Introducing pluggable menus

[skateman]

These changes will allow us to declare menu items in external plugins. I implemented a new Menu::CustomLoader singleton, in which you can .register your menu items. For now this can be done from an initializer block declared in a Rails Engine.

The .register method can take a Menu::Section or a Menu::Item as an argument with the same syntax as we're using in the Menu::DefaultMenu.

For example this will create a new Test section with a Test item pointing to the /test URL:

# inside a rails engine definition
initializer 'ui.plugin' do
  Menu::CustomLoader.register(
    Menu::Section.new(:spike, N_('Test'), 'fa fa-map-pin', [
      Menu::Item.new('plug', N_('Test'), 'some_feature', {:feature => 'some_feature', :any => true}, '/test')
    ])
)
end

In the future I'd like to take out the menu declarations into a better place, e.g. app/menus and have some kind of auto-registering feature inside the engine. The syntax of the menu declaration should be also DSL-ized and used in the Menu::DefaultMenu too.

@martinpovolny what do you think?

[miq-bot]

Checked commits skateman/manageiq-ui-classic@52e71a5~...c020733 with ruby 2.2.6, rubocop 0.47.1, and haml-lint 0.20.0
5 files checked, 9 offenses detected

app/presenters/menu/yaml_loader.rb

• ❗ - Line 12, Col 16 - Rails/FilePath - Please use Rails.root.join('path', 'to') instead.
• ❗ - Line 12, Col 7 - Rails/FilePath - Please use Rails.root.join('path', 'to') instead.
• ❗ - Line 21, Col 25 - Security/YAMLLoad - Prefer using YAML.safe_load over YAML.load.
• ❗ - Line 33, Col 9 - Style/MultilineIfModifier - Favor a normal if-statement over a modifier clause in a multiline statement.
• ❗ - Line 37, Col 29 - Style/AlignParameters - Align the parameters of a method call if they span more than one line.
• ❗ - Line 38, Col 29 - Style/AlignParameters - Align the parameters of a method call if they span more than one line.
• ❗ - Line 39, Col 29 - Style/AlignParameters - Align the parameters of a method call if they span more than one line.
• ❗ - Line 40, Col 29 - Style/AlignParameters - Align the parameters of a method call if they span more than one line.
• ❗ - Line 41, Col 29 - Style/AlignParameters - Align the parameters of a method call if they span more than one line.

[martinpovolny]

Cool. Pretty minimal changes to reach the goal. 👍

[martinpovolny]

I think that there's no need to spend time on the "future steps" at this point. Rather we can attack the other items on the minimal requirements list for a pluggable UI.

[skateman]

Sure, I wasn't thinking about doing anything more in this PR. However, I'll create a separate one where we have our extended Rails Engine with some plugin definition DSL where we can register menus and other stuff.

Marking it as a non-wip...

[martinpovolny]

Have you tested the old custom menu loading (Insights)?

[skateman]

@martinpovolny I copied some productization ymls to my development setup, it's showing up in the Menu::Manager.instance but not in the menu, not even on master so I'm probably missing something. Going to try on an appliance...

[skateman]

@martinpovolny tested, it works