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Yandex Cloud Functions

Creating a trigger for a message queue

Triggers is currently at the Preview stage.

Create a trigger for the message queue of Yandex Message Queue and process messages using the function Cloud Functions.

Warning

  • The trigger must be in the same cloud as the queue that messages are read from.
  • Only one trigger can be created for each message queue.

Before you start

To create a trigger, you need:

  1. Service accounts with rights to read messages from a message queue and to call a function. You can use the same service account for both operations. If you don't have a service account, create one.
  2. A message queue that the trigger will pick up messages from. If you don't have a queue, create one.
  3. Functions the trigger will send messages to for processing. If you don't have a function:

Create a trigger

Create a trigger for the message queue.

Note

The trigger is initiated within 5 minutes of being created.

If you don't have the Yandex.Cloud command line interface yet, install 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.

Create a trigger:

  • --name: Trigger name.

  • --queue: Unique queue ID.

    To find out the unique queue ID:

    1. Open Message Queue in the management console.
    2. Click in the row of the queue you would like to create a trigger for.
    3. In the Overview page, under General information, copy the unique queue ID from the ARN field.

  • --invoke-function-id: Unique function ID.

  • --queue-service-account-name: Service account with rights to read messages from the queue.

  • --invoke-function-service-account-id: Service account with rights to call the function.

  • --batch-size: Message batch size. Optional parameter. Values can be from 1 to 10. The default is 1.

$ yc serverless trigger create message-queue \
    --name test-trigger \
    --queue yrn:yc:ymq:ru-central1:aoek49ghmknnpj1ll45e:my-mq \
    --queue-service-account-id bfbqqeo6jkpls2tse5o6 \
    --invoke-function-id b09e5lu91ta21vdrrgma \
    --invoke-function-service-account-id bfbqqeo6jkpls2tse5o6 \
    --batch-size 10
id: dd0cspdch6dslu9n3i5g
folder_id: aoek49ghmknnpj1ll45e
created_at: "2019-08-28T12:14:45.762915Z"
name: test-trigger
rule:
  message_queue:
    arn: yrn:yc:ymq:ru-central1:aoek49ghmknnpj1ll45e:my-mq
    service_account_id: bfbqqeo6jkpls2tse5o6
    batch_settings:
      size: "10"
      cutoff: 10s
    invoke_function:
      function_id: b09e5lu91ta21vdrrgma
      function_tag: $latest
      service_account_id: bfbqqeo6jkpls2tse5o6

Check the results

Make sure that the trigger works correctly: in Message Queue, you see that messages are picked up from the queue, while in Cloud Functions you see that the function was started.

Check the function logs to see if the function was run:

  1. The function logs should contain information about the function call. In this example, the function outputs information about the messages processed.

    $ yc serverless function logs b09e5lu91ta21vdrrgma

2019-08-28 12:26:50     START RequestID: a5e4f3a3-9533-4eca-820c-82887258da46 Version: b09m126ee29375fq7qva
2019-08-28 12:26:51     MESSAGE_BATCH
2019-08-28 12:26:51     [
2019-08-28 12:26:51       {
2019-08-28 12:26:51         "event_metadata": {
2019-08-28 12:26:51           "event_id": "1cc52025-f485e7bd-32441eed-3bce2ebc",
2019-08-28 12:26:51           "event_type": "yandex.cloud.events.messagequeue.QueueMessage",
2019-08-28 12:26:51           "created_at": {
2019-08-28 12:26:51             "seconds": 1566995011,
2019-08-28 12:26:51             "nanos": 111000000
2019-08-28 12:26:51           },
2019-08-28 12:26:51           "cloud_id": "aoegtvhtp8ob9rqq8sto",
2019-08-28 12:26:51           "folder_id": "aoek49ghmknnpj1ll45e"
2019-08-28 12:26:51         },
2019-08-28 12:26:51         "details": {
2019-08-28 12:26:51           "queue_arn": "yrn:yc:ymq:ru-central1:aoek49ghmknnpj1ll45e:my-mq",
2019-08-28 12:26:51           "message_id": "1cc52025-f485e7bd-32441eed-3bce2ebc",
2019-08-28 12:26:51           "content_hash": "ed076287532e86365e841e92bfc50d8c",
2019-08-28 12:26:51           "body": "SGVsbG8gV29ybGQh",
2019-08-28 12:26:51           "system_attributes": {
2019-08-28 12:26:51             "ApproximateFirstReceiveTimestamp": "1566995209950",
2019-08-28 12:26:51             "ApproximateReceiveCount": "1",
2019-08-28 12:26:51             "SentTimestamp": "1566995011111"
2019-08-28 12:26:51           }
2019-08-28 12:26:51         }
2019-08-28 12:26:51       }
2019-08-28 12:26:51     ]
2019-08-28 12:26:51     END RequestID: a5e4f3a3-9533-4eca-820c-82887258da46
2019-08-28 12:26:51     REPORT RequestID: a5e4f3a3-9533-4eca-820c-82887258da46 Duration: 444.728 ms Billed Duration: 500 ms Memory Size: 128 MB Max Memory Used: 13 MB

Check the queue statistics to see if the number of enqueued messages is decreasing:

  1. Open the Message Queue section.
  2. Click in the row of the queue that the trigger was created for.
  3. Go to Statistics. Pay attention to the Messages in queue chart.
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