CSC 395 – Software Engineering Lecture 24: Apache Ant –or– Programming the results of...

CSC 395 –Software Engineering

Lecture 24:

Apache Ant –or– Programming the results of programming

Based upon a talk by Anthony Wat

In This Lecture

Provide overview of using Apache Ant What does Ant do? How do we use it? Why should I care?

Ant in a Nutshell

Java-based build tool Uses scripts to automate large processes

Enables multiplatform actions Useful aspect of Java-based implementation Scripts must be written to take advantage

Many built-in tasks available Javac, Copy, Delete, etc. Can write & import additional tasks

Sample Build Script

<?xml version="1.0"?><project name=“build” default=“all”>

<target name=“all” depends=“hello”><echo message=“Good bye world.” />

</target>

<target name=“hello”><echo message=“Hello world.” />

</target>

</project>

Properties

Name-value pair used like variables in scripts Many ways of defining/importing Some properties automatically available

basedir ant.file ant.version ant.project.name ant.java.version

Define In External File

File written in plain text (usually XYZ.properties) Specify in file using name=value

Example:bin.dir=${basedir}/binHelloWorldStr=Hello world.

Load file using <property> task: Example:<project name=“build” default=“all”>

<property file=“build.properties” />

Define Properties Other Ways

Use name & value attributes of <property> Example:<project name=“build” default=“all”> <property name=“HelloWorldStr” value=“Hello world.” />

Specify in command that calls Ant Example:ant -Ddate=050206

Using Properties

Syntax similar to UNIX environment variables Examples:<echo message=“${HelloWorldStr}” /><delete dir=“${bin.dir}” quiet=“yes” />

First line could do 1 of 2 things If HelloWorldStr defined, then ${HelloWorldStr} replaced by its value

Otherwise, prints literal value “${HelloWorldStr}”

Caution!

Characters must escaped in properties files Must escape ‘\’ in Windows-based directories: C:\tmp is bad (\t replaced to become “C:mp”) C:\\tmp is good

Do NOT escape ‘\’ inside build script, but instead escape XML characters (e.g. ‘<’ becomes &lt;)

Properties like final variable in Java Once defined, cannot easily modify values

Filesets

A fundamental structures in Ant Define rules including and/or excluding files:

Include only .java files in build directory Delete backup files generated by a program Copy only files specified in a list

Using Filesets in Ant

Use <fileset> to delete .bak files:<delete quiet=“yes”> <fileset dir=“doc”

includes=“**/*.bak” /></delete>

or

<delete quiet=“yes”> <fileset dir=“doc”> <include name=“**/*.bak” /> </fileset></delete>

Can often nest multiple <filesets>

Implicit Filesets

Some tasks define implicit filesets Include <javac>, <tar>, <zip>

Treat task like genuine <fileset> To compile Ant’s Java files:<javac srcdir=“src” destdir=“bin”>

<include name=“org/apache/ant/**/*.java” /></javac>

Chaining Scripts

Usually not necessary <ant> task calls another script

Example:<ant antfile=“other.xml” />

Runs Ant script named other.xml Called script inherits all defined properties New script can also define new properties

Enables combining individual projects into single larger project

Helper Target

Helper targets used like a method Can be called using different parameters

<antcall> task used to call targets Specify parameters using <param>

<param> can also override global properties Initially set a default message globally Use <param> to override message when needed

Helper Target (cont.)

<target name=“echoTwice”><echo message=“${message}” /><echo message=“… and again: ${message}” />

</target>

…<antcall target=“echoTwice”><param name=“message” value=“Hi.” />

</antcall>

Building With Ant

Run single script to build end-to-end Can also make daily builds

Schedule daily builds to run automatically Send e-mails when build available Send e-mails whenever submission breaks build

One-Step Build Process

Ant provides a lot of useful tasks: <cvs> check out and update repository <copy> & <delete> rearrange files <javac> & <java> compile and run Java

programs <exec> executes program from command-line

But this will be specific to the system and OS <zip> & <jar> helps package software

Also provides ability to write your own tasks!

One-Step Build Process (cont.)

Should be enough for end-to-end build Can fit everything into build.xml script

Default name for Ant script Otherwise must use -buildfile parameter to

run script Start build by running Ant

Uses ant or ant.bat in ant\bin directory

Build Notification

Send as part of build script <mail> sends e-mail

<mail mailhost=“smtp.canisius.edu” subject=“Build Successful”>

<from address=“me@canisius.edu” />

<to address=“developers@canisius.edu” />

<message>Today’s build is done</message>

</mail>

Build Notification – Mail Logger

Another way is to use the mail logger org.apache.tools.ant.listener.MailLogger

Call Ant using the -logger option to specify the logger

Example: ant -logger org.apache.tools.ant.listener.MailLogger –DMailLogger.properties.file=mail.properties

All of the required properties for the mail logger (SMTP, addresses, etc.) are defined in mail.properties

Build Notification – Mail Logger (cont.)

Instead of piping output to console, it will be cached and sent as e-mail when the build finishes successfully or fails

The logs can be sent to developers Schedule Ant builds with cron (UNIX) or

Task Scheduler (Windows)

Summary

We’ve looked at: Properties and filesets Multiple build scripts and helper targets, which

provide better maintainability of build scripts How to achieve one-step automated build process

using Ant Ant is used everywhere – from open source

projects to commercial software projects A good skill to have

For Next Lecture

Read about SCM Change is inevitable SCM looks to control the results of changes that

occur