.. include:: ../../common.defs .. _header_freq-plugin: Header Frequency Plugin *********************** .. Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements. See the NOTICE file distributed with this work for additional information regarding copyright ownership. The ASF licenses this file to you under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. The Header Frequency plugin keeps track of the number of times headers have been seen in transactions. Two separate counteres are kept for the origin and the client. This information is accessible via the ``log`` plugin message. By default the data is sent to traffic.out but it can alternatively be appended to an arbitrary file. The following logs the stats to ``traffic.out``:: traffic_ctl plugin msg header_freq log The following appends the stats to ``/tmp/log.txt``. Note that this file must be writeable by the traffic_server process's user:: traffic_ctl plugin msg header_freq log:/tmp/log.txt Installation ------------ Since Header Frequency plugin is an expiremental plugin. To make this plugin available, you must enable experimental plugins when building |TS| by passing the ``-DBUILD_EXPERIMENTAL_PLUGINS=ON`` to the ``cmake`` command when building. Once built, add the following line to :file:`plugin.config` and restart |TS| to use it:: header_freq.so