Principal

Users/Service accounts which have access for DNS binding on the intranet VPC corresponding to the consumer project. Principal can be a user or a service account. For example: For specifying user user@example.com use {"user": "user@example.com"} and for specifying service account service-account@gserviceaccount.com use {"serviceAccount": "service-account@gserviceaccount.com"}.

JSON representation 
{

  // The following is a list of mutually exclusive fields. At most one of the
  // fields will be set in a response:
  "user": string,
  "serviceAccount": string
  // End of mutually exclusive fields.
}
Fields
The consumer provided user/service account which needs to be granted permission to DNS bind with the intranet VPC corresponding to the consumer project. Principal can be a user or a service account. For example: For specifying user user@example.com use {"user": "user@example.com"} and for specifying service account service-account@gserviceaccount.com use {"serviceAccount": "service-account@gserviceaccount.com"}. The following is a list of mutually exclusive fields. At most one of the fields will be set in a response:
user

string

The user who needs to be granted permission.
serviceAccount

string

The service account which needs to be granted the permission.
End of mutually exclusive fields.