Varnish cache hit ratio widget for Shopify's Dashing dashboard

README.md

Varnish Cache hit ratio widget for Dashing

Description

Varnish Dashing widget to display the ratio of cache hit/miss.

Dependencies

No dependencies

Usage

To use this widget:

• copy varnish.rb into your /jobs folder

Then include the widget in a dashboard, by adding the following snippet to your dashboard layout file:

	<li data-row="1" data-col="1" data-sizex="1" data-sizey="1">
      <div data-id="varnish_hit_rates" data-view="Meter" style="background-color: #2759a7"  data-title="Varnish hit ratio"></div>
    </li>

varnish.rb

def get_stats
	output = %x(varnishstat -1)

	stats = {
		:cache_hit => /cache_hit\s*(?<count>\d*)/m.match(output)[:count].to_i,
		:cache_miss => /cache_miss\s*(?<count>\d*)/m.match(output)[:count].to_i
	}
end

SCHEDULER.every('15s', first_in: '1s') {

	stats = get_stats

	if stats[:cache_miss] == 0 && stats[:cache_hit] == 0
		hit_rates = 0
	else
		hit_rates = stats[:cache_hit] * 100 / (stats[:cache_hit] + stats[:cache_miss])
	end

	# Send memory usage stats in bytes
	send_event('varnish_hit_rates', {
		"min" => 0,
		"max" => 100,
		value: hit_rates
	})
}