Oracle Cloud Infrastructure Documentation

Message Management

Read about how to publish, consume, and manage messages in a queue.

Example Queue Flow

The following diagram provides an example where producer sends a message to a queue and two consumers attempt to process it.

Diagram representing the production, update, consumption, and deletion of a message.

  1. A producer sends a message to the queue with default message retention time.

    The producer receives confirmation that the Queue service received and stored the message.

  2. Consumer A tries to receive the message.

    Consumer A receives the message, which it's supposed to process within Visibility Timeout A.

  3. Consumer B tries to receive a message.

    Consumer B receives nothing, because the only available message was already consumed by Consumer A.

  4. Consumer A fails to process message within Visibility Timeout A, so it updates the message to extend the visibility timeout.
  5. Consumer B tries to receive a message again.

    Consumer B receives nothing, because the only available message was consumed and extended by Consumer A.

  6. The extended visibility timeout elapses.
  7. Consumer B tries to receive a message a third time.

    Consumer B receives the message, which it's supposed to process within Visibility Timeout B.

  8. Consumer A tries to receive the message, but receives nothing, because Consumer B consumed the message.

    Consumer A can no longer extend the message's visibility timeout or delete the message.

  9. Consumer B processes the message successfully and tries to delete the message from the queue.

    Consumer B receives confirmation that the message was permanently deleted, so it can't be delivered to any other consumer.

Note

Every time a message is delivered to a consumer, the message's Delivery Count field is incremented. When a message's delivery count reaches the configured maximum, it's sent to a dead letter queue.

Messages Endpoint

To produce to a queue or consume from a queue, you need to know the messages endpoint used by that queue. A queue's messages endpoint looks something such as this:

https://cell-1.queue.messaging.<region>.oci.oraclecloud.com

To find a queue's messages endpoint:

  1. Open the navigation menu and click Developer Services. Under Application Integration, click Queues.
  2. On the left side of the screen, click Queues.

    A list of existing queues is displayed.

  3. Click the name of a queue to display its Details page.
  4. The Queue information section contains the Messages endpoint.

You can find the messages endpoint using the API with a GetQueue request.

Required IAM Policy

See Queue Policies and Policy Examples for details on required permissions for queue management.

Next Steps