SOA Principles That Survived in Cloud-Native Architecture

The development world has changed a lot, but that does not mean that all things are not valid. Learn what principles you should be aware of.

Photo by Charles Deluvio on Unsplash

The world changes fast, and in IT, it changes even faster. We all know that, which usually means that we need to face new challenges and find new solutions. Samples of that approach are the trends we have seen in the last years: Containers, DevSecOps, Microservices, GitOps, Service Mesh…

But at the same time, we know that IT is a cycle in terms that the challenges that we face today are different evolution of challenges that have been addressed in the past. The main goal is to avoid re-inventing the wheel and avoiding making the same mistakes people before us.

So, I think it is worth it to review principles that Service-oriented Architectures (SOA) provided to us in the last decades and see which ones are relevant today.

Principles Definition

I will use the principles from Thomas Erl’s SOA Principles of Service Design and the definitions that we can found on the Wikipedia article:

1.- Service Abstraction

Design principle that is applied within the service-orientation design paradigm so that the information published in a service contract is limited to what is required to effectively utilize the service.

The main goal behind these principles is that a service consumer should not be aware of the particular component. The main advantage of that approach is that we need to change the current service provider. We can do it without impacting those consumers. This is still totally relevant today because of different reasons:

  • Service to service communication: Service Meshes and similar projects provide service registry and service discovery capabilities based on the same principles to avoid knowing the pod providing the functionality.
  • SaaS “protection-mode” enabled: Some backend systems are still here to stay even if they have more modern ways to be set up as SaaS platforms. That flexibility also provides a more easy way to move away or change the SaaS application providing the functionality. But all that flexibility is not real if you have that SaaS application totally coupled with the rest of the microservices and cloud-native application in your land space.

2.- Service Autonomy

Design principle that is applied within the service-orientation design paradigm, to provide services with improved independence from their execution environments.

We all know the importance of the service isolation that cloud-native development patterns provide based on containers’ capabilities to provide independence among execution environments.

Each service should have its own execution context isolated as much as possible from the execution context of the other services to avoid any interference between them.

So that is still relevant today but encouraged by today’s paradigms as the new normal way to do things because of the benefits shown.

3.- Service Statelessness

Design principle that is applied within the service-orientation design paradigm, in order to design scalable services by separating them from their state data whenever possible.

Stateless microservices do not maintain their own state within the services across calls. The services receive a request, handle it, and reply to the client requesting that information. If needed to store some state information, this should be done externally to the microservices using an external data store such as a relational database, a NoSQL database, or any other way to store information outside the microservice.

4.- Service Composability

Design of services that can be reused in multiple solutions that are themselves made up of composed services. The ability to recompose the service is ideally independent of the size and complexity of the service composition.

We all know that re-usability is not one of the principles behind the microservices because they argue that re-usability is against agility; when we have a shared service among many parties, we do not have an easy way to evolve it.

But this is more about leverage on existing services to create new ones that are the same approach that we follow with the API Orchestration & Choreography paradigm and the agility that provides leverage on the existing ones to create compounded services that meet the innovation targets from the business.

Summary

Cloud-native application development paradigms are a smooth evolution from the existing principles. We should leverage the ones that are still relevant and provide an updated view to them and update the needed ones.

In the end, in this industry, what we do each day is to do a new step of the long journey that is the history of the industry, and we leverage all the work that has been done in the past, and we learn from it.

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Alexandre Vazquez: