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

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 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 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 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:

     • 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 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, 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 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.