docs: def dns_log_graph(self, stream):
          ''' Build up a graph (nodes and edges from a Bro dns.log) '''
          dns_log = list(stream)
          print 'Entering dns_log_graph...(%d rows)' % len(dns_log)
          for row in dns_log:
              
              # Skip '-' hosts
              if (row['id.orig_h'] == '-'):
                  continue
  
              # Add the originating host
              self.add_node(row['id.orig_h'], row['id.orig_h'], ['host', 'origin'])
  
              # Add the query host
              self.add_node(row['query'], row['query'], ['host', 'dns_query'])
  
              # The relationship between origin host and query
              self.add_rel(row['id.orig_h'], row['query'], 'dns_query')
  
              # Add the DNS answers as hosts and add the relationships
              for answer in row['answers'].split(','):
                  self.add_node(answer, answer, ['host'])
                  self.add_rel(row['query'], answer, row['qtype_name'])