Pass pipeline variable from Designer to YAML job template

Question

I initially wanted to define pipeline variables in my azure-pipelines.yml that I can optionally set at queue time, but it seems that this is not supported at the moment: variables that can be set at queue time can only be defined in the Designer. This variable (comma-separated) is named nx_versions and will be used to build a matrix strategy. Here's a minimal example:

# azure-pipelines.yml
jobs:
- template: job-template.yml
  parameters:
    nx_versions: $(nx_versions)

and

# job-template.yml
parameters:
  nx_versions: 
    - 1

jobs:
  - job: build
    strategy:
      matrix:
        ${{ each nxver in parameters.nx_versions }}:
          NX_${{ nxver }}:
            NXVersion: ${{ nxver }}
    steps:
      - powershell: echo $(NXVersion)

Queuing the build with nx_versions = 2,3 (value doesn't actually matter) results in an error:

/job-template.yml (Line: 9, Col: 9): Expected a sequence or mapping. Actual value '$(nx_versions)'

Is this even possible? I also tried using ${{ nx_versions }} and ${{ variables.nx_versions }} to no avail.

This is possible with a full Designer solution.

Answer 1

The trivial pipeline (not referencing templates, but could be extended easily to do so)

parameters:
- name: nx_versions
  type: object
  default: 
  - 1
  - 4

jobs:
  - job: build
    strategy:
      matrix:
        ${{ each nxver in parameters.nx_versions }}:
          NX_${{ nxver }}:
            NXVersion: ${{ nxver }}
    steps:
      - powershell: echo $(NXVersion)

Expands to

parameters:
- name: nx_versions
  type: object
  default:
  - 1
  - 4
stages:
- stage: __default
  jobs:
  - job: build
    strategy:
      matrix:
        NX_1:
          NXVersion: 1
        NX_4:
          NXVersion: 4
    steps:
    - task: PowerShell@2
      inputs:
        targetType: inline
        script: echo $(NXVersion)

If you go to queue a build for that, you get a parameters page with the defaults:

that you can override:

which results in: