Microservices architecture is a common approach to building complex software applications, wherein the full system is broken down into a set of small, independent, and loosely coupled services that work together like a team in order to deliver business value. Each service focuses on performing a specific business task, and communicates with other services through lightweight APIs or messaging systems.
Building scalable and reliable systems with a microservices architecture is a smart approach, but it’s not without challenges. One challenge is managing the large number of APIs that accumulate as the system grows. Each service exposes its own API, which often needs to be consumed by other services. This might lead to a number of problems, including duplication of code, inconsistencies between schemas, poor API documentation, and other miscommunications.
As a way to mitigate these effects is by taking an API-driven approach and using automation tools.
What Is an API-driven Approach?
The API-driven strategy emphasizes the use of APIs as the primary channel of communication between microservices by thinking, defining, and standardizing the API definition first. In this approach, the whole system could be designed without thinking about the implementation, simply by adding an abstract layer. Automation tools help reduce the potential for user error to enter such a critical and complex layer.
Benefits of an API-driven Approach
The API-driven approach offers many benefits, which create a more reliable system,and a more predictable development experience.
1. Reduces Duplication
Each API needs to be consumed by other services. Using automation tools and generated code reduces the duplication, and makes sure that every service that is consuming the API is using exactly the same implementation, HTTP library, and error handlings as others. By taking this approach, not only is the API implementation standardized, it also ensures that the client usages are the same. You decide on a library that works best for your design and use it across the entire system.
2. Simplifies Validation
Large organizations often institute strict naming conventions and rules for their services. Taking this approach makes validation easier within pipelines. You can read more about API naming convention from Google.
Also, you can enjoy some basic validation for the user inputs for free. For example, in your specification, you define a parameter as required and the user is forced to provide a value.
3. Creates Built-in Documentation
Consuming an API requires some amount of knowledge about the API’s path, parameters, request body and response, authentication, and more. This information is traditionally stored in API documentation, but keeping documentation updated over a long time poses a challenge, and might be forgotten during the development process.
With an API-driven approach, teams are forced to think and design the API's information before implementing it. Whenever you update something in the specification, the changes are automatically applied to your documentation, meaning you can’t miss a newly added parameter or a change in the status codes.
4. Avoids Inconsistency
In most cases, models are used when implementing the API request or response body. When consuming APIs, each service creates its own version of the API models, which might result in inconsistencies between server output and the client version.
Imagine that, when services get updated, they introduce or update new fields. All services need to update their own models to use the updated version. This process is complicated.
Using an API-driven approach, clients of your API don’t need to create their own version of models. They simply use the generated version, which mirrors the server’s version. If an API changes or updates to a new version, you simply need to update the library that exposes the new API and use the new method generated for you with the latest model.
5. Implements Automated Tests
Automatically generating tests from specification comes with several benefits that enhances efficiency, accuracy, and maintainability of the API development process. It saves time, makes sure that the contract specified in the design is tested accurately, and improves test coverage. Automated testing tools provide confidence that APIs and models are working as expected.
In conclusion, API-driven development is essential in microservices architecture, especially for efficiency and consistency. It simplifies the complexities of service integrations and reduces code redundancy. Through automated testing and built-in documentation, it ensures that each microservice is reliable and well-documented, promoting a strong and flexible micro-services system. In another article, I explained how to follow the API-Driven approach.