doc: added hacking page

    -

      title: "Examples"

      url: "/classic_examples"

    #-

    #  title: "Hacking"

    #  url: "/classic_hacking"

    -

      title: "Hacking"

      url: "/classic_hacking"

  #fnordmetric_enterprise:

Hacking

-------

here be dragons

This is a random collection of short tips.

### Config in multiple files

here be dragons

You can easily split up your config into multiple files like this:

*fnordmetric_main.rb*

### Writing custom widgets / views

    FnordMetric.namespace :myapp do

      instance_eval(&MY_FNORDMETRIC_MODULE1)

      instance_eval(&MY_FNORDMETRIC_MODULE2)

    end

here be dragons

*fnordmetric_module1.rb*

    MY_FNORDMETRIC_MODULE1 = proc {

### Mounting as Rails app

      # DSL statements go here

    }

here be dragons

<br />

### Redis Memory usage

...disable active users, larger flush_timeout

If you want to reduce redis memory you can do it by using larger

flush_timeouts. Apart from that there are two few low hanging

fruits:

**Disable active users plugin**

    FnordMetric.options = {

      :enable_active_users => false

    }

**Drastically reduce queue TTLs**

    FnordMetric.options = {

      :event_queue_ttl => 60,

      :event_data_ttl => 60,

      :session_data_ttl => 1

    }

<br />

### Writing custom widgets / views

There is one straightforward hack that you can use to build

your own widgets without having to understand the full FnordMetric

source:

### StatsD interoparability

Save this to a file blubb_widget.rb

    class FnordMetric::BlubbWidget < FnordMetric::Widget

      def render

        data.merge(:klass => "HtmlWidget", :html => my_html)

      end

      def my_html

        "<h1>Yay, I can render custom HTML in FnordMetric. The current time is: #{Time.now.to_s}</h1>"

      end

    end

and then use it like this:

    require "blubb_widget.rb"

    widget "My Dashboard",

      :title => "My custom widget",

      :type => :blubb,

      :width => 100

<br />

### Mounting as Rails app

...

I currently don't know how this can be done, since FnordMetric

uses rack-websockets, but it *should* be possible. If somebody

has done this, please send a Pull Request for this page on

github :)