Gradle/Groovy - get Git build meta information

When creating a release package its nice to maintain a copy of all the metadata. I like to do this using the power of Groovy from within my Gradle build scripts.

 import groovy.xml.MarkupBuilder  
 task xmlGen << {  
      def tag = "git describe --abbrev=0 --tags".execute().text  
      def sha = "git rev-parse HEAD".execute().text  
      def fw = new FileWriter("build_info.xml" )  
      def xml = new groovy.xml.MarkupBuilder(fw)  
      xml.build(id:tag){  
           ProjectName("ORCA")  
           SHA1(sha)  
           Date(new Date())  
           Components("component1, component2, component3")  
      }  
 }  

And the output is:

 <build id="v1.3.0">  
  <ProjectName>MyProject</ProjectName>   
  <SHA1>1f661e69797dc23281d2955d6ca2dda3cdd81dc0</SHA1>   
  <Date>Thu May 02 16:14:33 BST 2013</Date>   
  <Components>component1, component2, component3</Components>   
 </build>