Azure DevOps–Create a build variable in Powershell

After executing the build pipeline, I add a tag to the specific git commit to track the deployed code. This is something that is built-in the Azure DevOps pipeline functionality through the Tag Sources:

Originally I used the $(build.buildNumber) variable to tag the code.  But I updated my project to use a VersionPrefix value inside my directory.build.props file:

	<Project>
	<Import Project="build/dependencies.props" />
	<PropertyGroup Label="Package information">
	<Authors>TBD</Authors>
	<Company>TBD/Company>
	<Product>SOFACore</Product>
	<PublishRepositoryUrl>true</PublishRepositoryUrl>
	<IncludeSymbols>true</IncludeSymbols>
	<SymbolPackageFormat>snupkg</SymbolPackageFormat>
	<EmbedUntrackedSources>true</EmbedUntrackedSources>
	<DebugType>embedded</DebugType>
	<VersionPrefix>2.0.0</VersionPrefix>
	</PropertyGroup>
	<PropertyGroup Condition="'$(TF_BUILD)' == 'true'">
	<ContinuousIntegrationBuild>true</ContinuousIntegrationBuild>
	</PropertyGroup>
	</Project>

view raw Directory.Build.props hosted with ❤ by GitHub

Of course this VersionPrefix value is not available as a variable inside my Azure DevOps pipeline. So the question is how can I create a new pipeline variable?

I solved this by creating a small Powershell script that reads the value from the Directory.Build.props file and uses the task.setvariable macro to create a pipeline variable:

More information: Set variables in scripts - Azure Pipelines | Microsoft Learn