The architectural styles for implementing a cloud service.

 

Introduction:

A web service for the cloud must be well suited for the business purpose its serves not only in its functionality but also in the non-functional aspects which are recorded in the Service-Level Agreements. The choice of architecture for a web service has a significant contribution to this effect. We review the choices between Web-Queue architectural style and the N-Service architectural style.

The web-queue can absorb the latencies from the events and user actions are translated to events. It decouples the frontend and the API layer so that they become more responsive to the users. All the actions taken by the user can be mapped to one or other form of messages that are sent to the message queue which is usually the service bus. The Web Queue can handle plenty of messages and can even scale out to catch up with the items in the queue. Each message is handled by a different handler and there is one-to-one mapping which makes it easy to view.

Some of the benefits of this architecture include the following: 1) It is relatively simple architecture that is easy to understand.2) It is Easy to deploy and manage. 3) There is a clear separation of concerns. 4) The front end is decoupled from the worker using asynchronous messaging and 5) the front end and the worker can be scaled independently.

Some of the challenges faced with this architecture include the following: The front end and the worker can both become arbitrarily large, monolithic components which increase the maintenance costs. It may also hide dependencies, if the front end and worker share data schemas or code modules.

Some of the best practices demonstrated by this code include It exposes a well-designed API to the client. It can auto scale to handle changes in the load. It caches semi-static data. It uses a CDN to host static content. It uses a polyglot persistence when appropriate. It partitions data to improve scalability, it reduces contention, and optimizes performance.

Some of the examples with this architectural style include applications with a relatively simple domain, those with some long-running workflows or batch operations or when there are managed services rather than infrastructure as a service (IaaS).