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.. Copyright 2015 Comcast Cable Communications Management, LLC
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.. Licensed under the Apache License, Version 2.0 (the "License");
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..     http://www.apache.org/licenses/LICENSE-2.0
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Traffic Stats
*************

Introduction
============
Traffic Stats is a utility written in `Go <http.golang.org>`_ that is 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 also calculates daily statistics from InfluxDb and stores them in the Traffic Ops database.

Software Requirements
=====================
To work on Traffic Stats you need a \*nix (MacOS and Linux are most commonly used) environment that has the following installed:

	* `Go 1.7.x or above <https://golang.org/doc/install>`_
	* Access to a working instance of Traffic Ops
	* Access to a working instance of Traffic Monitor
	* `InfluxDb version 1.0.0 or greater <https://influxdb.com/download/index.html>`_

Traffic Stats Project Tree Overview
=====================================
	* **traffic_control/traffic_stats** - contains Go source files and Files used to create the Traffic Stats rpm.
	* **traffic_control/traffic_stats/grafana/** - contains a javascript file which is installed on the grafana server.  This allows Traffic Ops to create custom dashboards for Delivery Services, Caches, etc.
	* **traffic_control/traffic_stats/influxdb_tools/** - contains one tool to create the databases and retention policies needed by Traffic Stats as well as continuous queries to downsample data; contains another tool to sync downsampled data between influxdb instances.  This is is helpful if you have multiple instances and they get out of sync with data.


Go Formatting Conventions
============================
In general `Go fmt <https://golang.org/cmd/gofmt/>`_ is the standard for formatting go code.  It is also recommended to use `Go lint <https://github.com/golang/lint>`_.

Installing The Developer Environment
====================================
To install the Traffic Ops Developer environment:

	- Clone the traffic_control repository using Git into a location accessible by your $GOPATH
	- Navigate to the traffic_ops/client directory of your cloned repository. (This is the directory containing Traffic Ops client code used by Traffic Stats)
	- From the traffic_ops/client directory run ``go test`` to test the client code.  This will run all unit tests for the client and return the results.  If there are missing dependencies you will need to run ``go get <dependency name>`` to get the dependency
	- Once the tests pass, run ``go install`` to build and install the Traffic Ops client package.  This makes it accessible to Traffic Stats.
	- Navigate to your cloned repo under Traffic Stats
	- Run ``go build traffic_stats.go`` to build traffic_stats.  You will need to run ``go get`` for any missing dependencies.


Test Cases
==========
	Currently there are no automated tests for Traffic Stats :( but pull requests are always welcome to fix this problem!