Create a trigger for Message Queue that sends messages to the Cloud Functions function

If you do not have the Yandex Cloud CLI installed yet, install and initialize it.

By default, the CLI uses the folder specified when creating the profile. To change the default folder, use the yc config set folder-id <folder_ID> command. You can also set a different folder for any specific command using the --folder-name or --folder-id parameter.

To create a trigger that invokes a function, run this command:

yc serverless trigger create message-queue \
  --name <trigger_name> \
  --queue <queue_ID> \
  --queue-service-account-id <service_account_ID> \
  --invoke-function-id <function_ID> \
  --invoke-function-service-account-id <service_account_ID> \
  --batch-size <message_group_size> \
  --batch-cutoff <maximum_timeout>

Where:

• --name: Trigger name.

• --queue: Queue ID

  To find out the queue ID:

  1. In the management console, go the folder containing the queue.
  2. Select Message Queue.
  3. Select the queue.
  4. You can see the queue ID under General information in the ARN field.

• --invoke-function-id: Function ID.

• --queue-service-account-name: ID of the service account with permissions to read messages from the queue.

• --invoke-function-service-account-id: ID of the service account with the permissions to invoke the function.

• --batch-size: Message batch size. This is an optional parameter. The values may range from 1 to 1,000. The default value is 1.

• --batch-cutoff: Maximum wait time. This is an optional parameter. The values may range from 0 to 20 seconds. The default value is 10 seconds. 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.

Result:

id: dd0cspdch6**********
folder_id: aoek49ghmk**********
created_at: "2019-08-28T12:14:45.762915Z"
name: ymq-trigger
rule:
  message_queue:
    queue_id: yrn:yc:ymq:ru-central1:aoek49ghmk**********:my-mq
    service_account_id: bfbqqeo6jk**********
    batch_settings:
      size: "1"
      cutoff: 10s
    invoke_function:
      function_id: b09e5lu91t**********
      function_tag: $latest
      service_account_id: bfbqqeo6j**********
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 relevant documentation on the Terraform website or its mirror.

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

To create a trigger for Message Queue:

1. In the configuration file, describe the trigger parameters:

   resource "yandex_function_trigger" "my_trigger" {
     name        = "<trigger_name>"
     description = "<trigger_description>"
     function {
       id                 = "<function_ID>"
       service_account_id = "<service_account_ID>"
     }
     message_queue {
       queue_id           = "<queue_ID>"
       service_account_id = "<service_account_ID>"
       batch_size         = "<message_group_size>"
       batch_cutoff       = "<maximum_timeout>"
   }
   

   Where:

   • name: Trigger name. The name format is as follows:

     • It must be from 2 to 63 characters long.
     • 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 parameters:

     • id: Function ID.
     • service_account_id: ID of the service account with the permissions to invoke the function.

   • message_queue: Trigger parameters:

     • queue_id: Message queue ID.

       To find out the queue ID:

       1. In the management console, go the folder containing the queue.
       2. Select Message Queue.
       3. Select the queue.
       4. You can see the queue ID under General information in the ARN field.

     • service_account_id: ID of the service account with permissions to read messages from the queue.

     • batch_size: Message batch size. This is an optional parameter. The values may range from 1 to 1,000. The default value is 1.

     • batch_cutoff: Maximum wait time. This is an optional parameter. The values may range from 0 to 20 seconds. The default value is 10 seconds. 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.

   For more information about the yandex_function_trigger resource parameters, see the provider documentation.

2. Create resources:

   1. In the terminal, go to the directory where you edited the configuration file.

   2. Make sure the configuration file is correct using this command:

      terraform validate
      

      If the configuration is correct, you will get this message:

      Success! The configuration is valid.
      

   3. Run this command:

      terraform plan
      

      You will see a detailed list of resources. No changes will be made at this step. If the configuration contains any errors, Terraform will show them.

   4. Apply the 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 a trigger for Yandex Message Queue, use the create REST API method for the Trigger resource or the TriggerService/Create gRPC API call.

Check that the number of enqueued messages is decreasing. To do this, view the queue statistics:

1. In the management console, select Message Queue.
2. Select the queue that you created the trigger for.
3. Go to Monitoring. Check the Messages in the queue chart.