flexi_logger 0.24.2

An easy-to-configure and flexible logger that writes logs to stderr or stdout and/or to files. It allows custom logline formats, and it allows changing the log specification at runtime. It also allows defining additional log streams, e.g. for alert or security messages.
Documentation 
mod test_utils;

use flexi_logger::{detailed_format, FileSpec, Logger};
use log::*;

#[test]
fn test_mods() {
    let handle = Logger::try_with_env_or_str(
        "info, test_mods::mymod1=debug, test_mods::mymod2=error, test_mods::mymod1::mysubmod = off",
    )
    .unwrap()
    .format(detailed_format)
    .log_to_file(
        FileSpec::default()
            .suppress_timestamp()
            .directory(self::test_utils::dir()),
    )
    .start()
    .unwrap_or_else(|e| panic!("Logger initialization failed with {e}"));

    error!("This is an error message");
    warn!("This is a warning");
    info!("This is an info message");
    debug!("This is a debug message - you must not see it!");
    trace!("This is a trace message - you must not see it!");

    mymod1::test_traces();
    mymod2::test_traces();

    handle.validate_logs(&[
        ("ERROR", "test_mods", "error"),
        ("WARN", "test_mods", "warning"),
        ("INFO", "test_mods", "info"),
        ("ERROR", "test_mods::mymod1", "error"),
        ("WARN", "test_mods::mymod1", "warning"),
        ("INFO", "test_mods::mymod1", "info"),
        ("DEBUG", "test_mods::mymod1", "debug"),
        ("ERROR", "test_mods::mymod2", "error"),
    ]);
}

mod mymod1 {
    use log::*;
    pub fn test_traces() {
        error!("This is an error message");
        warn!("This is a warning");
        info!("This is an info message");
        debug!("This is a debug message");
        trace!("This is a trace message - you must not see it!");

        self::mysubmod::test_traces();
    }
    mod mysubmod {
        use log::*;
        pub fn test_traces() {
            error!("This is an error message - you must not see it!");
            warn!("This is a warning - you must not see it!");
            info!("This is an info message - you must not see it!");
            debug!("This is a debug message - you must not see it!");
            trace!("This is a trace message - you must not see it!");
        }
    }
}
mod mymod2 {
    use log::*;
    pub fn test_traces() {
        error!("This is an error message");
        warn!("This is a warning - you must not see it!");
        info!("This is an info message - you must not see it!");
        debug!("This is a debug message - you must not see it!");
        trace!("This is a trace message - you must not see it!");
    }
}