How to include PS code with shared YAML templates in Azure DevOps Server 2020?

Question

We use shared YAML templates extensively in our YAML builds. Something like this:

trigger: none

resources:
  repositories:
    - repository: templates
      type: git
      name: DFDevOps\cicd-templates
      ref: refs/tags/stable-1
      # http://tdc1tfsapp01:8080/tfs/DefaultCollection/DFDevOps/_git/cicd-templates

name: $(BuildVersionPrefix).$(DayOfYear)$(Date:HH)

jobs:
  - job: Build
    pool:
      demands: DotNetFramework
    workspace:
      clean: outputs
    timeoutInMinutes: 180
    steps:
      - checkout: self # self represents the repo where the initial Pipelines YAML file was found
        clean: true
        lfs: true

      - template: ci/ci-build.yml@templates
        parameters:
          releaseBranch: $(ReleaseBranch)

However, the shared YAML templates often need to execute Powershell code. So far we either embed it or put it in a PS module, which the templates load.

I hate both approaches. I hate embedding because:

1. No intellisens
2. No unit testing
3. No proper error reporting on pipeline failures

I hate putting in a module, because it is detached from the origin and requires a lot of overhead.

My question - is it possible to have the PS code in dedicated ps1 files in the same repo as the YAML templates and yet have them available at run time?

Answer 1

So, checkout: self will refer to the repository in which that particular pipeline YAML lives - not the templates repository (unless they are one and the same).

I would add a second checkout step - checkout: templates - in the pipeline and then in the inputs for your powershell script task (in the template), specify the path to the script you just checked out:

        scriptType: filePath
        scriptPath: $(Build.SourcesDirectory)/templates/pathToscript.ps1

The template is just expanded in place into the pipeline at compile time, so it should have access to that folder. You can verify this now in the YAML pipeline editor by downloading the expanded pipeline: Download full YAML