[#4558] Refactor facter binary using optparse

Simplify the binary by moving all application specific code into a new
Facter::Application module. This module is then refactored to use
OptionParser and to simplify invocation logic, while maintaining
existing behavior.

1 files changed, 99 insertions, 0 deletions

diff --git a/lib/facter/application.rb b/lib/facter/application.rb
new file mode 100644
index 0000000..51dbd14
--- /dev/null
+++ b/lib/facter/application.rb
@@ -0,0 +1,99 @@
+module Facter
+  module Application
+    def self.run(argv)
+      require 'optparse'
+      require 'facter'
+
+      options = parse(argv)
+
+      # Accept fact names to return from the command line
+      names = argv
+
+      # Create the facts hash that is printed to standard out
+      if names.empty?
+        facts = Facter.to_hash
+      else
+        facts = {}
+        names.each { |name|
+          begin
+            facts[name] = Facter.value(name)
+          rescue => error
+            $stderr.puts "Could not retrieve #{name}: #{error}"
+            exit 10
+          end
+        }
+      end
+
+      # Print the facts as YAML and exit
+      if options[:yaml]
+        require 'yaml'
+        puts YAML.dump(facts)
+        exit(0)
+      end
+
+      # Print the value of a single fact, otherwise print a list sorted by fact
+      # name and separated by "=>"
+      if facts.length == 1
+        if value = facts.values.first
+          puts value
+        end
+      else
+        facts.sort_by{ |fact| fact.first }.each do |name,value|
+          puts "#{name} => #{value}"
+        end
+      end
+
+    rescue => e
+      $stderr.puts "Error: #{e}"
+      exit(12)
+    end
+
+    private
+
+    def self.parse(argv)
+      options = {}
+      OptionParser.new do |opts|
+        opts.on("-y", "--yaml")   { |v| options[:yaml]   = v }
+
+        opts.on("-d", "--debug")  { |v| Facter.debugging(1) }
+        opts.on("-p", "--puppet") { |v| load_puppet }
+
+        opts.on_tail("-v", "--version") do
+          puts Facter.version
+          exit(0)
+        end
+
+        opts.on_tail("-h", "--help") do
+          begin
+            require 'rdoc/ri/ri_paths'
+            require 'rdoc/usage'
+            puts RDoc.usage
+          ensure
+            exit
+          end
+        end
+      end.parse!
+
+      options
+    rescue OptionParser::InvalidOption => e
+      $stderr.puts e.message
+      exit(12)
+    end
+
+    def self.load_puppet
+      require 'puppet'
+      Puppet.parse_config
+
+      # If you've set 'vardir' but not 'libdir' in your
+      # puppet.conf, then the hook to add libdir to $:
+      # won't get triggered.  This makes sure that it's setup
+      # correctly.
+      unless $LOAD_PATH.include?(Puppet[:libdir])
+        $LOAD_PATH << Puppet[:libdir]
+      end
+    rescue LoadError => detail
+      $stderr.puts "Could not load Puppet: #{detail}"
+    end
+
+  end
+end