FlashLog

A blazingly fast Rust logging library with lazy evaluation.

Features

• Lazy Evaluation: Most evaluations are performed in the logger thread, resulting in exceptional performance.
• JSON Output: Log messages are printed in JSON format for easy parsing and analysis.
• LazyString: Provides LazyString for optimized string interpolation.
• Customizable: Flexible configuration options for file output, console reporting, buffer size, and more.
• Timezone Support: Ability to set local or custom timezones for log timestamps.

Quick Start

Add FlashLog to your Cargo.toml:

[dependencies]

flashlog = "0.1"

Basic usage example:

use flashlog::{Logger, LogLevel, info};

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let logger = Logger::initialize()
        .with_file("logs", "message")?
        .with_max_log_level(LogLevel::Info)
        .launch();

    info!("Hello, FlashLog!");

    Ok(())
}

Advanced Usage

Logging Structs

FlashLog can easily log custom structs:

use serde::{Deserialize, Serialize};
use flashlog::{Logger, LogLevel, log_info};

#[derive(Debug, Serialize, Deserialize, Clone)]
pub struct LogStruct {
    data: [u64; 10],
}

impl Default for LogStruct {
    fn default() -> Self {
        LogStruct { data: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10] }
    }
}

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let logger = Logger::initialize()
        .with_file("logs", "message")?
        .with_max_log_level(LogLevel::Info)
        .launch();

    let log_struct = LogStruct::default();
    log_info!("Log message", log_struct = log_struct);

    Ok(())
}

Using LazyString for Optimization

use flashlog::{lazy_string::LazyString, log_info};

// The format in the LazyString is evaluated in the logger thread. 
// The creation takes around 1.5 ns regardless of the interpolation number
let lazy_msg = LazyString::new(|| format!("{} {} {}", 1, 2, 3)); 
log_info!("LazyOne", msg = lazy_msg);

Configuration Options

FlashLog offers various configuration options:

let logger = Logger::initialize()
    .with_file("logs", "message")? // 
    .with_console_report(false)
    .with_msg_buffer_size(1_000_000)
    .with_msg_flush_interval(1_000_000)
    .with_max_log_level(LogLevel::Info)
    .with_timezone(TimeZone::Local)
    .launch();

Output Format

Logs are outputted in JSON format for easy parsing:

{
  "data": {"text": "Warm up"},
  "date": "20240829",
  "level": "Info",
  "offset": 9,
  "src": "src/main.rs:135",
  "time": "20:08:21.071:409:907",
  "topic": "not given"
}

Benchmark

Test configurations

Print 500,000 logs. Perform the test 5 times. Before each test, sleep for 2 seconds, then print a warm-up message, and then continuously print 500,000 messages. Test has been done on two types: i32 and

struct LogStruct {
    data: [u64; 10],
}

message examples for the struct

flashlog: test-file

{"data": {"test_struct":{"data":[1,2,3,4,5,6,7,8,9,10]}},
"date":"20240829","level":"Info",
"offset":9,"src":"src/main.rs:48","time":"09:22:14.328:084:318","topic":"Log message"}

ftlog: test-file

2024-08-29 09:39:13.503+09 0ms INFO main [src/main.rs:57] Log message: LogStruct { data: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10] }

fast_log: test-file

2024-08-29 10:31:16.7598955 [INFO] Log message: LogStruct { data: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10] }

slog: test-file

Aug 29 01:53:20.725 INFO Log message: LogStruct { data: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10] }

fern: test-file

[2024-08-29T05:59:56.608510100Z INFO example_fern] Log message: LogStruct { data: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10] }

tracing: test-file

2024-08-30T01:17:18.997070Z  INFO example_tracing: Log message: LogStruct { data: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10] }

Performance comparisons

Test machine: Ryzen 7 7700, 3.8 Ghz

Test machine: i5-14400F, 2.5Ghz

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

Authors

• Junbeom Lee
• Youngjin Park

License

This project is licensed under the MIT License - see the LICENSE file for details.