Service Lifecycles: Singleton, Scoped, Transient

In the software development process, the goal is to reduce dependencies and create more flexible and testable software by utilizing Dependency Injection. During the application of this design pattern, the creation of services and their lifecycles play a significant role. In this article, we will explore three distinct lifecycles: Singleton, Scoped, and Transient.

** Singleton Lifecycles for Services**

Singleton services are created once throughout the application's lifecycle and share the same instance across all incoming requests. When the application is stopped and restarted, the initial instance that was produced continues to be returned.

Singleton services are typically employed in scenarios where shared state is used or for objects with a costly construction process.

Scoped Lifecycles for Services

Scoped services generate a new instance for each request, and requests within the same request pipeline utilize the same instance. For instance, throughout a request's lifecycle, this service type can be employed to access the relevant user session data. This allows for the provision of services that store user-specific data such as state or authentication information.

Scoped services are useful in situations where state specific to each user or request needs to be maintained.

Transient Lifecycles for Services

A new instance is created for each individual request. For example, Transient services can be used for stateless operations like a calculation function or a temporary data storage service.

When comparing service lifecycles with an example:

• Singleton services are like a shared tool in a household that everyone uses and remembers its state across different tasks.

• Scoped services are akin to a personal workspace in an office where each person has their materials, ensuring privacy and personalization.

• Transient services are comparable to disposable utensils in a cafeteria, with a new set given for every meal, ensuring hygiene and independence.

Remember, choosing the appropriate service lifecycle is crucial in achieving the desired application behavior and resource management.