Introduce Handler (experimental feature)

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

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"

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

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

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

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

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

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
+

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
 

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
@@ -151,61 +156,58 @@ 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
 
       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

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