Conquering Deployment with build.xml: An Example for EAR in WebSphere 6

Deploying applications can be a daunting challenge, especially when working with enterprise-grade servers like WebSphere. One common question developers face is how to set up an effective build process using Ant to deploy an Enterprise Archive (EAR) file. In this article, we’ll walk through a detailed example of creating a build.xml file designed specifically for deploying EAR applications in WebSphere 6.1. We aim to help you streamline this process, ensuring your application can be recompiled and redeployed easily anywhere, anytime.

The Challenge of EAR Deployment

Why Use Ant?

In a development environment, many developers are transitioning from Rational Application Development to using Apache Ant due to its straightforward structure and accessibility. Ant allows developers to automate the build process, which is crucial for deployment consistency.

If you’re trying to convince your peers to switch to Ant, you must provide them with practical examples and an easy way to manage deployments. This is where a well-structured build.xml comes into play.

Setting Up Your Environment

Before diving into the code, it’s important to know that you’ll need the following:

• Environment: Make sure you are running WebSphere Application Server (WAS) 6.1 on an appropriate platform, such as Fedora 8.
• ANT: Ensure that you have Apache Ant set up in your environment to utilize its tasks effectively.

Understanding the build.xml Structure

The build.xml file guides the build process. Below is a sample configuration focusing on the deployment of an EAR file using Ant.

Listing Applications

First, we’ll create a target to list the applications installed in WAS.

<?xml version="1.0"?>
<project name="project" default="wasListApps" basedir=".">
    <description>Script for listing installed apps.</description>
    <property name="was_home" value="/opt/IBM/SDP70/runtimes/base_v61/"/>

    <path id="was.runtime">
        <fileset dir="${was_home}/lib">
            <include name="**/*.jar"/>
        </fileset>
        <fileset dir="${was_home}/plugins">
            <include name="**/*.jar"/>
        </fileset>
    </path>

    <target name="wasListApps">
        <taskdef name="wsListApp" classname="com.ibm.websphere.ant.tasks.ListApplications" classpath="${was.runtime}"/>
        <wsListApp wasHome="${was_home}"/>
    </target>
</project>

Deploying an EAR File

Next, we’ll set up a deployment target in the same build.xml file:

<project name="project" default="default" basedir=".">
    <description>Build/Deploy an EAR to WebSphere Application Server 6.1</description>
    <property name="was_home" value="/opt/IBM/SDP70/runtimes/base_v61/"/>
    <path id="was.runtime">
        <fileset dir="${was_home}/lib">
            <include name="**/*.jar"/>
        </fileset>
        <fileset dir="${was_home}/plugins">
            <include name="**/*.jar"/>
        </fileset>
    </path>
    <property name="ear" value="${env.HOME}/IBM/rationalsdp7.0/workspace/mywebappDeploy/mywebappEAR.ear"/>

    <target name="default" depends="deployEar"/>

    <target name="deployEar" depends="generateEar">
        <taskdef name="wsInstallApp" classname="com.ibm.websphere.ant.tasks.InstallApplication" classpath="${was.runtime}"/>
        <wsInstallApp ear="${ear}" failonerror="true" debug="true" taskname="" washome="${was_home}"/>
    </target>
</project>

Key Sections and Considerations

Notes for Deployment

• Single Use: You can only run the installation target once if the application name is currently in use. If needed, look into using the wsUninstallApp task to remove existing applications first.
• Server Environment: This script is meant to be run from the server’s profile bin directory to take advantage of the required environment settings.
• Error Handling: Pay attention to the failonerror attribute; setting it to true ensures that if something goes wrong, it will halt execution and give you a chance to troubleshoot.

Alternatives to Consider

If you find working with Ant a bit cumbersome, consider using Java Management Extensions (JMX). By writing a file-upload servlet on the server that accepts an EAR file, you can utilize deployment MBeans over HTTP, making your deployment process more flexible and independent of the specific development environment.

Conclusion

By following these structured examples and guidelines, you will be well-equipped to create and run a build.xml file that effectively deploys EAR applications using Ant in WebSphere 6. This not only simplifies your deployment process but also makes collaboration with your development team much more efficient. Transitioning to Ant might feel challenging at first, but with practice and the right resources, you can streamline your workflow significantly.

Feel free to use this guide as a reference while setting up your own build process. Happy coding!