How Azure DevOps Pipeline condition evaluates parameters?

Question

Given the following Azure DevOps pipeline template:

parameters:
  - name: AUTH_TYPE
    type: string

steps:
  - task: Bash@3
    displayName: Parameter print
    inputs:
      targetType: inline
      script: echo "AUTH_TYPE = '${{ parameters.AUTH_TYPE }}'"

  - task: Bash@3
    displayName: Variable print
    inputs:
      targetType: inline
      script: echo "AUTH_TYPE = '${{ variables.AUTH_TYPE }}'"


  - task: Bash@3
    displayName: OIDC auth
    inputs:
      targetType: inline
      script: echo OIDC authentication
    condition: ${{ eq(parameters.AUTH_TYPE, 'oidc') }}
  - task: Bash@3
    displayName: Password auth
    inputs:
      targetType: inline
      script: echo Password authentication
    condition: ${{ eq(parameters.AUTH_TYPE, 'password') }}

Calling:

# ...
variables:
  - group: pipeline-vars

steps:
  - checkout: shared-library
  - template: pipeline-templates/auth.yaml@shared-library
    parameters:
      AUTH_TYPE: $(AUTH_TYPE)

The problem is, the Parameter print outputs the AUTH_TYPE value correctly (oidc in the example) but the corresponding OIDC auth task condition evaluates to false (it is skipped in the pipeline run).

Can anyone help me what is wrong with this? I am totally new in Azure DevOps Pipelines and I currently struggling with understanding how the templates evaluated by the runtime.

Answer 1

Your template yaml looks good with slight modification, I have just test it and the OIDC auth condition works.

But you can not pass the variable into template parameters. the template yaml be compiled to a big-yaml will accept the parameters at compile time, but variables values work in run-time.

parameters:
- name: AUTH_TYPE
  type: string
  default: 'oidc'

variables:
- name: var1
  value: ${{ parameters.AUTH_TYPE }} 

steps:
- task: Bash@3
  displayName: Parameter print
  inputs:
    targetType: inline
    script: echo "AUTH_TYPE = ${{ parameters.AUTH_TYPE }}"

- task: Bash@3
  displayName: Variable print
  inputs:
    targetType: inline
    script: echo "AUTH_TYPE = ${{ variables.var1 }}"

- task: Bash@3
  displayName: OIDC auth
  inputs:
    targetType: inline
    script: echo OIDC authentication
  condition: ${{ eq(parameters.AUTH_TYPE, 'oidc') }}
- task: Bash@3
  displayName: Password auth
  inputs:
    targetType: inline
    script: echo Password authentication
  condition: ${{ eq(parameters.AUTH_TYPE, 'password') }}