Can't run a templated yaml Azure Devops pipeline with dynamically created stage - azure-devops

Question

My problem
I try to create templated yaml Azure Devops pipeline:
parameters:
- name: envs
type: object
default:
- QUAL
- PROD
- PREPROD
stages:
- template: Orchestrator.yml
parameters:
name: envs
type: object
default:
- QUAL
- PROD
- PREPROD
This is my template:
parameters:
envs: {}
stages:
- ${{ each env in parameters.envs }}:
- stage: ${{ env }}
jobs:
- job: Deploy
steps:
- script: echo Deploy project
displayName: 'Deploy'
- job: Tests
steps:
- script: echo Unit tests
displayName: Test 1
But I get this error message:
An error occurred while loading the YAML build pipeline. The array
must contain at least one element. Parameter name: stages
OK, I modify my main script like this:
parameters:
- name: envs
type: object
default:
- QUAL
- PROD
- PREPROD
stages:
- stage: Build
jobs:
- job: Build
steps:
- script: echo Compilation completed...
displayName: 'Compile'
- template: Orchestrator.yml
parameters:
name: envs
type: object
default:
- QUAL
- PROD
- PREPROD
This time pipeline runs, but only first Job. The Template is not loaded.
What I need
I was able to make this scenario working with a single file script, but I would like to make it working with a templated script.
Is this scenario supported? How I can do?
thanks

Answer 1

Here I have a sample as reference:
In the template YAML file (here I name it template.yaml), write as this.
parameters:
- name: envs
type: object
default:
- QUAL
- PROD
- PREPROD
stages:
- ${{ each env in parameters.envs }}:
- stage: ${{ env }}
displayName: 'Stage ${{ env }}'
jobs:
- job: job1
displayName: 'Job 1'
steps:
- bash: echo "Current job is job1 in ${{ env }}"
- job: job2
displayName: 'Job 2'
steps:
- bash: echo "Current job is job2 in ${{ env }}"
In the pipeline YAML (here I name it pipeline.yaml), write as this.
trigger:
- main
extends:
template: template.yaml
Result
If you do not want to hardcode the value of the parameter 'envs' in template.yaml, you can write like as below.
In template.yaml write as this.
parameters:
- name: envs
type: object
default: []
stages:
- ${{ each env in parameters.envs }}:
- stage: ${{ env }}
displayName: 'Stage ${{ env }}'
jobs:
- job: job1
displayName: 'Job 1'
steps:
- bash: echo "Current job is job1 in ${{ env }}"
- job: job2
displayName: 'Job 2'
steps:
- bash: echo "Current job is job2 in ${{ env }}"
In pipeline.yaml write as this.
trigger:
- main
stages:
- template: template.yaml
parameters:
envs:
- QUAL
- PROD
- PREPROD
Result. Same as above.
To view more details, you can see "YAML schema reference".