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.. Copyright 2015 Comcast Cable Communications Management, LLC
.. 
.. Licensed 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
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..     http://www.apache.org/licenses/LICENSE-2.0
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.. 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
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.. _reference-label-tc-ts:
.. |arrow| image:: fwda.png


Traffic Stats
=============
Traffic Stats is a collection of utilities written in `Go <http.golang.org>`_ that are used to acquire and store statistics about CDNs controlled by Traffic Control.  Traffic Stats mines metrics from Traffic Monitor's JSON APIs and stores the data in `InfluxDb <http://influxdb.com>`_.  Data is typically stored in InfluxDb on a short-term basis (30 days or less) and is used to drive graphs created by `Grafana <http://grafana.org>`_ which are linked from Traffic Ops.  Traffic Stats contains two separate services: write traffic stats and ts daily summary.  See below for more information. 

|arrow| Write Traffic Stats
---------------------------
Write Traffic Stats gathers stat data for Edge Caches and Delivery Services at a configurable interval from the Traffic Monitor API's and stores the data in InfluxDb.  Write Traffic Stats stores data in two seperate databases: cache_stats and deliveryservice_stats. 

	- cache_stats:  The cache_stats database is used to store data gathered from edge caches.  The `measurements <https://influxdb.com/docs/v0.9/concepts/glossary.html#measurement>`_ stored by cache are: bandwidth, maxKbps, and client_connections (ats.proxy.process.http.current_client_connections).  Cache Data is stored with `tags <https://influxdb.com/docs/v0.9/concepts/glossary.html#tag>`_ for hostname, cachegroup, and CDN.  Data can be queried using tags.


	- deliveryservice_stats:  The deliveryservice_stats database is used to store data for delivery services.  The measurements stored by delivery service are:  kbps, status_4xx, status_5xx, tps_2xx, tps_3xx, tps_4xx, tps_5xx, and tps_total.  Delivery Service stats are stored with tags for cachegroup, CDN, and Deliveryservice xml_id.  

|arrow| TS Daily Summary
--------------------------
TS (Traffic Stats) Daily Summary is a process that runs once a day, gathers summary data for the previous day from InfluxDb, and stores it in the Traffic Ops Database as well as the daily_stats table in influxDb.  The stats that are currently summarized are Max Bandwidth and Bytes Served and they are stored by CDN.

------------

Any number of Traffic Stats instances may run on a given CDN to collect metrics from Traffic Monitor, however, integration with a long term metrics storage system is implementation dependent. 

Traffic Stats does not influence overall CDN operation, but is required in order to display charts in Traffic Operations.