Provision an array of blob containers and reduce their SasToken to an app settings

[scrocquesel-ml150]

Hi,

Given a variable array like

param containerList array = ['foo', 'bar']

I'm trying to build a configuration for a web site that would look like

resource appSettings 'Microsoft.Web/sites/config@2022-09-01' = {
  parent: webSiteResource
  name: 'appsettings'
  properties: {
      'blobs:0:token': '<sas token of foo>'
      'blobs:1:token': '<sas token of bar>'
  }
}

I managed to build something but I'm stuck with This expression is being used in the for-body of the variable "WSInfo", which requires values that can be calculated at the start of the deployment.bicep(BCP182)

var WSInfo = [for (containerName, index) in containerList: {
  sas: listServiceSas(storageAccountResource.name, '2023-01-01', {
    canonicalizedResource: '/blob/${storageAccountResource.name}/${containerName}'
    signedResource: 'c'
    signedProtocol: 'https'
    signedPermission: 'rwl'
    signedServices: 'b'
    signedExpiry: '2022-07-01T00:00:00Z'
  }).serviceSasToken
}]

var flat = reduce(WSInfo, {}, (cur, next) => union(cur, {
  'blob:${length(cur)}:token' : next.sas
}))

resource appSettings 'Microsoft.Web/sites/config@2022-09-01' = {
  parent: webSiteResource
  name: 'appsettings'
  properties: flat
}