A simple plugin manager, it stores one plugin each of a specific type the idea is that we can only have one security provider, one connector etc.
Adds a plugin to the list of plugins, we expect a hash like:
{:type => "base", :class => foo.new}
or like:
{:type => "base", :class => "Foo::Bar"}
In the event that we already have a class with the given type an exception will be raised.
If the :class passed is a String then we will delay instantiation till the first time someone asks for the plugin, this is because most likely the registration gets done by inherited() hooks, at which point the plugin class is not final.
If we were to do a .new here the Class initialize method would get called and not the plugins, we there for only initialize the classes when they get requested via []
By default all plugin instances are cached and returned later so there’s always a single instance. You can pass :single_instance => false when calling this to instruct it to always return a new instance when a copy is requested. This only works with sending a String for :class.
# File lib/mcollective/pluginmanager.rb, line 30 def self.<<(plugin) plugin[:single_instance] = true unless plugin.include?(:single_instance) type = plugin[:type] klass = plugin[:class] single = plugin[:single_instance] raise("Plugin #{type} already loaded") if @plugins.include?(type) # If we get a string then store 'nil' as the instance, signalling that we'll # create the class later on demand. if klass.is_a?(String) @plugins[type] = {:loadtime => Time.now, :class => klass, :instance => nil, :single => single} Log.debug("Registering plugin #{type} with class #{klass} single_instance: #{single}") else @plugins[type] = {:loadtime => Time.now, :class => klass.class, :instance => klass, :single => true} Log.debug("Registering plugin #{type} with class #{klass.class} single_instance: true") end end
Gets a plugin by type
# File lib/mcollective/pluginmanager.rb, line 72 def self.[](plugin) raise("No plugin #{plugin} defined") unless @plugins.include?(plugin) klass = @plugins[plugin][:class] if @plugins[plugin][:single] # Create an instance of the class if one hasn't been done before if @plugins[plugin][:instance] == nil Log.debug("Returning new plugin #{plugin} with class #{klass}") @plugins[plugin][:instance] = create_instance(klass) else Log.debug("Returning cached plugin #{plugin} with class #{klass}") end @plugins[plugin][:instance] else Log.debug("Returning new plugin #{plugin} with class #{klass}") create_instance(klass) end end
deletes all registered plugins
# File lib/mcollective/pluginmanager.rb, line 67 def self.clear @plugins.clear end
use eval to create an instance of a class
# File lib/mcollective/pluginmanager.rb, line 94 def self.create_instance(klass) begin eval("#{klass}.new") rescue Exception => e raise("Could not create instance of plugin #{klass}: #{e}") end end
Removes a plugim the list
# File lib/mcollective/pluginmanager.rb, line 52 def self.delete(plugin) @plugins.delete(plugin) if @plugins.include?(plugin) end
Finds plugins in all configured libdirs
find("agent")
will return an array of just agent names, for example:
["puppetd", "package"]
Can also be used to find files of other extensions:
find("agent", "ddl")
Will return the same list but only of files with extension .ddl in the agent subdirectory
# File lib/mcollective/pluginmanager.rb, line 116 def self.find(type, extension="rb") extension = ".#{extension}" unless extension.match(/^\./) plugins = [] Config.instance.libdir.each do |libdir| plugdir = File.join([libdir, "mcollective", type.to_s]) next unless File.directory?(plugdir) Dir.new(plugdir).grep(/#{extension}$/).map do |plugin| plugins << File.basename(plugin, extension) end end plugins.sort.uniq end
Finds and loads from disk all plugins from all libdirs that match certain criteria.
find_and_load("pluginpackager")
Will find all .rb files in the libdir/mcollective/pluginpackager/ directory in all libdirs and load them from disk.
You can influence what plugins get loaded using a block notation:
find_and_load("pluginpackager") do |plugin| plugin.match(/puppet/) end
This will load only plugins matching /puppet/
# File lib/mcollective/pluginmanager.rb, line 148 def self.find_and_load(type, extension="rb") extension = ".#{extension}" unless extension.match(/^\./) klasses = find(type, extension).map do |plugin| if block_given? next unless yield(plugin) end "%s::%s::%s" % [ "MCollective", type.capitalize, plugin.capitalize ] end.compact klasses.sort.uniq.each {|klass| loadclass(klass, true)} end
Grep’s over the plugin list and returns the list found
# File lib/mcollective/pluginmanager.rb, line 176 def self.grep(regex) @plugins.keys.grep(regex) end
Finds out if we have a plugin with the given name
# File lib/mcollective/pluginmanager.rb, line 57 def self.include?(plugin) @plugins.include?(plugin) end
Loads a class from file by doing some simple search/replace on class names and then doing a require.
# File lib/mcollective/pluginmanager.rb, line 164 def self.loadclass(klass, squash_failures=false) fname = klass.gsub("::", "/").downcase + ".rb" Log.debug("Loading #{klass} from #{fname}") load fname rescue Exception => e Log.error("Failed to load #{klass}: #{e}") raise unless squash_failures end
Provides a list of plugins we know about
# File lib/mcollective/pluginmanager.rb, line 62 def self.pluginlist @plugins.keys.sort end