feat(azure/cloud): support passing authentication credentials as variables

nullplatform/cloud/azure/cloud/main.tf

@@ -6,7 +6,14 @@ resource "nullplatform_provider_config" "azure" {
   dimensions = var.dimensions
 
   attributes = jsonencode({
-    authentication = {},
+    authentication = {
+      for k, v in {
+        client_id       = var.client_id
+        client_secret   = var.client_secret
+        subscription_id = var.subscription_id
+        tenant_id       = var.tenant_id
+      } : k => v if v != null
+    },
     networking = {
       application_domain                   = var.application_domain,
       domain_name                          = var.domain_name,
@@ -17,6 +24,14 @@ resource "nullplatform_provider_config" "azure" {
     }
   })
   lifecycle {
+    precondition {
+      condition = (
+        (var.client_id == null) == (var.client_secret == null) &&
+        (var.client_id == null) == (var.subscription_id == null) &&
+        (var.client_id == null) == (var.tenant_id == null)
+      )
+      error_message = "Authentication credentials must all be set or all be null (client_id, client_secret, subscription_id, tenant_id)."
+    }
     ignore_changes = [attributes]
   }
 }

nullplatform/cloud/azure/cloud/tests/azure_cloud.tftest.hcl

@@ -34,6 +34,54 @@ run "attributes_contain_resource_groups" {
   }
 }
 
+run "with_authentication_credentials" {
+  command = plan
+
+  variables {
+    client_id       = "11111111-0000-0000-0000-000000000001"
+    client_secret   = "dummy-secret-for-testing-purposes-only!"
+    subscription_id = "22222222-0000-0000-0000-000000000002"
+    tenant_id       = "33333333-0000-0000-0000-000000000003"
+  }
+
+  assert {
+    condition     = strcontains(nullplatform_provider_config.azure.attributes, "11111111-0000-0000-0000-000000000001")
+    error_message = "Attributes should contain the client_id when provided"
+  }
+
+  assert {
+    condition     = strcontains(nullplatform_provider_config.azure.attributes, "22222222-0000-0000-0000-000000000002")
+    error_message = "Attributes should contain the subscription_id when provided"
+  }
+
+  assert {
+    condition     = strcontains(nullplatform_provider_config.azure.attributes, "33333333-0000-0000-0000-000000000003")
+    error_message = "Attributes should contain the tenant_id when provided"
+  }
+}
+
+run "without_authentication_credentials" {
+  command = plan
+
+  assert {
+    condition     = strcontains(nullplatform_provider_config.azure.attributes, "\"authentication\":{}") || strcontains(nullplatform_provider_config.azure.attributes, "\"authentication\": {}")
+    error_message = "Authentication block should be empty when no credentials provided (inherits from parent)"
+  }
+}
+
+run "partial_authentication_fails" {
+  command = plan
+
+  variables {
+    client_id = "11111111-0000-0000-0000-000000000001"
+    # client_secret, subscription_id, tenant_id omitted intentionally
+  }
+
+  expect_failures = [
+    nullplatform_provider_config.azure,
+  ]
+}
+
 run "with_domain_name" {
   command = plan
 

nullplatform/cloud/azure/cloud/variables.tf

@@ -3,6 +3,31 @@ variable "nrn" {
   description = "The NRN of your nullplatform account"
 }
 
+variable "client_id" {
+  type        = string
+  description = "Azure Service Principal client ID. If omitted, inherits from a parent cloud provider."
+  default     = null
+}
+
+variable "client_secret" {
+  type        = string
+  description = "Azure Service Principal client secret. If omitted, inherits from a parent cloud provider."
+  sensitive   = true
+  default     = null
+}
+
+variable "subscription_id" {
+  type        = string
+  description = "Azure subscription ID. If omitted, inherits from a parent cloud provider."
+  default     = null
+}
+
+variable "tenant_id" {
+  type        = string
+  description = "Azure Active Directory tenant ID. If omitted, inherits from a parent cloud provider."
+  default     = null
+}
+
 variable "domain_name" {
   description = "The domain name to be used"
   type        = string