Quickstart: Rust

By the end of this page you will have a Rust program that works out when a support ticket is due, counting only working hours, and how much of its SLA has been used.

InstallCopy Anchor Link

In a Cargo project (cargo new support-sla creates one), add workclock and jiff. workclock needs Rust 1.85 or later.

cargo add workclock jiff

The Rust API takes and returns jiff 0.2 types, so Rust code depends on jiff too.

Write the programCopy Anchor Link

A support desk in London works 09:00–17:00 on weekdays with a lunch hour, and is closed on 25 and 28 December 2026. A ticket opened at 16:30 on Christmas Eve with an 8-hour SLA is due at 09:30 on 30 December. At 11:00 on 29 December, 2 hours 30 minutes of the SLA have been used.

In Rust, put this in src/main.rs:

use jiff::civil::{date, time};
use jiff::{SignedDuration, Zoned};
use workclock::{Break, Holidays, Schedule, Weekdays, WorkDay};

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let days = Weekdays::MON_TO_FRI;
    let support = Schedule::builder()
        .time_zone("Europe/London")
        .rule(WorkDay::new(time(9, 0, 0, 0), time(17, 0, 0, 0), days))
        .rule(Break::new(time(12, 0, 0, 0), time(13, 0, 0, 0), days))
        .rule(Holidays::new([date(2026, 12, 25), date(2026, 12, 28)]))
        .build()?;

    let opened: Zoned = "2026-12-24T16:30[Europe/London]".parse()?;
    let due = support.add(&opened, SignedDuration::from_hours(8))?;
    assert_eq!(due.to_string(), "2026-12-30T09:30:00Z");

    let now: Zoned = "2026-12-29T11:00[Europe/London]".parse()?;
    let used = support.between(&opened, &now);
    assert_eq!(used, SignedDuration::from_mins(150));

    println!("due {due}, used {used:#}");
    Ok(())
}

Run itCopy Anchor Link

cargo run

It prints:

due 2026-12-30T09:30:00Z, used 2h 30m

London time is UTC in December, so 09:30 UTC is 09:30 London time:

What just happenedCopy Anchor Link

Schedule::builder() built a workclock::Schedule whose rules are read in Europe/London: a WorkDay rule for 09:00–17:00 on workclock::Weekdays::MON_TO_FRI, a Break rule for 12:00–13:00, and a Holidays rule for 25 and 28 December. support.add counted 8 hours of working time from the moment the ticket was opened, skipping the evening, the weekend, the holidays and the lunch hour, and returned the due instant as a jiff::Timestamp. support.between returned the working time between two instants as a jiff::SignedDuration. crates/workclock/examples/sla.rs extends this program: it prints the due time in London time and uses next_period to find when the current stretch of working time ends.

Next stepsCopy Anchor Link

• Schedules: how rules combine into working time.
• Adding time: what add and sub return, including at the edges of working time.