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templatesvariablesdynamicazure-devopsyaml
Roman Lushkin
Roman Lushkin

Reputation: 181

Azure Pipeline dynamic parameters to template file from YAML pipeline

I am currently working with Azure Devops Build Pipelines, and am trying to call a template file to do some tasks from my build yaml.

I am facing some difficulties to pass parameters to the template file. Let assume that this is my template file (simplified) which works fine :

parameters:
 iterations: []

steps:
- ${{ each i in parameters.iterations }}:
- task: PowerShell@2
  displayName: "Get key values ${{i}}"
  name: getKeyValues_${{i}}
  inputs:
    targetType: 'inline'
    script: |
      $item = "${{i}}"
      Write-Host "item : $($item)"
      $keyVal = $item -split "_"
      Write-Host $keyVal
      Write-Host "key: $($keyVal[0]) | value: $($keyVal[1])"
      echo "##vso[task.setvariable variable=key;isOutput=true]$($keyVal[0])"
      echo "##vso[task.setvariable variable=value;isOutput=true]$($keyVal[1])"

So I want my iterations parameter contain something like this : 

iterations: ["1_60", "2_40"]

Inside my Yaml pipeline I have the following code(also simplified) :

Not working scenario

- task: PowerShell@2
   displayName: Calculate iterations for $(copies) copies
   name: calculateIterations
   inputs:
   targetType: 'inline'
   script: |
       # Do some stuf here to get the arrow below from int value = 100 
       $iterations = ["1_60, "2_40"]
       echo "##vso[task.setvariable variable=iterations;isOutput=true]$($iterations)"

- template: container-template.yml 
   parameters:
     iterations: $(calculateIterations.iterations)

Working scenario

- task: PowerShell@2
   displayName: Calculate iterations for $(copies) copies
   name: calculateIterations
   inputs:
   targetType: 'inline'
   script: |
       # Do some stuf here to get the arrow below from int value = 100 
       $iterations = ["1_60, "2_40"]
       echo "##vso[task.setvariable variable=iterations;isOutput=true]$($iterations)"

- template: container-template.yml 
   parameters:
     iterations: ["1_60, "2_40"]

As you can see, the problem is that I am unable to use the output variable of my script to pass it as parameter to my template. When I run the not working scenario I have the following error : enter image description here

I have found this post, but no solutions yet...

Upvotes: 8

Views: 16768

Answers (1)

Mengdi Liang
Mengdi Liang

Reputation: 18978

As 4c74356b41 said, we cannot dynamically generate lists in ADO pipeline template expressions. The not working scenario you mentioned is not supported currently.

For now, we must let the template know the clear text at compile time. This limitation makes it difficult to do 2 or more things in one step, especially compiling variable values, passing dynamic arguments to a template, etc.

Expected a sequence or mapping. Actual value '$(calculateIterations.iterations)'

More detailed, during compile time (after you click Run but before pipeline start truely):

1) Firstly we map the value that come from YAML pipeline, to make sure the - ${{ each i in parameters.iterations }} has clear value to start.

2) After it is done, then parse exact value on name: getKeyValues_${{i}} in script order.

In your scenario, it cannot even satisfy the first step since what you passed is a variable, and we do not has parse value process here. That's why you saw error said Expected a sequence or mapping. Actual value '$(calculateIterations.iterations)'.

Another expression of this error message is: The template is looking for exact value(s) to map to our dynamic parameters, but what you gave is unrecognized content $(calculateIterations.iterations). Because of this, the template cannot start.

Upvotes: 5

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