How to lookup the latest git commit hash from an ant build script
How can I lookup the latest git commit hash from an ant build script?
I am currently working on a new open source project which I store on github. I would like to extend my existing ANT build file to allow me to create numbered builds. I am imagining that I would launch the build with something like "ant buildnum -Dnum=12".
I would like the resulting jar to have two crucial bits of information in it's manifest file:
- build.number=12
- build.gitcommit=
I know how to create the build.number line. However, I am unsure of the best ant plumbing to lookup the latest git commit hash which is the value I want to fill in for .
Answer
I wrote the following ant target for a project on github. Usage:
- stores version in property "repository.version"
- works if no git is installed or no .git directory is present (fallback)
- other targets must depend on this target if they need the git version
- only one git command gets executed (--always)
<available file=".git" type="dir" property="git.present"/>
<target name="git.revision" description="Store git revision in ${repository.version}" if="git.present">
<exec executable="git" outputproperty="git.revision" failifexecutionfails="false" errorproperty="">
<arg value="describe"/>
<arg value="--tags"/>
<arg value="--always"/>
<arg value="HEAD"/>
</exec>
<condition property="repository.version" value="${git.revision}" else="unknown">
<and>
<isset property="git.revision"/>
<length string="${git.revision}" trim="yes" length="0" when="greater"/>
</and>
</condition>
</target>
It e.g. be used for expanding the token @repository.version@ in a template file:
<target name="index.html" depends="git.revision" description="build index.html from template">
<copy file="index.html.template" tofile="index.html" overwrite="yes">
<filterchain>
<replacetokens>
<token key="repository.version" value="${repository.version}" />
</replacetokens>
</filterchain>
</copy>
</target>