Rust logging into journald configured by the `RUST_LOG` environment variable

Cargo.toml

anyhow = "1"
log = "0.4"
tracing = { git = "https://github.com/tokio-rs/tracing", rev = "f81426b" }
tracing-subscriber = { git = "https://github.com/tokio-rs/tracing", rev = "f81426b"  }
tracing-journald = { git = "https://github.com/tokio-rs/tracing", rev = "f81426b"  }

lib.rs

use anyhow::{Context, Result};

pub fn init_journald_logging() -> Result<()> {
    use tracing_subscriber::{prelude::*, registry, EnvFilter};
    registry()
        .with(EnvFilter::try_from_default_env().context("couldn't parse `RUST_LOG` env var")?)
        .with(tracing_journald::subscriber().context("couldn't connect to journald")?)
        .init();
    Ok(())
}

main.rs

use anyhow::Result;

fn main() -> Result<()> {
    lib::init_journald_logging()?;

    log::info!("Tracing intercepts log events, so you can just continue using it");
    tracing::error!(foo = "bar", "Or you can use events to pass structural data");

    Ok(())
}