Extract Kamal::Git as gateway for all git usage

lib/kamal/cli/build.rb

@@ -19,7 +19,7 @@ class Kamal::Cli::Build < Kamal::Cli::Base
       verify_local_dependencies
       run_hook "pre-build"
 
-      if (uncommitted_changes = Kamal::Utils.uncommitted_changes).present?
+      if (uncommitted_changes = Kamal::Git.uncommitted_changes).present?
         say "The following paths have uncommitted changes:\n #{uncommitted_changes}", :yellow
       end
 

lib/kamal/commands/lock.rb

@@ -56,7 +56,7 @@ class Kamal::Commands::Lock < Kamal::Commands::Base
     end
 
     def locked_by
-      `git config user.name`.strip
+      Kamal::Git.user_name
     rescue Errno::ENOENT
       "Unknown"
     end

lib/kamal/configuration.rb

@@ -278,10 +278,8 @@ class Kamal::Configuration
 
     def git_version
       @git_version ||=
-        if system("git rev-parse")
-          uncommitted_suffix = Kamal::Utils.uncommitted_changes.present? ? "_uncommitted_#{SecureRandom.hex(8)}" : ""
-
-          "#{`git rev-parse HEAD`.strip}#{uncommitted_suffix}"
+        if Kamal::Git.used?
+          [ Kamal::Git.revision, Kamal::Git.uncommitted_changes.present? ? "_uncommitted_#{SecureRandom.hex(8)}" : "" ].join
         else
           raise "Can't use commit hash as version, no git repository found in #{Dir.pwd}"
         end

lib/kamal/git.rb

@@ -0,0 +1,19 @@
+module Kamal::Git
+  extend self
+
+  def used?
+    system("git rev-parse")
+  end
+
+  def user_name
+    `git config user.name`.strip
+  end
+
+  def revision
+    `git rev-parse HEAD`.strip
+  end
+
+  def uncommitted_changes
+    `git status --porcelain`.strip
+  end
+end

lib/kamal/utils.rb

@@ -86,10 +86,6 @@ module Kamal::Utils
     value.to_s.dump[1..-2].gsub(/\\"/, "\"")
   end
 
-  def uncommitted_changes
-    `git status --porcelain`.strip
-  end
-
   def docker_env_file_line(key, value)
     "#{key.to_s}=#{escape_docker_env_file_value(value)}\n"
   end