Using module outputs in Scope

[JPullinger]

Recently using a Naming module to apply standard naming convention's across a project, I ran into the issue that you can't use a output from the Naming module (RG Name) in the Scope. VSCode obviously tell's me the code is broken.

Example:
scope: az.resourceGroup(deploymentsubscription, naming_module_001.outputs.resourceGroupName)

Although you can just code/hardcode RG names is there any potential in the future that a naming module output could be used in the Scope?

[jeskew]

ARM is unlikely to remove this restriction in the future, but there are a couple of alternative approaches you could try.

Assuming the "naming module" just does some calculations on parameters and returns the results as outputs without deploying any resources, you could try using user-defined functions instead. These can be reused across templates with import statements.

If the naming module needs to remain a module (i.e., if it deploys resources) and the naming logic can't be factored out, you can use an output of one module as the scope of another by introducing an extra layer of indirection:

main.bicep

module namingModule 'namingModule.bicep' = {
  ...
}

module otherModule 'indirection.bicep' = {
  name: 'other'
  parameters: {
    targetResourceGroupName: namingModule.outputs.resourceGroupName
  }
}

indirection.bicep

param targetResourceGroupName string

resource targetRg 'Microsoft.Resources/resourceGroups@2021-04-01' existing = {
  name: targetResourceGroupName
}

module mod 'mod.bicep' = {
  name: 'mod'
  scope: targetRg
  ...
}

I wouldn't recommend this approach if you can avoid it because it is verbose and thwarts many kinds of static analysis (e.g., you cannot use What-If if you follow this pattern).