Timer that invokes a Serverless Containers container
Timer is a trigger that invokes a Serverless Containers container on a schedule. The schedule is entered as a cron expression. The cron expression uses UTC time
A timer needs a service account to invoke a container.
For more information about creating a timer, see Creating a timer that invokes a Serverless Containers container.
Cron expression format
The order of fields in the cron expression: Minutes Hours Day-of-month Month Day-of-week Year
.
Possible field values
Note
Special characters used, as well as the names of months and days of the week, are case-insensitive: MON
is the same as mon
.
Field name |
Required field |
Acceptable values |
Special characters supported |
---|---|---|---|
Minutes |
Yes | 0-59 | , , - , * , / |
Hours |
Yes | 0-23 | , , - , * , / |
Day of month |
Yes | 1-31 | , , - , * , ? , / , L , W |
Month |
Yes | 1-12, JAN-DEC |
, , - , * , / |
Day of week |
Yes | 1-7, SUN-SAT |
, , - , * , ? , / , L , # |
Year |
No | empty, 1970-2099 | , , - , * , / |
Special characters
You can use the following special characters in cron expressions:
-
*
: Select all values in the field.The
*
character in theMinutes
field: The trigger startsevery minute
. -
?
: Select any field value. You can't fillDay of month
andDay of week
at the same time. If you entered a value in one of these fields, enter?
in the other field.10
inDay of month
and?
inDay of week
: The trigger is launched every 10th day of the month. -
-
: Select a range of values.The
10-12
range inHours
: the trigger runs at 10 AM, 11 AM, and noon. -
,
: Select multiple values.MON,WED,FRI
in theDay of week
field: the trigger runs on Monday, Wednesday, and Friday. -
/
: Increment the value.0/15
in theMinutes
field: The trigger starts at 0, 15, 30, and 45 minutes past each hour. -
L
: This character functions differently in the two fields where it's used:- In the
Day of month
field, it means the last day of the month. - In the
Day of week
field, it means the last day of the week,7
(Saturday,SAT
).
L
in theDay of month
field: the trigger runs on January 31, February 28, and so on. - In the
-
W
: Select the weekday nearest to the specified date.15W
in theDay of month
field: The trigger is run on the weekday nearest to the 15th day of the month. If the 15th day is Saturday, the trigger runs on Friday the 14th.Note
The characters
L
andW
in theDay of month
field can be also merged intoLW
: The trigger is run on the last weekday of the month. -
#
: Select the Nth day of the month.The value
6#3
in theDay of week
field: The trigger runs on the third Friday of the month (6 — Friday, 3 — the third Friday of the month).
Examples of cron expressions
Cron expression | Description |
---|---|
* * * * ? * |
The trigger is run every minute. |
0 * ? * * * |
The trigger is run every hour. |
15 10 ? * * * |
The trigger is run every day at 10:15 AM. |
Roles required for timers to run correctly
- To create a timer, you need a permission for the service account under which the timer executes the operation. This permission comes with the iam.serviceAccounts.user and editor roles or higher.
- To run a timer, the service account needs the
serverless.containers.invoker
role for the folder with the container to be invoked by the timer.
Read more about access management.
Timer message format
After the trigger is activated, it sends the following message to the container:
{
"messages": [
{
"event_metadata": {
"event_id": "a1s41g2n5g0o********",
"event_type": "yandex.cloud.events.serverless.triggers.TimerMessage",
"created_at": "2019-12-04T12:05:14.227761Z",
"cloud_id": "b1gvlrnlei4l********",
"folder_id": "b1g88tflru0e********"
},
"details": {
"trigger_id": "a1sfe084v4se********",
"payload": "payload-message"
}
}
]
}