debug <Trace|
        logger.level = Level::Trace;
        // Remove old log files. This is determined by the
        // StartDate in the filename.
        logger.remove_old_logs()
    } else {
        0
    };
    Log::noticeln(&format!("Remove {} files.", remove_num));

    Log::infoln(
        "Hello, world!!
こんにちわ、世界！！",
    );

    if Log::enabled(Level::Info) {
        let x = 100; // Time-consuming preparation, here.
        Log::infoln(&format!("x is {}.", x));
    }

    Log::trace("A,");
    Log::traceln("B,");
    Log::debug("C,");
    Log::debugln("D,");
    Log::info("E,");
    Log::infoln("F,");
    Log::notice("G,");
    Log::noticeln("H,");
    Log::warn("I,");
    Log::warnln("J,");
    Log::error("K,");
    Log::errorln("L,");
    Log::fatal("M,");
    Log::fatalln("N!");
}

Output ./default-2020-07-12.log.toml auto generated:

["Now=2020-07-12 14:18:13&Pid=7528&Thr=ThreadId(1)&Seq=1"]
Notice = "Remove 0 files.\r\n"

["Now=2020-07-12 14:18:13&Pid=7528&Thr=ThreadId(1)&Seq=2"]
Info = """
Hello, world!!
こんにちわ、世界！！\r\n
"""

["Now=2020-07-12 14:18:13&Pid=7528&Thr=ThreadId(1)&Seq=3"]
Info = "x is 100.\r\n"

["Now=2020-07-12 14:18:13&Pid=7528&Thr=ThreadId(1)&Seq=4"]
Info = """
The sky is from top to bottom!!
上から下まで空です！！\r\n
"""
ABird = "fly in the sky."
ThreeMonkeys = """
climb
a tall
tree.
"""
TwoFish = "swim."

["Now=2020-07-12 14:18:13&Pid=7528&Thr=ThreadId(1)&Seq=5"]
Trace = "A,"

["Now=2020-07-12 14:18:13&Pid=7528&Thr=ThreadId(1)&Seq=6"]
Trace = "B,\r\n"

["Now=2020-07-12 14:18:13&Pid=7528&Thr=ThreadId(1)&Seq=7"]
Debug = "C,"

["Now=2020-07-12 14:18:13&Pid=7528&Thr=ThreadId(1)&Seq=8"]
Debug = "D,\r\n"

["Now=2020-07-12 14:18:13&Pid=7528&Thr=ThreadId(1)&Seq=9"]
Info = "E,"

["Now=2020-07-12 14:18:13&Pid=7528&Thr=ThreadId(1)&Seq=10"]
Info = "F,\r\n"

["Now=2020-07-12 14:18:13&Pid=7528&Thr=ThreadId(1)&Seq=11"]
Notice = "G,"

["Now=2020-07-12 14:18:13&Pid=7528&Thr=ThreadId(1)&Seq=12"]
Notice = "H,\r\n"

["Now=2020-07-12 14:18:13&Pid=7528&Thr=ThreadId(1)&Seq=13"]
Warn = "I,"

["Now=2020-07-12 14:18:13&Pid=7528&Thr=ThreadId(1)&Seq=14"]
Warn = "J,\r\n"

["Now=2020-07-12 14:18:13&Pid=7528&Thr=ThreadId(1)&Seq=15"]
Error = "K,"

["Now=2020-07-12 14:18:13&Pid=7528&Thr=ThreadId(1)&Seq=16"]
Error = "L,\r\n"

["Now=2020-07-12 14:18:13&Pid=7528&Thr=ThreadId(1)&Seq=17"]
Fatal = "M,"

["Now=2020-07-12 14:18:13&Pid=7528&Thr=ThreadId(1)&Seq=18"]
Fatal = "N!\r\n"

At third, Description

Code:

use casual_logger::{Level, Log, Table, LOGGER};

At the timing of the first writing, a file with a
time stamp in its name is automatically generated.
For example: ./tic-tac-toe-2020-07-12.log.toml

Description:

It is difficult to explain the file path for beginners.
Therefore, it does not move.

Excite yourself with a prefix.

StartDate is basically today.
If the rotation fails, it is the start date.

Suffix to be safe, include a word that
clearly states that you can delete the file.

If you don't like the .toml extension, leave
the suffix empty and the .log extension.

Set up, Code:

fn main() {
    if let Ok(mut logger) = LOGGER.lock() {
        logger.set_file_name("tic-tac-toe", ".log", ".toml");
        logger.retention_days = 2;
        logger.level = Level::Trace;
    }

    // ...
}

Log rotation, Code:

    let remove_num = if let Ok(mut logger) = LOGGER.lock() {
        logger.remove_old_logs()
    } else {
        0
    };
    Log::noticeln(&format!("Remove {} files.", remove_num));

Logger Properties

Example of retention_days:

• retention_days is 2.
• Today is 2020-07-12.
• The ./default-2020-07-09.log.toml file will be deleted.
• The ./default-2020-07-10.log.toml remains.
• Delete old files by date in filename.

Example of level:

• There are 7 log levels.
  • |Fatal< Error < Warn < Notice < Info < Debug <Trace|
  • |<-- Small ------------------------------ Large -->|
  • |<-- Concise -------------------------- Verbose -->|
  • |<-- Low Level --------------------- High level -->|
  • |<-- High priority --------------- Low priority -->|

Code:

    // Multi-line string.
    Log::infoln(
        "Hello, world!!
こんにちわ、世界！！",
    );

    // After explicitly checking the level.
    if Log::enabled(Level::Info) {
        let x = 100; // Time-consuming preparation, here.
        Log::infoln(&format!("x is {}.", x));
    }

    // Suffix '_t'. TOML say a table. So-called map.
    Log::infoln_t(
        "The sky is from top to bottom!!
上から下まで空です！！",
        Table::default()
            .str(
                // Do not include spaces in your key.
                "ABird",
                "fly in the sky.",
            )
            .str("TwoFish", "swim.")
            .str(
                "ThreeMonkeys",
                "climb
a tall
tree.",
            ),
    );

    // The level is implicitly confirmed.
    Log::trace("A,");
    Log::traceln("B,");
    Log::debug("C,");
    Log::debugln("D,");
    Log::info("E,");
    Log::infoln("F,");
    Log::notice("G,");
    Log::noticeln("H,");
    Log::warn("I,");
    Log::warnln("J,");
    Log::error("K,");
    Log::errorln("L,");
    Log::fatal("M,");
    Log::fatalln("N!");

TODO

• Adding table items as toml.
  • str.
  • Other type...
• Spawn another thread for logging.

Tested environment

• OS: Windows 10.
• Editor: Visual studio code.

Appendix

Customize method

Code: main.rs

use casual_logger::Log;

pub trait LogExt {
    fn println(s: &str);
}
impl LogExt for Log {
    /// Info level logging and add print to stdout.
    fn println(s: &str) {
        println!("{}", s);
        Log::infoln(s);
    }
}

Usage: other.rs

use crate::LogExt;

pub fn test() {
    Log::println("Hello, world!!");
}