Microservice DRY or WET ?

The principles of WET (Write Everything Twice) and DRY (Don't Repeat Yourself) are often debated when it comes to designing microservices. However, in general, it is recommended that microservices should follow the DRY principle.

The DRY principle aims to reduce duplication of code and logic, which can lead to improved maintainability, scalability, and agility. By avoiding repetition, microservices can be easier to update, test, and deploy, and can also reduce the risk of errors or inconsistencies.

On the other hand, following the WET principle can lead to a lot of duplicated code and logic, which can make it harder to maintain and scale the microservices. This approach can also lead to inconsistencies in the codebase, which can cause issues during testing and deployment.

That being said, there may be situations where some duplication of code and logic is necessary in microservices. For example, if two microservices require similar functionality, it may be better to duplicate the code to avoid unnecessary dependencies between the microservices. However, in general, the DRY principle should be followed as much as possible to ensure a more maintainable and scalable microservices architecture.

Pros of using DRY in microservices:

1. Code reusability: DRY allows for the reuse of code and logic across multiple microservices, which can lead to more efficient and effective development.
2. Maintainability: DRY makes it easier to maintain and update the codebase, as changes only need to be made in one place rather than multiple places.
3. Testability: DRY makes testing easier, as code is centralized and can be tested independently of other microservices.
4. Scalability: DRY reduces the amount of code duplication, which can help to make the microservices more scalable and easier to manage.

Cons of using WET in microservices:

1. Increased complexity: WET can lead to increased complexity in the codebase, as similar code and logic may be implemented in multiple microservices. This can make it harder to maintain and update the codebase.
2. Inconsistency: WET can lead to inconsistencies in the codebase, as similar functionality may be implemented differently in different microservices. This can cause issues during testing and deployment.
3. Reduced agility: WET can make it harder to make changes to the codebase, as changes may need to be made in multiple places. This can reduce the agility of the development process and make it harder to respond to changing requirements.
4. Increased costs: WET can lead to increased development and maintenance costs, as more code and logic may need to be developed and maintained.

How to implement DRY in microservice :

1. Modularization: Break down the functionality of your microservices into smaller, reusable modules that can be used across multiple microservices. This helps to reduce duplication and promotes code reusability.
2. Shared libraries: Develop and maintain shared libraries or common modules that can be used across multiple microservices. This can help to reduce duplication and promote consistency in the codebase.
3. Service contracts: Establish clear service contracts between microservices that define the input and output parameters and the functionality of each microservice. This helps to promote consistency in the codebase and reduces the likelihood of inconsistencies and duplication.
4. Code reviews: Conduct regular code reviews to ensure that code is following DRY principles and that any duplication is justified and necessary.
5. Continuous integration and deployment (CI/CD): Use CI/CD practices to automate testing and deployment of code changes, which helps to ensure that changes are consistent and promote code reusability.
6. Use of templates and frameworks: Use templates and frameworks to reduce the amount of repetitive code that needs to be written for each microservice. This can help to reduce duplication and promote consistency in the codebase.
7. Collaboration: Encourage collaboration between development teams to ensure that best practices are being followed and that code is being developed in a consistent and reusable manner.

There may be some situations where using the WET principle may be beneficial, the DRY principle is generally preferred in microservices architecture as it leads to more efficient and effective development, testing, and maintenance, and can improve scalability and agility.

Disclaimer: The opinions and views expressed in this blog post are solely those of the author and do not necessarily reflect the views or opinions of their employer. The information contained in this blog post is based on the author's personal experiences and research, and should not be considered as professional or legal advice.