# NAME

rrdruby - About the RRD Ruby bindings

# SYNOPSIS

    require "RRD"
    RRD.create(
       rrd,
       "--step", "300",
       "DS:a:GAUGE:600:U:U",
       "DS:b:GAUGE:600:U:U",
       "RRA:AVERAGE:0.5:1:300")

# DESCRIPTION

The rrdtool functions are directly callable via the Ruby programming language. This wrapper implementation has been written from the scratch (without SWIG)

The API simply expects string parameters to the functions. Please refer to the other rrdtool documentation for functions and valid arguments.

# EXAMPLE

    $: << '/path/to/rrdtool/lib/ruby/1.8/i386-linux'
    require "RRD"

    name = "test"
    rrd = "#{name}.rrd"
    start = Time.now.to_i

    RRD.create(
       rrd,
       "--start", "#{start - 1}",
       "--step", "300",
           "DS:a:GAUGE:600:U:U",
       "DS:b:GAUGE:600:U:U",
       "RRA:AVERAGE:0.5:1:300")
    puts

    puts "updating #{rrd}"
    start.to_i.step(start.to_i + 300 * 300, 300) { |i|
       RRD.update(rrd, "#{i}:#{rand(100)}:#{Math.sin(i / 800) * 50 + 50}")
    }
    puts

    puts "fetching data from #{rrd}"
    (fstart, fend, data, step) = RRD.fetch(rrd, "--start", start.to_s, "--end",
         (start + 300 * 300).to_s, "AVERAGE")
    puts "got #{data.length} data points from #{fstart} to #{fend}"
    puts

    puts "generating graph #{name}.png"
    RRD.graph(
      "#{name}.png",
       "--title", " RubyRRD Demo",
       "--start", "#{start+3600}",
       "--end", "start + 1000 min",
       "--interlaced",
       "--imgformat", "PNG",
       "--width=450",
       "DEF:a=#{rrd}:a:AVERAGE",
       "DEF:b=#{rrd}:b:AVERAGE",
       "CDEF:line=TIME,2400,%,300,LT,a,UNKN,IF",
       "AREA:b#00b6e4:beta",
       "AREA:line#0022e9:alpha",
       "LINE3:line#ff0000")
    puts

If you use the --ruby-site-install configure option you can drop the $: line since the RRDtool module will be found automatically.

If RRDtool runs into trouble, it will throw an exception which you might want to catch.

# SEE ALSO

rrdcreate, rrdupdate, rrdgraph, rrddump, rrdfetch, rrdtune, rrdlast, rrdxport, rrdinfo

# AUTHOR

Loïs Lherbier <lois.lherbier@covadis.ch>

Miles Egan <miles@caddr.com>