Crate ftail 

Ftail

Ftail is a simple logging implementation for the log crate with support for multiple channels, including console output, files, and custom loggers.

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Features

• Multiple logging channels: console, formatted console, single file, daily file, and custom
• Level and target filtering
• Optional timestamp formatting and timezone support
• Automatic log rotation and retention
• Use RUST_LOG environment variable for dynamic log level control (use ‘_env_level’ postfix)

---

Quick Start

Add Ftail to your Cargo.toml:

[dependencies]
ftail = "0.3"

Initialize Ftail in your main.rs or lib.rs:

use ftail::Ftail;
use log::LevelFilter;

fn main() -> Result<(), Box<dyn std::error::Error>> {
    Ftail::new()
        .console(LevelFilter::Info)        // log to console
        .daily_file("logs", LevelFilter::Error) // log errors to daily files
        .init()?; // initialize logger

    log::info!("Hello, Ftail!");
    log::error!("This is an error message");
    Ok(())
}

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Configuration Options

Option	Description	Notes
.datetime_format()	Set the datetime format	Ex: "%Y-%m-%d %H:%M:%S%.3f"
.timezone()	Set the timezone	Requires timezone feature
.max_file_size()	Maximum file size in MB	Older logs renamed .old{N}
.retention_days()	Number of days to keep log files	Daily file only
.filter_levels()	Log only the specified levels	Vec<Level>
.filter_targets()	Log only the specified targets	Vec<&str>

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Channels

Console

Logs to the standard output without formatting.

Ftail::new()
    .console(LevelFilter::Trace)
    .init()?;

Output:

2024-09-13 17:35:18 TRACE console This is a trace message
2024-09-13 17:35:18 DEBUG console This is a debug message
2024-09-13 17:35:18 INFO foo bar
2024-09-13 17:35:18 WARN console This is a warning message
2024-09-13 17:35:18 ERROR console This is an error message

---

Formatted Console

Logs with formatted and colored output.

Ftail::new()
    .formatted_console(LevelFilter::Trace)
    .init()?;

Output:

2024-09-13 17:35:37 · TRACE
This is a trace message
examples/formatted_console/src/main.rs:9

2024-09-13 17:35:37 · DEBUG
This is a debug message
examples/formatted_console/src/main.rs:11

---

Single File

Logs to a single file (e.g., logs/demo.log).

Ftail::new()
    .single_file(Path::new("logs/demo.log"), true, LevelFilter::Trace)
    .init()?;

• append = true keeps existing logs, false overwrites.

---

Daily File

Logs to daily files in a directory (e.g., logs/2025-09-25.log).

Ftail::new()
    .daily_file(Path::new("logs"), LevelFilter::Trace)
    .init()?;

• Automatically rotates files per day.

---

Custom Channel

Create your own logger by implementing the log::Log trait:

Ftail::new()
    .custom(
        |config| Box::new(CustomLogger { config }) as Box<dyn Log + Send + Sync>,
        LevelFilter::Debug,
    )
    .datetime_format("%H:%M:%S%.3f")
    .init()?;

struct CustomLogger {
    config: ftail::Config,
}

impl log::Log for CustomLogger {
    fn enabled(&self, metadata: &log::Metadata) -> bool {
        metadata.level() <= self.config.level_filter
    }

    fn log(&self, record: &log::Record) {
        if !self.enabled(record.metadata()) {
            return;
        }
        let time = chrono::Local::now()
            .format(&self.config.datetime_format)
            .to_string();
        println!("[{}] {}: {}", time, record.level(), record.args());
    }

    fn flush(&self) {}
}

Output:

19:37:22.402 [DEBUG] This is a debug message
19:37:22.403 [INFO] bar
19:37:22.403 [WARN] This is a warning message
19:37:22.403 [ERROR] This is an error message

---

Tips

• Use .console(LevelFilter::Debug) for development.
• Use .daily_file() in production to organize logs by date.
• Combine .max_file_size() and .retention_days() to prevent disk bloat.
• Only enable the channels you need to reduce overhead by disabling default features in Cargo.toml.

Modules

ansi_escape

Module containing the ANSI escape codes.

channels

Module containing the channels.

error

Module containing the error type.

Structs

Config

The configuration struct for the logger. Required for custom channels.

Ftail

The main struct for configuring the logger.