[Yandex Cloud documentation](../../../../index.md) > [Yandex Serverless Integrations](../../../index.md) > [Step-by-step guides](../../index.md) > EventRouter > Managing a rule > Creating a rule > Cloud Functions

# Creating a rule with a Yandex Cloud Functions target

{% list tabs group=instructions %}

- Management console {#console}

  1. In the [management console](https://console.yandex.cloud), select the folder where you want to create a [rule](../../../concepts/eventrouter/rule.md).
  1. Navigate to **Serverless Integrations**.
  1. In the left-hand panel, click ![image](../../../../_assets/console-icons/object-align-center-vertical.svg) **EventRouter**.
  1. Select the [bus](../../../concepts/eventrouter/bus.md) you need.
  1. Navigate to the ![image](../../../../_assets/console-icons/target-dart.svg) **Rules** tab.
  1. In the top-right corner, click **Create rule**.

  1. Optionally, expand the **Filter** section and enter a [jq template](https://jqlang.github.io/jq/manual/) to [filter](../../../concepts/eventrouter/rule.md#filter) events.
  1. Under **Targets**, click **Add** and configure the target:

      1. Specify `Yandex Cloud Functions` as the target type.
      1. Select the [function](../../../../functions/concepts/function.md) to receive the messages matching the rule and the [function version](../../../../functions/concepts/function.md#version).
      1. Select a [service account](../../../../iam/concepts/users/service-accounts.md) with the `functions.functionInvoker` [role](../../../../functions/security/index.md#functions-functionInvoker) or higher for the selected function or [create](../../../../iam/operations/sa/create.md) a new one.
      1. Optionally, click ![plus](../../../../_assets/console-icons/plus.svg) **Repeat send settings** and specify:
         
         * **Number of attempts**: 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, h**: 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.
      1. Optionally, click ![plus](../../../../_assets/console-icons/plus.svg) **Batch message settings** and specify:
         
         * **Batch message 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.
         * **Batch byte count**: 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.
         * **Cutoff, s**: Maximum period during which EventRouter groups messages before sending them to the target. Valid values ​​range from 0 to 60 seconds. The default value is 60 seconds.
      1. (Optional) Open the **Transformer** field and enter a [jq template](https://jqlang.github.io/jq/manual/) to transform events. If no template is specified, the event will not be transformed.
      1. (Optional) Expand the **Dead Letter settings** section:
         
         1. Specify the `Yandex Message Queue` listener type.
         1. Specify a folder or DLQ to which messages the target failed to process will be redirected.
         1. Select the service account to which the `ymq.writer` [role](../../../../message-queue/security/index.md#ymq-writer) or higher is assigned for the selected DLQ or [create](../../../../iam/operations/sa/create.md) a new account.

  1. 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 Cyrillic letters, numbers, hyphens, underscores, and spaces.
         * The first character must be a letter. The last character cannot be a hyphen, underscore, or space.
     
     1. Optionally, add labels:
     
         * Click **Add label**.
         * Enter a label in `key: value` format.
         * Press **Enter**.
     
     1. Optionally, enable deletion protection. You cannot delete a rule with this option enabled.
  1. Click **Create**.

- CLI {#cli}

  If you do not have the Yandex Cloud CLI yet, [install and initialize it](../../../../cli/quickstart.md#install).

  The folder used by default is the one specified when [creating](../../../../cli/operations/profile/profile-create.md) 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.

  1. See the description of the CLI command for creating a [rule](../../../concepts/eventrouter/rule.md):

      ```bash
      yc serverless eventrouter rule create --help
      ```

  1. Create a rule with a Yandex Cloud Functions target:

      ```bash
      yc serverless eventrouter rule create \
        --bus-id <bus_ID> \
        --filter '<jq_template>' \
        --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](../../../concepts/eventrouter/bus.md) ID.
      * `--filter`: [jq template](https://jqlang.github.io/jq/manual/) for event [filtering](../../../concepts/eventrouter/rule.md#filter).

      * `--function-target`: Parameter for configuring the `Yandex Cloud Functions` target and its properties:

          * `function-id`: ID of the [function](../../../../functions/concepts/function.md) to receive the messages matching the rule.
          * `function-tag`: Function [version tag](../../../../functions/concepts/function.md#tag).
          * `service-account-id`: ID of the [service account](../../../../iam/concepts/users/service-accounts.md) with the `functions.functionInvoker` [role](../../../../functions/security/index.md#functions-functionInvoker) 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](https://jqlang.github.io/jq/manual/) 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](../../../../message-queue/security/index.md#ymq-writer) 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 Cyrillic 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:

      ```text
      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
      ```

- Terraform {#tf}

  With [Terraform](https://www.terraform.io/), 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](https://github.com/hashicorp/terraform/blob/main/LICENSE). The [Yandex Cloud provider for Terraform](https://github.com/yandex-cloud/terraform-provider-yandex) is distributed under the [MPL-2.0](https://www.mozilla.org/en-US/MPL/2.0/) license.
  
  For more information about the provider resources, see the guides on the [Terraform](https://www.terraform.io/docs/providers/yandex/index.html) website or [its mirror](../../../../terraform/index.md).

  If you do not have Terraform yet, [install it and configure the Yandex Cloud provider](../../../../tutorials/infrastructure-management/terraform-quickstart.md#install-terraform).
  
  
  To manage infrastructure using Terraform under a service account or user accounts (a Yandex account, a federated account, or a local user), [authenticate](../../../../terraform/authentication.md) using the appropriate method.

  To create a [rule](../../../concepts/eventrouter/rule.md) with a Yandex Cloud Functions target:

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

      ```hcl
      resource "yandex_serverless_eventrouter_rule" "example_rule" {
        bus_id    = "<bus_ID>"
        jq_filter = "<jq_template>"
       
        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](../../../concepts/eventrouter/bus.md) ID.
      * `jq_filter`: [jq template](https://jqlang.github.io/jq/manual/) for event [filtering](../../../concepts/eventrouter/rule.md#filter).
      * `function`: Section to configure the `Yandex Cloud Functions` target and its parameters:

          * `function_id`: ID of the [function](../../../../functions/concepts/function.md) to receive the messages matching the rule.
          * `function_tag`: Function [version tag](../../../../functions/concepts/function.md#tag).
          * `service_account_id`: ID of the [service account](../../../../iam/concepts/users/service-accounts.md) with the `functions.functionInvoker` [role](../../../../functions/security/index.md#functions-functionInvoker) 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 Cyrillic 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 on the properties of the `yandex_serverless_eventrouter_rule` resource, see [this provider guide](../../../../terraform/resources/serverless_eventrouter_rule.md).

  1. Create the resources:

      1. In the terminal, navigate to the configuration file directory.
      1. Make sure the configuration is correct using this command:
      
         ```bash
         terraform validate
         ```
      
         If the configuration is valid, you will get this message:
      
         ```bash
         Success! The configuration is valid.
         ```
      
      1. Run this command:
      
         ```bash
         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.
      1. Apply the configuration changes:
      
         ```bash
         terraform apply
         ```
      
      1. Type `yes` and press **Enter** to confirm the changes.

      Terraform will create all the required resources. You can check the new resources in the [management console](https://console.yandex.cloud) or using this [CLI](../../../../cli/index.md) command:

      ```bash
      yc serverless eventrouter rule list
      ```

- API {#api}

  To create a [rule](../../../concepts/eventrouter/rule.md) with a Yandex Cloud Functions target, use the [Create](../../../eventrouter/api-ref/Rule/create.md) REST API method for the [rule](../../../eventrouter/api-ref/Rule/index.md) resource or the [rule/Create](../../../eventrouter/api-ref/grpc/Rule/create.md) gRPC API call.

{% endlist %}

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