Module: RRDm

Extended by:
RRDm
Included in:
RRDm
Defined in:
lib/gri/rrd.rb

Constant Summary collapse

@@rrdtool_path = 
(Dir.glob('/usr/local/rrdtool-*/bin/rrdtool').sort.reverse +
  ['/usr/local/bin/rrdtool', '/usr/bin/rrdtool']).find {|path|
  File.executable? path.untaint
}

Instance Attribute Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#version ⇒ Object (readonly)

Returns the value of attribute version.



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# File 'lib/gri/rrd.rb', line 13

def version
  @version
end

Instance Method Details

#close ⇒ Object 



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# File 'lib/gri/rrd.rb', line 73

def close
  @sequence = nil
  @in.close
  @out.close
  @err.close
end

#cmd(*args) ⇒ Object 



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# File 'lib/gri/rrd.rb', line 66

def cmd(*args)
  @sequence = 'C'
  cmd = args.join(' ')
  @in.print cmd, "\n"
  @last_cmd = cmd
end

#read(out = nil) ⇒ Object

Raises:

  • (RuntimeError) 


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# File 'lib/gri/rrd.rb', line 37

def read out=nil
  unless @sequence == 'C'
    raise RuntimeError, 'RRDm.read can only be called after RRDm.cmd'
  end
  @sequence == 'R'
  lines = []
  errline = nil

  while line = @out.gets
    if line =~ /^ERROR/
	errline = line.gsub(/\n/, "\\n")
      raise RuntimeError, errline
    elsif line =~ /^OK u:([\d\.]+) s:([\d\.]+) r:([\d\.]+)/
	sys, user, real = $1.to_f, $2.to_f, $3.to_f
	if errline
 raise RuntimeError, errline
	else
 return [lines.join(''), sys, user, real]
	end
    end
    if out
      out.write line
    else
      lines.push line
    end
  end
  raise RuntimeError, 'unexpected EOF'
end

#running? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/gri/rrd.rb', line 33

def running?
  @sequence
end

#start(rrdtool_path = nil) ⇒ Object

Raises:

  • (RuntimeError) 


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# File 'lib/gri/rrd.rb', line 15

def start rrdtool_path=nil
  rrdtool_path ||= @@rrdtool_path
  raise RuntimeError, 'rrdtool is already running' if @sequence
  unless rrdtool_path and File.exist?(rrdtool_path)
    raise Exception, "rrdtool #{rrdtool_path} not found"
  end
  @sequence = 'S'
  @last_cmd = nil

  @in, @out, @err = Open3.popen3("#{rrdtool_path} -")
  @in.sync = true
  @out.sync = true

  cmd 'version'
  line, = read
  @version, = line.scan(/^RRDtool\s+(\S+)/)[0]
end