Dead Letter Queue

A Dead Letter Queue (DLQ) is a queue that messages which could not be processed by a triggered function in Cloud Functions or container in Serverless Containers are redirected to. A message is considered processed if its recipient function or container ran to completion without errors. Messages moved to the DLQ are stored there for further analysis.

If a function or a container failed to process a message over a specified number of attempts, it is redirected to the DLQ. The number of attempted function or container calls and the queue to serve as the DLQ are defined in a redirect policy.

If no redirect policy is configured, messages that a function or a container failed to process are deleted.

Redrive policy

The redrive policy defines the conditions for moving messages to the DLQ.

To configure the redrive policy for all triggers except a trigger for Yandex Message Queue, specify the following when creating a trigger:

• The queue to move messages to.
• A service account with rights to write messages to the queue.
• A timeout for a repeat function or container call if the current call fails.
• The number of invocation retries before the trigger moves a message to the queue.

The redrive policy for a Yandex Message Queue trigger is configured when creating a queue whose messages are processed by a triggered function or container.

The message keeps its ID after moving to the DLQ.