Publishing NuGet Packages to Azure Artifacts from Azure Pipelines

This repository contains a simple .Net Core class library and a pipeline that demonstrates building the library, creating a NuGet package and publishing the package to Azure Artifacts with somewhat automatic version management.

Creating the NuGet Package

The following pipeline task creates the NuGet package:

          - task: DotNetCoreCLI@2
            inputs:
              command: pack
              packagesToPack: '**/*.csproj'
              versioningScheme: byEnvVar
              versionEnvVar: 'PackageVersion'
              arguments: '--configuration $(buildConfiguration) --output $(Build.ArtifactStagingDirectory)

Note the inputs versioningScheme and versionEnvVar, these are key to how the version gets set on the NuGet package. The versioningScheme value, byEnvVar tells the pack command to source the value for the version number from an environment variable named PackageVersion. In this case, PackageVersion is a pipeline variable. The mechanics of this variable are described below.

Publishing the NuGet Package

The following pipeline tasks publish the NuGet package to an Azure Artifacts NuGet feed:

          - task: NuGetAuthenticate@0
            displayName: 'Authenticate to NuGet Feed'
          
          - task: NuGetCommand@2
            displayName: 'NuGet push'
            inputs:
              command: push
              packagesToPush: '$(Pipeline.Workspace)/NuGet/*.nupkg'
              publishVstsFeed: '$(ProjectName)/$(FeedName)'

The first command authenticates to Azure Artifacts. The second command publishes the package to the feed. For the publishVstsFeed input value, set $(ProjectName) to the name of the project that hosts your feed and $(FeedName) to the name of your NuGet feed.

Version Management

Versioning of NuGet packages using the approach demonstrated in this pipeline relies on several pipeline variables. The following table lists those variables and their initial values.

Variable Name	Description	Initial Value
Major	The major version number for your package, following SemVer semantics	1, or any major version number you wish to begin at
Minor	The minor version number for your package, following SemVer semantics	0, or any minor version number you wish to start at
PackageVersion	This value will be used in the pipeline to provide the version number used on when your NuGet package is created. The expression provided in the Initial Value column should not be changed	$(Major).$(Minor).$(Patch)$(PackageVersionType)
PackageVersionType	Use this variable if you want to create a pre-release version of your package. Set it to -alpha, -beta, -rc or whatever identifier you want to use to indicate the package is pre-release. Note the value of this variable MUST begin with a - (hyphen)	Leave blank for non pre-release, otherwise set the approrpiate suffix, remembering the value must begin with a hyphen
Patch	The patch version number for your package, following SemVer semantics. Note the value of this variable uses an expression based on the counter() expression. This expression maintains a stateful counter that will increment automatically each time your pipeline runs until either the Major or Minor variables are changed. If either Major or Minor are changed, the value of this variable will automatically reset to zero, then begin incrementing on subseuent pipeline runs. The expression provided in the Initial Value should not be changed.	$[counter(format('{0}.{1}', variables['Major'], variables['Minor']), 0)]

Creating the Variables

These variables should be defined at the pipeline level so that they are persisted across pipeline runs. To create the variables, in the Azure Pipelines Editor, click the Variables button at the top right of the editor:

When you've created your variables, you should see something that looks like this:

Updating Major and Minor Version Numbers

As mentioned abovie, updating either the Major or Minor version variables causes the Patch variable to reset to zero. There are two possible approaches to updating these variables, however only one will result in the desired behavior for automatically incrementing and resetting the Patch variable, so it is important you follow the correct approach. To correctly update either Major or Minor, you must edit the pipeline definition in Azure DevOps and make the change by clicking the Variables button at the top right of the screen in the pipeline editor. Edit your pipeline definition, click the Variables button, make the necessary changes to Major and/or Minor, then click Save to dismiss the Variables dialog. From there you can either click Run to initiate a pipeline run using the new value(s) or wait for a triggered run of your pipeline from a PR/commit.

It is also possible to update pipeline variables when you manually run a pipeline in Azure Pipelines. It is important that you do not update Major or Minor using this approach. Doing so does not persist the values for future pipeline runs and will result in the automatic incrementing of the Patch parameter not behaving as expected.