filter {

    grok {

        match => [

             "message" , "\s*%{IPORHOST:clientip}\s+\-\s+\-\s+\[%{HTTPDATE:time}\]\s+\"%{WORD:verb}\s+(?<api>(\S+))\?.*\s+HTTP/%{NUMBER:httpversion}\"\s+%{NUMBER:http_status_code}\s+%{NUMBER:bytes}\s+(%{BASE16FLOAT:request_time})\s+%{IPORHOST:remoteip}",

              "message" ,"\s*%{IPORHOST:clientip}\s+\-\s+\-\s+\[%{HTTPDATE:time}\]\s+\"%{WORD:verb}\s+(?<api>(\S+))\s+HTTP/%{NUMBER:httpversion}\"\s+%{NUMBER:http_status_code}\s+%{NUMBER:bytes}\s+(%{BASE16FLOAT:request_time})\s+%{IPORHOST:remoteip}",

             "message" ,"\s*%{IPORHOST:clientip}\s+\-\s+\-\s+\[%{HTTPDATE:time}\]\s+\"%{WORD:verb}\s+(?<api>(\S+))\s+HTTP/%{NUMBER:httpversion}\"\s+%{NUMBER:http_status_code}\s+\-\s+(%{BASE16FLOAT:request_time})\s+%{IPORHOST:remoteip}"

        ]

    }

        mutate {

                        convert => [ "request_time", "float"]

                       add_field =>["response_time","%{request_time}"]

                        remove_field =>["request_time"]

                }

   date {

        match => ["time", "dd/MMM/yyyy:HH:mm:ss Z"]

    }

}