better doc and error handling

generators/grid5000.rb

@@ -10,10 +10,12 @@ usage = %{
   A tool to generate the Grid5000 reference data.
   
   Usage:
-    ruby grid5000.rb [input files] [options]
+    ruby grid5000.rb [input files] [config files] [options]
   Options:
     -s : simulation mode
-    
+  Notes:
+    input files must be RUBY files and end with a .rb extension.
+    config files mst be YAML files and end with a .yaml extension.
 }
 
 # true if we want to simulate:
@@ -21,10 +23,10 @@ simulation_mode = !$*.delete("-s").nil?
 
 if $*.empty?
   puts usage
-  exit -1
-elsif ($*.map{|file| File.exists?(file) && (File.extname(file) == ".rb" || File.extname(file) == ".yaml")}.include? false)
-  puts "Error: your input files do not exist or are not ruby files (.rb extension) or config files (.yaml extension)."
-  exit -1
+  exit 1
+elsif ($*.map{|file| File.exists?(file)}.include? false)
+  puts "Error: one of your input file do not exist."
+  exit 2
 else
   description_files = $*
   input = {}

generators/lib/g5k_generator.rb

@@ -65,8 +65,9 @@ class ReferenceGenerator
     Resolv.getaddress(network_address)
   end
   
+  # Lookup a key in one of the configuration files passed to the generator
   #
-  # usage:
+  # Usage:
   #   lookup('nancy', 'nodes', 'paramount-1', 'property_name')
   # or
   #   lookup('nancy', 'nodes') { |result| result['paramount-1']['property_name'] }
@@ -158,7 +159,8 @@ class ReferenceGenerator
   # Initializes a new generator that will generate data files in a hierachical way. 
   # The root of the tree will be named with the value of <tt>data_description[:uid]</tt>.
   def initialize(data_description = {:uid => ""}, options = {:input => {}, :config => {}})
-    @input = options[:input] || raise(ArgumentError, "INPUT cannot be null.")
+    @input = options[:input]
+    raise(ArgumentError, "INPUT cannot be null or empty.") if input.nil? || input.empty?
     @config = options[:config] || {}
     @data = G5K::Tree.new.replace(data_description)
     @context = @data