jiff support

[LeoniePhiline]

Transitioning from chrono to jiff, I came across use of the tracing-subscriber "chrono" feature and the tracing_subscriber::fmt::time::ChronoLocal time formatter.

Are there any plans to support jiff based formatters?

Would you accept pull requests adding tracing_subscriber::fmt::time::JiffUtc and tracing_subscriber::fmt::time::JiffZoned behind a "jiff" feature flag?

[kevinbader]

Maybe it helps someone, here's how to use jiff to format the current time. Note that I prefer jiff's temporal formatter, and locatime over UTC.

fn setup_logging() {
    struct JiffTimer {}

    impl FormatTime for JiffTimer {
        fn format_time(
            &self,
            w: &mut tracing_subscriber::fmt::format::Writer<'_>,
        ) -> std::fmt::Result {
            static PRINTER: DateTimePrinter =
                DateTimePrinter::new().separator(b' ').precision(Some(0));
            PRINTER
                .print_datetime(&jiff::Zoned::now().datetime(), jiff::fmt::StdFmtWrite(w))
                .map_err(|_| std::fmt::Error)
        }
    }
    
    tracing_subscriber::fmt::fmt()
        .with_timer(JiffTimer {})
        ...
}

Before:

2025-05-04T12:25:29.299761Z ERROR src/main.rs:86: this is error

After:

2025-05-04 14:42:23 ERROR src/main.rs:90: this is error

[BurntSushi]

A small simplification to that if you don't mind the T separator:

fn setup_logging() {
    struct JiffTimer {}

    impl FormatTime for JiffTimer {
        fn format_time(
            &self,
            w: &mut tracing_subscriber::fmt::format::Writer<'_>,
        ) -> std::fmt::Result {
            write!(w, "{}", jiff::Zoned::now().datetime())
        }
    }

    tracing_subscriber::fmt::fmt()
        .with_timer(JiffTimer {})
        ...
}