Merge pull request #843 from fluent/introduce-plugin-helpers

add new Plugin::Base class and PluginHelper modules

lib/fluent/log.rb

@@ -245,6 +245,10 @@ def flush
       @out.flush
     end
 
+    def reset
+      @out.reset if @out.respond_to?(:reset)
+    end
+
     private
 
     def dump_stacktrace(backtrace, level)

lib/fluent/plugin.rb

@@ -18,7 +18,7 @@
 require 'fluent/config/error'
 
 module Fluent
-  class Plugin
+  module Plugin
     SEARCH_PATHS = []
 
     # plugins for fluentd:         fluent/plugin/type_NAME.rb
@@ -35,24 +35,6 @@ class Plugin
 
     REGISTRIES = [INPUT_REGISTRY, OUTPUT_REGISTRY, FILTER_REGISTRY, BUFFER_REGISTRY, PARSER_REGISTRY, FORMATTER_REGISTRY]
 
-    def self.lookup_type_from_class(klass_or_its_name)
-      klass = if klass_or_its_name.is_a? Class
-                klass_or_its_name
-              elsif klass_or_its_name.is_a? String
-                eval(klass_or_its_name) # const_get can't handle qualified klass name (ex: A::B)
-              else
-                raise ArgumentError, "invalid argument type #{klass_or_its_name.class}: #{klass_or_its_name}"
-              end
-      REGISTRIES.reduce(nil){|a, r| a || r.reverse_lookup(klass) }
-    end
-
-    def self.add_plugin_dir(dir)
-      REGISTRIES.each do |r|
-        r.paths.push(dir)
-      end
-      nil
-    end
-
     def self.register_input(type, klass)
       register_impl('input', INPUT_REGISTRY, type, klass)
     end
@@ -89,6 +71,24 @@ def self.register_formatter(type, klass_or_proc)
       end
     end
 
+    def self.lookup_type_from_class(klass_or_its_name)
+      klass = if klass_or_its_name.is_a? Class
+                klass_or_its_name
+              elsif klass_or_its_name.is_a? String
+                eval(klass_or_its_name) # const_get can't handle qualified klass name (ex: A::B)
+              else
+                raise ArgumentError, "invalid argument type #{klass_or_its_name.class}: #{klass_or_its_name}"
+              end
+      REGISTRIES.reduce(nil){|a, r| a || r.reverse_lookup(klass) }
+    end
+
+    def self.add_plugin_dir(dir)
+      REGISTRIES.each do |r|
+        r.paths.push(dir)
+      end
+      nil
+    end
+
     def self.new_input(type)
       new_impl('input', INPUT_REGISTRY, type)
     end

lib/fluent/plugin/base.rb

@@ -0,0 +1,100 @@
+#
+# Fluentd
+#
+#    Licensed under the Apache License, Version 2.0 (the "License");
+#    you may not use this file except in compliance with the License.
+#    You may obtain a copy of the License at
+#
+#        http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS,
+#    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#    See the License for the specific language governing permissions and
+#    limitations under the License.
+#
+
+require 'fluent/plugin'
+require 'fluent/configurable'
+require 'fluent/plugin_id'
+require 'fluent/log'
+require 'fluent/plugin_helper'
+
+module Fluent
+  module Plugin
+    class Base
+      include Configurable
+      include PluginId
+      include PluginLoggerMixin
+      include PluginHelper::Mixin
+
+      State = Struct.new(:configure, :start, :stop, :shutdown, :close, :terminate)
+
+      def initialize
+        super
+        @state = State.new(false, false, false, false, false, false)
+      end
+
+      def has_router?
+        false
+      end
+
+      def configure(conf)
+        super
+        @state.configure = true
+        self
+      end
+
+      def start
+        @log.reset
+        @state.start = true
+        self
+      end
+
+      def stop
+        @state.stop = true
+        self
+      end
+
+      def shutdown
+        @state.shutdown = true
+        self
+      end
+
+      def close
+        @state.close = true
+        self
+      end
+
+      def terminate
+        @state.terminate = true
+        @log.reset
+        self
+      end
+
+      def configured?
+        @state.configure
+      end
+
+      def started?
+        @state.start
+      end
+
+      def stopped?
+        @state.stop
+      end
+
+      def shutdown?
+        @state.shutdown
+      end
+
+      def closed?
+        @state.close
+      end
+
+      def terminated?
+        @state.terminate
+      end
+    end
+  end
+end

lib/fluent/plugin_helper.rb

@@ -0,0 +1,36 @@
+#
+# Fluentd
+#
+#    Licensed under the Apache License, Version 2.0 (the "License");
+#    you may not use this file except in compliance with the License.
+#    You may obtain a copy of the License at
+#
+#        http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS,
+#    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#    See the License for the specific language governing permissions and
+#    limitations under the License.
+#
+
+require 'fluent/plugin_helper/event_emitter'
+require 'fluent/plugin_helper/thread'
+require 'fluent/plugin_helper/event_loop'
+require 'fluent/plugin_helper/timer'
+require 'fluent/plugin_helper/child_process'
+
+module Fluent
+  module PluginHelper
+    module Mixin
+      def self.included(mod)
+        mod.extend(Fluent::PluginHelper)
+      end
+    end
+
+    def helpers(*snake_case_symbols)
+      helper_modules = snake_case_symbols.map{|name| Fluent::PluginHelper.const_get(name.to_s.split('_').map(&:capitalize).join) }
+      include *helper_modules
+    end
+  end
+end