How do I defined subnets in Bicep such that the parent Vnet has a reference and that I can dependOn the subnet deployment?

Question

I have a situation where I need to define my subnets in the properties.subnets field of the parent virtual network otherwise I get the 'InUseSubnetCannotBeDeleted' problem

Option 1 - Defined inline

However if I define my subnets directly in the properties.subnet array (see below) then they are not created as children and I cannot seem to create a reference them as a resource for when I want to create a dependsOn reference for another resource.

resource virtualNetwork 'Microsoft.Network/virtualNetworks@2021-08-01' = {
  // ... other fields
  properties: {
    subnets: [
      // How can I get a reference to these that I can 'dependOn'?
      {
        name: 'subnet-1'
        // ... other fields
      }
      {
        name: 'subnet-2'
        // ... other fields
      }
    ]
  }
}

Option 2 - Defined separately

resource virtualNetwork 'Microsoft.Network/virtualNetworks@2021-08-01' = {
  // ... other fields
  properties: {
    subnets: [
      subnet1 // Gives a circular reference error
    ]
  }
}

resource subnet1 'Microsoft.Network/virtualNetworks/subnets@2021-08-01' = {
  parent: virtualNetwork
  name: 'subnet-1'
  // ... other fields
}

I have tried defining the subnets as separate resources and then reference the resources in the properties.subnet array but, since subnets need a reference to the parent virtual network proeprty, Bicep complains about a circular reference.

It seems that ARM templates can use textual references using the name of the subnet in properties.subnets whcih could get around the circular reference, however Bicep does not allow this.

So how do I defined my subnets so that I can simulteneously satisfy the virtual network's required to have a reference to the subnets in properties.subnets as well as be able to have a resource reference that I can use in dependsOn clauses?

Answer 1

Maybe this will work. Bicep builds it without errors, but I have not tried to deploy it.

resource virtualNetwork 'Microsoft.Network/virtualNetworks@2021-08-01' = {
  name: 'myvnet'
  location: 'swedencentral'
  properties: {
    addressSpace: {
      addressPrefixes: [
        '10.0.0.0/20'
      ]
    }
    subnets: [
      {
        name: 'subnet-1'
        properties: {
          addressPrefix: '10.0.0.0/24'
        }
      }
    ]
  }
}

resource subnet 'Microsoft.Network/virtualNetworks/subnets@2022-01-01' existing = {
  name: 'myvnet/subnet-1'
  scope: resourceGroup()
}

resource storage 'Microsoft.Storage/storageAccounts@2021-09-01' =  {
  name: 'mystorage'
  location: 'swedencentral'
  dependsOn: [
    subnet
  ]
  sku: {
    name: 'Standard_LRS'
  }
  kind: 'StorageV2'
}