The QA team requested the ability to run pipeline jobs in a loop with a parameter that would specify the number of iterations.

My solution:

trigger:
- master

parameters:
  - name: myarray 
    type: object
    default:
    - '1'
    - '2'
    - '3'
    - '4'
    - '5'
    
  - name: counter
    type: string
    default: 3

pool:
  name: AWS_DEV_Linux

jobs:
  - ${{ each value in parameters.myarray }}:
    - ${{ if ge(parameters.counter, value) }}:
      - job: job_${{ value }}
        steps:
        - script: echo ${{ value }}

The output:

The problems of my solution:

1. Is expected to have more than 20 iterations (in my example only 5)
2. The array can be modified when someone run the pipeline manually and that can broke the pipeline (like in image)

An array as a variable could solve a part of this but is not allowed for my version (Version Azure DevOps Server 2022.2)

Question: How to create a loop more elegant and safe?

The QA team requested the ability to run pipeline jobs in a loop with a parameter that would specify the number of iterations.

My solution:

trigger:
- master

parameters:
  - name: myarray 
    type: object
    default:
    - '1'
    - '2'
    - '3'
    - '4'
    - '5'
    
  - name: counter
    type: string
    default: 3

pool:
  name: AWS_DEV_Linux

jobs:
  - ${{ each value in parameters.myarray }}:
    - ${{ if ge(parameters.counter, value) }}:
      - job: job_${{ value }}
        steps:
        - script: echo ${{ value }}

The output:

The problems of my solution:

1. Is expected to have more than 20 iterations (in my example only 5)
2. The array can be modified when someone run the pipeline manually and that can broke the pipeline (like in image)

An array as a variable could solve a part of this but is not allowed for my version (Version Azure DevOps Server 2022.2)

https://developercommunity.visualstudio/t/variables-in-yaml-pipeline-are-not-allowing-to-def/812728

Question: How to create a loop more elegant and safe?

• azure-devops
• yaml
• devops
• pipeline

Share Follow asked Mar 7 at 14:08 MacLeonMacLeon 11 1

• Hi @MacLeon, please check whether the answers below are helpful for you. If they don't work, provide more details so that others can help you. – Ziyang Liu-MSFT Commented Mar 25 at 6:20

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2 Answers 2

Sorted by: Reset to default 1

I don't fully understand the intention behind your example, but if you convert the jobs section into a template, you could iterate over an array that isn't sourced from a pipeline parameter, as shown in the example below:

# example-pipeline.yaml
parameters:
  - name: counter
    type: number
    default: 3

jobs:

- template: example-template.yaml
  parameters:
    myarray: [1,2,3,4,5]
    counter: ${{ parameters.counter }}

# example-template.yaml
parameters:
  - name: myarray 
    type: object
    
  - name: counter
    type: number

jobs:

  - ${{ each value in parameters.myarray }}:
    - ${{ if ge(parameters.counter, value) }}:
      - job: job_${{ value }}
        steps:
        - script: echo ${{ value }}

Run with counter 3

Run with counter 7

Hope this helps! Good luck.

Edit: Changed your parameter type of counter to type number (integer) otherwise it would parse incorrectly for 2-digit values >10 with the ge expression

If the elements for myarray are fixed and not changed often, you can set myarray as a static variable in the YAML pipeline, and its value is a string which is a comma-separated list of the elements.

And then you can use the split function to the variable value (a string) to be into substrings based on the comma character (,). This function returns an array of the substrings. You can loop the array to access each substring.

See below example as reference:

parameters:
- name: counter
  type: string
  default: '3'

variables:
  myArray: '1,2,3,4,5'

jobs:
- ${{ each value in split(variables.myArray, ',') }}:
  - ${{ if ge(parameters.counter, value) }}:
    - job: job_${{ value }}
      steps:
      - script: echo ${{ value }}

With above configuration, when users manually run the pipeline, they can only change the value of counter parameter, can cannot change the value of myArray. If you want to change value of myArray, you need to edit in the pipeline YAML file.