This website is written in Ruby using the Sinatra framework and hosted with Passenger / Nginx on the Raspberry Pi ( temporarily not on a Pi! ) assisted by Cloudflare and a dash of jsDelivr

Live Raspberry Pi System Stats

I get a lot of people asking how I've put together the live system info on this very website. It's a lot easier than it looks to pull off, and I've opted to go a slightly more complex route than is sufficient. I use Ruby, Thin, EventMachine and other things that I'm assuming a basic knowledge of in this brief guide, in most cases you're best adapting the below code to your own language and server choices, but I'm aiming to write a more complete Ruby guide soon.

In its basic form, the stats are simply pumped out as HTML with the rest of the page and update only when you refresh the page. The only complexity here is the system commands needed to extract free disk space and memory. If you're a Rubyist, you can get everything you need with the following code ( which was previously shown in my post: Using the Palm m500 as a Raspberry Pi LCD ):

def self.get()
    @diskinfo = `df | grep rootfs | awk '{print $2,$4,$5}'`
    @diskinfo = @diskinfo.split(' ')
    @diskinfo_size = (@diskinfo[0].to_f / 1024 / 1024).round(2)
    @diskinfo_free = (@diskinfo[1].to_f / 1024 / 1024).round(2)
    @diskinfo_perc = @diskinfo[2].sub('%','')

    @cpu_perc = `vmstat | awk '{print $13}'`.split("\n").last

    @mem	  = `cat /proc/meminfo | grep Mem | awk '{print $2}'`
    @mem_total= (Float(@mem.split("\n").first) / 1024).round(2)
    @mem_free = (Float(@mem.split("\n").last) / 1024).round(2)

    @mem_perc = ((100/@mem_total)*(@mem_total-@mem_free)).round.to_s

    @uptime = `uptime`.chomp.to_s.to_s.sub('load average','load')

To make things more exciting, however, I wrapped up this code in a WebSocket server, using EventMachine's WebSocket library and just a little touch of MemCache to try and avoid the poor Pi being DDoS'd. You can see the full Ruby file here:

I run this using the "Thin" Ruby server, with a yml file something like this:

rackup: /home/pi/Web/
pid: tmp/pids/
log: log/thin.log
timeout: 30
max_conns: 1024
port: 8070
max_persistent_conns: 512
chdir: /home/pi/Web
environment: production
servers: 1
daemonize: true

« Back to index Posted on 2012-12-12 by