Example for setting up a minimal logger to both file and stdout with tracing

Cargo.toml

[features]
default = ["tracy"]
tracy = []

[dependencies]
tracing = "0.1"
tracing-appender = "0.2"
tracing-subscriber = { version = "0.3", features = ["env-filter"] }
tracing-tracy = "0.11.0"

logging.rs

#[allow(unused_imports)]
use tracing::{info,warn,debug,error};

use std::{io, fs};
use std::path::Path;
use tracing_appender::non_blocking::WorkerGuard;
use tracing_subscriber::{fmt, layer::SubscriberExt, EnvFilter };

/// Sets up logging to both stdout and files
pub fn setup<P: AsRef<Path> + Clone>(crate_name: &str, dir: P) -> WorkerGuard {
    // Ensures logging dir exists
    fs::create_dir_all(dir.clone()).expect("Failed to create tempdir");

    // Common formatting options for all outputs
    let format = fmt::format()
        .compact()
        .with_thread_ids(true)
    ;

    // Logging to file
    let file_appender = tracing_appender::rolling::daily(dir.as_ref(), dir.as_ref().join(format!("{crate_name}.log")));
    let (non_blocking, guard) = tracing_appender::non_blocking(file_appender);

    // Setup the subscriber
    let subscriber = tracing_subscriber::registry()
        .with(EnvFilter::try_from_default_env().unwrap_or_else(|_| format!("warn,{crate_name}=info").into()))
        .with(fmt::Layer::new().with_writer(io::stdout).event_format(format.clone()))
        .with(fmt::Layer::new().with_writer(non_blocking).with_ansi(false).event_format(format))
    ;

    #[cfg(feature = "tracy")]
    let subscriber = subscriber.with(tracing_tracy::TracyLayer::default());

    tracing::subscriber::set_global_default(subscriber).expect("Unable to set a global subscriber");

    guard
}

main.rs

fn main() -> anyhow::Result<()> {
    let _guard = logging::setup("foo", "./logs");
  
    // do work

    Ok(())
}