Refactor Elasticsearch checks to SystemCheck

lib/system_check/app/elasticsearch_check.rb

+module SystemCheck
+  module App
+    class ElasticsearchCheck < SystemCheck::BaseCheck
+      set_name 'Elasticsearch version 5.1 - 5.3?'
+      set_skip_reason 'skipped (elasticsearch is disabled)'
+      set_check_pass -> { "yes (#{self.current_version})" }
+      set_check_fail -> { "no (#{self.current_version})" }
+
+      def self.current_version
+        @current_version ||= begin
+          client = Gitlab::Elastic::Client.build(current_application_settings.elasticsearch_config)
+          Gitlab::VersionInfo.parse(client.info['version']['number'])
+        end
+      end
+
+      def skip?
+        !current_application_settings.elasticsearch_indexing?
+      end
+
+      def check?
+        current_version.major == 5 && (1..3).cover?(version.minor)
+      end
+    end
+  end
+end

lib/tasks/gitlab/check.rake

@@ -33,11 +33,11 @@ namespace :gitlab do
         SystemCheck::App::RedisVersionCheck,
         SystemCheck::App::RubyVersionCheck,
         SystemCheck::App::GitVersionCheck,
-        SystemCheck::App::ActiveUsersCheck
+        SystemCheck::App::ActiveUsersCheck,
+        SystemCheck::App::ElasticsearchCheck
       ]
 
       SystemCheck.run('GitLab', checks)
-      check_elasticsearch if current_application_settings.elasticsearch_indexing?
     end
   end
 
@@ -661,20 +661,6 @@ namespace :gitlab do
     end
   end
 
-  def check_elasticsearch
-    client = Gitlab::Elastic::Client.build(current_application_settings.elasticsearch_config)
-
-    print "Elasticsearch version 5.1 - 5.3? ... "
-
-    version = Gitlab::VersionInfo.parse(client.info["version"]["number"])
-
-    if version.major == 5 && (1..3).cover?(version.minor)
-      puts "yes (#{version})".color(:green)
-    else
-      puts "no, you have #{version}".color(:red)
-    end
-  end
-
   def check_gitlab_geo_node(node)
     display_error = proc do |e|
       puts 'no'.color(:red)