Best mechanism for converting a resource ID into name/resourceGroup/subscription?

[adrianhall]

I want to use resources created outside of my bicep template - for example, using a database server or API Management instance, but allowing my bicep template to create the database or API. To do this, I want to pass the ID of the resource as a parameter and then decode it to get the reference to the resource.

targetScope = 'resourceGroup'

@description('ID of the database service')
param databaseServiceId string

resource databaseService 'Microsoft.Network/sqlServers@2022-08-01' existing = {
  name: reference(databaseServiceId).name
  scope: reference(databaseServiceId).resourceGroup
}

Obviously, the reference function exists, but the resourceGroup, etc. don't.

What's the best way to get a reference to a resource based on the ID, so that it can be used for resource creation in the rest of the bicep script?

[alex-frankel]

The best way to do this is with the split() function. There's an example provided here:
#1722 (comment)

But #2245/#2246 will address this more completely, so going to close this.