Logging in Ant : Live Practical Example

Hi! Hows it going guys! Today is an auspicious Indian day - Holi : the festival of colors. On this good auspicious day am also presenting a fresh new 200th post.

Let's look into a simple concept - how to take logs in Apache Ant builds. By taking logs I mean how to capture the console output in a log file.

The foremost thing you need to be aware of is the <record> task with which we tell Ant when and where to capture the console into a log. Detailed explanation of the task can be read at Ant Official Manual.

Let's use a familiar example that we used in our earlier posts - Ant build.xml updates : Feb 28 and Ant - Build.xml Introduction.

Check out our new updated build.xml below :

<?xml version="1.0" encoding="UTF-8"?>

<project name="AntBuildTest" default="generate-docs" basedir=".">

<property name="build.home" value="${basedir}" />

<property file="build.properties"/>

<tstamp>

<format property="timestamp" pattern="dd-MM-yyyy"/>

</tstamp>

<target name="clean">

<delete dir="${build.home}/src" />

<delete dir="${build.home}/bin" />

<delete dir="${build.home}/lib" />

<delete dir="${build.home}/test" />

<delete dir="${build.home}/dist" />

<delete dir="${build.home}/docs" />

<delete dir="${build.home}/logs" />

</target>

<target name="createdir" depends="clean">

<mkdir dir="${build.home}/src" />

<mkdir dir="${build.home}/bin" />

<mkdir dir="${build.home}/lib" />

<mkdir dir="${build.home}/test" />

<mkdir dir="${build.home}/dist" />

<mkdir dir="${build.home}/docs" />

<mkdir dir="${build.home}/logs" />

<record name="${build.home}/logs/build.log" action="start" append="no" loglevel="verbose" />

</target>

<path id="classpath">

<pathelement location="${build.home}/bin"></pathelement>

<fileset dir="${lib.dir}" includes="**/*.jar"/>

</path>

<target name="copydir" depends="createdir">

<copydir src="${workspace.src}"

dest="${build.home}/src"></copydir>

</target>

<target name="compile" depends="copydir, clean">

<javac classpathref="classpath" includeantruntime="false"

srcdir="${build.home}/src"

destdir="${build.home}/bin"

includes="**/*.java"></javac>

</target>

<target name="create-jar" depends="compile">

<jar basedir="${build.home}/bin" destfile="${build.home}/dist/${timestamp}-TestJar-${versionnum}.jar"

includes="**/*.class">

<manifest>

<attribute name="Main-class" value="com.ironcladzone.FileSize"/>

</manifest>

</jar>

</target>

<target name="generate-docs" depends="create-jar">

<javadoc sourcepath="${build.home}/${src.dir}" destdir="docs"/>

<record name="${build.home}/logs/build.log" action="stop" append="no" />

</target>

</project>

Notice the "createdir" task where we started the recorder and in the "generate-docs" we stopped it. The loglevel parameter is an optional one. In this example you see we have set the loglevel to verbose. It means it will have much detailed information in the logs than the default console output. However it can have any of the 5 possible values - error, warn, info, verbose, debug. Experiment with each level to see the difference.

Btw check the directory structure for reference.