Leading organizations realize the benefits of transitioning current programmes to a microservices architecture and using it for new developments. However, application designers, architects, and developers face intrinsic hurdles in terms of scalability, performance, and deployment.
Unless you’ve been creating applications in a cave, you’ve probably heard about microservices. They are agile, straightforward, and an improvement over monolithic and service-oriented architecture. However, with all of the advantages of microservices comes a new set of challenges.
Benefits of a Microservices Architecture
When migrating from a monolithic application to a microservices architecture correctly, the following advantages should be realised:
- You should be able to create a microservice in your preferred language, distribute it independently, and scale it independently.
- Because multiple teams within an organisation might independently own certain microservices, time to market should be reduced due to parallel development and increased reuse.
- You obtain enhanced fault isolation since faults in one microservice can be contained so that the rest of the ecosystem is not harmed.
Top 6 Microservices Design Principles and Best Practices
1. Single concern microservice
Having a single concern means that a microservice should only do one thing. For example, if the microservice is meant to support authentication, it should solely perform authentication. This means that its interface should only provide authentication-relevant access points. And the microservice should only have authentication behaviour internally. There should be no side behaviour in the authentication response, for example, such as supplying employee contact information.
Having a single point of contact simplifies the microservice’s maintenance and scaling. This is related to the following principle.
2. Ensure high cohesion and low coupling
When characterising a microservices architecture, the terms cohesion and coupling are frequently used interchangeably. Intradependence refers to how closely knit the modules of an application are, while interdependence points to the extent of connection between them.
Microservices should be designed with strong cohesion and low coupling. This strategy generates microservices that are changeable, scalable, and extensible over time. Because the modules collaborate, the stronger the cohesiveness, the better. When cohesiveness is low, the application sends too many communications back and forth between the services, resulting in poor performance and scalability.
When two components are loosely connected, they are not interdependent, i.e., they can function independently of one another and any change in one component does not disrupt the functionality of the other. Because the component is isolatable, loosely linked components in an application should be simple to test.
3. Compatibility
Maintain backward compatibility as much as feasible so that your customers do not face broken APIs. The most common method is to adhere to path level compatibility guarantees such as /api/v1 or /api/v2. Any updates that are incompatible with previous versions are routed to a new URL, such as /api/v3.
However, despite our best efforts as software developers, we must sometimes deprecate APIs so that we are not forced to use them indefinitely. Your microservices can warn your API customers by easily injecting deprecation notices with the original API response or attaching a “deprecation header” similar to Kubernetes.
4. API-Driven Design
This is my favourite Microservice design principle, and it comes in handy when creating Microservices. Microservices, according to this approach, should be developed around APIs, with each service exposing a well-defined set of APIs for communication with other services.
A Microservice, for example, may expose an API for retrieving customer information, which other microservices could use to access that information.
This guideline also supports the prior design idea that Microservices should not share databases. You must develop APIs for other services that require data access, which will then drive your own Microservice design.
5.Fail fast by using a circuit breaker to achieve fault tolerance
When your microservice is depending on a response from an external system, and that response takes longer than expected, it can greatly impact the specified Service Level Agreement (SLA). This delay can have a negative effect on the total response times of your organization. One easy microservices best practice you can employ to avoid this problem and reply promptly is to use a circuit breaker to time out the external request and provide a default response or an error. The references below explain the Circuit Breaker pattern.
This will isolate the failing services on which your service depends without generating cascade failures, hence keeping your microservice healthy. You can leverage popular products made by Netflix, such as Hystrix. This is preferable to utilising the HTTP CONNECT_TIMEOUT and READ_TIMEOUT parameters since it does not create additional threads beyond what is specified.
6. Statelessness
According to this principle, microservices should be stateless, which means they should not keep any client-specific state between requests.
Microservices should not store persistent user data, such as shopping cart info, but instead receive it from a database on each request. This is a good practice for better performance and easier maintenance.
Conclusion
Microservices architecture is an increasingly popular approach to developing software applications. It enables teams to develop, deploy, and maintain applications more quickly and efficiently. In this article, we have explored the principles and best practices of microservices architecture that are essential for successful implementation of this approach. We have discussed how to design services, create a service registry, use containers for deployment, and ensure security and scalability.
