Creating a rule with a Yandex Cloud Functions target

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Yandex Cloud

Updated at April 14, 2025

Management console

CLI

Terraform

API

In the management console, select the folder where you want to create a rule.
Select Serverless Integrations.
In the left-hand panel, click EventRouter.
Select the bus you need.
Navigate to the Rules tab.
In the top-right corner, click Create rule.
Optionally, expand the Filter section and enter a jq expression to filter events.
Under Targets, click Add and configure the target:
1. Specify Yandex Cloud Functions as the target type.
2. Select the function to receive the messages matching the rule and the function version.
3. Select a service account with the functions.functionInvoker role or higher for the selected function or create a new one.
4. Optionally, click Message retry settings and specify the following:
  - Number of retries: Number of message retries before EventRouter moves the messages to the dead-letter queue (DLQ). Valid values range from 0 to 1,000. The default value is 3.
  - Interval: Time, in hours, before a retry attempt to send the messages if the current attempt fails. Valid values range from 0 to 60 hours. The default value is 10.
5. (Optional) Click Message grouping settings and specify the following:
  - Number of messages per group: Maximum number of messages EventRouter will group before sending them to the target. The number of messages per group cannot exceed the specified value. Valid values range from 0 to 1,000. The default value is 1.
  - Number of bytes per group: Maximum total amount of data in the messages. If the data comes in a single message, this limit may be exceeded. Valid values range from 0 to 262,144 bytes. The default value is 10,000 bytes.
  - Timeout: Maximum time during which EventRouter is grouping messages before sending them to the target. Valid values range from 0 to 60 seconds. The default value is 60 seconds.
6. (Optional) Open the Transformer field and enter a jq template to transform events. If no template is specified, the event will not be transformed.
7. (Optional) Expand the Dead Letter settings section:
  1. Specify the Yandex Message Queue listener type.
  2. Specify a folder or DLQ to which messages the target failed to process will be redirected.
  3. Select the service account to which the ymq.writer role or higher is assigned for the selected DLQ or create a new account.
Expand Additional parameters:
1. Specify the rule name and description. Follow these naming requirements:
  - The name must be from 3 to 63 characters long.
  - It may contain uppercase and lowercase Latin and Russian letters, numbers, hyphens, underscores, and spaces.
  - The first character must be a letter. The last character cannot be a hyphen, underscore, or space.
2. Optionally, add labels:
  - Click Add label.
  - Enter a label in key: value format.
  - Press Enter.
3. Optionally, enable deletion protection. You cannot delete a rule with this option enabled.
Click Create.

If you do not have the Yandex Cloud CLI 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 parameters.

See the description of the CLI command for creating a rule:
```
yc serverless eventrouter rule create --help
```
Create a rule with a Yandex Cloud Functions target:
```
yc serverless eventrouter rule create \
  --bus-id <bus_ID> \
  --filter '<jq_expression>' \
  --function-target \
function-id=<function_ID>,\
function-tag=<function_version_tag>,\
service-account-id=<function_service_account_ID>,\
retry-attempts=<number_of_attempts>,\
maximum-age=<interval>,\
max-count=<max_number_of_messages>,\
max-bytes=<max_number_of_bytes>,\
cutoff=<timeout>,\
transformer=<jq_template>,\
dlq-arn=<DLQ>,\
dlq-service-account-id=<DLQ_service_account_ID> \
  --name <rule_name> \
  --description "<rule_description>" \
  --deletion-protection \
  --labels <label_list>
```
Where:
- --bus-id: EventRouter bus ID.
- --filter: jq expression for event filtering.
- --function-target: Flag to configure the Yandex Cloud Functions target and its parameters:
  - function-id: ID of the function to receive the messages matching the rule.
  - function-tag: Function version tag.
  - service-account-id: ID of the service account with the functions.functionInvoker role or higher for the selected function.
  - retry-attempts: Number of message retries before EventRouter moves the messages to the dead-letter queue (DLQ). Valid values range from 0 to 1,000. This is an optional parameter.
  - maximum-age: Time interval before a retry attempt to send the messages if the current attempt fails. Valid values range from 0 to 60 hours. This is an optional parameter.
  - transformer: jq template to transform events. If no template is specified, the event will not be transformed. This is an optional parameter.
  - max-count: Maximum number of messages EventRouter will group before sending them to the target. The number of messages per group cannot exceed the specified value. Valid values range from 0 to 1,000. The default value is 1. This is an optional parameter.
  - max-bytes: Maximum total amount of data in the messages. If the data comes in a single message, this limit may be exceeded. Valid values range from 0 to 262,144 bytes. The default value is 10,000 bytes. This is an optional parameter.
  - cutoff: Maximum period during which EventRouter groups messages before sending them to the target, e.g., 10s. Valid values range from 0 to 60 seconds. The default value is 60 seconds. This is an optional parameter.
  - dlq-arn: ARN of the DLQ to which messages that the target could not process will be redirected. This is an optional parameter.
  - dlq-service-account-id: ID of the service account to which the ymq.writer role or higher is assigned for the selected DLQ. This is an optional parameter.
- --name: Rule name. Follow these naming requirements:
  - The name must be from 3 to 63 characters long.
  - It may contain uppercase and lowercase Latin and Russian letters, numbers, hyphens, underscores, and spaces.
  - The first character must be a letter. The last character cannot be a hyphen, underscore, or space.
- --description: Rule description. This is an optional parameter.
- --deletion-protection: Rule deletion protection. By default, protection is disabled. You cannot delete a rule with this option enabled. To disable deletion protection, specify --no-deletion-protection. This is an optional parameter.
- --labels: List of labels. This is an optional parameter.
  
  You can specify one or more labels separated by commas in <key1>=<value1>,<key2>=<value2> format.
Result:
```
id: f66vfpjrkc35********
bus_id: f66epjc9llqt********
folder_id: b1g681qpemb4********
cloud_id: b1gia87mbaom********
created_at: "2025-02-26T14:04:47.710918Z"
name: new-rule
description: created via cli
labels:
  owner: admin
  version: beta
filter:
  jq_filter: .firstName == "Ivan"
targets:
  - function:
      function_id: d4e27bc01uu7********
      service_account_id: ajelprpohp7r********
      batch_settings:
        max_count: "1"
        max_bytes: "10000"
        cutoff: 60s
    transformer:
      jq_transformer: .
    retry_settings:
      retry_attempts: "3"
      maximum_age: 600s
    dead_letter_queue:
      queue_arn: yrn:yc:ymq:ru-central1:b1g681qpemb4********:dlq-42
      service_account_id: ajelprpohp7r********
    status: ENABLED
status: ENABLED
```

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 documentation on the Terraform website or mirror website.

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

To create a rule with a Yandex Cloud Functions target:

In the configuration file, define the parameters of the resources you want to create:
```
resource "yandex_serverless_eventrouter_rule" "example_rule" {
  bus_id    = "<bus_ID>"
  jq_filter = "<jq_expression>"
 
  function {
    function_id        = "<function_ID>"
    function_tag       = "<function_version_tag>"
    service_account_id = "<service_account_ID>"
    
    batch_settings {
      max_bytes  = <max_number_of_bytes>
      max_count  = <max_number_of_messages>
      cutoff     = "<timeout>"
    }
  }
 
  name        = "<rule_name>"
  description = "<rule_description>"
   
  labels = {
    <key_1> = "<value_1>"
    <key_2> = "<value_2>"
    ...
    <key_n> = "<value_n>"
  }
}
```
Where:
- bus_id: EventRouter bus ID.
- jq_filter: jq expression for event filtering.
- function: Section to configure the Yandex Cloud Functions target and its parameters:
  - function_id: ID of the function to receive the messages matching the rule.
  - function_tag: Function version tag.
  - service_account_id: ID of the service account with the functions.functionInvoker role or higher for the selected function.
  - max_bytes: Maximum total amount of data in the messages. If the data comes in a single message, this limit may be exceeded. Valid values range from 0 to 262,144 bytes. The default value is 0. This is an optional parameter.
  - max_count: Maximum number of messages EventRouter will group before sending them to the target. The number of messages per group cannot exceed the specified value. Valid values range from 0 to 1,000. The default value is 0. This is an optional parameter.
  - cutoff: Maximum time for EventRouter to group messages before sending them to the target, e.g., 10s. The values may range from 0 to 60 seconds. The default value is 0. This is an optional parameter.
- name: Rule name. The naming requirements are as follows:
  - The name must be from 3 to 63 characters long.
  - It may contain uppercase and lowercase Latin and Russian letters, numbers, hyphens, underscores, and spaces.
  - The first character must be a letter. The last character cannot be a hyphen, underscore, or space.
- description: Rule description. This is an optional parameter.
- labels: List of labels. Provide labels in <key> = "<value>" format. This is an optional parameter.
For more information about the yandex_serverless_eventrouter_rule resource parameters, see this Terraform article.
Create the 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 eventrouter rule list
```

To create a rule with a Yandex Cloud Functions target, use the Create REST API method for the rule resource or the rule/Create gRPC API call.

All newly created rules are enabled by default. To stop events matching the rule from being routed to the target, disable the rule.

Creating a rule with a Yandex Cloud Functions target

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