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.. _dev-traffic-stats:

*************
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 the :ref:`tm-api` 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
=====================
* A \*nix (MacOS and Linux are most commonly used) environment
* `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://influxdata.com/downloads>`_

Traffic Stats Project Tree Overview
=====================================
* :file:`traffic_stats/` - contains Go source files and files used to create the Traffic Stats RPM.

	* :file:`grafana/` - contains a javascript file which is installed on the Grafana server. This allows Traffic Ops to create custom dashboards for :term:`Delivery Services`, :term:cache server`\ s, etc.
	* :file:`influxdb_tools/` - contains :ref:`sync_ts_databases` and :ref:`create_ts_databases` which are 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
====================================
#. Clone the traffic_control repository using Git into a location accessible by your $GOPATH
#. Navigate to the :atc-file:`traffic_ops/v4-client` directory of your cloned repository. (This is the directory containing Traffic Ops client code used by Traffic Stats)
#. From the :atc-file:`traffic_ops/v4-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 mod vendor -v`` to get the dependencies
#. 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 repository under Traffic Stats
#. Run ``go build traffic_stats.go`` to build traffic_stats.  You will need to run ``go mod vendor -v`` for any missing dependencies.