Creating an email trigger that invokes Cloud Functions

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Yandex Cloud

Improved by

Danila N.

Updated at September 30, 2026

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Getting started
Creating a trigger
Checking the result

Create an email trigger that invokes Cloud Functions when an email arrives. Cloud Functions will automatically generate an email address when creating the trigger.

Getting started

To create a trigger, you will need:

Function the trigger will invoke. If you do not have a function:
- Create a function.
- Create a function version.
Optionally, a dead-letter queue where to redirect the messages the function failed to process. If you do not have a queue, create one.
Service accounts with the following permissions:
- To invoke a function.
- Optionally, to write to a dead-letter queue.
- Optionally, to upload objects to buckets.
You can use the same service account or different ones. If you do not have a service account, create one.
Optionally, bucket to save email attachments to. If you do not have a bucket, create one with restricted access.

Creating a trigger

Note

The trigger is initiated within five minutes after it is created.

Management console

CLI

Terraform

API

In the management console, select the folder where you want to create your trigger.
Navigate to Cloud Functions.
In the left-hand panel, select Triggers.
Click Create trigger.
Under Basic settings:
- Optionally, enter a trigger name and description.
- In the Labels field, click Add label and specify the labels in key: value format.
- In the Type field, select Email.
Optionally, under Settings for saving attachments:
- In the Bucket field, select the bucket to save email attachments to.
- In the Service account field, specify a service account with permissions to upload objects to the Object Storage bucket.
Under Batch message settings, specify the following:
- Waiting time, s. The values may range from 1 to 60 seconds. The default value is 1 second.
- Batch size. The values may range from 1 to 1,000. The default value is 1.
The trigger groups events within the specified wait time and sends them to the target. The number of events cannot exceed the specified batch size.
Under Targets:
1. In the Target type field, select Function.
2. Under Function settings, select a function and specify:
  - Function version tag.
  - Service account to use for invoking the function.
3. Optionally, under Repeat request settings:
  - In the Interval field, specify how long to wait before retrying the function if it fails. The values may range from 10 to 60 seconds. The default value is 10 seconds.
  - In the Number of attempts field, specify the number of function retries before the trigger sends a message to the dead letter queue. The values may range from 1 to 5. The default value is 1.
4. Optionally, under Dead Letter Queue settings, select a dead-letter queue and a service account with write permissions for that queue.
5. Optionally, in the Filter field, specify a jq template to filter events sent to the target. If no filter is specified, all events are sent to the target.
6. Optionally, in the Transformation template field, specify a jq template to transform events before sending them to the target. If no template is specified, no transformations apply to the events.
Click Create trigger.

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_timeout> \
  --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 guides on the Terraform website or its mirror.

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

To manage infrastructure using Terraform under a service account or user accounts (a Yandex account, a federated account, or a local user), authenticate using the appropriate method.

To create an email trigger that invokes a function:

Describe the trigger in the configuration file:
```
resource "yandex_serverless_triggers" "my_trigger" {
  name = "<trigger_name>"
  source {
    mail {
      attachments_bucket {
        bucket_id          = "<bucket_name>"
        service_account_id = "<service_account_ID>"
      }
      batch_settings {
        max_count = "<max_number_of_messages>"
        max_bytes = "<max_group_size_in_bytes>"
        cutoff    = "<maximum_wait_time>"
      }
    }
  }
  action {
    invoke_function {
      function_id        = "<function_ID>"
      service_account_id = "<service_account_ID>"
    }
    retry_policy {
      retry_attempts = "<number_of_retries>"
      interval       = "<interval_between_retries>"
    }
    dead_letter {
      dead_letter_queue {
        queue_arn          = "<Dead_Letter_Queue_ARN>"
        service_account_id = "<service_account_ID>"
      }
    }
  }
}
```
Where:
- name: Trigger name. The name format is as follows:
  - 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. This is an optional parameter.
- labels: Trigger labels in key:value format. This is an optional parameter.
- source: Event source settings:
  - mail: Mail trigger settings:
    - attachments_bucket: Settings of the bucket to save email attachments to. This is an optional section:
      - bucket_id: Bucket name.
      - service_account_id: ID of the service account with permissions to upload objects to the Object Storage bucket.
    - batch_settings: Event grouping settings. This is an optional section.
      - cutoff: Maximum event grouping time. This is a required setting. After the specified time has passed, the trigger sends the event group, even if it is not complete.
      - max_count: Maximum number of events per group.
      - max_bytes: Maximum total size of events per group, in bytes.
      At least one of the parameters, max_count or max_bytes, must be greater than 0.
- action: Target settings. You can specify this section multiple times so that the trigger calls multiple resources, including those of different types. There are limits on the maximum number of resources.
  - invoke_function: Function settings:
    - function_id: Function ID.
    - function_tag: Function version tag. This is an optional parameter. If it is not specified, the latest version of the function is called.
    - service_account_id: ID of the service account with permissions to invoke the function.
  - filter: Filtering events before sending them to the target. This is an optional section.
    - jq: jq template to filter events sent to the target. It not specified, all events reach the target.
  - transformer: Transforming events before sending them to the target. This is an optional section.
    - jq: jq template to transform events before sending them to the target. It omitted, no transformations apply to the events.
  - retry_policy: Repeated request settings. This is an optional section.
    - interval: Time interval before a retry attempt to send the event if the current attempt fails.
    - retry_attempts: Number of retry attempts before the trigger moves the event to the dead-letter queue.
  - dead_letter: Dead-letter queue settings. This is an optional section.
    - dead_letter_queue: Queue settings:
      - queue_arn: Queue ARN.
      - service_account_id: ID of the service account with permissions to write to the queue.
      - message_attributes: Attributes to add to each message in the queue, in key:value format. This is an optional parameter.
The email address to send the mail to will be assigned to the trigger when it is created; you can view it in the trigger properties.

For more on the properties of the yandex_serverless_triggers resource, see this provider guide.
Configuration for the yandex_function_trigger resource
```
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     = <time_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 timeout. This is an optional setting. The values may range from 1 to 60 seconds. The default value is 1 second. The trigger groups messages for a period not exceeding batch-cutoff and sends them to a 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 on the properties of the yandex_function_trigger resource, see this provider guide.
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.

Cloud Functions will automatically generate an email address for which the trigger will fire when messages are sent to it. To view it, get trigger details.

Checking the result

Check that the trigger works correctly. To do this, view function logs that show information on invocations.

Creating an email trigger that invokes Cloud Functions

Getting started

Creating a trigger

Checking the result

Useful links

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Creating an email trigger that invokes Cloud Functions

Getting startedGetting started

Creating a triggerCreating a trigger

Checking the resultChecking the result

Useful linksUseful links

Was the article helpful?

Getting started

Creating a trigger

Checking the result

Useful links