Send null logConfig if subnetwork is L7ILB (#2635)

* Send null logConfig if subnetwork is L7ILB

* Move subnet ilb check to only if logConfig unspecified

products/compute/api.yaml

@@ -9184,7 +9184,8 @@ objects:
         update_id: 'logConfig'
         description: |
           Denotes the logging options for the subnetwork flow logs. If logging is enabled
-          logs will be exported to Stackdriver.
+          logs will be exported to Stackdriver. This field cannot be set if the `purpose` of this
+          subnetwork is `INTERNAL_HTTPS_LOAD_BALANCER`
         properties:
           - !ruby/object:Api::Type::Enum
             name: 'aggregationInterval'

templates/terraform/custom_expand/subnetwork_log_config.go.erb

@@ -16,10 +16,17 @@ func expand<%= prefix -%><%= titlelize_property(property) -%>(v interface{}, d T
 	l := v.([]interface{})
 	transformed := make(map[string]interface{})
 	if len(l) == 0 || l[0] == nil {
+		purpose, ok := d.GetOkExists("purpose")
+
+		if ok && purpose.(string) == "INTERNAL_HTTPS_LOAD_BALANCER" {
+			// Subnetworks for L7ILB do not accept any values for logConfig
+			return nil, nil
+		}
 		// send enable = false to ensure logging is disabled if there is no config
 		transformed["enable"] = false
 		return transformed, nil
 	}
+
 	raw := l[0]
 	original := raw.(map[string]interface{})