Harbor

Providers

The concept of a provider is fundamental to the design of Harbor. The term provider has become synonymous with the strategy pattern popularized by the Gang of Four in their seminal book Design Patterns: Elements of Reusable Object-Oriented Software. The basic idea behind a provider is that you can define an abstract interface, or trait in Rust terminology, and types that implement that trait can vary in terms of the algorithm they apply internally when called. This is very useful in scenarios where you have a finite set of operations that you want to perform, but you want to be able to swap out the concrete implementation based on some context.

The TaskProvider trait is an example of a provider that you can use. With this trait, Harbor can be extended with new tasks that fit within the model, and can be swapped based on parameters or configuration. See the cli crate for more concrete examples.