Creating an email trigger that invokes a Cloud Functions function

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Updated at November 14, 2024

Getting started
Creating a trigger
Checking the result
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Create an email trigger to invoke a Cloud Functions function when an email arrives. The service automatically generates an email address when creating the trigger.

Getting started

To create a trigger, you need:

A function to be invoked by the trigger. If you do not have a function:
- Create a function.
- Create a function version.
(Optional) A dead-letter queue where messages that could not be processed by a function will be redirected. 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, a 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 5 minutes of being created.

Management console

CLI

Terraform

API

In the management console, select the folder where you want to create a trigger.
Select Cloud Functions.
In the left-hand panel, select Triggers.
Click Create trigger.
Under Basic settings:
- Optionally, enter a trigger name and description.
- In the Type field, select Email.
- In the Launched resource field, select Function.
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 authorized to upload objects to the Object Storage bucket.
Under Batch message settings, specify:
- 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 100. The default value is 1.
The trigger groups messages for a period of time not exceeding the specified timeout and sends them to a function. The number of messages cannot exceed the specified batch size.
Under Function settings, select a function and specify:
- Function version tag.
- Service account to invoke the function under.
Optionally, under Repeat request settings:
- In the Interval field, specify the time after which the function will be invoked again if the current attempt 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 invocation retries before the trigger moves a message to the Dead Letter Queue. The values may range from 1 to 5. The default value is 1.
Optionally, under Dead Letter Queue settings, select the dead-letter queue and the service account with write permissions for this queue.
Click Create trigger.

If you do not 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 that invokes a function, run this command:

yc serverless trigger create mail \
  --name <trigger_name> \
  --batch-size <message_group_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 parameter. The values may range from 1 to 10. The default value is 1.
--batch-cutoff: Maximum wait time. This is an optional parameter. 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.

--attachements-bucket: Name of the bucket to save email attachments to. This is an optional parameter.
--attachements-service-account-id: ID of the service account authorized to upload objects to Object Storage buckets. This is an optional parameter.

--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 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 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 to the dead-letter queue. This is an optional parameter.

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

Terraform allows you to quickly create a cloud infrastructure in Yandex Cloud and manage it using configuration files. Configuration files store the infrastructure description in the HashiCorp Configuration Language (HCL). Terraform and its providers are distributed under the Business Source License.

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

If you change the configuration files, Terraform automatically detects which part of your configuration is already deployed, and what should be added or removed.

If you don't have Terraform, install it and configure the Yandex Cloud provider.

To create an email trigger that invokes a function:

In the configuration file, describe the trigger parameters:
```
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_timeout>
    batch_size            = <message_group_size>
  }
  dlq {
    queue_id           = "<dead-letter_queue_ID>"
    service_account_id = "<service_account_ID>"
  }
}
```
Where:
- name: Trigger name. The name format is as follows:
  - The name must be from 3 to 63 characters long.
  - It may contain lowercase Latin letters, numbers, and hyphens.
  - The first character must be a letter and the last character cannot be 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.
- mail: Trigger parameters:
  - attachments_bucket_id: Name of the bucket to save email attachments to. This is an optional parameter.
  - service_account_id: ID of the service account authorized to upload objects to the Object Storage bucket. This is an optional parameter.
  - batch_cutoff: Maximum timeout. This is an optional parameter. 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 parameter. The values may range from 1 to 10. The default value is 1.
- 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 parameters in Terraform, see the provider documentation.
Create resources:
1. In the terminal, change to the folder where you edited the configuration file.
2. Make sure the configuration file is correct using the command:
```
terraform validate
```
  If the configuration is correct, the following message is returned:
```
Success! The configuration is valid.
```
3. Run the command:
```
terraform plan
```
  The terminal will display a list of resources with parameters. No changes are made at this step. If the configuration contains errors, Terraform will point them out.
4. Apply the configuration changes:
```
terraform apply
```
5. Confirm the changes: type yes in the terminal and press Enter.
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 that will cause the trigger to fire when messages are sent to it. To see it, retrieve detailed trigger information.

Checking the result

Check that the trigger operates correctly. Do it by viewing function logs that present information on invocations.

Creating an email trigger that invokes a Cloud Functions function

Getting startedGetting started

Creating a triggerCreating a trigger

Checking the resultChecking the result

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