GraphIT ?
=========

GraphIT is a really simple monitoring solution. Unlike other
solutions like Cacti, GraphIT is very quick to setup, and very easy
to use. On the other side, GraphIT is not designed for large monitoring
task, and it targets geek who want to monitor their server in a simple
way.

GraphIT is client/server based, uses SQLite as database backend and
HTTP as transport protocol. It use REST (Representational State 
Transfer) principle to exchange data between agents and server, and
server and frontend. All data are formated in JSON format.

Agent is a simple HTTP client that support POST request. A Python
library is provided to facilitate agents creation in Python.

Frontend is a simple web page with JavaScript that queries GraphIT
server with Ajax. Charts are rendered with flot JS library.

Setup
=====

Installation
------------

The installation is *really* simple, you just have to type that
command (after installing setuptools package on your distro):

``easy_install graphit``

Configuration
-------------

Configuration is exclusively made with help of ``graphitd`` command
parameters. Type ``graphitd --help`` to have a list of available
parameters.

GraphITize installation
-----------------------

GraphITize is the JavaScript/HTML frontend of GraphIT. Download from
http://idevelop.org/p/graphit/downloads/ 
the latests version of GraphITize. Uncompress it on your web server.

Rely on provided index.html to understand how GraphITize work (it's so
simple !!).

You can host GraphITize on other server than GraphIT, and even run it
on your desktop, without web server.

GraphIT implement ``JSONP`` and ``OPTIONS`` http method for Ajax Cross domain.
JSONP is used by default because OPTIONS http method is only implemented
on recent Firefox and Webkit versions. To use this latter, remove the 
"callback" parameter in your URL when you call ``graphitize()``.

Using Watchers
==============

Watchers are prefabricated agents for GraphIT. They are distributed with
GraphIT.

Watchers needs to be run regulary, you can use a crontask to do that, 
and you just have to choose an interval (which depend on the need of
accuracy on the data).

Some watchers need a specific execution interval. For exemple 
graphit-vnstat is used to get network trafic speed on a specified
interface. If you make a "snapshot" of speed every five minutes, you
will have data that will be not representative of average speed of the
last five minutes, but just during watcher's execution.

To prevent this problem, vnstat is executed for a time specified by user
(60 seconds by default), and returns trafic speed average for this time.

In this case, you CAN'T execute watcher more than one time by time
specified, or many watcher instance will be executed at the same 
time.

Watchers binaries starts with "graphit-" prefix, and are installed at
the same location as graphid binary.

Agent creation
==============

Agent Python library is installed with server package 
(see Setup/`Installation`_). To use it, you have to import 
``GraphItAgent`` in ``graphit.client`` :

>>> from graphit.client import GraphItAgent

Then, you have just to instanciate it :

>>> agent = GraphItAgent('http://my-graphit-server/', login='graphit', passwd='secret')

Finally, to submit monitoring data use add_value method :

>>> agent.add_value(set='df', feed='sda', value=42, unit='%')

It's that easy!

Changelog
=========

O.5:
 
 - This release introduce "Watchers". Watchers are littles scripts that
   uses Watchers framework and allow to submit data to GraphIT daemon 
   (through Python library for GraphIT). They are somehow prefabricated 
   GraphIT agents, distributed with GraphIT, and usable with a common 
   cli interface.
   Watchers added in this release are graphit-loadavg and graphit-mem.
   See setup to learn how to use it.
   More coming soon.

0.4.1:

 - Bugfix release for a bug introduced in 0.4 release. Graphit will
   now start if index already exists on database.
 - Index will be automatically added if it doesnt exists.


0.4:

 - Graphid database now use index on it database. That really improve 
   response time on query... The modification only concerns new database 
   creation, so, to create index on old database : ``sqlite3 <path to 
   database> "CREATE INDEX "main"."idx" ON "monitdata" ("date" DESC, 
   "set" ASC, "feed" ASC)"`` Thanks to Thibault VINCENT for idea.
