Use more concrete error class on plugin not found

lib/fluent/config/error.rb

@@ -29,4 +29,16 @@ class SetNil < Exception
 
   class SetDefault < Exception
   end
+
+  class NotFoundPluginError < ConfigError
+    attr_reader :type, :kind
+
+    def initialize(msg, type: nil, kind: nil)
+      @msg = msg
+      @type = type
+      @kind = kind
+
+      super(msg)
+    end
+  end
 end

lib/fluent/registry.rb

@@ -45,7 +45,8 @@ def lookup(type)
       if value = @map[type]
         return value
       end
-      raise ConfigError, "Unknown #{@kind} plugin '#{type}'. Run 'gem search -rd fluent-plugin' to find plugins"  # TODO error class
+      raise NotFoundPluginError.new("Unknown #{@kind} plugin '#{type}'. Run 'gem search -rd fluent-plugin' to find plugins",
+                                    kind: @kind, type: type)
     end
 
     def reverse_lookup(value)

test/compat/test_parser.rb

@@ -22,7 +22,7 @@ def parse(text)
   Fluent::TextParser.register_template('multi_event_test', Proc.new { MultiEventTestParser.new })
 
   def test_lookup_unknown_format
-    assert_raise Fluent::ConfigError do
+    assert_raise Fluent::NotFoundPluginError do
       Fluent::Plugin.new_parser('unknown')
     end
   end

test/plugin/test_filter_parser.rb

@@ -46,7 +46,7 @@ def test_configure
     assert_raise(Fluent::ConfigError) {
       create_driver('')
     }
-    assert_raise(Fluent::ConfigError) {
+    assert_raise(Fluent::NotFoundPluginError) {
       create_driver %[
         key_name foo
         <parse>

test/plugin/test_filter_stdout.rb

@@ -63,7 +63,7 @@ def test_output_type(data)
       end
 
       def test_invalid_output_type
-        assert_raise(Fluent::ConfigError) do
+        assert_raise(Fluent::NotFoundPluginError) do
           d = create_driver(CONFIG + config_element("", "", { "output_type" => "foo" }))
           d.run {}
         end
@@ -139,7 +139,7 @@ def test_output_type(data)
       def test_invalid_output_type
         conf = config_element
         conf.elements << config_element("format", "", { "@type" => "stdout", "output_type" => "foo" })
-        assert_raise(Fluent::ConfigError) do
+        assert_raise(Fluent::NotFoundPluginError) do
           d = create_driver(conf)
           d.run {}
         end

test/plugin/test_out_stdout.rb

@@ -32,7 +32,7 @@ def create_driver(conf = CONFIG)
       assert_kind_of Fluent::Plugin::StdoutFormatter, d.instance.formatter
       assert_equal 'hash', d.instance.formatter.output_type
 
-      assert_raise(Fluent::ConfigError) do
+      assert_raise(Fluent::NotFoundPluginError) do
         d = create_driver(CONFIG + "\noutput_type foo")
       end
     end
@@ -126,7 +126,7 @@ def create_driver(conf = CONFIG)
       assert_kind_of Fluent::Plugin::StdoutFormatter, d.instance.formatter
       assert_equal 'hash', d.instance.formatter.output_type
 
-      assert_raise(Fluent::ConfigError) do
+      assert_raise(Fluent::NotFoundPluginError) do
         create_driver(config_element("ROOT", "", {"output_type" => "foo"}, [config_element("buffer")]))
       end
     end

test/test_formatter.rb

@@ -349,7 +349,7 @@ class FormatterLookupTest < ::Test::Unit::TestCase
     include FormatterTest
 
     def test_unknown_format
-      assert_raise ConfigError do
+      assert_raise NotFoundPluginError do
         Fluent::Plugin.new_formatter('unknown')
       end
     end