How to find out dependency versions in your .csproj files using PowerShell?

Time needed: 15 minutes

How to read Major and Minor version from dependencies in a pipeline in Azure DevOps?

1. Create a new PowerShell task for figuring out the variables

   In order to find the references to our dependencies, we’ll need a PowerShell task that’ll find the .csproj files from your checked-out source and go through the contents.
   
   So – that’s what we start with. A PowerShell task in your pipeline some time after your checkout task. In YAML, it’ll look something like below:
     - checkout: $(your-repo)

  - task: PowerShell@2
    displayName: Get new semver from files
    inputs:
      targetType: inline
      pwsh: true
      script: |
Write-Host "Time for some PowerShell magic!"

2. Figure out where your .csproj file is

   Now that you have your source checked out, it’ll be located in $(Build.SourcesDirectory). You could, for example, find your .csproj files by running this:
   cd $(Build.SourcesDirectory)
$projects = Get-ChildItem *.csproj -Recurse
   
   In this guide I presume we don’t know which of the .csproj files has the dependencies we are interested in, so we’ll need them all for now.
3. Read the dependency version from the .csproj file

   Since we don’t know which .csproj file has the dependencies we’re interested in, we’ll go through them until we find what we want!
   
   Somewhat like below:
   $projects | Foreach-Object {
  Write-Host "Path to .csproj file: " $_
  $subPath = Split-Path -Path $_

  $content = Get-Content $_

  $content | foreach { if ($_ -match "Contoso.Core") { if ($_ -match "[0-9]+\.[0-9]+\.[0-9]+") { Write-Host $matches[0]; $semverFound = $true } } }
  if ($matches.Count -eq 0) {
    continue;
  }

  $semver = $matches[0].Split(".")

  $major = $semver[0]
  $minor = $semver[1]

# At this point, we've got the variables in the local task, but not beyond that scope.
# To make them available for the rest of the job, you can do this:
Write-Host "##vso[task.setvariable variable=Major;]$major"
Write-Host "##vso[task.setvariable variable=Minor;]$minor"
   
   # If you’ll need them in other jobs and stages, see steps 4

  break;
}
   
   

4. (OPTIONAL) If you’re using pipeline variables, you need a new task for them to be updated

   One important point to note is that the values of pipeline variables are not updated during the execution of the task – so if you want to verify what was set as a value to your Major and Minor pipeline variables, you’ll need a new task for it. It’ll have the updated values.
   
   So $(Major) and $(Minor) should be undefined for the rest of your script in step 3. But if you have a new task (in the same job), they should work just fine!
   
   The PowerShell can now be something as simple as:
  - task: PowerShell@2
    displayName: Log new Major and Minor versions
    name: outputVersion
    inputs:
      targetType: inline
      pwsh: true
      script: |
        Write-Host "The version is now: $(Major).$(Minor)"

5. (OPTIONAL) Handle the complexity around multiple jobs and/or stages

   If you have a multi-job or multi-stage pipeline (as I believe most of us do), the updated values are not going to be available for the rest of the jobs or stages, as they’ll be freshly initiated on new virtual machines that are unaware of the pipeline variable value changes.
   
   Yeah, this adds a lot of convolutedness to the process, but what are you going to do…
   
   So if you don’t want to run the rest of your steps in the same job you set the new values in, what can you do?
   
   Well, we’ll need to set our Major and Minor to be output variables, which will be available for later stages and jobs to reference.
   
     - task: PowerShell@2
    displayName: Output new Major and Minor versions
    name: outputVersion
    inputs:
      targetType: inline
      pwsh: true
      script: |
        Write-Host "Exporting the Major & Minor semantic version as output to be used in later stages"
        Write-Host "##vso[task.setvariable variable=Major;isOutput=true;]$Major"
Write-Host "##vso[task.setvariable variable=Minor;isOutput=true;]$Minor"