Creating an email trigger that invokes Cloud Functions

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

The folder used by default is the one specified when creating the CLI profile. To change the default folder, use the yc config set folder-id <folder_ID> command. You can also specify a different folder for any command using --folder-name or --folder-id. If you access a resource by its name, the search will be limited to the default folder. If you access a resource by its ID, the search will be global, i.e., through all folders based on access permissions.

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

yc serverless trigger create mail \
  --name <trigger_name> \
  --batch-size <message_batch_size> \
  --batch-cutoff <maximum_wait_time> \
  --attachements-bucket <bucket_name> \
  --attachements-service-account-id <service_account_ID> \
  --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: Trigger name.

• --batch-size: Message batch size. This is an optional setting. The values may range from 1 to 10. The default value is 1.
• --batch-cutoff: Maximum wait time. This is an optional setting. The values may range from 1 to 60 seconds. The default value is 1 second. The trigger groups messages within the batch-cutoff period and sends them to the function. The number of messages cannot exceed batch-size.

• --attachements-bucket: Name of the bucket to save email attachments to. This is an optional setting.
• --attachements-service-account-id: ID of the service account with permissions to upload objects to the Object Storage bucket. This is an optional setting.

• --invoke-function-id: Function ID.
• --invoke-function-service-account-id: ID of the service account with permissions to invoke the function.
• --retry-attempts: Number of invocation retries before the trigger sends a message to the dead-letter queue. This is an optional setting. The values may range from 1 to 5. The default value is 1.
• --retry-interval: Time to wait before retrying the function if it fails. This is an optional setting. 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 setting.
• --dlq-service-account-id: ID of the service account with write permissions for the dead-letter queue. This is an optional setting.

Result:

id: a1sfe084v4**********
folder_id: b1g88tflru**********
created_at: "2022-12-04T08:45:31.131391Z"
name: mail-trigger
rule:
  mail:
    email: a1s8h8avgl**********-cho1****@serverless.yandexcloud.net
    batch_settings:
      size: "3"
      cutoff: 20s
    attachments_bucket:
      bucket_id: bucket-for-attachments
      service_account_id: ajejeis235ma********
    invoke_function:
      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 an email trigger that invokes a function:

1. In the configuration file, describe the trigger properties:

   resource "yandex_function_trigger" "my_trigger" {
     name = "<trigger_name>"
     function {
       id                 = "<function_ID>"
       service_account_id = "<service_account_ID>"
       retry_attempts     = <number_of_retry_attempts>
       retry_interval     = <interval_between_retry_attempts>
     }
     mail {
       attachments_bucket_id = "<bucket_name>"
       service_account_id    = "<service_account_ID>"
       batch_cutoff          = <maximum_wait_time>
       batch_size            = <message_batch_size>
     }
     dlq {
       queue_id           = "<dead-letter_queue_ID>"
       service_account_id = "<service_account_ID>"
     }
   }
   

   Where:

   • name: Trigger name. Follow these naming requirements:

     • Length: between 3 and 63 characters.
     • 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 settings:

     • 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 sends a message to the dead-letter queue. This is an optional setting. The values may range from 1 to 5. The default value is 1.
     • retry_interval: Time to wait before retrying the function if it fails. This is an optional setting. The values may range from 10 to 60 seconds. The default value is 10 seconds.

   • mail: Trigger settings:

     • attachments_bucket_id: Name of the bucket to save email attachments to. This is an optional setting.
     • service_account_id: ID of the service account with permissions to upload objects to the Object Storage bucket. This is an optional setting.
     • batch_cutoff: Maximum wait time. This is an optional setting. The values may range from 1 to 60 seconds. The default value is 1 second. The trigger groups messages within the batch-cutoff period and sends them to the function. The number of messages cannot exceed batch-size.
     • batch_size: Message batch size. This is an optional setting. The values may range from 1 to 10. The default value is 1.
   • dlq: Dead-letter queue settings:
     • queue_id: Dead-letter queue ID.
     • service_account_id: ID of the service account with write permissions for the dead-letter queue.

   For more information about the yandex_function_trigger properties in Terraform, see this provider guide.

2. Create the resources:

   1. In the terminal, navigate to the configuration file directory.

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

      terraform validate
      

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

      Success! The configuration is valid.
      

   3. Run this command:

      terraform plan
      

      You will see a list of resources and their properties. No changes will be made at this step. Terraform will show any errors in the configuration.

   4. Apply the configuration 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 an email trigger, use the create REST API method for the Trigger resource or the TriggerService/Create gRPC API call.