Create Your First Swift Package Command Plugin

How to write and debug a Swift Package Command plugin

Photo by Jess Bailey on Unsplash

This year, Apple released a new feature for the Swift Package Manager: Swift Package Plugins. We can now write two kinds of plugins that are automatically integrated with Xcode:

• Build (and pre-build) Plugins.
• Command Plugins.

I already talked about building plugins in a couple of articles: “Implement Your First Swift Package Build Plugin” and “How to Use Xcode Plugins in Your iOS App”.

Today, I want to share with you which steps are required to create a Command Plugin. The developer experience for these plugins is not great, so I want to share also a technique to debug them.

You can find more information about Swift Package Plugins in these WWDC22 videos: Meet Swift Package Plugins, Create Swift Package Plugins

The plugin

In this article, you are going to create a Command Plugin that generates some Swift code from a JSON specification.

To create a Command plugin, you need various pieces:

• A Package.swift file to define the structure of the Plugin.
• A proper folder structure.
• A Swift struct that…