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CLI

Technologies

• click with click_shell

Responsibilities

• Allow users to Create, Remove, Update, Delete files in local and remote libraries.

Overview

Extensibility

In order to make adding mew commands easier, we aim to follow the Open-Closed principle. Thus, new functionality should be able to be added without modifying existing code. Click Command Groups, Dependency injection, and @pass_controller help us to abide by OCP.

Click Command Groups

The entry point, the dmr command, is itself a command group. Other subcommands such as add and remove can be nested under the dmr command using click's Group.add_command() to create dmr add and dmr remove. Ideally, the names of the each of the subcommands would be obtained from a file, so that source code does not have to be modified to modify the command groups. Command groups can be nested recursively.

Dependency Injection

The Dependency Inversion Principle (DIP) helps us to abide by OCP. We use the Python dependency_injector framework to enable DIP. Each controller's module should have a container and (perhaps several) providers which specify how to wire all of the controller's dependencies. Containers can reference lower level containers and providers, but they should not reference higher level containers and providers.

@pass_controller

The utils.pass_controller decorator is similar to the suggested pass_obj decorator in the click documentation. It takes in, as an argument, a controller's provider and returns a function that will invoke the provider and pass the controller into the decorated function.