Injecting an input to a step provided in a stepList? - azure-devops

Question

I have a pipeline template that takes a stepList:
parameters:
- name: applicationDeploySteps
type: stepList
default: []
And injects the stepList into the template:
- deployment: Deploy_App
displayName: Deploy Application
pool: ${{ variables.AgentPool }}
environment: ${{ parameters.Stage }}
variables:
- name: ServiceConnection
value: SomeServiceConnection
strategy:
runOnce:
deploy:
steps:
- ${{ each step in parameters.applicationDeploySteps }}:
- ${{ each pair in step }}:
${{ pair.key }}: ${{ pair.value }}
However, I'd like to provide an AzureCLI#2 step, with the azureSubscription parameter being sourced from a variable inaccessible to the AzureCLI#2 step at the time of template compilation:
extends:
template: main.yml
parameters:
applicationDeploySteps:
- task: AzureCLI#2
inputs:
azureSubscription: $(ServiceConnection)
addSpnToEnvironment: true
scriptType: 'bash'
scriptLocation: 'inlineScript'
inlineScript: |
echo "do azurey things here"
The problem is in azureSubscription: $(ServiceConnection). Obviously, that variable can't resolve. So the solution I'm shooting for is to inject the azureSubscription value in the template. However, I can't find a way to effectively iterate over the values provided in the input block.
- ${{ each pair in step }}:
${{ pair.key }}: ${{ pair.value }}
will let me interrogate the type of the step. Trying to take it further just gives me a null reference exception when trying to queue the pipeline:
- ${{ each pair in step }}:
${{ if eq(pair.key, 'inputs') }}:
- ${{ each input in pair.value }}:
${{ if eq(input.key, 'azureSubscription') }}:
${{ input.key }}: ${{ variables.ServiceConnection }}
${{ else }}:
${{ input.key }}: ${{ input.value }}
${{ else }}:
${{ pair.key }}: ${{ pair.value }}
That attempt gives me: Object reference not set to an instance of an object. with no corresponding line number. I'm guessing it's failing to iterate over pair.value, but I have no idea how to troubleshoot it further or get an idea of what I can and cannot iterate over. The documentation does not include more comprehensive examples, just checking if, say, it's a script task and blocking execution.
Note that this is similar, but not the scenario that I'm implementing.

Answer 1

I figured it out.
- ${{ each step in parameters.applicationDeploySteps }}:
- ${{ each pair in step }}:
${{ if eq(pair.key, 'inputs') }}:
inputs:
${{ each input in pair.value }}:
${{ if eq(input.key, 'azureSubscription') }}:
${{ input.key }}: ${{ variables.ServiceConnection }}
${{ else }}:
${{ input.key }}: ${{ input.value }}
${{ else }}:
${{ pair.key }}: ${{ pair.value }}
This document was useful for pointing me in the right direction, but honestly it was mostly trial-and-error.