WIP SystemCheck library for executing checks from a rake task

lib/system_check.rb

+module SystemCheck
+  def self.run(component, checks = {}, executor_klass = SimpleExecutor)
+    unless executor_klass.is_a? BaseExecutor
+      raise ArgumentError, 'Invalid executor'
+    end
+
+    executor = executor_klass.new(component)
+    executor.checks = checks.map do |check|
+      raise ArgumentError unless check.is_a? BaseCheck
+    end
+  end
+end

lib/system_check/base_check.rb

+module SystemCheck
+  class BaseCheck
+    def check?
+      raise NotImplementedError
+    end
+
+    def show_error
+      raise NotImplementedError
+    end
+
+    def skip?
+      false
+    end
+
+    def skip_message
+    end
+
+    protected
+
+    def try_fixing_it(*steps)
+      steps = steps.shift if steps.first.is_a?(Array)
+
+      puts '  Try fixing it:'.color(:blue)
+      steps.each do |step|
+        puts "  #{step}"
+      end
+    end
+
+    def fix_and_rerun
+      puts '  Please fix the error above and rerun the checks.'.color(:red)
+    end
+
+    def for_more_information(*sources)
+      sources = sources.shift if sources.first.is_a?(Array)
+
+      puts '  For more information see:'.color(:blue)
+      sources.each do |source|
+        puts '  #{source}'
+      end
+    end
+  end
+end

lib/system_check/base_executor.rb

+module SystemCheck
+  class BaseExecutor
+    attr_reader :checks
+    attr_reader :component
+
+    def initialize(component)
+      raise ArgumentError unless component.is_a? String
+
+      @component = component
+      @checks = Set.new
+    end
+
+    def <<(check)
+      raise ArgumentError unless check.is_a? BaseCheck
+      @checks << check
+    end
+  end
+end

lib/system_check/simple_executor.rb

+module SystemCheck
+  class SimpleExecutor < BaseExecutor
+    def execute
+      start_checking(component)
+
+      @checks.each do |check|
+        print "#{check.name}"
+        if check.skip?
+          puts "skipped #{'('+skip_message+')' if skip_message}".color(:magenta)
+        elsif check.check?
+          puts 'yes'.color(:green)
+        else
+          puts 'no'.color(:red)
+          check.show_error
+        end
+      end
+
+      finished_checking(component)
+    end
+
+    private
+
+    def start_checking(component)
+      puts "Checking #{component.color(:yellow)} ..."
+      puts ''
+    end
+
+    def finished_checking(component)
+      puts ''
+      puts "Checking #{component.color(:yellow)} ... #{"Finished".color(:green)}"
+      puts ''
+    end
+  end
+end

lib/tasks/gitlab/check.rake

@@ -848,10 +848,12 @@ namespace :gitlab do
   # Helper methods
   ##########################
 
+  # @deprecated Please use SystemChecks
   def fix_and_rerun
     puts "  Please fix the error above and rerun the checks.".color(:red)
   end
 
+  # @deprecated Please use SystemChecks
   def for_more_information(*sources)
     sources = sources.shift if sources.first.is_a?(Array)
 
@@ -861,6 +863,7 @@ namespace :gitlab do
     end
   end
 
+  # @deprecated Please use SystemChecks
   def finished_checking(component)
     puts ""
     puts "Checking #{component.color(:yellow)} ... #{"Finished".color(:green)}"
@@ -883,11 +886,13 @@ namespace :gitlab do
     Gitlab.config.gitlab.user
   end
 
+  # @deprecated Please use SystemChecks
   def start_checking(component)
     puts "Checking #{component.color(:yellow)} ..."
     puts ""
   end
 
+  # @deprecated Please use SystemChecks
   def try_fixing_it(*steps)
     steps = steps.shift if steps.first.is_a?(Array)