Update live-nodes-list on the startup.

The serf agent updates the list at first.
After that, the engine loads the list.

lib/droonga/command/remote.rb

@@ -397,18 +397,7 @@ def unjoining_node?
 
       class UpdateLiveNodesList < Base
         def process
-          path = Path.live_nodes_list
-          new_list = live_nodes_list
-          file_contents = JSON.pretty_generate(new_list)
-          SafeFileWriter.write(path) do |output, file|
-            output.puts(file_contents)
-            @service_installation.ensure_correct_file_permission(file)
-          end
-        end
-
-        private
-        def live_nodes_list
-          @serf.live_nodes_list
+          @serf.update_live_nodes_list
         end
       end
     end

lib/droonga/engine.rb

@@ -33,6 +33,7 @@ class Engine
     attr_writer :on_ready
     def initialize(loop, name, internal_name)
       @state = EngineState.new(loop, name, internal_name)
+      @state.live_nodes_list = load_live_nodes_list
       @catalog = load_catalog
       @state.catalog = @catalog
       @dispatcher = create_dispatcher

lib/droonga/serf.rb

@@ -25,6 +25,8 @@
 require "droonga/node_status"
 require "droonga/serf_downloader"
 require "droonga/line_buffer"
+require "droonga/safe_file_writer"
+require "droonga/service_installation"
 
 module Droonga
   class Serf
@@ -45,6 +47,7 @@ def initialize(loop, name)
       @loop = loop
       @name = name
       @agent = nil
+      @service_installation = ServiceInstallation.new
     end
 
     def start
@@ -64,6 +67,7 @@ def start
                    "-tag", "role=#{role}",
                    "-tag", "cluster_id=#{cluster_id}",
                    *retry_joins)
+      update_live_nodes_list
       logger.trace("start: done")
     end
 
@@ -116,6 +120,16 @@ def send_query(query, payload)
       result
     end
 
+    def update_live_nodes_list
+      path = Path.live_nodes_list
+      new_list = live_nodes_list
+      file_contents = JSON.pretty_generate(new_list)
+      SafeFileWriter.write(path) do |output, file|
+        output.puts(file_contents)
+        @service_installation.ensure_correct_file_permission(file)
+      end
+    end
+
     def live_nodes_list
       ensure_serf
       nodes_list = {}