How to log the host of Public Base URL instead of upstream host in custom access logging by Logging Policy

Issue

• Logging Policy is enabled with the following custom logging format:

  [{{time_local}}] {{host}}:{{server_port}} {{http_x_forwarded_for}} {{remote_addr}}:{{remote_port}} \"{{request}}\" 
  {{status}} {{body_bytes_sent}} ({{request_time}}) {{post_action_impact}}
  

  {{host}} logs the host of upstream (backend). How can the host of Public Base URL of the product be logged like default access log?

• In custom logging format of Logging policy, it specifies {{host}} in order to log the host accessed from a client.
  It works as expected when a request fails with error, such as 403(Authentication failed) and 429(Usage limit exceeded), but when a API request succeeds, the upstream host is logged instead.
  Is it possible to log the hostname of the product always?