Creating a timer that invokes a Cloud Functions function

If you do not have the Yandex Cloud CLI installed yet, install and initialize it.

By default, the CLI uses the folder specified when creating the profile. To change the default folder, use the yc config set folder-id <folder_ID> command. You can also set a different folder for any specific command using the --folder-name or --folder-id parameter.

To create a trigger that invokes a function, run this command:

yc serverless trigger create timer \
  --name <timer_name> \
  --cron-expression '<cron_expression>' \
  --payload <message> \
  --invoke-function-id <function_ID> \
  --invoke-function-service-account-id <service_account_ID> \
  --retry-attempts <number_of_retry_attempts> \
  --retry-interval <interval_between_retry_attempts> \
  --dlq-queue-id <dead-letter_queue_ID> \
  --dlq-service-account-id <service_account_ID>

Where:

• --name: Timer name.
• --cron-expression: Function invocation schedule specified as a cron expression.
• --payload: Message that will be sent to the function if the timer fires. The string length must not exceed 4,096 characters.

• --invoke-function-id: Function ID.
• --invoke-function-service-account-id: ID of the service account with permissions to call the function.
• --retry-attempts: Number of invocation retries before the trigger sends a message to the dead-letter queue. This is an optional parameter. The values may range from 1 to 5. The default value is 1.
• --retry-interval: Time after which the function will be invoked again if the current attempt fails. This is an optional parameter. The values may range from 10 to 60 seconds. The default value is 10 seconds.
• --dlq-queue-id: Dead-letter queue ID. This is an optional parameter.
• --dlq-service-account-id: ID of the service account with write permissions for the dead-letter queue. This is an optional parameter.

Result:

id: a1sfe084v4**********
folder_id: b1g88tflru**********
created_at: "2019-12-04T08:45:31.131391Z"
name: timer
rule:
  timer:
    cron_expression: 5 12 * * ? *
    payload: <message>
    invoke_function_with_retry:
      function_id: d4eofc7n0m**********
      function_tag: $latest
      service_account_id: aje3932acd**********
      retry_settings:
        retry_attempts: "1"
        interval: 10s
      dead_letter_queue:
        queue-id: yrn:yc:ymq:ru-central1:aoek49ghmk**********:dlq
        service-account-id: aje3932acd**********
status: ACTIVE

With Terraform, you can quickly create a cloud infrastructure in Yandex Cloud and manage it using configuration files. These files store the infrastructure description written in HashiCorp Configuration Language (HCL). If you change the configuration files, Terraform automatically detects which part of your configuration is already deployed, and what should be added or removed.

Terraform is distributed under the Business Source License. The Yandex Cloud provider for Terraform is distributed under the MPL-2.0 license.

For more information about the provider resources, see the relevant documentation on the Terraform website or its mirror.

If you do not have Terraform yet, install it and configure the Yandex Cloud provider.

To create a timer:

1. In the Terraform configuration file, describe the parameters of the resources you want to create:

   resource "yandex_function_trigger" "my_trigger" {
     name        = "<trigger_name>"
     description = "<trigger_description>"
     function {
       id                 = "<function_ID>"
       service_account_id = "<service_account_ID>"
       retry_attempts     = "<number_of_retry_attempts>"
       retry_interval     = "<interval_between_retry_attempts>"
     }
     timer {
       cron_expression = "<cron_expression>"
       payload         = "<message>"
     }
     dlq {
       queue_id           = "<dead-letter_queue_ID>"
       service_account_id = "<service_account_ID>"
     }
   }
   

   Where:

   • name: Trigger name. The name format is as follows:

     • It must be from 2 to 63 characters long.
     • It can only contain lowercase Latin letters, numbers, and hyphens.
     • It must start with a letter and cannot end with a hyphen.

   • description: Trigger description.

   • function: Function parameters:

     • id: Function ID.
     • service_account_id: ID of the service account with permissions to invoke the function.
     • retry_attempts: Number of invocation retries before the trigger moves a message to the dead-letter queue. This is an optional parameter. The values may range from 1 to 5. The default value is 1.
     • retry_interval: Time until another attempt is made to invoke the function if the current attempt fails. This is an optional parameter. The values may range from 10 to 60 seconds. The default value is 10 seconds.

   • timer: Trigger parameters:

     • cron_expression: Function invocation schedule specified as a cron expression.
     • payload: Message that will be sent to the function if the timer fires. The string length must not exceed 4,096 characters.
   • dlq: Dead-letter queue message parameters:
     • queue_id: Dead-letter queue ID. This is an optional parameter.
     • service_account_id: ID of the service account with write permissions to the dead-letter queue. This is an optional parameter.

   For more information about the yandex_function_trigger resource properties, see the provider documentation.

2. Create resources:

   1. In the terminal, go to the directory where you edited the configuration file.

   2. Make sure the configuration file is correct using this command:

      terraform validate
      

      If the configuration is correct, you will get this message:

      Success! The configuration is valid.
      

   3. Run this command:

      terraform plan
      

      You will see a detailed list of resources. No changes will be made at this step. If the configuration contains any errors, Terraform will show them.

   4. Apply the changes:

      terraform apply
      

   5. Type yes and press Enter to confirm the changes.

   Terraform will create all the required resources. You can check the new resources using the management console or this CLI command:

   yc serverless trigger list
   

To create a timer, use the create REST API method for the Trigger resource or the TriggerService/Create gRPC API call.