Merge pull request #1717 from fluent/add-ruby-version-to-start-log

Show running ruby version in startup log

Author: repeatedly

lib/fluent/supervisor.rb

@@ -513,7 +513,7 @@ def run_worker
       install_main_process_signal_handlers
 
       # This is the only log messsage for @standalone_worker
-      $log.info "starting fluentd-#{Fluent::VERSION} without supervision", pid: Process.pid if @standalone_worker
+      $log.info "starting fluentd-#{Fluent::VERSION} without supervision", pid: Process.pid, ruby: RUBY_VERSION if @standalone_worker
 
       main_process do
         create_socket_manager if @standalone_worker
@@ -535,7 +535,7 @@ def create_socket_manager
     end
 
     def dry_run_cmd
-      $log.info "starting fluentd-#{Fluent::VERSION} as dry run mode"
+      $log.info "starting fluentd-#{Fluent::VERSION} as dry run mode", ruby: RUBY_VERSION
       @system_config.suppress_config_dump = true
       dry_run
       exit 0
@@ -571,7 +571,7 @@ def supervise
       dry_run
 
       Process.setproctitle("supervisor:#{@process_name}") if @process_name
-      $log.info "starting fluentd-#{Fluent::VERSION}", pid: Process.pid
+      $log.info "starting fluentd-#{Fluent::VERSION}", pid: Process.pid, ruby: RUBY_VERSION
 
       rubyopt = ENV["RUBYOPT"]
       fluentd_spawn_cmd = [ServerEngine.ruby_bin_path, "-Eascii-8bit:ascii-8bit"]