How to specify a condition for a loop in yaml pipelines - yaml

Question

I'm trying to download multiple artifacts into different servers(like web, db) using environments. Currently i have added the task DownloadPipelineArtifact#2 in a file and using template to add that task in azure-pipelines.yml. As i'm having multiple artifacts, im trying to use for loop where i'm getting issues.
#azure-pipelines.yml
- template: artifacts-download.yml
parameters:
pipeline:
- pipeline1
- pipeline2
- pipeline3
path:
- path1
- path2
- path3
I need to write loop in yaml so that it should download the pipeline1 artifacts to path1 and so on. Can someone please help??

Answer 1

Object-type parameters are your friend. They are incredibly powerful. As qBasicBoy answered, you'll want to make sure that you group the multiple properties together. If you're finding that you have a high number of properties per object, though, you can do a multi-line equivalent.
The following is an equivalent parameter structure to what qBasicBoy posted:
parameters:
- name: pipelines
type: object
default:
- Name: pipeline1
Path: path1
- Name: pipeline2
Path: path2
- Name: pipeline3
Path: path3
An example where you can stack many properties to a single object is as follows:
parameters:
- name: big_honkin_object
type: object
default:
config:
- appA: this
appB: is
appC: a
appD: really
appE: long
appF: set
appG: of
appH: properties
- appA: and
appB: here
appC: we
appD: go
appE: again
appF: making
appG: more
appH: properties
settings:
startuptype: service
recovery: no
You can, in essence, create an entire dumping ground for everything that you want to do by sticking it in one single object structure and properly segmenting everything. Sure, you could have had "startuptype" and "recovery" as separate string parameters with defaults of "service" and "no" respectively, but this way, we can pass a single large parameter from a high level pipeline to a called template, rather than passing a huge list of parameters AND defining said parameters in the template yaml scripts (remember, that's necessary!).
If you then want to access JUST a single setting, you can do something along the lines of:
- task: PowerShell#2
inputs:
targetType: 'inline'
script: |
# Write your PowerShell commands here.
Write-Host "Apps start as a "${{ parameters.settings.startuptype }}
Write-Host "Do the applications recover? "${{ parameters.settings.recovery }}
This will give you the following output:
Apps start as a service
Do the applications recover? no
YAML and Azure Pipelines are incredibly powerful tools. I can't recommend enough going through the entire contents of learn.microsoft.com on the subject. You'll spend a couple hours there, but you'll come out the other end with an incredibly knowledge of how these pipelines can be tailored to do everything you could ever NOT want to do yourself!
Notable links that helped me a TON (only learned this a couple months ago):
How to work with the YAML language in Pipelines
https://learn.microsoft.com/en-us/azure/devops/pipelines/yaml-schema?view=azure-devops&tabs=schema%2Cparameter-schema
How to compose expressions (also contains useful functions like convertToJSON for your object parameters!)
https://learn.microsoft.com/en-us/azure/devops/pipelines/process/expressions?view=azure-devops
How to create variables (separate from parameters, still useful)
https://learn.microsoft.com/en-us/azure/devops/pipelines/build/variables?view=azure-devops&tabs=yaml
SLEEPER ALERT!!! Templates are HUGELY helpful!!!
https://learn.microsoft.com/en-us/azure/devops/pipelines/process/templates?view=azure-devops

Answer 2

You could use an object with multiple properties
parameters:
- name: pipelines
type: object
default:
- { Name: pipeline1, Path: path1 }
- { Name: pipeline2, Path: path2 }
- { Name: pipeline3, Path: path3 }
steps:
- ${{each pipeline in parameters.pipelines}}:
# use pipeline.Name or pipeline.Path