[Yandex Cloud documentation](../../../index.md) > [Yandex Cloud Functions](../../index.md) > [Step-by-step guides](../index.md) > Invoking a function > Invoking a function asynchronously

# Invoking a function asynchronously

{% note info %}

This feature is at the [Preview](../../../overview/concepts/launch-stages.md) stage.

{% endnote %}

## Configure asynchronous invocation {#async}

{% list tabs group=instructions %}

- Management console {#console}
    
    1. In the [management console](https://console.yandex.cloud), navigate to the folder containing the function.
    1. Navigate to **Cloud Functions**.
    1. Select the function.
    1. Navigate to the **Editor** tab.
    1. Under **Asynchronous call**, select **Enable**.
    1. In the **Number of retries** field, specify the number of retries before the invocation fails.
    1. In the **Service account** field, specify a service account with permissions to invoke the function.
    1. In the **Destination for successful result** and **Destination for unsuccessful result** fields, specify where to send messages about successful and failed function invocations respectively:
        * `Not specified`: Do not send messages.
        * `Message Queue`: Send messages to a Message Queue.
            * **Message Queue**: Message Queue to send messages to.
            * **Service account**: Service account with permissions to write messages to the queue.
    1. Click **Save changes**.

- 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.

    To configure asynchronous invocation, run this command:

    ```bash
    yc serverless function version create \
      --function-name=<function_name> \
      --runtime <runtime_environment> \
      --entrypoint <entry_point> \
      --memory <RAM_size> \
      --execution-timeout <execution_timeout> \
      --source-version-id <version_ID> \
      --async-max-retries <number_of_retry_attempts> \
      --async-service-account-id <service_account_ID> \
      --async-success-ymq-arn <message_queue> \
      --async-success-sa-id <service_account_ID> \
      --async-failure-ymq-arn <message_queue> \
      --async-failure-sa-id <service_account_ID>
    ```

    Where:

    * `--function-name`: Function name.
    * `--runtime`: Runtime.
    * `--entrypoint`: Entry point in `<function_file_name>.<handler_name>` format.
    * `--memory`: Amount of RAM.
    * `--execution-timeout`: Maximum function execution time before timeout.
    * `--source-version-id`: ID of the function version from which you want to copy the code.
    * `--async-max-retries`: Number of retries before the invocation fails.
    * `--async-service-account-id`: ID of the service account with permissions to invoke the function.
    * `--async-success-ymq-arn`: ARN of the destination queue in Message Queue for messages about successful function invocations. If you skip this setting, no messages will be sent.
    * `--async-success-sa-id`: ID of the service account with permissions to write to the `async-success-ymq-arn` queue.
    * `--async-failure-ymq-arn`: ARN of the destination queue in Message Queue for messages about failed function invocations. If you skip this setting, no messages will be sent.
    * `--async-failure-sa-id`: ID of the service account with permissions to write to the `async-failure-ymq-arn` queue.

- 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 configure asynchronous invocation:

  1. Open the Terraform configuration file and add the `async_invocation` section to the function description:

     ```hcl
     resource "yandex_function" "test-function" {
       name               = "<function_name>"
       user_hash          = "<function_hash>"
       runtime            = "<runtime>"
       entrypoint         = "<entry_point>"
       memory             = "<RAM_amount>"
       execution_timeout  = "<execution_timeout>"
       service_account_id = "<service_account_ID>"

       async_invocation {
         retries_count       = "<number_of_retry_attempts>"
         service_account_id  = "<service_account_ID>"
         ymq_failure_target {
           service_account_id = "<service_account_ID>"
           arn                = "<message_queue>"
         }
         ymq_success_target {
           service_account_id = "service_account_ID"
           arn                = "<message_queue>"
         }
       }
     }
     ```

     Where:
     
     * `async_invocation`: Asynchronous invocation settings:
       * `retries_count`: Number of retries before the invocation fails.
       * `service_account_id`: Service account with permissions to invoke the function.
       * `ymq_failure_target`: Settings of the queue for failed invocations:
         * `service_account_id`: Service account with permissions to write to the queue for failed asynchronous invocations.
         * `arn`: ARN of the destination queue in Message Queue for messages about failed function invocations. If you skip this setting, no messages will be sent.
       * `ymq_success_target`: Settings of the queue for successful invocations:
         * `service_account_id`: Service account with permissions to write to the queue for successful asynchronous invocations.
         * `arn`: ARN of the destination queue in Message Queue for messages about successful function invocations. If you skip this setting, no messages will be sent.

     For more on the properties of the `yandex_function` resource, see [this provider guide](../../../terraform/resources/function.md).

  1. Apply the changes:

     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.

  You can check the function update and its settings using the [management console](https://console.yandex.cloud) or this [CLI](../../../cli/quickstart.md) command:

  ```bash
  yc serverless function version get <function_version_ID>
  ```

- API {#api}

    To configure asynchronous invocation, use the [createVersion](../../functions/api-ref/Function/createVersion.md) REST API method for the [Function](../../functions/api-ref/Function/index.md) resource or the [FunctionService/CreateVersion](../../functions/api-ref/grpc/Function/createVersion.md) gRPC API call.

{% endlist %}

## Invoke the function {#invoke}

[Call the function](function-invoke.md) via HTTPS, specifying the `?integration=async` query string parameter.

## Useful links {#see-also}

* [Asynchronous function invocation](../../concepts/function-invoke-async.md)