Monday, September 28, 2015

Automatic update of assembly version using TFS2013

To successfully implement Octopus Deploy you need to have unique version numbers for each build. If you don't want to manually edit the assembly info this could be a real pain in the ***. With the following trick you can automatically generate version numbers using TFS Build server 2013.

What I did was create a BuildCommon.targets that automatically searches for the AssemblyInfo and updates the version number that matches the build number as generated by TFS, and check this file in your codetree. In our case the file is named: BuildCommon.targets and is placed next to the root of the solution:

<Project xmlns="" ToolsVersion="4.0">

    Defining custom Targets to execute before project compilation starts.

    Creates modified version of AssemblyInfo.cs, replaces [AssemblyVersion] attribute with the one specifying actual build version (from MSBuild properties), and includes that file instead of the original AssemblyInfo.cs in the compilation.

    Works with both, .cs and .vb version of the AssemblyInfo file, meaning it supports C# and VB.Net projects simultaneously.
<Target Name="CommonBuildDefineModifiedAssemblyVersion" Condition="'$(VersionAssembly)' != ''">
    <!-- Find AssemblyInfo.cs or AssemblyInfo.vb in the "Compile" Items. Remove it from "Compile" Items because we will use a modified version instead. -->
        <VersionAssembly>$([System.Text.RegularExpressions.Regex]::Replace($(VersionAssembly), `[\w|\D]+_`, ``, System.Text.RegularExpressions.RegexOptions.IgnoreCase))</VersionAssembly>
        <OriginalAssemblyInfo Include="@(Compile)" Condition="(%(Filename) == 'AssemblyInfo') And (%(Extension) == '.vb' Or %(Extension) == '.cs')" />
        <Compile Remove="**/AssemblyInfo.vb" />
        <Compile Remove="**/AssemblyInfo.cs" />
    <!-- Copy the original AssemblyInfo.cs/.vb to obj\ folder, i.e. $(IntermediateOutputPath). The copied filepath is saved into @(ModifiedAssemblyInfo) Item. -->
    <Copy SourceFiles="@(OriginalAssemblyInfo)"
        <Output TaskParameter="DestinationFiles" ItemName="ModifiedAssemblyInfo"/>
    <!-- Replace the version bit (in AssemblyVersion and AssemblyFileVersion attributes) using regular expression. Use the defined property: $(VersionAssembly). -->
    <Message Text="Setting AssemblyVersion to $(VersionAssembly)" />
    <RegexUpdateFile Files="@(ModifiedAssemblyInfo)"
    <!-- Include the modified AssemblyInfo.cs/.vb file in "Compile" items (instead of the original). -->
        <Compile Include="@(ModifiedAssemblyInfo)" />

<UsingTask TaskName="RegexUpdateFile" TaskFactory="CodeTaskFactory" AssemblyFile="$(MSBuildToolsPath)\Microsoft.Build.Tasks.v4.0.dll">
        <Files ParameterType="Microsoft.Build.Framework.ITaskItem[]" Required="true" />
        <Regex ParameterType="System.String" Required="true" />
        <ReplacementText ParameterType="System.String" Required="true" />
        <Reference Include="System.Core" />
        <Using Namespace="System" />
        <Using Namespace="System.IO" />
        <Using Namespace="System.Text.RegularExpressions" />
        <Using Namespace="Microsoft.Build.Framework" />
        <Using Namespace="Microsoft.Build.Utilities" />
        <Code Type="Fragment" Language="cs">
            try {
                var rx = new System.Text.RegularExpressions.Regex(this.Regex);
                for (int i = 0; i < Files.Length; ++i)
                    var path = Files[i].GetMetadata("FullPath");
                    if (!File.Exists(path)) continue;

                    var txt = File.ReadAllText(path);
                    txt = rx.Replace(txt, this.ReplacementText);
                    File.WriteAllText(path, txt);
                return true;
            catch (Exception ex) {
                return false;


Then change the build number format to:

and the MSBuild arguments:
/p:CustomAfterMicrosoftCommonTargets="$(TF_BUILD_SOURCESDIRECTORY)\src\BuildCommon.targets" /p:RunOctoPack=true /p:OctoPackPublishApiKey=API-123465 /p:OctoPackPublishPackageToHttp=http://octopus-server/nuget/packages /p:VersionAssembly=$(TF_BUILD_BUILDNUMBER)

This should result in unique assembly versions for each build.

Many thanks for the creators of these posts to help me create this: