diff --git a/itamae.gemspec b/itamae.gemspec
index fa8f93a6..4c84ee34 100644
--- a/itamae.gemspec
+++ b/itamae.gemspec
@@ -30,4 +30,5 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency "pry-byebug"
   spec.add_development_dependency "docker-api", "~> 1.20"
   spec.add_development_dependency "fakefs"
+  spec.add_development_dependency "fluent-logger"
 end
diff --git a/lib/itamae.rb b/lib/itamae.rb
index 889201c4..ff143137 100644
--- a/lib/itamae.rb
+++ b/lib/itamae.rb
@@ -3,6 +3,8 @@
 require "itamae/cli"
 require "itamae/recipe"
 require "itamae/resource"
+require "itamae/handler"
+require "itamae/handler_proxy"
 require "itamae/recipe_children"
 require "itamae/logger"
 require "itamae/node"
diff --git a/lib/itamae/handler.rb b/lib/itamae/handler.rb
new file mode 100644
index 00000000..43f30a32
--- /dev/null
+++ b/lib/itamae/handler.rb
@@ -0,0 +1,21 @@
+require 'itamae/handler/base'
+
+module Itamae
+  module Handler
+    def self.from_type(type)
+      first_time = true
+
+      class_name = type.split('_').map(&:capitalize).join
+      self.const_get(class_name)
+    rescue NameError
+      require "itamae/handler/#{type}"
+
+      if first_time
+        first_time = false
+        retry
+      else
+        raise
+      end
+    end
+  end
+end
diff --git a/lib/itamae/handler/base.rb b/lib/itamae/handler/base.rb
new file mode 100644
index 00000000..86c9c868
--- /dev/null
+++ b/lib/itamae/handler/base.rb
@@ -0,0 +1,40 @@
+require 'socket'
+
+module Itamae
+  module Handler
+    class Base
+      attr_reader :recipes, :resources, :actions
+
+      def initialize(options)
+        @options = options
+
+        @recipes = []
+        @resources = []
+        @actions = []
+      end
+
+      def event(type, payload = {})
+        case type
+        when :recipe_started
+          @recipes << payload
+        when :recipe_completed, :recipe_failed
+          @recipes.pop
+        when :resource_started
+          @resources << payload
+        when :resource_completed, :resource_failed
+          @resources.pop
+        when :action_started
+          @actions << payload
+        when :action_completed, :action_failed
+          @actions.pop
+        end
+      end
+
+      private
+
+      def hostname
+        @hostname ||= @options['hostname'] || Socket.gethostname
+      end
+    end
+  end
+end
diff --git a/lib/itamae/handler/debug.rb b/lib/itamae/handler/debug.rb
new file mode 100644
index 00000000..af7f289c
--- /dev/null
+++ b/lib/itamae/handler/debug.rb
@@ -0,0 +1,10 @@
+module Itamae
+  module Handler
+    class Debug < Base
+      def event(type, payload = {})
+        super
+        Itamae.logger.info("EVENT:#{type} #{payload}")
+      end
+    end
+  end
+end
diff --git a/lib/itamae/handler/fluentd.rb b/lib/itamae/handler/fluentd.rb
new file mode 100644
index 00000000..5d78b08c
--- /dev/null
+++ b/lib/itamae/handler/fluentd.rb
@@ -0,0 +1,44 @@
+module Itamae
+  module Handler
+    class Fluentd < Base
+      attr_accessor :fluent_logger # for test
+
+      def initialize(*)
+        super
+        load_fluent_logger
+      end
+
+      def event(type, payload = {})
+        super
+
+        unless @fluent_logger.post(type, payload.merge(hostname: hostname))
+          Itamae.logger.warn "Sending logs to Fluentd failed: #{@fluent_logger.last_error}"
+        end
+      end
+
+      private
+
+      def load_fluent_logger
+        begin
+          require 'fluent-logger'
+        rescue LoadError
+          raise "Loading fluent-logger gem failed. Please install 'fluent-logger' gem to use fluentd handler."
+        end
+
+        @fluent_logger = Fluent::Logger::FluentLogger.new(tag_prefix, host: fluentd_host, port: fluentd_port)
+      end
+
+      def tag_prefix
+        @options['tag_prefix'] || 'itamae_server'
+      end
+
+      def fluentd_host
+        @options['host'] || 'localhost'
+      end
+
+      def fluentd_port
+        (@options['port'] || 24224).to_i
+      end
+    end
+  end
+end
diff --git a/lib/itamae/handler/json.rb b/lib/itamae/handler/json.rb
new file mode 100644
index 00000000..bbe6fbd4
--- /dev/null
+++ b/lib/itamae/handler/json.rb
@@ -0,0 +1,22 @@
+module Itamae
+  module Handler
+    class Json < Base
+      def initialize(*)
+        super
+        require 'time'
+        open_file
+      end
+
+      def event(type, payload = {})
+        super
+        @f.puts({'time' => Time.now.iso8601, 'event' => type, 'payload' => payload}.to_json)
+      end
+
+      private
+
+      def open_file
+        @f = open(@options.fetch('path'), 'a')
+      end
+    end
+  end
+end
diff --git a/lib/itamae/handler_proxy.rb b/lib/itamae/handler_proxy.rb
new file mode 100644
index 00000000..c8c206be
--- /dev/null
+++ b/lib/itamae/handler_proxy.rb
@@ -0,0 +1,38 @@
+module Itamae
+  class HandlerProxy
+    def initialize
+      @instances = []
+    end
+
+    def register_instance(instance)
+      @instances << instance
+    end
+
+    def event(*args, &block)
+      if block_given?
+        _event_with_block(*args, &block)
+      else
+        _event(*args)
+      end
+    end
+
+    private
+
+    def _event(*args)
+      @instances.each do |i|
+        i.event(*args)
+      end
+    end
+
+    def _event_with_block(event_name, *args, &block)
+      event("#{event_name}_started".to_sym, *args)
+      block.call
+    rescue
+      event("#{event_name}_failed".to_sym, *args)
+      raise
+    else
+      event("#{event_name}_completed".to_sym, *args)
+    end
+  end
+end
+
diff --git a/lib/itamae/recipe.rb b/lib/itamae/recipe.rb
index e923fa24..68eafce0 100644
--- a/lib/itamae/recipe.rb
+++ b/lib/itamae/recipe.rb
@@ -61,9 +61,11 @@ def load(vars = {})
     def run
       show_banner
 
-      Itamae.logger.with_indent do
-        @children.run
-        run_delayed_notifications
+      @runner.handler.event(:recipe, path: @path) do
+        Itamae.logger.with_indent do
+          @children.run
+          run_delayed_notifications
+        end
       end
     end
 
diff --git a/lib/itamae/resource/base.rb b/lib/itamae/resource/base.rb
index 36ce7faa..f3d3400f 100644
--- a/lib/itamae/resource/base.rb
+++ b/lib/itamae/resource/base.rb
@@ -121,26 +121,31 @@ def initialize(recipe, resource_name, &block)
       end
 
       def run(specific_action = nil)
-        Itamae.logger.debug "#{resource_type}[#{resource_name}]"
-
-        Itamae.logger.with_indent_if(Itamae.logger.debug?) do
-          if do_not_run_because_of_only_if?
-            Itamae.logger.debug "#{resource_type}[#{resource_name}] Execution skipped because of only_if attribute"
-            return
-          elsif do_not_run_because_of_not_if?
-            Itamae.logger.debug "#{resource_type}[#{resource_name}] Execution skipped because of not_if attribute"
-            return
-          end
+        runner.handler.event(:resource, resource_type: resource_type, resource_name: resource_name) do
+          Itamae.logger.debug "#{resource_type}[#{resource_name}]"
+
+          Itamae.logger.with_indent_if(Itamae.logger.debug?) do
+            if do_not_run_because_of_only_if?
+              Itamae.logger.debug "#{resource_type}[#{resource_name}] Execution skipped because of only_if attribute"
+              return
+            elsif do_not_run_because_of_not_if?
+              Itamae.logger.debug "#{resource_type}[#{resource_name}] Execution skipped because of not_if attribute"
+              return
+            end
+
+            [specific_action || attributes.action].flatten.each do |action|
+              run_action(action)
+            end
 
-          [specific_action || attributes.action].flatten.each do |action|
-            run_action(action)
+            verify unless runner.dry_run?
+            if updated?
+              notify
+              runner.handler.event(:resource_updated)
+            end
           end
 
-          verify unless runner.dry_run?
-          notify if updated?
+          @updated = false
         end
-
-        @updated = false
       rescue Backend::CommandExecutionError
         Itamae.logger.error "#{resource_type}[#{resource_name}] Failed."
         exit 2
@@ -151,15 +156,7 @@ def action_nothing
       end
 
       def resource_type
-        humps = []
-        self.class.name.split("::").last.each_char do |c|
-          if "A" <= c && c <= "Z"
-            humps << c.downcase
-          else
-            humps.last << c
-          end
-        end
-        humps.join('_')
+        self.class.name.split("::").last.scan(/[A-Z][^A-Z]+/).map(&:downcase).join('_')
       end
 
       private
@@ -167,45 +164,50 @@ def resource_type
       alias_method :current, :current_attributes
 
       def run_action(action)
-        original_attributes = @attributes # preserve and restore later
-        @current_action = action
+        runner.handler.event(:action, action: action) do
+          original_attributes = @attributes # preserve and restore later
+          @current_action = action
 
-        clear_current_attributes
+          clear_current_attributes
 
-        Itamae.logger.debug "#{resource_type}[#{resource_name}] action: #{action}"
+          Itamae.logger.debug "#{resource_type}[#{resource_name}] action: #{action}"
 
-        return if action == :nothing
+          return if action == :nothing
 
-        Itamae.logger.with_indent_if(Itamae.logger.debug?) do
-          Itamae.logger.debug "(in pre_action)"
-          pre_action
+          Itamae.logger.with_indent_if(Itamae.logger.debug?) do
+            Itamae.logger.debug "(in pre_action)"
+            pre_action
 
-          Itamae.logger.debug "(in set_current_attributes)"
-          set_current_attributes
+            Itamae.logger.debug "(in set_current_attributes)"
+            set_current_attributes
 
-          Itamae.logger.debug "(in show_differences)"
-          show_differences
+            Itamae.logger.debug "(in show_differences)"
+            show_differences
 
-          method_name = "action_#{action}"
-          if runner.dry_run?
-            unless respond_to?(method_name)
-              Itamae.logger.error "action #{action.inspect} is unavailable"
-            end
-          else
-            args = [method_name]
-            if method(method_name).arity == 1
-              # for plugin compatibility
-              args << runner.options
+            method_name = "action_#{action}"
+            if runner.dry_run?
+              unless respond_to?(method_name)
+                Itamae.logger.error "action #{action.inspect} is unavailable"
+              end
+            else
+              args = [method_name]
+              if method(method_name).arity == 1
+                # for plugin compatibility
+                args << runner.options
+              end
+
+              public_send(*args)
             end
 
-            public_send(*args)
+            if different?
+              updated!
+              runner.handler.event(:attribute_changed, from: @current_attributes, to: @attributes)
+            end
           end
 
-          updated! if different?
+          @current_action = nil
+          @attributes = original_attributes
         end
-
-        @current_action = nil
-        @attributes = original_attributes
       end
 
       def clear_current_attributes
diff --git a/lib/itamae/resource/file.rb b/lib/itamae/resource/file.rb
index 69e0ad7d..9fc253f4 100644
--- a/lib/itamae/resource/file.rb
+++ b/lib/itamae/resource/file.rb
@@ -50,8 +50,8 @@ def show_differences
 
         super
 
-        if current.exist && @temppath
-          show_file_diff
+        if @temppath
+          compare_file
         end
       end
 
@@ -113,8 +113,14 @@ def action_edit(options)
 
       private
 
-      def show_file_diff
-        diff = run_command(["diff", "-u", attributes.path, @temppath], error: false)
+      def compare_file
+        compare_to = if current.exist
+                       attributes.path
+                     else
+                       '/dev/null'
+                     end
+
+        diff = run_command(["diff", "-u", compare_to, @temppath], error: false)
         if diff.exit_status == 0
           # no change
           Itamae.logger.debug "file content will not change"
@@ -132,6 +138,7 @@ def show_file_diff
               Itamae.logger.info line.chomp
             end
           end
+          runner.handler.event(:file_content_changed, diff: diff.stdout)
         end
       end
 
diff --git a/lib/itamae/runner.rb b/lib/itamae/runner.rb
index d3aa2858..136aa268 100644
--- a/lib/itamae/runner.rb
+++ b/lib/itamae/runner.rb
@@ -20,11 +20,14 @@ def run(recipe_files, backend_type, options)
     attr_reader :node
     attr_reader :tmpdir
     attr_reader :children
+    attr_reader :handler
 
     def initialize(backend, options)
       @backend = backend
       @options = options
 
+      prepare_handler
+
       @node = create_node
       @tmpdir = "/tmp/itamae_tmp"
       @children = RecipeChildren.new
@@ -106,5 +109,16 @@ def create_node
 
       Node.new(hash, @backend)
     end
+
+    def prepare_handler
+      @handler = HandlerProxy.new
+      (@options[:handlers] || []).each do |handler|
+        type = handler.delete('type')
+        unless type
+          raise "#{type} field is not set"
+        end
+        @handler.register_instance(Handler.from_type(type).new(handler))
+      end
+    end
   end
 end
diff --git a/spec/unit/lib/itamae/handler/base_spec.rb b/spec/unit/lib/itamae/handler/base_spec.rb
new file mode 100644
index 00000000..e24e4192
--- /dev/null
+++ b/spec/unit/lib/itamae/handler/base_spec.rb
@@ -0,0 +1,34 @@
+require 'spec_helper'
+
+describe Itamae::Handler::Base do
+  subject(:handler) { described_class.new({}) }
+
+  context "when receiving recipe_started event" do
+    it "stores the payload" do
+      subject.event(:recipe_started, :payload)
+      expect(subject.recipes).to eq([:payload])
+    end
+  end
+
+  context "when receiving recipe_completed event" do
+    before do
+      subject.event(:recipe_started, :payload)
+    end
+
+    it "pops the payload" do
+      subject.event(:recipe_completed, :payload)
+      expect(subject.recipes).to eq([])
+    end
+  end
+
+  context "when receiving recipe_failed event" do
+    before do
+      subject.event(:recipe_started, :payload)
+    end
+
+    it "pops the payload" do
+      subject.event(:recipe_failed, :payload)
+      expect(subject.recipes).to eq([])
+    end
+  end
+end
diff --git a/spec/unit/lib/itamae/handler/fluentd_spec.rb b/spec/unit/lib/itamae/handler/fluentd_spec.rb
new file mode 100644
index 00000000..9b2a4a0f
--- /dev/null
+++ b/spec/unit/lib/itamae/handler/fluentd_spec.rb
@@ -0,0 +1,19 @@
+require 'spec_helper'
+require 'itamae/handler/fluentd'
+
+describe Itamae::Handler::Fluentd do
+  subject(:handler) do
+    described_class.new(options).tap do |h|
+      h.fluent_logger = fluent_logger
+    end
+  end
+  let(:options) { {'hostname' => 'me'} }
+  let(:fluent_logger) { Fluent::Logger::TestLogger.new }
+
+  describe '#event' do
+    it 'posts a record to fluent logger' do
+      subject.event(:type, {arg: 'value'})
+      expect(fluent_logger.queue).to eq([{arg: 'value', hostname: 'me'}])
+    end
+  end
+end
diff --git a/spec/unit/lib/itamae/handler_proxy_spec.rb b/spec/unit/lib/itamae/handler_proxy_spec.rb
new file mode 100644
index 00000000..48dfcef3
--- /dev/null
+++ b/spec/unit/lib/itamae/handler_proxy_spec.rb
@@ -0,0 +1,38 @@
+require 'spec_helper'
+
+module Itamae
+  describe HandlerProxy do
+    let(:handler) { instance_double(Handler::Base) }
+    before { subject.register_instance(handler) }
+
+    describe "#event" do
+      context "with block" do
+        context "when the block completes" do
+          it "fires *_started and *_completed events" do
+            expect(handler).to receive(:event).with(:name_started, :arg)
+            expect(handler).to receive(:event).with(:name_completed, :arg)
+            subject.event(:name, :arg) { }
+          end
+        end
+
+        context "when the block fails" do
+          it "fires *_started and *_failed events" do
+            expect(handler).to receive(:event).with(:name_started, :arg)
+            expect(handler).to receive(:event).with(:name_failed, :arg)
+            expect {
+              subject.event(:name, :arg) { raise }
+            }.to raise_error
+          end
+        end
+      end
+
+      context "without block" do
+        it "fires the event" do
+          expect(handler).to receive(:event).with(:name, :arg)
+          subject.event(:name, :arg)
+        end
+      end
+    end
+  end
+end
+
diff --git a/spec/unit/lib/itamae/handler_spec.rb b/spec/unit/lib/itamae/handler_spec.rb
new file mode 100644
index 00000000..830c3d40
--- /dev/null
+++ b/spec/unit/lib/itamae/handler_spec.rb
@@ -0,0 +1,11 @@
+require 'spec_helper'
+
+module Itamae
+  describe Handler do
+    describe ".from_type" do
+      it "returns handler class" do
+        expect(described_class.from_type('debug')).to eq(Handler::Debug)
+      end
+    end
+  end
+end
diff --git a/spec/unit/lib/itamae/resource/base_spec.rb b/spec/unit/lib/itamae/resource/base_spec.rb
index 65da8851..8da23229 100644
--- a/spec/unit/lib/itamae/resource/base_spec.rb
+++ b/spec/unit/lib/itamae/resource/base_spec.rb
@@ -100,14 +100,15 @@ class TestResource < Itamae::Resource::Base
 describe TestResource do
   subject(:resource) { described_class.new(recipe, "name") }
 
-  let(:commands) { double(:commands) }
+  let(:handler) { Itamae::HandlerProxy.new }
   let(:runner) do
     instance_double(Itamae::Runner).tap do |r|
       allow(r).to receive(:dry_run?).and_return(false)
+      allow(r).to receive(:handler).and_return(handler)
     end
   end
   let(:recipe) do
-    double(:recipe).tap do |r|
+    instance_double(Itamae::Recipe).tap do |r|
       allow(r).to receive(:runner).and_return(runner)
     end
   end