The Anatomy of a NAnt Build File

Over the weekend I was looking at building a simple NAnt file layout that I could use for building one of my projects. Previously, I'd considered NAnt files to be problematical because they have a tendency of evolving into unmanageable behemoths that are thousands of lines long. For example, the build file we use at my day job is a little over 2600 lines and has a layout like this:

<project name="Unmanageable" default="build">

    ...

    <target name="build">
        <call target="buildProject1" />
        <call target="buildProject2" />
        <call target="buildProject3" />
    </target>

    ...

    <target name="buildProject1">
        <csc target="library" output="buildProject1.dll">
            <sources>
                <include name="**/*.cs" />
            </sources>
            <references>
                <include name="System.dll" />
                ...
            </references>
        </csc>
    </target>
    <target name="buildProject2" depends="buildProject1">
        ...
    </target>
    <target name="buildProject3" 
            depends="buildProject1, buildProject2">
        ...
    </target>
</project>

Add in 30 or 40 other projects and about 100 lines worth of property definitions and before you know it you've got a file that will turn developers pale at its very mention. That might not be so bad, but because of the way references have to be entered manually under the <csc> tag, everytime you update a reference under one of your projects, it has to be added to the build file as well; so the build file ends up being updated constantly.

Not wanting to run into this problem in my own projects, I started looking for a better way to build projects, and quickly discovered the NAnt <solution> task (NAnt solution task documentation). This task can theoretically read a solution or project file, build dependencies, then build the file's target; thus working around the normal NAnt "creep". Sounds great, but it only supports VS 2002 and 2003 solution files, so in practice it's not much use.

MSBuild

With the release of Visual Studio 2005, Microsoft started to include a new build tool called MSBuild (MSBuild documentation). In its most basic form, the MSBuild command can be used with a few command line switches to build a VS solution or project: MSBuild "path/Project.csproj" /v:n /t:Build /p:Configuration=release;OutDir="path/bin/"

MSBuild is more than just a command though; it can also be used to read an MSBuild file written in XML to follow much more complex sets of instructions in a similar fashion to NAnt. I haven't had the chance to explore it fully, but I hope to do a future post comparing its features and ease-of-use to NAnt's.

For now, I found that calling the MSBuild executable from my NAnt scripts acts like a drop-in replacement for NAnt's <solution> task with one important difference — MSBuild works.

A NAnt Solution

Without further ado, I'd like to present a template that I've been using for my projects that can build multiple application targets using MSBuild, and as you'd expect, has testing targets.

<project name="BrandursExcellentTemplate" default="rebuild">

    
    
    

    
    <property name="configuration" value="release" />

    
    <property name="bin-directory" value="${directory::get-current-directory()}/bin/" />

    
    <property name="msbuild" value="${framework::get-framework-directory(framework::get-target-framework())}\MSBuild.exe" />

    
    
    

    <target name="clean" description="Delete all previously compiled binaries.">
        <delete>
            <fileset>
                <include name="**/bin/**" />
                <include name="**/obj/**" />
                <include name="**/*.suo" />
                <include name="**/*.user" />
            </fileset>
        </delete>
    </target>

    <target name="build" description="Build all application targets.">
        <mkdir dir="${bin-directory}" />
        
        
        
        
        <call target="build.app1" />
        <call target="build.app2" />
    </target>

    <target name="rebuild" depends="clean, build" />

    <target name="test" description="Build test project and run all tests.">
        <mkdir dir="${bin-directory}" />
        <call target="build.tests" />
        <nunit2>
            <formatter type="Plain" />
            <test assemblyname="${bin-directory}/Test.dll" />
        </nunit2>
    </target>

    <target name="testimmediate" description="Build test project and run all tests.">
        <mkdir dir="${bin-directory}" />
        <call target="build.tests" />
        <nunit2>
            <formatter type="Plain" />
            <test>
                <assemblies>
                    <include name="${bin-directory}/Test.dll" />
                </assemblies>
                <categories>
                    <include name="Immediate" />
                </categories>
            </test>
        </nunit2>
    </target>

    
    
    

    <target name="build.app1">
        <exec program="${msbuild}" commandline='"src/App1/App1.csproj" /v:n /nologo /t:Build /p:Configuration=${configuration};OutDir="${directory::get-current-directory()}/bin/"' />
    </target>

    <target name="build.app2">
        <exec program="${msbuild}" commandline='"src/App2/App2.csproj" /v:n /nologo /t:Build /p:Configuration=${configuration};OutDir="${directory::get-current-directory()}/bin/"' />
    </target>

    <target name="build.tests">
        
        <exec program="${msbuild}" commandline='"src/Test/Test.csproj" /v:q /nologo /t:Build /p:Configuration=Debug;OutDir="${directory::get-current-directory()}/bin/"' />
    </target>

</project>

One part of the template I'll comment on is the testimmediate target. At work, we used to categorize all our tests using NUnit's category feature, but found over time that we weren't gaining a whole lot of value from the process. Instead of letting categories go to waste, my boss came up with the idea of tagging test fixtures relevant to current features with [Category("Immediate")]. That way, developers can run only the immediate category to quickly run the most immediately important tests. I've frequently started using the same concept outside of work as well.

Posted on June 2, 2009 from Calgary

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My name is Brandur. I'm a polyglot software engineer and part-time designer working at Heroku in San Francisco, California. I'm a Canadian expat. My name is Icelandic. Drop me a line at brandur@mutelight.org.

Aside from technology, I'm interested in energy and how it relates to our society, travel, longboarding, muay thai, symphonic metal, and the guitar.

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