Support for configuration of keyVaultReferenceIdentity in azurerm_app_service

[orjan]

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Description

Some apps need to reference secrets at creation time, when a system-assigned identity would not yet be available. In these cases, a user-assigned identity can be created and given access to the vault in advance.

• Accessing key vault from app service

Today there's no way to configure this through terraform making it hard to resolve key vault values needed a startup e.g. @Microsoft.KeyVault(VaultName=myvault;SecretName=mysecret) so we'll need to resort to a manual configuration similar to the one below.

userAssignedIdentityResourceId=$(az identity show -g MyResourceGroupName -n MyUserAssignedIdentityName --query id -o tsv)
appResourceId=$(az webapp show -g MyResourceGroupName -n MyAppName --query id -o tsv)
az rest --method PATCH --uri "${appResourceId}?api-version=2021-01-01" --body "{'properties':{'keyVaultReferenceIdentity':'${userAssignedIdentityResourceId}'}}"

New or Affected Resource(s)

• azurerm_app_service

Potential Terraform Configuration

resource "azurerm_app_service" "example" {
  key_vault_reference_identity_id = azurerm_user_assigned_identity.default.id
}

References

• Accessing key vault from app service
• app_service#acr_user_managed_identity_client_id

[orjan]

Maybe it's better to use key_vault_reference_identity since there are 3 potential values:

• azurerm_user_assigned_identity.default.id
• "SystemAssigned"
• null

I don't know how we could set null due to models.go looks like this:

	if s.KeyVaultReferenceIdentity != nil {
		objectMap["keyVaultReferenceIdentity"] = s.KeyVaultReferenceIdentity
	}

There is a NullValue present i another part in the Azure SDK but I'm not sure if we can use it?
https://github.com/Azure/azure-sdk-for-go/blob/main/sdk/azcore/core.go#L20

[github-actions]

This functionality has been released in v2.83.0 of the Terraform Provider. Please see the Terraform documentation on provider versioning or reach out if you need any assistance upgrading.

For further feature requests or bug reports with this functionality, please create a new GitHub issue following the template. Thank you!

[orjan]

It’s working as expected, great work @patst!

[github-actions]

This functionality has been released in v2.83.0 of the Terraform Provider. Please see the Terraform documentation on provider versioning or reach out if you need any assistance upgrading.

For further feature requests or bug reports with this functionality, please create a new GitHub issue following the template. Thank you!

[sebader]

Would be awesome if this could also be added to Function Apps! #13960

[github-actions]

I'm going to lock this issue because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active issues.
If you have found a problem that seems similar to this, please open a new issue and complete the issue template so we can capture all the details necessary to investigate further.