Added support to specify a directory for custom formatters.

- The builtin formatters are source first.
- If a directory containing custom formatters is specified (via 'formatter_dir' in the config or -F on the command line)
 they will be sourced second.
- Any conflicts (i.e. custom formatters with the same name as a built in) will be handled by giving priority to the custom formatter(s).

lib/nagios-herald/formatter_loader.rb

@@ -10,25 +10,51 @@ module NagiosHerald
   class FormatterLoader
   include NagiosHerald::Logging
 
-    attr_accessor :formatter_path
+    attr_accessor :builtin_formatter_path
+    attr_accessor :custom_formatter_path
 
+    # Public: Initialize the formatter loader module.
+    # Adds the path to the built-in formatters to the module variable @formatter_paths.
+    # Adds the path to custom formatters if that option is passed to `nagios-herald`
+    # via '-F|--formatter-dir' on the command line or via the 'formatter-dir'
+    # option in the configuration file.
     def initialize
-      # TODO: add support for @options.formatter_path
-      @formatter_path = File.expand_path("formatters", File.dirname(__FILE__))
+      @builtin_formatter_path = File.expand_path("formatters", File.dirname(__FILE__))
+      @custom_formatter_path = Config.config['formatter_dir'] if Config.config['formatter_dir']
     end
 
     # Public: Enumerate the available formatter class files.
     #
-    # Returns an array of the class files' absolute paths
-    def enum_formatter_class_files(formatter_path)
-      formatter_class_files = Dir.glob(File.expand_path("*.rb", formatter_path))
+    # Returns a hash of the class files' absolute paths whose
+    # key is the formatter file's basename and the 
+    # value is the full path to the file.
+    def enum_formatter_class_files
+      formatter_class_files = {}
+
+      # Iterate over the builtin formatters first.
+      builtin_formatter_class_files = Dir.glob(File.expand_path("*.rb", @builtin_formatter_path))
+      builtin_formatter_class_files.each do |builtin_formatter_class_file|
+        formatter_class_files[File.basename(builtin_formatter_class_file)] = builtin_formatter_class_file
+      end
+      # If we've been told about custom formatters, add them to the hash.
+      # If there are conflicts, naively merge them, with the custom formatters getting
+      # priority.
+      if @custom_formatter_path
+        custom_formatters = {}
+        custom_formatter_class_files = Dir.glob(File.expand_path("*.rb", @custom_formatter_path))
+        custom_formatter_class_files.each do |custom_formatter_class_file|
+          custom_formatters[File.basename(custom_formatter_class_file)] = custom_formatter_class_file
+        end
+        formatter_class_files.merge!(custom_formatters)
+      end
+      formatter_class_files
     end
 
     # Public: An array of class files' paths.
     #
     # Returns an array of class files' paths.
     def formatter_class_files
-      @formatter_class_files ||= enum_formatter_class_files(@formatter_path)
+      @formatter_class_files ||= enum_formatter_class_files
     end
 
     # Public: Load the formatters into the namespace.
@@ -37,10 +63,15 @@ def formatter_class_files
     # Returns nothing but loads the classes into the namespace.
     def load_formatters
       if formatter_class_files.empty?
-        logger.fatal "#{$0}: No formatters were found in '#{@formatter_path}'"
+        if @custom_formatter_path
+          puts "#{$0}: No formatters were found in '#{@builtin_formatter_path}'" \
+          " or '#{@custom_formatter_path}' (as defined by the 'formatter_dir' option)!"
+        else
+          puts "#{$0}: No formatters were found in '#{@builtin_formatter_path}'!"
+        end
         exit 1
       else
-        formatter_class_files.each do |formatter_class_file|
+        formatter_class_files.each do |formatter_class, formatter_class_file|
           Kernel.load formatter_class_file
         end
       end

lib/nagios-herald/formatters/check_disk.rb

@@ -1,8 +1,5 @@
 # CheckDisk formatter
 # Colorizes and bolds text generated by the 'check_disk' NRPE check.
-# Downloads a Ganglia graph of the host's overall disk utilization.
-# Queries Splunk to determine how many times this alert has fired for this host
-# in the last 7 days.
 
 module NagiosHerald
   class Formatter