A cron demon in Lua

The module cron exports a single function cron that implements a cron scheduler. It receives two arguments, entries and verbose. entries is a list of cron jobs, specified as a table with fields callback (a function that is called without arguments when the job is run) and a set of constraints:

• weekday (0..6, Sunday is 0)
• hour (0..23)
• minute (0..59)
• day (1..31)
• month (1..12)

Constrains can contain ranges 5-7 and enumerations 1-2,5.

An unconstrained job runs every minute.

Don't do funny things as e. g. constraints that never become true.

Example

cron = require "cron"

job1 = {
    callback = function()
        print "Going to work…"
    end,
    hour = "9",
    minute = "15",
    day = "1-5"
}

job2 = {
    callback = function()
        print "Yoga classes"
    end,
    hour = "18",
    minute = "30",
    day = "1,4,7"
}

cron.cron{job1, job2}

Requirements

• Luaposix
• granularity of os.time has to be at least seconds
• for testing: Luaunit