Bicep variable creation from module output - azure-bicep

Question

I-m trying to create multiple app services with bicep using a for loop on a module.
The module has the following output:
output id string = appServiceAppResource.id
output name string = appServiceAppResource.name
output vnetIntegrationOn bool = allowVnetIntegration[appServicePlan.sku.name]
output principalId string = appServiceAppResource.identity.principalId // <-- important
After this, i want to create a key vault, and provide "get" access to all the app services previously created using an access policy:
...
param appServices object
...
module appServicePlanModules 'modules/appServicePlan.bicep' = [for appServicesConfig in appServicePlans.appServicesConfig: {
name: '${appServicesConfig.name}-appserviceplan-module'
params: {
location: location
name: appServicesConfig.name
sku: appServicesConfig.sku
}
}]
...
var accessPolicy = [ for i in range(0, appServices.instanceCount) : {
objectId: appServiceModule[i].outputs.principalId
permissions: {
secrets: ['get']
}
tenantId: subscription().tenantId
}]
module keyValutModule 'modules/keyvault.bicep' = {
name: 'key-valut-module'
dependsOn: [appServiceModule]
params: {
location: location
accessPolicies: accessPolicy
publicNetworkAccess: keyvault.publicNetworkAccess
keyVaultName: keyvault.name
}
}
The problem is that when i try to create that access policy, it fails
What puzzles me is that, this is working:
var accessPolicy = [{
objectId: appServiceModule[0].outputs.principalId
permissions: {
secrets: ['get']
}
tenantId: subscription().tenantId
}
{
objectId: appServiceModule[1].outputs.principalId
permissions: {
secrets: ['get']
}
tenantId: subscription().tenantId
}]
And also this:
var accessPolicies = [ for i in range(0,1):{
objectId: '52xxxxxx-25xx-4xxf-axxx-xxdxx3axxdff'
permissions: {
secrets: ['get']
}
tenantId: subscription().tenantId
}]
Since I want to use this template for multiple env, I want it to be more generic (so that i can have 1 or 5 service apps), so that for loop wold be very useful for me.
I'm not sure why, if I use a for loop in combination of a module output this is not working.
Do you have any idea why, or of there is a workaround on this.
Thank you!
Best regards,
Dorin