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Help Center/ FunctionGraph/ User Guide/ Creating Triggers/ Cron Expressions for a Function Timer Trigger

Cron Expressions for a Function Timer Trigger

Updated on 2024-11-12 GMT+08:00

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You can configure a cron expression in the following formats for a function timer trigger:

@every format

The format is "@every N unit". N is a positive integer. unit can be ns, µs, ms, s, m, or h. An @every expression means to invoke a function every N time units, as shown in Table 1.

**Table 1** Example expressions
Expression	Meaning
@every 30m	Triggers a function every 30 minutes.
@every 1.5h	Triggers a function every 1.5 hours.
@every 2h30m	Triggers a function every 2.5 hours.

Standard format

The format is "seconds minutes hours day-of-month month day-of-week". day-of-week is optional. The fields must be separated from each other using a space. Table 2 describes the fields in a standard cron expression.

**Table 2** Parameter description
Parameter	Mandatory	Value Range	Special Characters Allowed
CRON_TZ	No. If this parameter is not set, the region's time zone is used by default.	-	-
Seconds	Yes	0–59	, - * /
Minutes	Yes	0–59	, - * /
Hours	Yes	0–23	, - * /
Day-of-month	Yes	1–31	, - * ? /
Month	Yes	1–12 or Jan–Dec. The value is case-insensitive, as shown in Table 3.	, - * /
Day-of-week	No	0–6 or Sun–Sat. The value is case-insensitive, as shown in Table 4. 0 means Sunday.	, - * ? /

**Table 3** Value description of the month field
Month	Digit	Abbreviation
January	1	Jan
February	2	Feb
March	3	Mar
April	4	Apr
May	5	May
June	6	Jun
July	7	Jul
August	8	Aug
September	9	Sep
October	10	Oct
November	11	Nov
December	12	Dec

**Table 4** Value description of the day-of-week field
Day of Week	Digit	Abbreviation
Monday	1	Mon
Tuesday	2	Tue
Wednesday	3	Wed
Thursday	4	Thu
Friday	5	Fri
Saturday	6	Sat
Sunday	0	Sun

Table 5 describes the special characters that can be used in a cron expression.

**Table 5** Special character description
Special Character	Meaning	Description
*	Used to specify all values within a field.	* in the minutes field means every minute.
,	Used to specify multiple values, which can be discontinuous.	For example, "Jan,Apr,Jul,Oct" or "1,4,7,10" in the month field and "Sat,Sun" or "6,0" in the day-of-week field.
-	Used to specify a range.	For example, "0-3" in the minutes field.
?	Used to specify something in one of the two fields in which the character is allowed, but not the other.	You can specify something only in the day-of-month or day-of-week field. For example, if you want your function to be executed on a particular day (such as the 10th) of the month, but do not care what day of the week that is, then put "10" in the day-of-month field and "?" in the day-of-week field.
/	Used to specify increments. The character before the slash indicates when to start, and the one after the slash represents the increment.	For example, "1/3" in the minutes field means to trigger the function every 3 minutes starting from 00:01:00 of the hour.

Table 6 describes several example cron expressions.

**Table 6** Example cron expressions
Function Scheduling Example	Cron Expression (Beijing Time)
12:00 every day	CRON_TZ=Asia/Shanghai 0 0 12 * * *
12:30 every day	CRON_TZ=Asia/Shanghai 0 30 12 * * *
26th, 29th, and 33rd minutes of each hour	CRON_TZ=Asia/Shanghai 0 26,29,33 * * * *
12:30 from Monday to Friday	CRON_TZ=Asia/Shanghai 0 30 12 ? * MON-FRI
Every 5 minutes during 12:00 and 14:59 from Monday to Friday	CRON_TZ=Asia/Shanghai 0 0/5 12-14 ? * MON-FRI
12:00 every day from January to April	CRON_TZ=Asia/Shanghai 0 0 12 ? JAN,FEB,MAR,APR *

NOTE:

If no cron expression is set, the region's time zone is used by default. If your task will run in a specific time zone, use CRON_TZ to specify the time zone. For example, to trigger your function at 04:00 on the first day of each month (Beijing time), use CRON_TZ=Asia/Shanghai 0 0 4 1 * *. The time zone expression varies depending on the region.

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