The taskdef (step 3) is not required if the ivy jar is located in a standard ANT library directory.
I would recommend including a special "bootstrap" target that will install the ivy jar. Once this is done all other dependencies (including 3rd party ANT tasks) can be downloaded by ivy as a build dependency.
Here is my default build file that demonstrates the concept:
<project name="demo" default="resolve" xmlns:ivy="antlib:org.apache.ivy.ant">
<target name="bootstrap" description="Install ivy">
<mkdir dir="${user.home}/.ant/lib"/>
<get dest="${user.home}/.ant/lib/ivy.jar" src="http://search.maven.org/remotecontent?filepath=org/apache/ivy/ivy/2.3.0/ivy-2.3.0.jar"/>
</target>
<target name="resolve" description="Use ivy to resolve classpaths">
<ivy:resolve/>
<ivy:report todir='build/ivy-reports' graph='false' xml='false'/>
<ivy:cachepath pathid="compile.path" conf="compile"/>
<ivy:cachepath pathid="test.path" conf="test"/>
</target>
<target name="clean" description="Cleanup build files">
<delete dir="build"/>
</target>
<target name="clean-all" depends="clean" description="Additionally purge ivy cache">
<ivy:cleancache/>
</target>
</project>
Notes:
- The "bootstrap" target only needs to be run once on a new development environment. Once installed the ivy jar is available to all future ANT runs.
- This example doesn't use "$ANT_HOME/lib" (which you may not have write permissions for). Instead it uses the lesser known "$HOME/.ant/lib" directory which serves the same purpose.