content: # Copyright Contributors to the Amundsen project.
  # SPDX-License-Identifier: Apache-2.0
  
  from flask import current_app as flask_app
  from flask import request
  
  from amundsen_common.log.caller_retrieval import BaseCallerRetriever
  
  CALLER_HEADER_KEY = 'CALLER_HEADER_KEY'
  
  
  class HttpHeaderCallerRetrieval(BaseCallerRetriever):
      def get_caller(self) -> str:
          header_key = flask_app.config.get(CALLER_HEADER_KEY, 'user-agent')
          return request.headers.get(header_key) or 'UNKNOWN'
  