Using cron and rate expressions to schedule rules in Amazon EventBridge - Amazon EventBridge
Cron expressionsRate expressions
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Using cron and rate expressions to schedule rules in Amazon EventBridge

When you create a scheduled rule in EventBridge you can specify a schedule pattern that determines when EventBridge runs the rule:

  • Use a cron expression to run the rule at specific times and dates.

  • Use a rate expression to run the rule at regular intervals.

Cron expressions

Cron expressions have six required fields, which are separated by white space.

Syntax

cron(fields)
Field Values Wildcards

Minutes

0-59

, - * /

Hours

0-23

, - * /

Day-of-month

1-31

, - * ? / L W

Month

1-12 or JAN-DEC

, - * /

Day-of-week

1-7 or SUN-SAT

, - * ? L #

Year

1970-2199

, - * /
Wildcards

  • The , (comma) wildcard includes additional values. In the Month field, JAN,FEB,MAR includes January, February, and March.

  • The - (dash) wildcard specifies ranges. In the Day field, 1-15 includes days 1 through 15 of the specified month.

  • The * (asterisk) wildcard includes all values in the field. In the Hours field, * includes every hour. You can't use * in both the Day-of-month and Day-of-week fields. If you use it in one, you must use ? in the other.

  • The / (slash) wildcard specifies increments. In the Minutes field, you could enter 1/10 to specify every tenth minute, starting from the first minute of the hour (for example, the 11th, 21st, and 31st minute, and so on).

  • The ? (question mark) wildcard specifies any. In the Day-of-month field you could enter 7 and if any day of the week was acceptable, you could enter ? in the Day-of-week field.

  • The L wildcard in the Day-of-month or Day-of-week fields specifies the last day of the month or week.

  • The W wildcard in the Day-of-month field specifies a weekday. In the Day-of-month field, 3W specifies the weekday closest to the third day of the month.

  • The # wildcard in the Day-of-week field specifies a certain instance of the specified day of the week within a month. For example, 3#2 would be the second Tuesday of the month: the 3 refers to Tuesday because it is the third day of each week, and the 2 refers to the second day of that type within the month.

    Note

    If you use a '#' character, you can define only one expression in the day-of-week field. For example, "3#1,6#3" is not valid because it is interpreted as two expressions.

Limitations

  • You can't specify the Day-of-month and Day-of-week fields in the same cron expression. If you specify a value or a * (asterisk) in one of the fields, you must use a ? (question mark) in the other.

  • Cron expressions that lead to rates faster than 1 minute are not supported.

Examples

You can use the following sample cron strings when creating a rule with schedule.

Minutes Hours Day of month Month Day of week Year Meaning

0

10

*

*

?

*

Run at 10:00 am (UTC+0) every day

15

12

*

*

?

*

Run at 12:15 pm (UTC+0) every day

0

18

?

*

MON-FRI

*

Run at 6:00 pm (UTC+0) every Monday through Friday

0

8

1

*

?

*

Run at 8:00 am (UTC+0) every 1st day of the month

0/15

*

*

*

?

*

Run every 15 minutes

0/10

*

?

*

MON-FRI

*

Run every 10 minutes Monday through Friday

0/5

8-17

?

*

MON-FRI

*

Run every 5 minutes Monday through Friday between 8:00 am and 5:55 pm (UTC+0)

0/30

20-2

?

*

MON-FRI

*

Run every 30 minutes Monday through Friday between 10:00 pm on the starting day to 2:00 am on the following day (UTC)

Run from 12:00 am to 2:00 am on Monday morning (UTC).

The following example creates a rule that runs every day at 12:00pm UTC+0.

aws events put-rule --schedule-expression "cron(0 12 * * ? *)" --name MyRule1

The following example creates a rule that runs every day, at 2:05pm and 2:35pm UTC+0.

aws events put-rule --schedule-expression "cron(5,35 14 * * ? *)" --name MyRule2

The following example creates a rule that runs at 10:15am UTC+0 on the last Friday of each month during the years 2019 to 2022.

aws events put-rule --schedule-expression "cron(15 10 ? * 6L 2019-2022)" --name MyRule3

Rate expressions

A rate expression starts when you create the scheduled event rule, and then it runs on a defined schedule.

Rate expressions have two required fields separated by white space.

Syntax

rate(value unit)
value

A positive number.

unit

The unit of time. Different units are required for values of 1, such as minute, and values over 1, such as minutes.

Valid values: minute | minutes | hour | hours | day | days

Limitations

If the value is equal to 1, then the unit must be singular. If the value is greater than 1, the unit must be plural. For example, rate(1 hours) and rate(5 hour) aren't valid, but rate(1 hour) and rate(5 hours) are valid.

Examples

The following examples show how to use rate expressions with the Amazon CLI put-rule command. The first example triggers the rule every minute, the next triggers it every five minutes, the third example triggers it once an hour, and the final example triggers it once per day.

aws events put-rule --schedule-expression "rate(1 minute)" --name MyRule2
aws events put-rule --schedule-expression "rate(5 minutes)" --name MyRule3
aws events put-rule --schedule-expression "rate(1 hour)" --name MyRule4
aws events put-rule --schedule-expression "rate(1 day)" --name MyRule5