cron Schedule Syntax Reference

This section describes the syntax for defining scheduled flow executions using cron in Cloud Dataprep by TRIFACTA®. Typically, this method is used for repeated executions of the flow to wrangle cyclical data for downstream consumption.

  • Flow owners can define scheduled executions of flows from within the Flow View page.
  • Collaborators can review and cannot edit schedules.
  • See Flow View Page.

Overview of cron

Cloud Dataprep by TRIFACTA allows you to make use of cron, a widely used syntax, for specifying times that recur at regular intervals. You can use cron to specify schedules on a per-minute or annual basis and arbitrary intervals in between.

Cron syntax

A cron scheduled is defined as a space-separated string of values. The following cron example defines a schedule to be triggered at 11:30:00pm on February 1:

minutehourday of monthmonthday of week
302312*

When all values are matched, the cron job is triggered.

NOTE: Specification of seconds is not supported.

Wildcards:

In the above cron expression, the wildcard * can be used to match any accepted value, which means that the cron value type is not a factor in determining this schedule. Since the wildcard is applied to the day of week value, the schedule can be triggered on any day of the week.

NOTE: You must use the * character in either the day-of-week or day-of-month fields. Specifying both fields in the same cron expression is not supported.

Legend:

Except for the final field (year), all fields are required in the cron expression. Special characters are described below the table.

ValueTypeDescriptionSupported Special Characters
30minute0-59, - * /
23hour0-23, - * /
1day of month1-31, - * / L W
2month1-12, - * /
*day of week

0 - 6 or Sun - Sat

0, Sun, SUN = Sunday

1, Mon, MON = Monday

...

6, Sat, SAT = Saturday

, - * / L #
*year(Optional) You can specify year settings if needed. Default is * ., - * /

Special characters

You can use the following special characters in your cron expressions.

CharacterDescription
*(“all values”) - Wildcard to match all possible values in the field. For example, if you wanted your trigger to fire every minute of the 10pm hour, the minute character in the expression is *. An example is below.
-Specify a range of values. For example, you could use 1-5 in the day-of-week field to match the work days of the week (Monday through Friday). An example is below.
,Specify a discrete set of values. For example, an entry of 1,10,20,30 for the day of month field is triggered on the 1st, 10th, 20th, and 30th (if possible) of the month.
/Specify increments of the field in the units of the field. For example, 5/20 in the minutes field matches on the 5th, 20th, and 45th minute of each hour.
L

Last value accepted in the range is accepted in the following fields:

  • Day-of-month: Specifies the last day of the month for the currently selected month value.
    • In January, this value matches with 31.
    • In February, this value matches with 28 for non-leap years.
    • In April, this value matches with 30.
  • Day-of-week:
    • By itself, it specifies the last day of the week, which matches with 6 (Saturday).
    • When used with another value, it specifies the last matching value for the month. For example, 3L is the last Wednesday of the month.
W

Specifies the nearest matching weekday. For example, an entry of 22W in the day-of-month field matches on the nearest weekday to the 22nd of the month. If the 22nd is a Saturday, then the cron job matches on the 24th (the following Monday).

Tip: LW can used in the day-of-month field to match on the last weekday of the month.

#

Specifies the nth day of the month. Examples for the day-of-week field:

  • 3#4 - fourth Tuesday of the month
  • 5#2 - second Thursday of the month


Examples

Below are some example cron schedules.

Hourly

Runs at minute 15 of every hour:

15 * * * *

Daily

Runs every day at 10pm:

0 22 * * *

Runs every minute of the 10pm hour every day:

* 22 * * *

Weekly

Runs every Tuesday at 3am:

0 3 * * 2

Weekdays

Runs each weekday at 8pm:

0 20 * * 1-5

Note that the above schedule runs at 10pm on Monday night and each night of the week at that time.

To refresh the flow for each weekday morning, you might choose to start the schedules on Sunday, in which the day-of-week value starts with 0 and ends with 4.

Monthly

Runs the first day of each month at 2:30am:

30 2 1 * *

Yearly

Runs at midnight of January 1 each year:

0 0 1 1 * *


Other examples

ExpressionMeaning
0 12 * * *
Fire at 12pm (noon) every day
15 10 * * *
Fire at 10:15am every day
15 10 * * *
Fire at 10:15am every day
15 10 * * * *
Fire at 10:15am every day
15 10 * * * 2017
Fire at 10:15am every day during the year 2017
* 14 * * *
Fire every minute starting at 2pm and ending at 2:59pm, every day
0/5 14 * * *
Fire every 5 minutes starting at 2pm and ending at 2:55pm, every day
0/5 14,18 * * *
Fire every 5 minutes starting at 2pm and ending at 2:55pm, AND fire every 5 minutes starting at 6pm and ending at 6:55pm, every day
0-5 14 * * *
Fire every minute starting at 2pm and ending at 2:05pm, every day
10,44 14 * 3 WED
Fire at 2:10pm and at 2:44pm every Wednesday in the month of March.
15 10 * * MON-FRI
Fire at 10:15am every Monday, Tuesday, Wednesday, Thursday and Friday
15 10 15 * *
Fire at 10:15am on the 15th day of every month
15 10 L * *
Fire at 10:15am on the last day of every month
15 10 L-2 * *
Fire at 10:15am on the 2nd-to-last last day of every month
15 10 * * 6L
Fire at 10:15am on the last Friday of every month
15 10 * * 6L 2017-2019
Fire at 10:15am on every last friday of every month during the years 2017, 2018 and 2019
15 10 * * 6#3
Fire at 10:15am on the third Friday of every month
0 12 1/5 * *
Fire at 12pm (noon) every 5 days every month, starting on the first day of the month.
11 11 11 11 *
Fire every November 11th at 11:11am.

Invalid cron expressions

ExpressionMeaningReason
15 10 * * * 2001
Fire at 10:15am every day during the year 2001This cron expression is invalid because it will not generate any events in the future.
* * *

-

The cron expression should contain 6 or 7 fields.
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