Please help with complex schedule definition

[mitselek]

Could you please kindly assist with defining schedule that has:

• crontab = '1,2 * * * *'
• valid_from = '2014-11-01 00:00:00'
• valid_to = '2014-11-03 00:00:00'

[mitselek]

Currently Cron expressions are the most compact way to describe a schedule, but are slightly less flexible (no direct support for composite or exception schedules)

Does it mean my composite schedule cant be defined right now?

[bunkat]

If you are just looking to calculate occurrences, you can just supply the start and end dates to later.schedule(s).next.

var s = later.parse.cron('1,2 * * * *')
later.schedule(s).next(1, new Date(2014,10,1), new Date(2014,10,3))
> Sat Nov 01 2014 00:01:00 GMT-0700 (Pacific Daylight Time)

If you want to bake the start and end dates into the schedule itself, you can parse the cron into a schedule and then manually added the additional constraints. All schedules are just JSON objects so you can manually add whatever constraints you want to them. In this case, I added a year, month, and day constraint so that it is only valid during your range.

var s = later.parse.cron('1,2 * * * *')
s.schedules[0].Y = [2014]
s.schedules[0].M = [11]
s.schedules[0].D = [1,2,3]
later.schedule(s).next(1)
> Sat Nov 01 2014 00:01:00 GMT-0700 (Pacific Daylight Time)

[mitselek]

Great! If you some day happen to look for a job, give me a call :p

[mitselek]

var s = later.parse.cron('1,2 * * * *')
s.schedules[0].Y = [2014]
s.schedules[0].M = [11]
s.schedules[0].D = [1,2,3]

This makes my schedule valid between 2014-11-01 and 2014-11-03 (very poor choice of range from my side)
If I want to define ranges that overlap months (between 2014-10-28 and 2014-11-03), then alas.

Maybe You should allow start and end dates as optional parameters to timeout and interval methods?

[mitselek]

I will solve this for now with something like this - just added date range to your code:

var swSetTimeout = function(fn, sched, startDate, endDate) {
    if (endDate !== undefined ? endDate < Date.now() : false) {
        return {
            clear: function() {
                return
            }
        }
    }
    var s = later.schedule(sched), t
    if (startDate !== undefined ? startDate > Date.now() : false) {
        t = setTimeout(scheduleTimeout, startDate - Date.now())
        return {
            clear: function() {
                clearTimeout(t)
            }
        }
    }
    scheduleTimeout()
    function scheduleTimeout() {
        var now = Date.now(), next = s.next(2, now), diff = next[0].getTime() - now
        if (diff < 1e3) {
            diff = next[1].getTime() - now
        }
        if (diff < 2147483647) {
            t = setTimeout(fn, diff)
        } else {
            t = setTimeout(scheduleTimeout, 2147483647)
        }
    }
    return {
        clear: function() {
            clearTimeout(t)
        }
    }
}
var swSetInterval = function(fn, sched, startDate, endDate) {
    var t = swSetTimeout(scheduleTimeout, sched, startDate, endDate), done = false
    function scheduleTimeout() {
        if (!done) {
            fn()
            t = swSetTimeout(scheduleTimeout, sched, startDate, endDate)
        }
    }
    return {
        clear: function() {
            done = true
            t.clear()
        }
    }
}

[bunkat]

There is also a full date constraint that you could use alongside before and after modifiers to limit the schedule between two dates. I haven't fully tested/documented this but this is what I use when scheduling tasks.

var s = later.parse.cron('1,2 * * * *');
var start = (new Date(2014,9,28).getTime());
var end = (new Date(2014,10,3).getTime());

s.schedules[0].fd_a = [start];
s.schedules[0].fd_b = [end];

later.schedule(s).next(10);

I agree it would be nice to be able to pass start and end to the timeout and interval function as well.