[CI/CD] Creating a fastlane Plugin

Overview

This post covers how to create and distribute a custom fastlane Plugin.

Steps

1. Plugin Example

• fastlane-plugin-validate_ipa

2. Generating a Plugin Template

fastlane new_plugin

• Plugin naming should follow formats like testflight or upload_to_s3.

Would 'hacoma_' be okay to use for your plugin name?

• If the name contains the word plugin, it will be stripped as shown above, so be careful.
• Example: If you enter hacoma_plugin as the name, it will be changed to hacoma_.

Please enter a short summary of this fastlane plugin:

• Write a brief description of the Plugin.
• The entered string is used in the following places:
  • spec.summary in the fastlane-plugin-[plugin_name].gemspec file
  • About [plugin_name] in the README.md file
  • self.description in the plugin_name_action.rb file

Please enter a detailed description of this fastlane plugin:

• Write a more detailed description of the Plugin.
• The entered string is used in the following place:
  • self.details in the plugin_name_action.rb file

3. Plugin Folder Structure

3.1. fastlane/Fastfile

• Provides test lanes to demonstrate the features and usage of the Actions included in the Plugin.

3.2. fastlane-plugin-[plugin_name].gemspec

• fastlane Plugins are distributed and versioned through gems, and all gem-related information is written in the .gemspec file.
• Since the Plugin was created using a template, most of the information is already filled in. Uncomment spec.homepage and enter the GitHub repository URL for the Plugin.

3.3. lib/fastlane/plugin/plugin_name/actions/plugin_name_action.rb

• Implement the Actions supported by the Plugin in this file.
• For how to implement Actions, refer to the [CI/CD] Creating a fastlane Action post.
• If you want the Plugin to support multiple Actions, add additional files in the same directory.
  • Example: action1.rb, action2.rb, action3.rb, …

3.4. lib/fastlane/plugin/plugin_name/helper/plugin_name_helper.rb

• Implement utility functions used by Actions in this file. Methods implemented in the helper can be called from Actions.
• If supporting multiple Actions, create separate helper files named after each Action.

3.5. lib/fastlane/plugin/plugin_name/version.rb

• Defines the Plugin version. The following line in the .gemspec file references the version information written in the version.rb file.
• spec.version = Fastlane::HacomaWrapper::VERSION

3.6. README.md

• Write detailed sample code in the Example section for Plugin users.
• Add or modify any additional content as needed.

3.7. spec/plugin_name_action_spec.rb

• Write test code based on the BDD methodology.
• If supporting multiple Actions, create separate test files named after each Action.

4. Using the Plugin

• For how to use Plugins, refer to the [CI/CD] Using fastlane Plugins post.

5. Distributing the Plugin

5.1. RubyGems

1. Create an account on RubyGems.org.
2. Push the Plugin to a GitHub repository.
3. Update the .gemspec file. spec.homepage should be the URL of the GitHub repository where the Plugin was pushed.
4. Run the following commands to distribute:

    bundle install
    rake install
    rake release
   

• If you encounter the following error while running the commands, update the system gem:

  ERROR:  While executing gem ... (NameError)
      uninitialized constant Gem::ConfigFile::FileUtils
  Did you mean?  FileTest
  

  gem update --system
  

5.2. GitHub

• If you don’t want to distribute via RubyGems, you can distribute the Plugin through GitHub instead.

• However, use tags or another appropriate method for version management.

  gem "fastlane-plugin-[plugin_name]", git: "https://github.com/[user]/[plugin_name]"
  gem "fastlane-plugin-[plugin_name]", git: "https://github.com/[user]/[plugin_name]", tag: 1.0.0
  

References

• https://docs.fastlane.tools/plugins/create-plugin/
• https://bundler.io/guides/git.html
• https://rubygems.org/