fugit

Time tools for flor and the floraison group.

It uses et-orbi to represent time instances and raabro as a basis for its parsers.

Fugit is a core dependency of rufus-scheduler >= 3.5.

Related projects

Sister projects

The intersection of those two projects is where fugit is born:

rufus-scheduler — a cron/at/in/every/interval in-process scheduler, in fact, it's the father project to this fugit project
flor — a Ruby workflow engine, fugit provides the foundation for its time scheduling capabilities

Similar, sometimes overlapping projects

chronic — a pure Ruby natural language date parser
parse-cron — parses cron expressions and calculates the next occurrence after a given date
ice_cube — Ruby date recurrence library
ISO8601 — Ruby parser to work with ISO8601 dateTimes and durations
chrono — a chain of logics about chronology
CronCalc — calculates cron job occurrences
Recurrence — a simple library to handle recurring events
CronConfigParser — parse the cron configuration for readability
...

Projects using fugit

arask — "Automatic RAils taSKs" uses fugit to parse cron strings
sidekiq-cron — uses fugit to parse cron strings since version 1.0.0, it was using rufus-scheduler previously
rufus-scheduler — as seen above
flor — used in the cron procedure
que-scheduler — a reliable job scheduler for que
serial_scheduler — ruby task scheduler without threading
delayed_cron_job — an extension to Delayed::Job that allows you to set cron expressions for your jobs
GoodJob — a multithreaded, Postgres-based, Active Job backend for Ruby on Rails
Solid Queue — a DB-based queuing backend for Active Job, designed with simplicity and performance in mind
...

`Fugit.parse(s)`

The simplest way to use fugit is via Fugit.parse(s).

require 'fugit'

Fugit.parse('0 0 1 jan *').class         # ==> ::Fugit::Cron
Fugit.parse('12y12M').class              # ==> ::Fugit::Duration

Fugit.parse('2017-12-12').class          # ==> ::EtOrbi::EoTime
Fugit.parse('2017-12-12 UTC').class      # ==> ::EtOrbi::EoTime

Fugit.parse('every day at noon').class   # ==> ::Fugit::Cron

If fugit cannot extract a cron, duration or point in time out of the string, it will return nil.

Fugit.parse('nada')
  # ==> nil

`Fugit.do_parse(s)`

Fugit.do_parse(s) is equivalent to Fugit.parse(s), but instead of returning nil, it raises an error if the given string contains no time information.

Fugit.do_parse('nada')
  # ==> /home/jmettraux/w/fugit/lib/fugit/parse.rb:32
  #     :in `do_parse': found no time information in "nada" (ArgumentError)

parse_cron, parse_in, parse_at, parse_duration, and parse_nat

require 'fugit'

Fugit.parse_cron('0 0 1 jan *').class       # ==> ::Fugit::Cron
Fugit.parse_duration('12y12M').class        # ==> ::Fugit::Duration

Fugit.parse_at('2017-12-12').class          # ==> ::EtOrbi::EoTime
Fugit.parse_at('2017-12-12 UTC').class      # ==> ::EtOrbi::EoTime

Fugit.parse_nat('every day at noon').class  # ==> ::Fugit::Cron

do_parse_cron, do_parse_in, do_parse_at, do_parse_duration, and do_parse_nat

As Fugit.parse(s) returns nil when it doesn't grok its input, and Fugit.do_parse(s) fails when it doesn't grok, each of the parse_ methods has its partner do_parse_ method.

parse_cronish and do_parse_cronish

Sometimes you know a cron expression or an "every" natural expression will come in and you want to discard the rest.

require 'fugit'

Fugit.parse_cronish('0 0 1 jan *').class             # ==> ::Fugit::Cron
Fugit.parse_cronish('every saturday at noon').class  # ==> ::Fugit::Cron

Fugit.parse_cronish('12y12M')        # ==> nil

.parse_cronish(s) will return a Fugit::Cron instance or else nil.

.do_parse_cronish(s) will return a Fugit::Cron instance or else fail with an ArgumentError.

Introduced in fugit 1.8.0.

`Fugit::Cron`

A class Fugit::Cron to parse cron strings and then #next_time and #previous_time to compute the next or the previous occurrence respectively.

There is also a #brute_frequency method which returns an array [ shortest delta, longest delta, occurrence count ] where delta is the time between two occurrences.

require 'fugit'

c = Fugit::Cron.parse('0 0 * *  sun')
  # or
c = Fugit::Cron.new('0 0 * *  sun')

p Time.now  # => 2017-01-03 09:53:27 +0900

p c.next_time.to_s      # => 2017-01-08 00:00:00 +0900
p c.previous_time.to_s  # => 2017-01-01 00:00:00 +0900

p c.next_time(Time.parse('2024-06-01')).to_s
  # => "2024-06-02 00:00:00 +0900"
p c.previous_time(Time.parse('2024-06-01')).to_s
  # => "2024-05-26 00:00:00 +0900"
    #
    # `Fugit::Cron#next_time` and `#previous_time` accept a "start time"

c = Fugit.parse_cron('0 12 * * mon#2')

  # `#next` and `#prev` return Enumerable instances
  #
  # These two methods are available since fugit 1.10.0.
  #
c.next(Time.parse('2024-02-16 12:00:00'))
  .take(3)
  .map(&:to_s)
    # => [ '2024-03-11 12:00:00',
    #      '2024-04-08 12:00:00',
    #      '2024-05-13 12:00:00' ]
c.prev(Time.parse('2024-02-16 12:00:00'))
  .take(3)
  .map(&:to_s)
    # => [ '2024-02-12 12:00:00',
    #      '2024-01-08 12:00:00',
    #      '2023-12-11 12:00:00' ]

  # `#within` accepts a time range and returns an array of Eo::EoTime
  # instances that correspond to the occurrences of the cron within
  # the time range
  #
  # This method is available since fugit 1.10.0.
  #
c.within(Time.parse('2024-02-16 12:00')..Time.parse('2024-08-01 12:00'))
  .map(&:to_s)
    # => [ '2024-03-11 12:00:00',
    #      '2024-04-08 12:00:00',
    #      '2024-05-13 12:00:00',
    #      '2024-06-10 12:00:00',
    #      '2024-07-08 12:00:00' ]

p c.brute_frequency  # => [ 604800, 604800, 53 ]
                     #    [ delta min, delta max, occurrence count ]
p c.rough_frequency  # => 7 * 24 * 3600 (7d rough frequency)

p c.match?(Time.parse('2017-08-06'))  # => true
p c.match?(Time.parse('2017-08-07'))  # => false
p c.match?('2017-08-06')              # => true
p c.match?('2017-08-06 12:00')        # => false

Example of cron strings understood by fugit:

'5 0 * * *'         # 5 minutes after midnight, every day
'15 14 1 * *'       # at 1415 on the 1st of every month
'0 22 * * 1-5'      # at 2200 on weekdays
'0 22 * * mon-fri'  # idem
'23 0-23/2 * * *'   # 23 minutes after 00:00, 02:00, 04:00, ...

'@yearly'    # turns into '0 0 1 1 *'
'@monthly'   # turns into '0 0 1 * *'
'@weekly'    # turns into '0 0 * * 0'
'@daily'     # turns into '0 0 * * *'
'@midnight'  # turns into '0 0 * * *'
'@hourly'    # turns into '0 * * * *'

'0 0 L * *'     # last day of month at 00:00
'0 0 last * *'  # idem
'0 0 -7-L * *'  # from the seventh to last to the last day of month at 00:00

# and more...

Please note that '15/30 * * * *' is interpreted as '15-59/30 * * * *' since fugit 1.4.6.

time zones

Fugit accepts a IANA timezone identifier right after a cron string:

'5 0 * * *  Europe/Rome'      # 5 minutes after midnight, every day, Rome tz
'0 22 * * 1-5  Asia/Tbilisi'  # at 2200 on weekdays in Georgia

'@yearly Asia/Kuala_Lumpur'  # turns into '0 0 1 1 * Asia/Kuala_Lumpur'
'@monthly Asia/Jakarta'      # turns into '0 0 1 * * Asia/Jakarta'
  #
  # those two "ats" and friends since fugit 1.11.2...

When no time zone is specified, fugit uses Ruby's provided timezone.

the first Monday of the month

Fugit tries to follow the man 5 crontab documentation.

There is a surprising thing about this canon, all the columns are joined by ANDs, except for monthday and weekday which are joined together by OR if they are both set (they are not *).

Many people (me included) are surprised when they try to specify "at 05:00 on the first Monday of the month" as 0 5 1-7 * 1 or 0 5 1-7 * mon and the results are off.

The man page says:

Note: The day of a command's execution can be specified by two fields -- day of month, and day of week. If both fields are restricted (ie, are not *), the command will be run when either field matches the current time. For example, ``30 4 1,15 * 5'' would cause a command to be run at 4:30 am on the 1st and 15th of each month, plus every Friday.

Fugit follows this specification.

Since fugit 1.7.0, by adding & right after a day specifier, the day-of-month OR day-of-week becomes day-of-month AND day-of-week.

# standard cron

p Fugit.parse_cron('0 0 */2 * 1-5').next_time('2022-08-09').to_s
  # ==> "2022-08-10 00:00:00 +0900"

# with an &

p Fugit.parse_cron('0 0 */2 * 1-5&').next_time('2022-08-09').to_s # or
p Fugit.parse_cron('0 0 */2& * 1-5').next_time('2022-08-09').to_s
p Fugit.parse_cron('0 0 */2& * 1-5&').next_time('2022-08-09').to_s
  # ==> "2022-08-11 00:00:00 +0900"


# standard cron

p Fugit.parse_cron('59 6 1-7 * 2').next_time('2020-03-15').to_s
  # ==> "2020-03-17 06:59:00 +0900"

# with an &

p Fugit.parse_cron('59 6 1-7 * 2&').next_time('2020-03-15').to_s
p Fugit.parse_cron('59 6 1-7& * 2').next_time('2020-03-15').to_s
p Fugit.parse_cron('59 6 1-7& * 2&').next_time('2020-03-15').to_s
  # ==> "2020-04-07 06:59:00 +0900"

the hash extension

Fugit understands 0 5 * * 1#1 or 0 5 * * mon#1 as "each first Monday of the month, at 05:00".

The hash extension can only be used in the day-of-week field.

'0 5 * * 1#1'    #
'0 5 * * mon#1'  # the first Monday of the month at 05:00

'0 6 * * 5#4,5#5'      #
'0 6 * * fri#4,fri#5'  # the 4th and 5th Fridays of the month at 06:00

'0 7 * * 5#-1'    #
'0 7 * * fri#-1'  # the last Friday of the month at 07:00

'0 7 * * 5#L'       #
'0 7 * * fri#L'     #
'0 7 * * 5#last'    #
'0 7 * * fri#last'  # the last Friday of the month at 07:00

'0 23 * * mon#2,tue'  # the 2nd Monday of the month and every Tuesday, at 23:00

the modulo extension

Fugit, since 1.1.10, also understands cron strings like "9 0 * * sun%2" which can be read as "every other Sunday at 9am".

The modulo extension can only be used in the day-of-week field.

For odd Sundays, one can write 9 0 * * sun%2+1.

It can be combined, as in 9 0 * * sun%2,tue%3+2

But what does it reference to? It starts at 1 on 2019-01-01 (in the EtOrbi instance timezone, not the UTC "timezone").

require 'et-orbi' # >= 1.1.8

# the reference
p EtOrbi.parse('2019-01-01').wday       # => 2
p EtOrbi.parse('2019-01-01').rweek      # => 1
p EtOrbi.parse('2019-01-01').rweek % 2  # => 1

# today (as of this coding...)
p EtOrbi.parse('2019-04-11').wday       # => 4
p EtOrbi.parse('2019-04-11').rweek      # => 15
p EtOrbi.parse('2019-04-11').rweek % 2  # => 1

c = Fugit.parse('* * * * tue%2')
c.match?('2019-01-01')  # => false, since rweek % 2 == 1
c.match?('2019-01-08')  # => true, since rweek % 2 == 0

c = Fugit.parse('* * * * tue%2+1')
c.match?('2019-01-01')  # => true, since (rweek + 1) % 2 == 0
c.match?('2019-01-08')  # => false, since (rweek + 1) % 2 == 1

# ...

sun%2 matches if Sunday and current_date.rweek % 2 == 0 tue%3+2 matches if Tuesday and current_date.rweek + 2 % 3 == 0 tue%x+y matches if Tuesday and current_date.rweek + y % x == 0

the second extension

Fugit accepts cron strings with five elements, minute hour day-of-month month day-of-week, the standard cron format or six elements second minute hour day-of-month month day-of-week.

c = Fugit.parse('* * * * *') # every minute
c = Fugit.parse('5 * * * *') # every hour at minute 5
c = Fugit.parse('* * * * * *') # every second
c = Fugit.parse('5 * * * * *') # every minute at second 5

`Fugit::Nat`

Fugit understand some kind of "natural" language:

For example, those "every" get turned into Fugit::Cron instances:

Fugit::Nat.parse('every day at five')                         # ==> '0 5 * * *'
Fugit::Nat.parse('every weekday at five')                     # ==> '0 5 * * 1,2,3,4,5'
Fugit::Nat.parse('every day at 5 pm')                         # ==> '0 17 * * *'
Fugit::Nat.parse('every tuesday at 5 pm')                     # ==> '0 17 * * 2'
Fugit::Nat.parse('every wed at 5 pm')                         # ==> '0 17 * * 3'
Fugit::Nat.parse('every day at 16:30')                        # ==> '30 16 * * *'
Fugit::Nat.parse('every day at 16:00 and 18:00')              # ==> '0 16,18 * * *'
Fugit::Nat.parse('every day at noon')                         # ==> '0 12 * * *'
Fugit::Nat.parse('every day at midnight')                     # ==> '0 0 * * *'
Fugit::Nat.parse('every tuesday and monday at 5pm')           # ==> '0 17 * * 1,2'
Fugit::Nat.parse('every wed or Monday at 5pm and 11')         # ==> '0 11,17 * * 1,3'
Fugit::Nat.parse('every day at 5 pm on America/Los_Angeles')  # ==> '0 17 * * * America/Los_Angeles'
Fugit::Nat.parse('every day at 6 pm in Asia/Tokyo')           # ==> '0 18 * * * Asia/Tokyo'
Fugit::Nat.parse('every 3 hours')                             # ==> '0 */3 * * *'
Fugit::Nat.parse('every 4 months')                            # ==> '0 0 1 */4 *'
Fugit::Nat.parse('every 5 minutes')                           # ==> '*/5 * * * *'
Fugit::Nat.parse('every 15s')                                 # ==> '*/15 * * * * *'

Directly with Fugit.parse(s) is OK too:

Fugit.parse('every day at five')  # ==> Fugit::Cron instance '0 5 * * *'

Ambiguous nats

Not all strings result in a clean, single, cron expression. The multi: false|true|:fail argument to Fugit::Nat.parse could help.

Fugit::Nat.parse('every day at 16:00 and 18:00')
  .to_cron_s
    # ==> '0 16,18 * * *' (a single Fugit::Cron instances)
Fugit::Nat.parse('every day at 16:00 and 18:00', multi: true)
  .collect(&:to_cron_s)
    # ==> [ '0 16,18 * * *' ] (array of Fugit::Cron instances, here only one)

Fugit::Nat.parse('every day at 16:15 and 18:30')
  .to_cron_s
    # ==> '15 16 * * *' (a single of Fugit::Cron instances)
Fugit::Nat.parse('every day at 16:15 and 18:30', multi: true)
  .collect(&:to_cron_s)
    # ==> [ '15 16 * * *', '30 18 * * *' ] (two Fugit::Cron instances)

Fugit::Nat.parse('every day at 16:15 and 18:30', multi: :fail)
  # ==> ArgumentError: multiple crons in "every day at 16:15 and 18:30"
  #     (15 16 * * * | 30 18 * * *)
Fugit::Nat.parse('every day at 16:15 nada 18:30', multi: true)
  # ==> nil

multi: true indicates to Fugit::Nat that an array of Fugit::Cron instances is expected as a result.

multi: :fail tells Fugit::Nat.parse to fail if the result is more than 1 Fugit::Cron instances.

multi: false is the default behaviour, return a single Fugit::Cron instance or nil when it cannot parse.

Please note that "nat" input is limited to 256 characters (fugit 1.11.1).

Nat Midnight

"Every day at midnight" is supported, but "Every monday at midnight" will be interpreted (as of Fugit <= 1.4.x) as "Every monday at 00:00". Sorry about that.

12 AM and PM

How does fugit react with "12 am", "12 pm", "12 midnight", etc?

require 'fugit'

p Fugit.parse('every day at 12am').original  # ==> "0 0 * * *"
p Fugit.parse('every day at 12pm').original  # ==> "0 12 * * *"

p Fugit.parse('every day at 12:00am').original   # ==> "0 0 * * *"
p Fugit.parse('every day at 12:00pm').original   # ==> "0 12 * * *"
p Fugit.parse('every day at 12:00 am').original  # ==> "0 0 * * *"
p Fugit.parse('every day at 12:00 pm').original  # ==> "0 12 * * *"
p Fugit.parse('every day at 12:15am').original   # ==> "15 0 * * *"
p Fugit.parse('every day at 12:15pm').original   # ==> "15 12 * * *"
p Fugit.parse('every day at 12:15 am').original  # ==> "15 0 * * *"
p Fugit.parse('every day at 12:15 pm').original  # ==> "15 12 * * *"

p Fugit.parse('every day at 12 noon').original         # ==> "0 12 * * *"
p Fugit.parse('every day at 12 midnight').original     # ==> "0 24 * * *"
p Fugit.parse('every day at 12:00 noon').original      # ==> "0 12 * * *"
p Fugit.parse('every day at 12:00 midnight').original  # ==> "0 24 * * *"
p Fugit.parse('every day at 12:15 noon').original      # ==> "15 12 * * *"
p Fugit.parse('every day at 12:15 midnight').original  # ==> "15 24 * * *"

  # as of fugit 1.7.2

`Fugit::Duration`

A class Fugit::Duration to parse duration strings (vanilla rufus-scheduler ones and ISO 8601 ones).

Provides duration arithmetic tools.

require 'fugit'

d = Fugit::Duration.parse('1y2M1d4h')

p d.to_plain_s  # => "1Y2M1D4h"
p d.to_iso_s    # => "P1Y2M1DT4H" ISO 8601 duration
p d.to_long_s   # => "1 year, 2 months, 1 day, and 4 hours"

d += Fugit::Duration.parse('1y1h')

p d.to_long_s  # => "2 years, 2 months, 1 day, and 5 hours"

d += 3600

p d.to_plain_s  # => "2Y2M1D5h3600s"

p Fugit::Duration.parse('1y2M1d4h').to_sec # => 36820800

There is a #deflate method

Fugit::Duration.parse(1000).to_plain_s # => "1000s"
Fugit::Duration.parse(3600).to_plain_s # => "3600s"
Fugit::Duration.parse(1000).deflate.to_plain_s # => "16m40s"
Fugit::Duration.parse(3600).deflate.to_plain_s # => "1h"

# or event shorter
Fugit.parse(1000).deflate.to_plain_s # => "16m40s"
Fugit.parse(3600).deflate.to_plain_s # => "1h"

There is also an #inflate method

Fugit::Duration.parse('1h30m12').inflate.to_plain_s # => "5412s"
Fugit.parse('1h30m12').inflate.to_plain_s # => "5412s"

Fugit.parse('1h30m12').to_sec # => 5412
Fugit.parse('1h30m12').to_sec.to_s + 's' # => "5412s"

The to_*_s methods are also available as class methods:

p Fugit::Duration.to_plain_s('1y2M1d4h')
  # => "1Y2M1D4h"
p Fugit::Duration.to_iso_s('1y2M1d4h')
  # => "P1Y2M1DT4H" ISO 8601 duration
p Fugit::Duration.to_long_s('1y2M1d4h')
  # => "1 year, 2 months, 1 day, and 4 hours"

`Fugit::At`

Points in time are parsed and given back as EtOrbi::EoTime instances.

Fugit::At.parse('2017-12-12').to_s
  # ==> "2017-12-12 00:00:00 +0900" (at least here in Hiroshima)

Fugit::At.parse('2017-12-12 12:00:00 America/New_York').to_s
  # ==> "2017-12-12 12:00:00 -0500"

Directly with Fugit.parse_at(s) is OK too:

Fugit.parse_at('2017-12-12 12:00:00 America/New_York').to_s
  # ==> "2017-12-12 12:00:00 -0500"