Give the ability to specify what env variable to read the level specification from

[SpyrosRoum]

Hello, I believe it would be a good idea to allow for custom env variables (maybe with RUST_LOG being the default).
This way I can use flexi_logger for more than one apps at a time and each one can have their own log level

I'd be happy to help implement this. I am thinking the api would look something like Logger::try_with_env("ENV_VARIABLE_NAME") and Logger::try_with_env_or_str("ENV_VARIABLE_NAME", "info")

[emabee]

Hi Spyros,
I agree that the hard-coded treatment of RUST_LOG is questionable, but it's there since ever, to be compatible with env_logger.

The desired result can also be achieved with:

    use flexi_logger::Logger;

    let _logger = Logger::try_with_str(
        std::env::var("MY_ENV_VAR")
            .or(std::env::var("RUST_LOG"))
            .as_deref()
            .unwrap_or("info"),
    )?
    .start()?;

[SpyrosRoum]

I wasn't aware that env_logger has the same limitation.
Doing it the way you suggest was my backup, I was just hoping to get this abstracted in your library, especially since I assume it is a common thing people would like to do.

This might be starting to get ugly but you could introduce new methods like try_with_custom_env, this way doesn't break backwards compatibility either.