Question

I have a GWT project which has its source managed in SVN, is packaged using Maven and has its builds managed via Hudson. I want to get the SVN revision number of the latest check-in/build to be visible in a comment at the bottom of the application root HTML file. I don’t care where in the development process this happens!

Here are the options I’ve Googled for so far, with no success:

• Can I get Hudson to, after building, write the build/revision number
  to one of its build output files (namely the application root HTML
  file)? I’ve seen no way to do this.
• Can I get Maven to write the SVN revision number to one of its build
  output files (namely the application root HTML file)? I’ve seen ways
  of Maven writing this to a JAR/WAR manifest file (which can then be
  accessed in the Java code), but I’m not sure that this works in GWT
  (I’m not particularly knowledgeable about the internals of GWT).
• Can I get SubVersion to, as a pre-commit hook, write the version number to a particular file? I know it’s easy to write the version number to the file you’re editing, but not so sure about writing to a totally separate file (so that it’s updated on every commit, regardless of whether it was changed in that commit).

Does anyone have a complete, end-to-end example of how to get any of these working? I keep finding little snippets of code/config which do one part of the job, but not anything that is exactly what I’m looking for.

Thanks!

Answer 1

You can achieve what you’re looking for with a combination of Maven and Hudson. In this example let’s imagine you want the file version.txt at the root of your web app to contain the revision.

version.txt:

${SVN_REVISION}

In your project’s pom.xml enable filtering in the maven-war-plugin:

<plugin>
  <artifactId>maven-war-plugin</artifactId>
  <version>2.1</version>
  <configuration>
    <webResources>
      <webResource>
        <directory>src/main/webapp</directory>
        <filtering>true</filtering>
        <includes>
          <include>version.txt</include>
        </includes>
      </webResource>
    </webResources>
  </configuration>
</plugin>

Make sure that Hudson is building your project via. Subversion checkout and it will set the SVN_REVISION environment variable for every build and Maven will fill it in.