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This module implements the cron format for the scheduler. Cron formats are defined either with the cron macro or initCron

Example:

import taskman/cron
# * * * * *
# Default value for each field is every val
# The cron macro uses x in place of *
assert initCron() == cron(x, x, x, x, x)

# 4 10 * * *
assert initCron({4.MinuteRange}, {10.HourRange}) == cron(4, 10, x, x, x)

# 4-10 4,5,6 * * sun,mon
assert initCron(
  {4.MinuteRange .. 10},
  {4.HourRange, 5, 6}, 
  weekDays = {dSun, dMon}
) == cron(4 - 10, {4, 5, 6}, weekDays = {dSun, dMon})

# every second minute
assert initCron(everyMinute / 2) == cron(minutes = x / 2)

This implements cron in a slightly non standard way in that both monthDays and weekDays are checked e.g.

Example:

import taskman/cron
let 
  start = dateTime(2000, mJan, 1)
  form  = cron(x, x, 10, x, dSun)
# In normal cron it would match 2000-01-10 (Which is a monday)
assert start.next(form) == dateTime(2000, mSep, 10)

Types

Cron = object minutes*: set[MinuteRange] hours*: set[HourRange] monthDays*: set[MonthdayRange] months*: set[Month] weekDays*: set[WeekDay]: The five star (*) values of a cronjob Source Edit
TooFarAheadCron = object of CatchableError: Called in the rare case that a cron job cannot find a next available date Source Edit

Consts

everyHour = {0..23}: Use with cron task to run every hour Source Edit
everyMinute = {0..59}: Use with cron task to run every minute Source Edit
everyMonth = {mJan..mDec}: Use with cron task to run every month Source Edit
everyMonthDay = {1..31}: use with cron task to run every day in the month Source Edit
everyWeekDay = {dMon..dSun}: Use with cron task to run every day in the week Source Edit
maxYears = 3: Source Edit

Procs

func `/`[T: CronRanges](values: set[T]; n: int): set[T] {....raises: [].}: Returns every nth value starting from the first value in values
Example:

# Set of values to run every second day assert everyWeekDay / 2 == {dMon, dWed, dFri, dSun} # Only use every third hour in our range assert {5.HourRange .. 15} / 4 == {5.HourRange, 9, 13} # It only does every second value assert {dMon, dWed, dSun} / 2 == {dMon, dSun}
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func initCron(minutes = everyMinute; hours = everyHour; monthDays = everyMonthDay; months = everyMonth; weekDays = everyWeekDay): Cron {....raises: [], tags: [].}: Makes a new cron format. Sets passed in cannot be empty (Since that wouldn't make sense)
Example:

let everySecondMinute = initCron(minutes = everyMinute / 2) let weekendMornings = initCron(hours = {8.HourRange}, weekDays = {dSat, dSun})
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func isValid(format: Cron): bool {....raises: [], tags: [].}: Checks that a format is valid (Just checks it has no empty sets).
Example:

assert not Cron(minutes: {}).isValid
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proc next(now: DateTime; format: Cron): DateTime {....raises: [TooFarAheadCron], tags: [].}: Returns next date that a cron would run from now Source Edit

Macros

macro cron(minutes, hours, monthDays, months, weekDays: untyped = x): Cron: Macro to simplify creating cron formats. Syntax is similar to cron
/: Define count

{}: Provide list of values

-: Define range

x: Specify any value

Example:

assert cron(x, x, x, x, x) == initCron() # * * * * * assert cron(minutes = 5) == initCron(minutes = {5.MinuteRange}) # 5 * * * * # Do between minutes of 5 and 10 during either 1 am or 5 am # do this every second day of the month assert cron(5 - 10, {1, 5}, x / 2, x, x) == initCron( {5.MinuteRange .. 10}, {1.HourRange, 5}, everyMonthDay / 2 )
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