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Yandex Cloud Functions

Creating a timer

Create a timer, which is a trigger to run your function on a schedule.

Before you start

To create a trigger, you need:

  1. Functions that the trigger will call. If you don't have a function:
  2. The Dead Letter Queue where messages that the function couldn't process are moved. If you don't have a queue, create one.
  3. Service accounts with rights to invoke the function and write messages to the Dead Letter Queue. You can use the same service account or different ones. If you don't have a service account, create one.

Creating a trigger

Note

The trigger is initiated within 5 minutes of being created.

  1. In the management console, go to the folder where you want to create a trigger.
  2. Open Cloud Functions.
  3. Go to the Triggers tab.
  4. Click Create trigger.
  5. Under Basic parameters:
    • Enter a name and description for the trigger.
    • In the Type field, select Timer.
  6. Under Timer settings, specify the function invocation schedule in a cron expression.
  7. Under Function settings:
    • Select the function for the trigger to call.
    • Specify the function version tag.
    • Specify the service account to be used to call the function.
  8. Under Repeat request settings:
    • In the Interval field, specify the time after which the function will be invoked again if the current attempt fails. Acceptable values are from 10 to 60 seconds.
    • In the Number of attempts field, specify the number of invocation retries before the trigger moves a message to the Dead Letter Queue. Acceptable values are from 1 to 5.
  9. Under Dead Letter Queue settings, select the Dead Letter Queue and service account with rights to write messages to it.
  10. Click Create trigger.

If you don't have the Yandex.Cloud command line interface yet, install and initialize it.

The folder specified in the CLI profile is used by default. You can specify a different folder using the --folder-name or --folder-id parameter.

To create a trigger, run the command:

yc serverless trigger create timer \
    --name <timer name> \
    --cron-expression '<cron expression>' \
    --invoke-function-id <function ID> \
    --invoke-function-service-account-id <service account ID> \
    --retry-attempts 1 \
    --retry-interval 10s \
    --dlq-queue-id <Dead Letter Queue ID> \
    --dlq-service-account-id <service account ID>

where:

  • --name: Timer name.
  • --cron-expression: Function invocation schedule in cron expression format.
  • --invoke-function-id: Function ID.
  • --invoke-function-service-account-id: Service account with rights to call the function.
  • --retry-attempts: The time after which the function will be invoked again if the current attempt fails. Values can be from 10 to 60 seconds. The default is 10 seconds.
  • --retry-interval: The number of invocation retries before the trigger moves a message to the Dead Letter Queue. Values can be from 1 to 5. The default is 1.
  • --dlq-queue-id: ID of the Dead Letter Queue.
  • --dlq-service-account-id: Service account with rights to write messages to the Dead Letter Queue.

Result:

id: a1sfe084v4se4morbu2i
folder_id: b1g88tflru0ek1omtsu0
created_at: "2019-12-04T08:45:31.131391Z"
name: timer
rule:
  timer:
    cron_expression: 5 12 * * ? *
    invoke_function_with_retry:
      function_id: d4eofc7n0m03lmudse8l
      function_tag: $latest
      service_account_id: aje3932acd0c5ur7dagp
      retry_settings:
        retry_attempts: "1"
        interval: 10s
      dead_letter_queue:
        queue-id: yrn:yc:ymq:ru-central1:aoek49ghmknnpj1ll45e:dlq
        service-account-id: aje3932acd0c5ur7dagp
status: ACTIVE

You can create a timer using the create API method.

Checking the result

Make sure the trigger is working properly. To do this, view the function logs that show information about its invocations.

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