Azure DevOps Conditional String Variables - azure

Question

I've got a pipeline I've created that deploys some app settings to all our websites (multiple per file), and I'm trying to conditionally set a variable within the JSON structure without any sort of anti-patterns.
For conditional variables, all we have this syntax:
${{ if endsWith('EXISTING_STRING','MATCH_STRING') }}:
${{ else }}:
This syntax assumes that you're going to put the entirety of the string after condition, though. If my JSON structure is 50 lines long, I don't want to do that. Is there a way to do this without that cluttered code, whilst avoiding any sort of anti-patterns as well?
Here's the Azure Piplines Module:
- task: AzureAppServiceSettings#1
displayName: 'Deploy App Settings'
inputs:
azureSubscription: "${{ parameters.resource_group_name }}"
appName: "wz${{ parameters.default_environment }}"
resourceGroupName: "${{ parameters.resource_group_name }}"
appSettings: |
[
{
"name": "LaunchUrl",
"value": "False",
/* ^^^^
Value I want to be conditional based off:
if endsWith( parameters['default_environment'], 'matchString'
The resulting string also contains parameters.default_environment FYI
*/
"slotSetting": true
},
{
"name": "DisableFHIR",
"value": "False",
"slotSetting": true
},
...
Thanks

Answer 1

Putting conditionals inside a string literal is unfortunately not supported. However, one technique my team uses is define our JSON values as a string parameter and populate it with variables that are evaluated at runtime.
parameters:
- name: appSettings
type: string
default: |
'[
{
"name": "appSetting1",
"value": "$(appSetting1)",
"slotSetting": "true"
}
]'
Personally, I like to go one further and define them as a yaml parameter and then use the convertToJson expression. This avoids the potential for malformed JSON and I can also put comments in the YAML.
parameters:
- name: resource_group_name
type: string
- name: appSettings
type: object
default:
- name: 'LaunchUrl'
value: '$(launchUrl)'
slotSetting: true
- name: 'DisableFHIR'
value: 'false'
slotSetting: true
job:
variables:
${{ if endsWith('prd', parameters.resource_group_name) }}:
launchUrl: https://production.dot.com
${{ else }}:
launchUrl: http://somewhere.else.com
steps:
- task: AzureAppServiceSettings#1
inputs:
azureSubscription: "${{ parameters.resource_group_name }}"
appName: "wz${{ parameters.default_environment }}"
resourceGroupName: "${{ parameters.resource_group_name }}"
appSettings: ${{ convertToJson(parameters.appSettings) }}