Conditional task execution in ANT Scripts

Question

My requirement is pretty simple, I have an ANT task which is handling exceptions internally and not throwing any exception, instead it is throwing custom messages [these are not exceptions] to the console. A sample is shown below with the test "The workspace with the specified name does not exist".

My requirement here is, if there is any such message apart from "Build Successful", I should make sure my ANT script is failed so that it won't go further. But I am unable to do so as I don't know how do I read that custom message which was written to console.

I tried exploring on 'Record' task but I was unsuccessful as this log was written only to console and not to the file (don't know why). But even if it was written to a file I should ideally read each line of file to find out a particular text present or not.

Is there a simple way to try and read things from console which were executed before?

<target name="build">
    <record name="test.txt" action="start" append="true" loglevel="verbose" />
    <echo>Welcome to Apache Ant! Building the project in Cordys Middleware</echo>
    <property environment="env"/>
    <property name="bop.install.dir" value="${env.CORDYS_HOME}"/>
    <exec executable="${bop.install.dir}/components/cws/scripts/linux/CWSPackage.sh" failonerror="true" resultproperty="output">        
        <env key="CLASSPATH" value="/opt/Cordys/Oracle_Jar/ojdbc6.jar"/>
        <arg value="${ORG_NAME}"/>
        <arg value="${WORKSPACE_NAME}"/>
        <arg value="${PROJECT_NAME}"/>      
    </exec>
    <echo>Finishing the build</echo>
    <record name="test.txt" action="stop"/>
    <echo>${output}</echo>
    <fail>Something wrong here.</fail> <!-- I want to throw this error conditionally -->
</target>

Answer 1

What you're looking for is the exec task's outputproperty attribute.

You can do something like this:

<exec executable="${my.executable}" outputproperty="exec.output">
    <arg value="${my.arg}" />
</exec>

<fail message="Invalid output from exec task">
    <condition>
        <contains string="${exec.output}" substring="The workspace with the specified string does not exist." />
    </condition>
</fail>

Multiple conditions (any level of complexity in the boolean is allowed):

<fail message="Invalid output from exec task">
    <condition>
        <and>
            <not>
                <contains string="${exec.output}" substring="SUCCESS" />
            </not>
            <or>
                <contains string="${exec.output}" substring="ERROR" />
                <contains string="${exec.output}" substring="FAILED" />
            <or>
        </and>
    </condition>
</fail>

Regex:

<fail message="Invalid output from exec task">
    <condition>
        <matches string="${exec.output}" pattern="The .* does not exist." />
    </condition>
</fail>

Answer 2

<!-- *  This is an ANT script to build the project in development environment.
        Steps involved in this are
            * Building the project
            * Publishing the project
            * Creating the package for the project
 -->

<!-- 
    Sample command to execute this 
    ant build -DORG_NAME=businessservices3 -DWORKSPACE_NAME=ConfigurationManagement -DPROJECT_NAME='ConfigurationManagement'
 -->
<project name="Building Project" default="build">
    <property file="${PROJECT}" /> 
    <target name="build">
        <echo>Welcome to Apache Ant! Building the project in Cordys Middleware</echo>
        <property environment="env"/>
        <property name="bop.install.dir" value="${env.CORDYS_HOME}"/>

        <exec executable="${bop.install.dir}/components/cws/scripts/linux/CWSPackage.sh" outputproperty="exec.output">      
            <env key="CLASSPATH" value="/opt/Cordys/Oracle_Jar/ojdbc6.jar"/>
            <arg value="${ORG_NAME}"/>
            <arg value="${WORKSPACE_NAME}"/>
            <arg value="${PROJECT_NAME}"/>      
        </exec>
        <fail message="Build not successful for the project ${PROJECT_NAME}">
            <condition>
                <not>
                    <contains string="${exec.output}" substring="Operation  completed successful" />
                </not>
            </condition>
        </fail>

    </target>
</project>

This worked for me after so much of trail and error methods. Thanks Austin. Even though this is the ANT which is working, I would accept your answer only as this is a modified version of what you told :)