Customize AWS Elastic Beanstalk wsgi.conf without being wiped out after update of environment variables

customize_wsgi.config

files:
  "/opt/elasticbeanstalk/hooks/configdeploy/pre/99patchwsgi.py": &file
    mode: "000755"
    owner: root
    group: root
    content: |
      #!/usr/bin/env python
      import os
      import sys
      sys.path.append(os.path.dirname(os.path.dirname(os.path.dirname(os.path.abspath(__file__)))))
      import config

      def main():
        if 'EB_SYSTEM_STARTUP' in os.environ:
          return
        try:
          WSGI_STAGING_CONFIG = config.get_container_config('wsgi_staging_config')
          config.execute(['mkdir', '-p', '/etc/httpd/wsgi.conf.d'])
          config.execute(['sed', '-i', '/\<VirtualHost \*:80\>/a IncludeOptional /etc/httpd/wsgi.conf.d/*.conf', WSGI_STAGING_CONFIG])
        except Exception, e:
          config.emit_error_event(config.USER_ERROR_MESSAGES['badappconfig'])
          config.diagnostic('Error patching wsgi.conf during configdeploy/pre: %s' % str(e))
          sys.exit(1)

      if __name__ == '__main__':
        config.configure_stdout_logger()
        main()
  "/opt/elasticbeanstalk/hooks/appdeploy/pre/99patchwsgi.py": *file
  "/etc/httpd/wsgi.conf.d/enable_auth_header.conf":
    mode: "000755"
    owner: root
    group: root
    content: |
      WSGIPassAuthorization On

@djshen-ponddy can you elaborate steps how to deploy this script and will it be applicable in autoscale case?