How to use output of a powershell command as parameters in Azure pipeline?

Question

I have a PowerShell script task that gets the names of some files from a folder in my git repo and puts them into a variable. I want to use those file names in parameters and use "each" condition in another task (task: HelmDeploy@0) in order to run that task each time with one of the file names as valueFile variable.

Here is what I have tried, however it gives an error Template-Yaml/deploy-jobs.yaml@pipelinetemplates Expected a sequence or mapping. Actual value '$[dependencies.A.outputs['fileoutput.valuefiles']]' in line ${{each file in parameters.files}}

deploy-jobs.yaml

   parameters:
     files: []

   jobs:
     - job: Deploy
       pool:
         vmImage: 'ubuntu-latest'
       variables:
         filenames: ${{ parameters.files }}
       steps:
       - task: HelmInstaller@1
         displayName: 'Installing Helm'
         inputs:
           helmVersionToInstall: '2.15.1'

       - task: HelmDeploy@0
         displayName: 'Initializing Helm'
         inputs:
           connectionType: 'Azure Resource Manager'
           azureSubscription: $(azureSubscription)
           azureResourceGroup: $(azureResourceGroup)
           kubernetesCluster: $(kubernetesCluster)
           command: 'init'

       - task: AzureCLI@2
         inputs:
           azureSubscription: $(azureSubscription)
           scriptType: 'bash'
           scriptLocation: 'inlineScript'
           inlineScript: 
             echo "##vso[task.setvariable variable=imgtag]$(az acr repository show-tags --name myacr --repository myrepo --orderby time_desc --top 1 | awk ' /[[:digit:]]/ { print $0 } ' | tr -d '[:space:]')"

       - task: Bash@3
         displayName: 'Fetching repo-tag'
         inputs:
           targetType: 'inline'
           script: |
             echo tag=$(imgtag)
             echo filenames=$(filenames) ### output is: **/myfolder/dev/file1.yaml,**/myfolder/dev/file2.yaml

      - ${{each file in parameters.files}}: ##Error 
       - task: HelmDeploy@0
         displayName: 'Upgrading helmchart'
         inputs:
           connectionType: 'Azure Resource Manager'
           azureSubscription: $(azureSubscription)
           azureResourceGroup: $(azureResourceGroup)
           kubernetesCluster: $(kubernetesCluster)
           command: 'upgrade'
           chartType: 'FilePath'
           chartPath: $(chartPath)
           install: true
           releaseName: $(releaseName)
           ##valueFile: $(valuefiles)
           valueFile: ${{ file }}
           arguments: '--set image.tag=$(imgtag) --set domain=$(domain)'

azure-pipeline.yaml file is as following:

  trigger:
    branches:
      include:
        - master
        - refs/tags/v*
    paths:
      exclude:
        - readme.md

  variables:
    azureSubscription: 'myazuresubscription'
    chartPath: '**/mychart'
    containerRegistry: 'mysc'
    repository: 'myrepo'

  resources:
    repositories:
    - repository: pipelinetemplates
      type: github
      name: 'mygitorg/myrepo'
      endpoint: 'mygitorg'

  stages:
    - stage: Deploy_Cluster
      variables:
        azureResourceGroup: 'myresourcegroup'
        kubernetesCluster: 'mycluster'
        releaseName: 'mychartreleasename'
        #valueFile: '**/mychart/values.yaml'
        domain: 'mydomain'
      jobs:

 - job: A
   pool:
    vmImage: 'ubuntu-latest'
   steps:
   - task: PowerShell@2
     displayName: 'Fetching ValueFiles'
     inputs:
      targetType: 'inline'
      script: |
       Write-Host "Fetching value files"
       cd myfolder
       $a=git ls-files
       $List = $a | foreach {'**/myfolder/dev/' + $_}
       Write-Host $List
       $d = '"{0}"' -f ($List -join '","')
       Write-Host $d   ### output is: "**/myfolder/dev/file1.yaml","**/myfolder/dev/file2.yaml"
       Write-Host "##vso[task.setvariable variable=valuefiles;isOutput=true]$d"
     name: fileoutput

      - template: Template-Yaml/deploy-jobs.yaml@pipelinetemplates  ##Error expected a sequence or mapping
        parameters: 
          files : $[dependencies.Deploy.outputs['fileoutput.valuefiles']]

I got some idea from this page: https://www.aaron-powell.com/posts/2019-05-24-azure-pipeline-templates-and-parameters/ regarding using dependencies.

I googled a lot, however I couldn't find a solution to this issue so far, any help would be appreciated.

Tested the replied suggested by Levi:

parameters:
  files: []

jobs:
#- ${{each file in parameters.files}}:
   - job: Deploy
     dependsOn: A
     pool:
       vmImage: 'ubuntu-latest'  
     variables:
       filenames: ${{ parameters.file }} 
     steps:
     - task: Bash@3
       displayName: 'Fetching repo-tag'
       inputs:
         targetType: 'inline'
         script: |
           ##echo files=$(filenames) #output is files=file1.yaml,file2.yaml
           for i in $(filenames)
           do
              echo "valuefiles= $i "
           done

OutPut is valuefiles= files=file1.yaml,file2.yaml

Testing with PowerShell:

 - task: PowerShell@2
   displayName: 'Fetching ValueFiles'
   inputs:
     targetType: 'inline'
     script: |
       foreach ($i in ${{ parameters.files }}) {
           Write-Host "filenames=$i"
       }

Error: ObjectNotFound: ($[dependencies.A.ou\u2026output.valuefiles]]:String) [], ParentContainsErrorRecordException

- task: PowerShell@2
   displayName: 'Fetching ValueFiles'
   inputs:
     targetType: 'inline'
     script: |
       foreach ($i in $(filenames)) {
           Write-Host "filenames=$i"
       }

Error: foreach ($i in ) { + ~ Unexpected token ')' in expression or statement. + CategoryInfo : ParserError: (:) [], ParseException

Answer 1

The error occurred is because the files can only be caculated at runtime, but - ${{each file in parameters.files}} is valuated at compile time. Check here for more information about variable syntax.

- ${{each file in parameters.files}} won't work if the dynamic variables have been passed through parameters.

I doesnot know much about kubernetes, if you can manage to use powershell/bash script to do the HelmDeploy task. You can foreach the files inside script and deploy each file.

- powershell: |
          foreach ($i in $(filenames)) {helm.exe upgrade ....}

A similar issue has been submitted to Microsoft Develop team, and it is determined that above issue is by design. But you can still submit a feature request by clicking "Suggest a feature " and choose "azure devops"

Update:

azure-pipeline.yaml

trigger:
    branches:
      include:
        - master
 stages:
  - stage: Deploy_Cluster

    jobs:
    - job: A
      pool:
        vmImage: 'ubuntu-latest'
      steps:
      - task: PowerShell@2
        displayName: 'Fetching ValueFiles'
        inputs:
          targetType: 'inline'
          script: |
            Write-Host "Fetching value files"
            cd '$(system.defaultworkingdirectory)'
            $a=git ls-files
            $List = $a | foreach {'**/myfolder/dev/' + $_}
            Write-Host $List
            $d = '"{0}"' -f ($List -join '","')
            Write-Host $d  

            Write-Host "##vso[task.setvariable variable=valuefiles;isOutput=true]$d"

        name: fileoutput

    - job: B
      dependsOn: A
      pool:
        vmImage: 'ubuntu-latest'
      variables: 
        allfiles: $[dependencies.A.outputs['fileoutput.valuefiles']]
      steps:
      - template: deploy-jobs.yaml
        parameters: 
          files : $(allfiles)

deploy-jobs.yaml

parameters:
  files: []

steps :
- task: PowerShell@2
  displayName: 'Fetching ValueFiles'
  inputs:
    targetType: 'inline'
    script: >

      foreach ($i in ${{parameters.files}})
      {
        Write-Host "filenames=$i"
      }