Expose Custom Button visability/enablement

[imtayadeway]

Resolves https://www.pivotaltracker.com/story/show/149699953

Does a couple of things:

1. When asking for a Service's custom_actions or custom_action_buttons, will only return things whose visibility_expression evaluates to true for the object at hand
2. When asking for a Service's custom_actions, serializes the result of the enablement_expression evaluated in the context of the object at hand, along with the rest of the button's attributes

From what I understand, buttons have an attribute disabled_text which I am assuming is there to explain the reason for its being disabled - if correct then this is already serialized and returned in the response, so nothing further needs to be done here.

/cc @AllenBW
@miq-bot add-label enhancement
@miq-bot assign @gtanzillo

[miq-bot]

Checked commits imtayadeway/manageiq@e40f7d4~...906d915 with ruby 2.2.6, rubocop 0.47.1, and haml-lint 0.20.0
2 files checked, 0 offenses detected
Everything looks fine. 🍪

[AllenBW]

ALL HAIL 💃 🕺

[lpichler]

From what I understand, buttons have an attribute disabled_text which I am assuming is there to explain the reason for its being disabled.

yes you are right 👍

[imtayadeway]

@lpichler it was my understanding that https://github.com/ManageIQ/manageiq/blob/master/app/models/custom_button_set.rb#L29-L62 was made in support of this PR, but as you can see it's not being utilized here, and AFAICT anywhere else yet. Did I miss something?

[lpichler]

@imtayadeway

was made in support of this PR, ...

yes, probably you can use it (if it would be helpful) but now, it used only in controller repo
https://github.com/ManageIQ/manageiq-ui-classic/blob/master/app/helpers/application_helper/toolbar_builder.rb#L343

[imtayadeway]

@lpichler thanks! 🙇

[gtanzillo]

Looks really good 👍