document the plugin

plugins/puppet/puppetmaster

@@ -1,5 +1,28 @@
 #!/usr/bin/ruby
 
+# this plugin reports various performance statistics from a puppetmaster
+# server and client
+#
+# linked as puppet_mem, it will display memory usage of the puppet
+# client and puppet master on the local server.
+#
+# linked as puppet_clients, it will report the average compile time, the
+# number of clients that checked in in the last 5 minutes and 24h and
+# the number of known clients.
+#
+# it requires read access to the puppet logfile.
+#
+# CONFIGURATION
+#
+# [puppet*]
+# env.puppet_logfile /var/log/message
+# env.puppet_logformat "^%b %d"
+#
+# the logfile is where the puppetmaster is expected to log its
+# compilation statistics. the format is the format of the date syslog
+# writes to the file, which may vary according to locale and
+# configuration.
+
 # returns the mem usage of a given process
 def plist(psname)
 	counter = 0