[webui] Add understandable flash message in Kiwi

We added a more understandable error message in the Kiwi Editor and also
in the file view when the importation has a failure due to an invalid
kiwi file.

src/api/app/controllers/webui/kiwi/images_controller.rb

@@ -20,7 +20,7 @@ def import_from_package
         if package.kiwi_image.blank? || package.kiwi_image.destroyed?
           package.kiwi_image = ::Kiwi::Image.build_from_xml(package.source_file(kiwi_file), package.kiwi_file_md5)
           unless package.save
-            errors = ["Kiwi File '#{kiwi_file}' has errors:", package.kiwi_image.errors.full_messages].join('<br />')
+            errors = ["Kiwi File '#{kiwi_file}' has errors:", package.kiwi_image.errors.messages.map { |_key, value| value }].join('<br/>')
             redirect_to package_view_file_path(project: package.project, package: package, filename: kiwi_file), error: errors
             return
           end
@@ -45,8 +45,8 @@ def update
           @image.write_to_backend
         end
         redirect_to action: :show
-      rescue ActiveRecord::RecordInvalid, Timeout::Error => e
-        flash.now[:error] = "Cannot update kiwi image: #{@image.errors.full_messages.to_sentence} #{e.message}"
+      rescue ActiveRecord::RecordInvalid, Timeout::Error
+        flash.now[:error] = ['Cannot update kiwi image:', @image.errors.messages.map { |_key, value| value }].join('<br/>')
         @package_groups = @image.package_groups.select(&:kiwi_type_image?).first
         render action: :show
       end

src/api/app/models/kiwi/package.rb

@@ -2,7 +2,7 @@ class Kiwi::Package < ApplicationRecord
   belongs_to :package_group
   has_one :kiwi_image, through: :package_groups
 
-  validates :name, presence: true
+  validates :name, presence: { message: 'Package name can\'t be blank'}
 
   def to_h
     hash = { name: name }

src/api/app/models/kiwi/repository.rb

@@ -18,16 +18,17 @@ class Kiwi::Repository < ApplicationRecord
   #### Scopes (first the default_scope macro if is used)
 
   #### Validations macros
-  validates :alias, :source_path, uniqueness: { scope: :image }
-  validates :source_path, presence: true
+  validates :alias, :source_path, uniqueness: { scope: :image, message: "%{attribute} '%{value}' has already been taken."}
+  validates :source_path, presence: { message: '%{attribute} can\'t be nil.'}
   validate :source_path_format
-  validates :priority, numericality: { only_integer: true, allow_nil: true, greater_than_or_equal_to: 0, less_than: 100 }
+  validates :priority, numericality: { only_integer: true, allow_nil: true, greater_than_or_equal_to: 0,
+                                       less_than: 100, message: '%{attribute} must be between 0 and 99.' }
   validates :order, numericality: { only_integer: true, greater_than_or_equal_to: 1 }
   # TODO: repo_type value depends on packagemanager element
   # https://doc.opensuse.org/projects/kiwi/doc/#sec.description.repository
-  validates :repo_type, inclusion: { in: REPO_TYPES }
-  validates :replaceable, inclusion: { in: [true, false] }
-  validates :imageinclude, :prefer_license, inclusion: { in: [true, false] }, allow_nil: true
+  validates :repo_type, inclusion: { in: REPO_TYPES, message: "%{attribute} '%{value}' is not included in the list." }
+  validates :replaceable, inclusion: { in: [true, false], message: "%{attribute} has to be 'true' or 'false'" }
+  validates :imageinclude, :prefer_license, inclusion: { in: [true, false], message: "%{attribute} has to be 'true' or 'false'" }, allow_nil: true
   validates_associated :image, on: :update
 
   #### Class methods using self. (public and then private)
@@ -47,10 +48,10 @@ def source_path_format
     return if source_path =~ /\A#{URI.regexp(['ftp', 'http', 'https', 'plain'])}\z/
     if source_path_for_obs_repository?
       return if repo_type == 'rpm-md'
-      errors.add(:repo_type, "should be 'rpm-md' for obs:// repositories")
+      errors.add(:repo_type, "Repo type for '#{source_path}' should be 'rpm-md' for obs:// repositories.")
     end
     return if source_path_for_opensuse_repository?
-    errors.add(:source_path, "has an invalid format")
+    errors.add(:source_path, "Source path '#{source_path}' has an invalid format.")
   end
 
   def to_xml