Intent

Prioritize requests sent to services so that requests with a higher priority are received and processed more quickly than those of a lower priority. This pattern is useful in applications that offer different service level guarantees to individual clients.

Explanation

Applications may delegate specific tasks to other services; for example, to perform background processing or to integrate with other applications or services. In the cloud, a message queue is typically used to delegate tasks to background processing. In many cases the order in which requests are received by a service is not important. However, in some cases it may be necessary to prioritize specific requests. These requests should be processed earlier than others of a lower priority that may have been sent previously by the application.

Class diagram

Applicability

Use the Property pattern when

The system must handle multiple tasks that might have different priorities.
Different users or tenants should be served with different priority..

Real world examples

Priority Queue Pattern Microsoft Azure does not provide a queuing mechanism that natively support automatic prioritization of messages through sorting. However, it does provide Azure Service Bus topics and subscriptions, which support a queuing mechanism that provides message filtering, together with a wide range of flexible capabilities that make it ideal for use in almost all priority queue implementations.