cron-rs

A CRON expression parser and explorer. It is designed for space efficiency for caching and storage purposes such as in a CRON Scheduler.

Example

```rust use chrono::{DateTime, TimeZone, Utc}; use cron_rs::schedule::Schedule; use std::str::FromStr;

fn main() { // sec min hour day of month month day of week year let expression = "0 30 9,12,15 1,15 May-Aug Mon,Wed,Fri 2018/2"; let schedule = Schedule::from_str(expression).unwrap();

let mut last: Option<DateTime<Utc>> = None;
let from_date = Utc.ymd(2022, 6, 1).and_hms(8, 40, 1);

println!("Upcoming fire times:");
for datetime in schedule.iter_from(&from_date).take(10) {
    last = Some(datetime);
    println!("next -> {:?}", datetime);
}

println!("\nPrevious fire times:");
for datetime in schedule.iter_from(&last.unwrap()).rev().take(10) {
    println!("prev -> {:?}", datetime);
}

}

/* Upcoming fire times: next -> 2022-06-01T09:30:00Z next -> 2022-06-01T12:30:00Z next -> 2022-06-01T15:30:00Z next -> 2022-06-15T09:30:00Z next -> 2022-06-15T12:30:00Z next -> 2022-06-15T15:30:00Z next -> 2022-07-01T09:30:00Z next -> 2022-07-01T12:30:00Z next -> 2022-07-01T15:30:00Z next -> 2022-07-15T09:30:00Z

Previous fire times: prev -> 2022-07-01T15:30:00Z prev -> 2022-07-01T12:30:00Z prev -> 2022-07-01T09:30:00Z prev -> 2022-06-15T15:30:00Z prev -> 2022-06-15T12:30:00Z prev -> 2022-06-15T09:30:00Z prev -> 2022-06-01T15:30:00Z prev -> 2022-06-01T12:30:00Z prev -> 2022-06-01T09:30:00Z prev -> 2020-07-15T15:30:00Z */

```

Crontab:

```

┌───────────────────── minute (0 - 59)

│ ┌─────────────────── hour (0 - 23)

│ │ ┌───────────────── dom (1 - 31) day of month

│ │ │ ┌─────────────── month (1 - 12 or Jan-Dec)

│ │ │ │ ┌───────────── dow ((0 or 7) - 6 or Sun - Sat) day of week (Sunday to Saturday)

│ │ │ │ │

* * * * *

```

| Field | Required | Allowed values | Allowed special characters | | ------------ | -------- | ----------------------| -------------------------- | | Minutes | Yes | 0–59 | * , - / | | Hours | Yes | 0–23 | * , - / | | Day of month | Yes | 1–31 | * , - / | | Month | Yes | 1–12 or Jan-Dec | * , - / | | Day of week | Yes | (0 or 7)–6 or Sun-Sat | * , - / |

Vixie CRON:

```

┌─────────────────────── seconds (0 - 59)

│ ┌───────────────────── minute (0 - 59)

│ │ ┌─────────────────── hour (0 - 23)

│ │ │ ┌───────────────── dom (1 - 31) day of month

│ │ │ │ ┌─────────────── month (1 - 12 or Jan-Dec)

│ │ │ │ │ ┌───────────── dow (1-7 or Sun-Sat) day of week (Sunday to Saturday)

│ │ │ │ │ │ ┌──────────── year (1970-2099 Optional)

│ │ │ │ │ │ │

* * * * * * *

```

| Field | Required | Allowed values | Allowed special characters | | ------------ | -------- | --------------- | -------------------------- | | Seconds | Yes | 0–59 | * , - / | | Minutes | Yes | 0–59 | * , - / | | Hours | Yes | 0–23 | * , - / | | Day of month | Yes | 1–31 | * , - / | | Month | Yes | 1–12 or Jan-Dec | * , - / | | Day of week | Yes | 1–7 or Sun-Sat | * , - / | | Years | No | 1970-2099 | * , - / |

License

^{Licensed under either of Apache License, Version
2.0 or MIT license at your option.}

_{Unless you explicitly state otherwise, any contribution intentionally submitted
for inclusion in Proteus by you, as defined in the Apache-2.0 license, shall be
dual licensed as above, without any additional terms or conditions.}