crontab.rs

A lightweight crontab parser with minimal features that does not rely on Rust nightly. Has functions to enumerate the next time a cron schedule should be invoked.

Crontab expressions

MINUTES    HOURS    DAY_OF_MONTH    MONTHS    DAY_OF_WEEK

             Range:    Special characters:
Minutes      = [0,59]  , - * /
Hours        = [0,23]  , - * /
Day of month = [1,31]  , - * /
Months       = [1,12]  , - * /
Day of week  = [0,6]   , - * /

Ranges are inclusive.

(TODO: Write as EBNF notation.)

For example, crontab.rs supports the following:

• Wildcards: * * * * *
• Values: 0 0 1 1 *
• Multiple values: 0,5,10 * * * *
• Ranges: 0-30 * * * *
• Steps: */15 * * * *
• Combinations of all of the above: 1,2,3,5-10,*/15 * * * *

You can use crontab.guru to build and test your crontab expressions.

Usage

extern crate crontab;
extern crate time;

use crontab::Crontab;
use time::{Timespec, at_utc};

let crontab = Crontab::parse("0 * * * *").expect("unknown parse error"); // every hour

// Access to the underlying schedule components:
println!("Minutes: {:?}", crontab.schedule.minutes);
println!("Hours: {:?}", crontab.schedule.hours);

// See when the next event will occur:
crontab.find_next_event(); // Option<Tm>
crontab.find_next_event_utc(); // Option<Tm>

// Or when the next event relative to a given time is:
let time = at_utc(Timespec::new(1500001200, 0));
crontab.find_event_after(&time); // Option<Tm>

See examples/usage.rs, which is guaranteed to compile with the current library version and make use of the library features.

TODO

• Fix the scheduler to support day of week (currently ignored, though the values are correctly parsed).

• Support crontab extensions, such as second-resolution, year numbers, and stringly-valued components.

• Support keywords such as @yearly, etc.

License

BSD 4-clause

Copyright (c) 2017, Brandon Thomas. All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

3. All advertising materials mentioning features or use of this software must display the following acknowledgement:

   This product includes software developed by Brandon Thomas (bt@brand.io, echelon@gmail.com).

4. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY COPYRIGHT HOLDER "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL COPYRIGHT HOLDER BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.