rake task not found when create rails plugin

Question

I'm trying to create a gem plugin with a rake task. I just commented out pre-generated file in tasks folder but when I run rake my_plugin, error came out that

Don't know how to build task...

here is tasks/my_plugin.rake file

desc "Explaining what the task does"
task :my_plugin do
  # Task goes here
end

Answer 1

You run rake myplugin, but define task :my_plugin. You miss the underscore.

Answer 2

You need to load the custom tasks in your plugin's Railtie:

module MyPlugin
  class Railtie < ::Rails::Railtie
    rake_tasks do
      load 'tasks/my_plugin.rake'
    end
  end
end

https://api.rubyonrails.org/classes/Rails/Railtie.html