Promote Gitlab::Shell#version to a class method

This brings it more inline with, e.g., Gitlab::Workhorse

app/views/admin/dashboard/index.html.haml

@@ -99,7 +99,7 @@
           %p
             GitLab Shell
             %span.float-right
-              = Gitlab::Shell.new.version
+              = Gitlab::Shell.version
           %p
             GitLab Workhorse
             %span.float-right

config/initializers/5_backend.rb

 unless Rails.env.test?
   required_version = Gitlab::VersionInfo.parse(Gitlab::Shell.version_required)
-  current_version = Gitlab::VersionInfo.parse(Gitlab::Shell.new.version)
+  current_version = Gitlab::VersionInfo.parse(Gitlab::Shell.version)
 
   unless current_version.valid? && required_version <= current_version
     warn "WARNING: This version of GitLab depends on gitlab-shell #{required_version}, but you're running #{current_version}. Please update gitlab-shell."

lib/gitlab/shell.rb

@@ -34,6 +34,13 @@ module Gitlab
                                         .join('GITLAB_SHELL_VERSION')).strip
       end
 
+      # Return GitLab shell version
+      #
+      # @return [String] version
+      def version
+        @version ||= File.read(gitlab_shell_version_file).chomp if File.readable?(gitlab_shell_version_file)
+      end
+
       # Return a SSH url for a given project path
       #
       # @param [String] full_path project path (URL)
@@ -44,6 +51,14 @@ module Gitlab
 
       private
 
+      def gitlab_shell_path
+        File.expand_path(Gitlab.config.gitlab_shell.path)
+      end
+
+      def gitlab_shell_version_file
+        File.join(gitlab_shell_path, 'VERSION')
+      end
+
       # Create (if necessary) and link the secret token file
       def generate_and_link_secret_token
         secret_file = Gitlab.config.gitlab_shell.secret_file
@@ -244,17 +259,6 @@ module Gitlab
       false
     end
 
-    # Return GitLab shell version
-    #
-    # @return [String] version
-    def version
-      gitlab_shell_version_file = "#{gitlab_shell_path}/VERSION"
-
-      if File.readable?(gitlab_shell_version_file)
-        File.read(gitlab_shell_version_file).chomp
-      end
-    end
-
     # Check if repository exists on disk
     #
     # @example Check if repository exists
@@ -271,10 +275,6 @@ module Gitlab
 
     protected
 
-    def gitlab_shell_path
-      File.expand_path(Gitlab.config.gitlab_shell.path)
-    end
-
     def full_path(storage, dir_name)
       raise ArgumentError.new("Directory name can't be blank") if dir_name.blank?
 

lib/system_check/gitlab_shell_check.rb

@@ -50,7 +50,7 @@ module SystemCheck
     end
 
     def gitlab_shell_version
-      Gitlab::Shell.new.version
+      Gitlab::Shell.version
     end
   end
 end

lib/tasks/gitlab/info.rake

@@ -82,15 +82,10 @@ namespace :gitlab do
       puts "Using Omniauth:\t#{Gitlab::Auth.omniauth_enabled? ? "yes".color(:green) : "no"}"
       puts "Omniauth Providers: #{omniauth_providers.join(', ')}" if Gitlab::Auth.omniauth_enabled?
 
-      # check Gitolite version
-      gitlab_shell_version_file = "#{Gitlab.config.gitlab_shell.path}/VERSION"
-      if File.readable?(gitlab_shell_version_file)
-        gitlab_shell_version = File.read(gitlab_shell_version_file)
-      end
-
+      # check Gitlab Shell version
       puts ""
       puts "GitLab Shell".color(:yellow)
-      puts "Version:\t#{gitlab_shell_version || "unknown".color(:red)}"
+      puts "Version:\t#{Gitlab::Shell.version || "unknown".color(:red)}"
       puts "Repository storage paths:"
       Gitlab::GitalyClient::StorageSettings.allow_disk_access do
         Gitlab.config.repositories.storages.each do |name, repository_storage|