code: def get_db_args_env(self):
          
          db = {
              'name': self.args.dbname,
              'host': self.args.dbhost,
              'user': self.args.dbuser,
              'pass': self.args.dbpass
              }
  
          if not self.args.no_db_config:
              try:
                  c = self.external.get_config(force=True)
              except Exception as e:
                  log.warn('config.xml not found: %s', e)
                  c = {}
  
              for k in db:
                  try:
                      db[k] = c['omero.db.%s' % k]
                  except KeyError:
                      log.info(
                          'Failed to lookup parameter omero.db.%s, using %s',
                          k, db[k])
  
          if not db['name']:
              raise Exception('Database name required')
  
          env = os.environ.copy()
          env['PGPASSWORD'] = db['pass']
          return db, env
docs: Get a dictionary of database connection parameters, and create an
          environment for running postgres commands.
          Falls back to omego defaults.