contrib/collectd_unix_sock.rb: Ruby class which abstracts the plain text protocol.

Used to talk to the unixsock plugin.

Signed-off-by: Florian Forster <octo@leeloo.lan.home.verplant.org>

diff --git a/contrib/collectd_unix_sock.rb b/contrib/collectd_unix_sock.rb
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+# Ruby class to access collectd daemon through the UNIX socket
+# plugin.
+#
+# Requires collectd to be configured with the unixsock plugin, like so:
+#
+# LoadPlugin unixsock
+# <Plugin unixsock>
+#   SocketFile "/var/run/collectd-unixsock"
+#   SocketPerms "0775"
+# </Plugin>
+#
+# Copyright (C) 2009 Novell Inc.
+# Author: Duncan Mac-Vicar P. <dmacvicar@suse.de>
+#
+# Inspired in python version:
+# Copyright (C) 2008 Clay Loveless <clay@killersoft.com>
+#
+# This software is provided 'as-is', without any express or implied
+# warranty.  In no event will the author be held liable for any damages
+# arising from the use of this software.
+#
+# Permission is granted to anyone to use this software for any purpose,
+# including commercial applications, and to alter it and redistribute it
+# freely, subject to the following restrictions:
+#
+# 1. The origin of this software must not be misrepresented; you must not
+#    claim that you wrote the original software. If you use this software
+#    in a product, an acknowledgment in the product documentation would be
+#    appreciated but is not required.
+# 2. Altered source versions must be plainly marked as such, and must not be
+#    misrepresented as being the original software.
+# 3. This notice may not be removed or altered from any source distribution.
+#
+require 'socket'
+
+# Access to collectd data using the unix socket
+# interface
+#
+# see http://collectd.org/wiki/index.php/Plugin:UnixSock
+#
+class CollectdUnixSock
+  include Socket::Constants
+
+  # initializes the collectd interface
+  # path is the location of the collectd
+  # unix socket
+  #
+  # collectd = CollectdUnixSock.new
+  #
+  def initialize(path='/var/run/collectd-unixsock')
+    @socket = UNIXSocket.open(path)
+    # @socket = Socket.new(AF_UNIX, SOCK_STREAM, 0)
+    # @socket.connect(path)
+    @path = path
+  end
+
+  # iterates over available values, passing the
+  # identifier to the block and the time
+  # the data for this identifier was last
+  # updated
+  #
+  # collectd.each_value do |time, identifier|
+  #   ...
+  # end
+  def each_value
+    n_lines = cmd("LISTVAL")
+    n_lines.times do
+      line = @socket.readline
+      time_s, identifier = line.split(' ', 2)
+      time = Time.at(time_s.to_i)
+      yield time, identifier
+    end
+  end
+
+  # iterates over each value current data
+  #
+  # collectd.each_value_data('myhost/swap/swap-free') { |col, val| }
+  #
+  # each iteration gives the column name and the value for it.
+  #
+  # You can also disable flushing by specifying it as an option:
+  #
+  # client.each_value_data('tarro/swap/swap-free',
+  #                   :flush => false ) do |col, val|
+  #    # .. do something with col and val
+  # end
+  #
+  # :flush option is by default true
+  #
+  def each_value_data(identifier, opts={})
+    n_lines = cmd("GETVAL \"#{identifier}\"")
+    n_lines.times do
+      line = @socket.readline
+      col, val = line.split('=', 2)
+      yield col, val
+    end
+
+    # unless the user explicitly disabled
+    # flush...
+    unless opts[:flush] == false
+      cmd("FLUSH identifier=\"#{identifier}\"")
+    end
+    
+  end
+  
+  private
+  
+  # internal command execution
+  def cmd(c)
+    @socket.write("#{c}\n")
+    line = @socket.readline
+    status_string, message = line.split(' ', 2)
+    status = status_string.to_i
+    raise message if status < 0
+    status  
+  end
+  
+end
+
+if __FILE__ == $0
+
+  client = CollectdUnixSock.new
+  client.each_value do |time, id|
+    puts "#{time.to_i} - #{id}"
+  end
+
+  client.each_value_data("tarro/cpu-0/cpu-user") do |col, val|
+    puts "#{col} -> #{val}"
+  end
+  
+  client.each_value_data("tarro/interface/if_packets-eth0") do |col, val|
+    puts "#{col} -> #{val}"
+  end
+  
+end