From eb1478d5dead8cc036a2cf3970b7c3b138ce6e3f Mon Sep 17 00:00:00 2001
From: "Satoshi \"Moris\" Tagomori" <tagomoris@gmail.com>
Date: Tue, 9 Feb 2016 18:28:18 +0900
Subject: [PATCH] Merge pull request #795 from fluent/hash-syntax

enforce new hash syntax by `rubocop --only HashSyntax --auto-correct`
---
 Rakefile                                      |   4 +-
 lib/fluent/agent.rb                           |  12 +-
 lib/fluent/buffer.rb                          |   6 +-
 lib/fluent/engine.rb                          |   4 +-
 lib/fluent/formatter.rb                       |  46 ++++----
 lib/fluent/log.rb                             |   2 +-
 lib/fluent/output.rb                          |  45 ++++----
 lib/fluent/parser.rb                          |  46 ++++----
 lib/fluent/plugin/buf_file.rb                 |   4 +-
 lib/fluent/plugin/buf_memory.rb               |   2 +-
 lib/fluent/plugin/filter_grep.rb              |   6 +-
 .../plugin/filter_record_transformer.rb       |  22 ++--
 lib/fluent/plugin/filter_stdout.rb            |   2 +-
 lib/fluent/plugin/in_debug_agent.rb           |  10 +-
 lib/fluent/plugin/in_dummy.rb                 |   6 +-
 lib/fluent/plugin/in_exec.rb                  |  18 +--
 lib/fluent/plugin/in_forward.rb               |  22 ++--
 lib/fluent/plugin/in_gc_stat.rb               |   4 +-
 lib/fluent/plugin/in_http.rb                  |  26 ++---
 lib/fluent/plugin/in_monitor_agent.rb         |  20 ++--
 lib/fluent/plugin/in_object_space.rb          |   8 +-
 lib/fluent/plugin/in_stream.rb                |  12 +-
 lib/fluent/plugin/in_syslog.rb                |  22 ++--
 lib/fluent/plugin/in_tail.rb                  |  18 +--
 lib/fluent/plugin/in_tcp.rb                   |   2 +-
 lib/fluent/plugin/in_udp.rb                   |   2 +-
 lib/fluent/plugin/out_copy.rb                 |   2 +-
 lib/fluent/plugin/out_exec.rb                 |  10 +-
 lib/fluent/plugin/out_exec_filter.rb          |  50 ++++----
 lib/fluent/plugin/out_file.rb                 |  10 +-
 lib/fluent/plugin/out_forward.rb              |  42 +++----
 lib/fluent/plugin/out_stdout.rb               |   2 +-
 lib/fluent/plugin/out_stream.rb               |   4 +-
 lib/fluent/plugin/socket_util.rb              |  16 +--
 lib/fluent/process.rb                         |  16 +--
 lib/fluent/root_agent.rb                      |  10 +-
 lib/fluent/rpc.rb                             |  10 +-
 lib/fluent/supervisor.rb                      |  58 +++++-----
 test/config/test_configurable.rb              |  22 ++--
 test/config/test_configure_proxy.rb           |   2 +-
 test/plugin/test_filter_record_transformer.rb | 108 +++++++++---------
 test/test_config.rb                           |   4 +-
 42 files changed, 368 insertions(+), 369 deletions(-)

diff --git a/Rakefile b/Rakefile
index 9c968f3a6c..8b0184e462 100755
--- a/Rakefile
+++ b/Rakefile
@@ -5,7 +5,7 @@ require 'fileutils'
 require 'rake/testtask'
 require 'rake/clean'
 
-task :test => [:base_test]
+task test: [:base_test]
 
 desc 'Run test_unit based test'
 Rake::TestTask.new(:base_test) do |t|
@@ -30,4 +30,4 @@ task :coverage do |t|
   Rake::Task["test"].invoke
 end
 
-task :default => [:test, :build]
+task default: [:test, :build]
diff --git a/lib/fluent/agent.rb b/lib/fluent/agent.rb
index 5080f2377c..1c766fe197 100644
--- a/lib/fluent/agent.rb
+++ b/lib/fluent/agent.rb
@@ -81,7 +81,7 @@ def shutdown
             log.info "shutting down filter#{@context.nil? ? '' : " in #{@context}"}", type: Plugin.lookup_name_from_class(f.class), plugin_id: f.plugin_id
             f.shutdown
           rescue => e
-            log.warn "unexpected error while shutting down filter plugins", :plugin => f.class, :plugin_id => f.plugin_id, :error_class => e.class, :error => e
+            log.warn "unexpected error while shutting down filter plugins", plugin: f.class, plugin_id: f.plugin_id, error_class: e.class, error: e
             log.warn_backtrace
           end
         end
@@ -95,7 +95,7 @@ def shutdown
             log.info "shutting down output#{@context.nil? ? '' : " in #{@context}"}", type: Plugin.lookup_name_from_class(o.class), plugin_id: o.plugin_id
             o.shutdown
           rescue => e
-            log.warn "unexpected error while shutting down output plugins", :plugin => o.class, :plugin_id => o.plugin_id, :error_class => e.class, :error => e
+            log.warn "unexpected error while shutting down output plugins", plugin: o.class, plugin_id: o.plugin_id, error_class: e.class, error: e
             log.warn_backtrace
           end
         end
@@ -115,7 +115,7 @@ def flush_recursive(array)
             flush_recursive(o.outputs)
           end
         rescue => e
-          log.debug "error while force flushing", :error_class => e.class, :error => e
+          log.debug "error while force flushing", error_class: e.class, error: e
           log.debug_backtrace
         end
       }
@@ -163,16 +163,16 @@ def emit(tag, es, chain)
         c = (@count += 1)
         if c < 512
           if Math.log(c) / Math.log(2) % 1.0 == 0
-            @log.warn "no patterns matched", :tag => tag
+            @log.warn "no patterns matched", tag: tag
             return
           end
         else
           if c % 512 == 0
-            @log.warn "no patterns matched", :tag => tag
+            @log.warn "no patterns matched", tag: tag
             return
           end
         end
-        @log.on_trace { @log.trace "no patterns matched", :tag => tag }
+        @log.on_trace { @log.trace "no patterns matched", tag: tag }
       end
 
       def start
diff --git a/lib/fluent/buffer.rb b/lib/fluent/buffer.rb
index 97f10d2ad0..2187d835f1 100644
--- a/lib/fluent/buffer.rb
+++ b/lib/fluent/buffer.rb
@@ -140,11 +140,11 @@ def enable_parallel(b=true)
     # Local file based plugins which should provide more reliability and efficiency
     # should override buffer_chunk_limit with a larger size.
     desc 'The size of each buffer chunk.'
-    config_param :buffer_chunk_limit, :size, :default => 8*1024*1024
+    config_param :buffer_chunk_limit, :size, default: 8*1024*1024
     desc 'The length limit of the chunk queue.'
-    config_param :buffer_queue_limit, :integer, :default => 256
+    config_param :buffer_queue_limit, :integer, default: 256
     desc 'The action when the size of buffer queue exceeds the buffer_queue_limit.'
-    config_param :buffer_queue_full_action, :enum, :list => [:exception, :block], :default => :exception
+    config_param :buffer_queue_full_action, :enum, list: [:exception, :block], default: :exception
 
     alias chunk_limit buffer_chunk_limit
     alias chunk_limit= buffer_chunk_limit=
diff --git a/lib/fluent/engine.rb b/lib/fluent/engine.rb
index 48acb7c4df..4bb8927a61 100644
--- a/lib/fluent/engine.rb
+++ b/lib/fluent/engine.rb
@@ -164,7 +164,7 @@ def log_event_loop
           begin
             @event_router.emit(tag, time, record)
           rescue => e
-            $log.error "failed to emit fluentd's log event", :tag => tag, :event => record, :error_class => e.class, :error => e
+            $log.error "failed to emit fluentd's log event", tag: tag, event: record, error_class: e.class, error: e
           end
         }
       end
@@ -193,7 +193,7 @@ def run
         end
 
       rescue => e
-        $log.error "unexpected error", :error_class=>e.class, :error=>e
+        $log.error "unexpected error", error_class: e.class, error: e
         $log.error_backtrace
       ensure
         $log.info "shutting down fluentd"
diff --git a/lib/fluent/formatter.rb b/lib/fluent/formatter.rb
index 5b14892f3a..dbc4c86b4b 100644
--- a/lib/fluent/formatter.rb
+++ b/lib/fluent/formatter.rb
@@ -33,13 +33,13 @@ module TextFormatter
     module HandleTagAndTimeMixin
       def self.included(klass)
         klass.instance_eval {
-          config_param :include_time_key, :bool, :default => false
-          config_param :time_key, :string, :default => 'time'
-          config_param :time_format, :string, :default => nil
-          config_param :include_tag_key, :bool, :default => false
-          config_param :tag_key, :string, :default => 'tag'
-          config_param :localtime, :bool, :default => true
-          config_param :timezone, :string, :default => nil
+          config_param :include_time_key, :bool, default: false
+          config_param :time_key, :string, default: 'time'
+          config_param :time_format, :string, default: nil
+          config_param :include_tag_key, :bool, default: false
+          config_param :tag_key, :string, default: 'tag'
+          config_param :localtime, :bool, default: true
+          config_param :timezone, :string, default: nil
         }
       end
 
@@ -65,9 +65,9 @@ def filter_record(tag, time, record)
     class OutFileFormatter < Formatter
       include HandleTagAndTimeMixin
 
-      config_param :output_time, :bool, :default => true
-      config_param :output_tag, :bool, :default => true
-      config_param :delimiter, :default => "\t" do |val|
+      config_param :output_time, :bool, default: true
+      config_param :output_tag, :bool, default: true
+      config_param :delimiter, default: "\t" do |val|
         case val
         when /SPACE/i then ' '
         when /COMMA/i then ','
@@ -85,7 +85,7 @@ def format(tag, time, record)
     end
 
     class StdoutFormatter < Formatter
-      config_param :output_type, :string, :default => 'json'
+      config_param :output_type, :string, default: 'json'
 
       def configure(conf)
         super
@@ -103,7 +103,7 @@ def format(tag, time, record)
     module StructuredFormatMixin
       def self.included(klass)
         klass.instance_eval {
-          config_param :time_as_epoch, :bool, :default => false
+          config_param :time_as_epoch, :bool, default: false
         }
       end
 
@@ -131,7 +131,7 @@ class JSONFormatter < Formatter
       include HandleTagAndTimeMixin
       include StructuredFormatMixin
 
-      config_param :json_parser, :string, :default => 'oj'
+      config_param :json_parser, :string, default: 'oj'
 
       def configure(conf)
         super
@@ -139,7 +139,7 @@ def configure(conf)
         begin
           raise LoadError unless @json_parser == 'oj'
           require 'oj'
-          Oj.default_options = {:mode => :compat}
+          Oj.default_options = {mode: :compat}
           @dump_proc = Oj.method(:dump)
         rescue LoadError
           @dump_proc = Yajl.method(:dump)
@@ -172,8 +172,8 @@ def format_record(record)
     class LabeledTSVFormatter < Formatter
       include HandleTagAndTimeMixin
 
-      config_param :delimiter, :string, :default => "\t"
-      config_param :label_delimiter, :string, :default =>  ":"
+      config_param :delimiter, :string, default: "\t"
+      config_param :label_delimiter, :string, default: ":"
 
       def format(tag, time, record)
         filter_record(tag, time, record)
@@ -189,11 +189,11 @@ def format(tag, time, record)
     class CsvFormatter < Formatter
       include HandleTagAndTimeMixin
 
-      config_param :delimiter, :default => ',' do |val|
+      config_param :delimiter, default: ',' do |val|
         ['\t', 'TAB'].include?(val) ? "\t" : val
       end
-      config_param :force_quotes, :bool, :default => true
-      config_param :fields, :default => [] do |val|
+      config_param :force_quotes, :bool, default: true
+      config_param :fields, default: [] do |val|
         val.split(',').map do |f|
           f.strip!
           f.size > 0 ? f : nil
@@ -211,14 +211,14 @@ def format(tag, time, record)
             memo << record[key]
             memo
         end
-        CSV.generate_line(row, :col_sep => @delimiter,
-                          :force_quotes => @force_quotes)
+        CSV.generate_line(row, col_sep: @delimiter,
+                          force_quotes: @force_quotes)
       end
     end
 
     class SingleValueFormatter < Formatter
-      config_param :message_key, :string, :default => 'message'
-      config_param :add_newline, :bool, :default => true
+      config_param :message_key, :string, default: 'message'
+      config_param :add_newline, :bool, default: true
 
       def format(tag, time, record)
         text = record[@message_key].to_s.dup
diff --git a/lib/fluent/log.rb b/lib/fluent/log.rb
index f14f27c32f..978da489d1 100644
--- a/lib/fluent/log.rb
+++ b/lib/fluent/log.rb
@@ -344,7 +344,7 @@ module PluginLoggerMixin
     def self.included(klass)
       klass.instance_eval {
         desc 'Allows the user to set different levels of logging for each plugin.'
-        config_param :log_level, :string, :default => nil, :alias => :@log_level
+        config_param :log_level, :string, default: nil, alias: :@log_level
       }
     end
 
diff --git a/lib/fluent/output.rb b/lib/fluent/output.rb
index 2b8523b283..ebeea00c34 100644
--- a/lib/fluent/output.rb
+++ b/lib/fluent/output.rb
@@ -88,7 +88,7 @@ def shutdown
 
     def secondary_init(primary)
       if primary.class != self.class
-        $log.warn "type of secondary output should be same as primary output", :primary=>primary.class.to_s, :secondary=>self.class.to_s
+        $log.warn "type of secondary output should be same as primary output", primary: primary.class.to_s, secondary: self.class.to_s
       end
     end
   end
@@ -152,7 +152,7 @@ def run
         @mutex.unlock
       end
     rescue
-      $log.error "error on output thread", :error=>$!.to_s
+      $log.error "error on output thread", error: $!.to_s
       $log.error_backtrace
       raise
     ensure
@@ -180,22 +180,22 @@ def initialize
     end
 
     desc 'The buffer type (memory, file)'
-    config_param :buffer_type, :string, :default => 'memory'
+    config_param :buffer_type, :string, default: 'memory'
     desc 'The interval between data flushes.'
-    config_param :flush_interval, :time, :default => 60
-    config_param :try_flush_interval, :float, :default => 1
+    config_param :flush_interval, :time, default: 60
+    config_param :try_flush_interval, :float, default: 1
     desc 'If true, the value of `retry_value` is ignored and there is no limit'
-    config_param :disable_retry_limit, :bool, :default => false
+    config_param :disable_retry_limit, :bool, default: false
     desc 'The limit on the number of retries before buffered data is discarded'
-    config_param :retry_limit, :integer, :default => 17
+    config_param :retry_limit, :integer, default: 17
     desc 'The initial intervals between write retries.'
-    config_param :retry_wait, :time, :default => 1.0
+    config_param :retry_wait, :time, default: 1.0
     desc 'The maximum intervals between write retries.'
-    config_param :max_retry_wait, :time, :default => nil
+    config_param :max_retry_wait, :time, default: nil
     desc 'The number of threads to flush the buffer.'
-    config_param :num_threads, :integer, :default => 1
+    config_param :num_threads, :integer, default: 1
     desc 'The interval between data flushes for queued chunk.'
-    config_param :queued_chunk_flush_interval, :time, :default => 1
+    config_param :queued_chunk_flush_interval, :time, default: 1
 
     def configure(conf)
       super
@@ -334,7 +334,7 @@ def try_flush
           @num_errors = 0
           # Note: don't notify to other threads to prevent
           #       burst to recovered server
-          $log.warn "retry succeeded.", :plugin_id=>plugin_id
+          $log.warn "retry succeeded.", plugin_id: plugin_id
         end
 
         if has_next
@@ -359,20 +359,20 @@ def try_flush
         end
 
         if @disable_retry_limit || error_count < @retry_limit
-          $log.warn "temporarily failed to flush the buffer.", :next_retry=>Time.at(@next_retry_time), :error_class=>e.class.to_s, :error=>e.to_s, :plugin_id=>plugin_id
+          $log.warn "temporarily failed to flush the buffer.", next_retry: Time.at(@next_retry_time), error_class: e.class.to_s, error: e.to_s, plugin_id: plugin_id
           $log.warn_backtrace e.backtrace
 
         elsif @secondary
           if error_count == @retry_limit
-            $log.warn "failed to flush the buffer.", :error_class=>e.class.to_s, :error=>e.to_s, :plugin_id=>plugin_id
+            $log.warn "failed to flush the buffer.", error_class: e.class.to_s, error: e.to_s, plugin_id: plugin_id
             $log.warn "retry count exceededs limit. falling back to secondary output."
             $log.warn_backtrace e.backtrace
             retry  # retry immediately
           elsif error_count <= @retry_limit + @secondary_limit
-            $log.warn "failed to flush the buffer, next retry will be with secondary output.", :next_retry=>Time.at(@next_retry_time), :error_class=>e.class.to_s, :error=>e.to_s, :plugin_id=>plugin_id
+            $log.warn "failed to flush the buffer, next retry will be with secondary output.", next_retry: Time.at(@next_retry_time), error_class: e.class.to_s, error: e.to_s, plugin_id: plugin_id
             $log.warn_backtrace e.backtrace
           else
-            $log.warn "failed to flush the buffer.", :error_class=>e.class, :error=>e.to_s, :plugin_id=>plugin_id
+            $log.warn "failed to flush the buffer.", error_class: e.class, error: e.to_s, plugin_id: plugin_id
             $log.warn "secondary retry count exceededs limit."
             $log.warn_backtrace e.backtrace
             write_abort
@@ -380,7 +380,7 @@ def try_flush
           end
 
         else
-          $log.warn "failed to flush the buffer.", :error_class=>e.class.to_s, :error=>e.to_s, :plugin_id=>plugin_id
+          $log.warn "failed to flush the buffer.", error_class: e.class.to_s, error: e.to_s, plugin_id: plugin_id
           $log.warn "retry count exceededs limit."
           $log.warn_backtrace e.backtrace
           write_abort
@@ -403,7 +403,7 @@ def before_shutdown
       begin
         @buffer.before_shutdown(self)
       rescue
-        $log.warn "before_shutdown failed", :error=>$!.to_s
+        $log.warn "before_shutdown failed", error: $!.to_s
         $log.warn_backtrace
       end
     end
@@ -425,7 +425,7 @@ def write_abort
       begin
         @buffer.clear!
       rescue
-        $log.error "unexpected error while aborting", :error=>$!.to_s
+        $log.error "unexpected error while aborting", error: $!.to_s
         $log.error_backtrace
       end
     end
@@ -483,11 +483,11 @@ def initialize
     end
 
     desc 'The time format used as part of the file name.'
-    config_param :time_slice_format, :string, :default => '%Y%m%d'
+    config_param :time_slice_format, :string, default: '%Y%m%d'
     desc 'The amount of time Fluentd will wait for old logs to arrive.'
-    config_param :time_slice_wait, :time, :default => 10*60
+    config_param :time_slice_wait, :time, default: 10*60
     desc 'Parse the time value in the specified timezone'
-    config_param :timezone, :string, :default => nil
+    config_param :timezone, :string, default: nil
     config_set_default :buffer_type, 'file'  # overwrite default buffer_type
     config_set_default :buffer_chunk_limit, 256*1024*1024  # overwrite default buffer_chunk_limit
     config_set_default :flush_interval, nil
@@ -609,4 +609,3 @@ class MultiOutput < Output
     #end
   end
 end
-
diff --git a/lib/fluent/parser.rb b/lib/fluent/parser.rb
index bd6674b8d6..ef14b46a09 100644
--- a/lib/fluent/parser.rb
+++ b/lib/fluent/parser.rb
@@ -27,7 +27,7 @@ class Parser
     # 'configure()' may raise errors for unexpected configurations
     attr_accessor :estimate_current_event
 
-    config_param :keep_time_key, :bool, :default => false
+    config_param :keep_time_key, :bool, default: false
 
     def initialize
       super
@@ -113,9 +113,9 @@ module TypeConverter
 
       def self.included(klass)
         klass.instance_eval {
-          config_param :types, :string, :default => nil
-          config_param :types_delimiter, :string, :default => ','
-          config_param :types_label_delimiter, :string, :default => ':'
+          config_param :types, :string, default: nil
+          config_param :types_delimiter, :string, default: ','
+          config_param :types_label_delimiter, :string, default: ':'
         }
       end
 
@@ -162,8 +162,8 @@ def parse_types_parameter
     class RegexpParser < Parser
       include TypeConverter
 
-      config_param :time_key, :string, :default => 'time'
-      config_param :time_format, :string, :default => nil
+      config_param :time_key, :string, default: 'time'
+      config_param :time_format, :string, default: nil
 
       def initialize(regexp, conf={})
         super()
@@ -235,9 +235,9 @@ def parse(text)
     end
 
     class JSONParser < Parser
-      config_param :time_key, :string, :default => 'time'
-      config_param :time_format, :string, :default => nil
-      config_param :json_parser, :string, :default => 'oj'
+      config_param :time_key, :string, default: 'time'
+      config_param :time_format, :string, default: nil
+      config_param :json_parser, :string, default: 'oj'
 
       def configure(conf)
         super
@@ -250,7 +250,7 @@ def configure(conf)
         begin
           raise LoadError unless @json_parser == 'oj'
           require 'oj'
-          Oj.default_options = {:bigdecimal_load => :float}
+          Oj.default_options = {bigdecimal_load: :float}
           @load_proc = Oj.method(:load)
           @error_class = Oj::ParseError
         rescue LoadError
@@ -298,17 +298,17 @@ def parse(text)
     class ValuesParser < Parser
       include TypeConverter
 
-      config_param :keys, :default => [] do |val|
+      config_param :keys, default: [] do |val|
         if val.start_with?('[') # This check is enough because keys parameter is simple. No '[' started column name.
           JSON.load(val)
         else
           val.split(",")
         end
       end
-      config_param :time_key, :string, :default => nil
-      config_param :time_format, :string, :default => nil
-      config_param :null_value_pattern, :string, :default => nil
-      config_param :null_empty_string, :bool, :default => false
+      config_param :time_key, :string, default: nil
+      config_param :time_format, :string, default: nil
+      config_param :null_value_pattern, :string, default: nil
+      config_param :null_empty_string, :bool, default: false
 
       def configure(conf)
         super
@@ -377,7 +377,7 @@ def convert_value_to_nil(value)
     end
 
     class TSVParser < ValuesParser
-      config_param :delimiter, :string, :default => "\t"
+      config_param :delimiter, :string, default: "\t"
 
       def configure(conf)
         super
@@ -394,9 +394,9 @@ def parse(text)
     end
 
     class LabeledTSVParser < ValuesParser
-      config_param :delimiter,       :string, :default => "\t"
-      config_param :label_delimiter, :string, :default =>  ":"
-      config_param :time_key, :string, :default =>  "time"
+      config_param :delimiter,       :string, default: "\t"
+      config_param :label_delimiter, :string, default: ":"
+      config_param :time_key, :string, default: "time"
 
       def configure(conf)
         conf['keys'] = conf['time_key'] || 'time'
@@ -437,7 +437,7 @@ def parse(text)
     end
 
     class NoneParser < Parser
-      config_param :message_key, :string, :default => 'message'
+      config_param :message_key, :string, default: 'message'
 
       def parse(text)
         record = {}
@@ -526,8 +526,8 @@ class SyslogParser < Parser
       # From in_syslog default pattern
       REGEXP_WITH_PRI = /^\<(?<pri>[0-9]+)\>(?<time>[^ ]* {1,2}[^ ]* [^ ]*) (?<host>[^ ]*) (?<ident>[a-zA-Z0-9_\/\.\-]*)(?:\[(?<pid>[0-9]+)\])?(?:[^\:]*\:)? *(?<message>.*)$/
 
-      config_param :time_format, :string, :default => "%b %d %H:%M:%S"
-      config_param :with_priority, :bool, :default => false
+      config_param :time_format, :string, default: "%b %d %H:%M:%S"
+      config_param :with_priority, :bool, default: false
 
       def initialize
         super
@@ -586,7 +586,7 @@ def parse(text)
     end
 
     class MultilineParser < Parser
-      config_param :format_firstline, :string, :default => nil
+      config_param :format_firstline, :string, default: nil
 
       FORMAT_MAX_NUM = 20
 
diff --git a/lib/fluent/plugin/buf_file.rb b/lib/fluent/plugin/buf_file.rb
index 15f161b2f0..c3285da110 100644
--- a/lib/fluent/plugin/buf_file.rb
+++ b/lib/fluent/plugin/buf_file.rb
@@ -85,7 +85,7 @@ def initialize
     desc 'The path where buffer chunks are stored.'
     config_param :buffer_path, :string
     desc 'If true, queued chunks are flushed at shutdown process.'
-    config_param :flush_at_shutdown, :bool, :default => false
+    config_param :flush_at_shutdown, :bool, default: false
 
     # 'symlink_path' is currently only for out_file.
     # That is the reason why this is not config_param, but attr_accessor.
@@ -112,7 +112,7 @@ def configure(conf)
     end
 
     def start
-      FileUtils.mkdir_p File.dirname(@buffer_path_prefix + "path"), :mode => DEFAULT_DIR_PERMISSION
+      FileUtils.mkdir_p File.dirname(@buffer_path_prefix + "path"), mode: DEFAULT_DIR_PERMISSION
       super
     end
 
diff --git a/lib/fluent/plugin/buf_memory.rb b/lib/fluent/plugin/buf_memory.rb
index 81d69256d8..7ed3a16d35 100644
--- a/lib/fluent/plugin/buf_memory.rb
+++ b/lib/fluent/plugin/buf_memory.rb
@@ -71,7 +71,7 @@ def initialize
     end
 
     desc 'If true, queued chunks are flushed at shutdown process. Otherwise queued chunks are discarded'
-    config_param :flush_at_shutdown, :bool, :default => true
+    config_param :flush_at_shutdown, :bool, default: true
     # Overwrite default BasicBuffer#buffer_queue_limit
     # to limit total memory usage upto 512MB.
     config_set_default :buffer_queue_limit, 64
diff --git a/lib/fluent/plugin/filter_grep.rb b/lib/fluent/plugin/filter_grep.rb
index 704d5d7d6f..95a21bcd3d 100644
--- a/lib/fluent/plugin/filter_grep.rb
+++ b/lib/fluent/plugin/filter_grep.rb
@@ -25,8 +25,8 @@ def initialize
 
     REGEXP_MAX_NUM = 20
 
-    (1..REGEXP_MAX_NUM).each {|i| config_param :"regexp#{i}",  :string, :default => nil }
-    (1..REGEXP_MAX_NUM).each {|i| config_param :"exclude#{i}", :string, :default => nil }
+    (1..REGEXP_MAX_NUM).each {|i| config_param :"regexp#{i}",  :string, default: nil }
+    (1..REGEXP_MAX_NUM).each {|i| config_param :"exclude#{i}", :string, default: nil }
 
     # for test
     attr_reader :regexps
@@ -67,7 +67,7 @@ def filter(tag, time, record)
           result = record
         end
       rescue => e
-        log.warn "failed to grep events", :error_class => e.class, :error => e.message
+        log.warn "failed to grep events", error_class: e.class, error: e.message
         log.warn_backtrace
       end
       result
diff --git a/lib/fluent/plugin/filter_record_transformer.rb b/lib/fluent/plugin/filter_record_transformer.rb
index 319917da35..3838c23700 100644
--- a/lib/fluent/plugin/filter_record_transformer.rb
+++ b/lib/fluent/plugin/filter_record_transformer.rb
@@ -26,17 +26,17 @@ def initialize
     end
 
     desc 'A comma-delimited list of keys to delete.'
-    config_param :remove_keys, :string, :default => nil
+    config_param :remove_keys, :string, default: nil
     desc 'A comma-delimited list of keys to keep.'
-    config_param :keep_keys, :string, :default => nil
+    config_param :keep_keys, :string, default: nil
     desc 'Create new Hash to transform incoming data'
-    config_param :renew_record, :bool, :default => false
+    config_param :renew_record, :bool, default: false
     desc 'Specify field name of the record to overwrite the time of events. Its value must be unix time.'
-    config_param :renew_time_key, :string, :default => nil
+    config_param :renew_time_key, :string, default: nil
     desc 'When set to true, the full Ruby syntax is enabled in the ${...} expression.'
-    config_param :enable_ruby, :bool, :default => false
+    config_param :enable_ruby, :bool, default: false
     desc 'Use original value type.'
-    config_param :auto_typecast, :bool, :default => false # false for lower version compatibility
+    config_param :auto_typecast, :bool, default: false # false for lower version compatibility
 
     def configure(conf)
       super
@@ -60,8 +60,8 @@ def configure(conf)
       end
 
       placeholder_expander_params = {
-        :log           => log,
-        :auto_typecast => @auto_typecast,
+        log: log,
+        auto_typecast: @auto_typecast,
       }
       @placeholder_expander =
         if @enable_ruby
@@ -105,7 +105,7 @@ def filter_stream(tag, es)
       end
       new_es
     rescue => e
-      log.warn "failed to reform records", :error_class => e.class, :error => e.message
+      log.warn "failed to reform records", error_class: e.class, error: e.message
       log.warn_backtrace
       log.debug "map:#{@map} record:#{last_record} placeholder_values:#{placeholder_values}"
     end
@@ -119,7 +119,7 @@ def parse_value(value_str)
         value_str
       end
     rescue => e
-      log.warn "failed to parse #{value_str} as json. Assuming #{value_str} is a string", :error_class => e.class, :error => e.message
+      log.warn "failed to parse #{value_str} as json. Assuming #{value_str} is a string", error_class: e.class, error: e.message
       value_str # emit as string
     end
 
@@ -307,7 +307,7 @@ def expand(str, force_stringify = false)
           @hostname,
         )
       rescue => e
-        log.warn "failed to expand `#{str}`", :error_class => e.class, :error => e.message
+        log.warn "failed to expand `#{str}`", error_class: e.class, error: e.message
         log.warn_backtrace
         nil
       end
diff --git a/lib/fluent/plugin/filter_stdout.rb b/lib/fluent/plugin/filter_stdout.rb
index 9e49d3d10c..5ab0290a99 100644
--- a/lib/fluent/plugin/filter_stdout.rb
+++ b/lib/fluent/plugin/filter_stdout.rb
@@ -22,7 +22,7 @@ class StdoutFilter < Filter
     attr_reader :formatter
 
     desc 'The format of the output.'
-    config_param :format, :string, :default => 'stdout'
+    config_param :format, :string, default: 'stdout'
     # config_param :output_type, :string, :default => 'json' (StdoutFormatter defines this)
 
     def configure(conf)
diff --git a/lib/fluent/plugin/in_debug_agent.rb b/lib/fluent/plugin/in_debug_agent.rb
index 17c87c0e56..60a6ffea97 100644
--- a/lib/fluent/plugin/in_debug_agent.rb
+++ b/lib/fluent/plugin/in_debug_agent.rb
@@ -24,11 +24,11 @@ def initialize
       super
     end
 
-    config_param :bind, :string, :default => '0.0.0.0'
-    config_param :port, :integer, :default => 24230
-    config_param :unix_path, :string, :default => nil
+    config_param :bind, :string, default: '0.0.0.0'
+    config_param :port, :integer, default: 24230
+    config_param :unix_path, :string, default: nil
     #config_param :unix_mode  # TODO
-    config_param :object, :string, :default => 'Engine'
+    config_param :object, :string, default: 'Engine'
 
     def configure(conf)
       super
@@ -46,7 +46,7 @@ def start
       else
         uri = "druby://#{@bind}:#{@port}"
       end
-      log.info "listening dRuby", :uri => uri, :object => @object
+      log.info "listening dRuby", uri: uri, object: @object
       obj = eval(@object)
       @server = DRb::DRbServer.new(uri, obj)
     end
diff --git a/lib/fluent/plugin/in_dummy.rb b/lib/fluent/plugin/in_dummy.rb
index 00492ce006..b436eb2210 100644
--- a/lib/fluent/plugin/in_dummy.rb
+++ b/lib/fluent/plugin/in_dummy.rb
@@ -23,11 +23,11 @@ class DummyInput < Input
     desc "The value is the tag assigned to the generated events."
     config_param :tag, :string
     desc "It configures how many events to generate per second."
-    config_param :rate, :integer, :default => 1
+    config_param :rate, :integer, default: 1
     desc "If specified, each generated event has an auto-incremented key field."
-    config_param :auto_increment_key, :string, :default => nil
+    config_param :auto_increment_key, :string, default: nil
     desc "The dummy data to be generated. An array of JSON hashes or a single JSON hash."
-    config_param :dummy, :default => [{"message"=>"dummy"}] do |val|
+    config_param :dummy, default: [{"message"=>"dummy"}] do |val|
       begin
         parsed = JSON.parse(val)
       rescue JSON::ParserError => e
diff --git a/lib/fluent/plugin/in_exec.rb b/lib/fluent/plugin/in_exec.rb
index bc7bd82178..b5ea3e3e97 100644
--- a/lib/fluent/plugin/in_exec.rb
+++ b/lib/fluent/plugin/in_exec.rb
@@ -27,21 +27,21 @@ def initialize
     desc 'The command (program) to execute.'
     config_param :command, :string
     desc 'The format used to map the program output to the incoming event.(tsv,json,msgpack)'
-    config_param :format, :string, :default => 'tsv'
+    config_param :format, :string, default: 'tsv'
     desc 'Specify the comma-separated keys when using the tsv format.'
-    config_param :keys, :default => [] do |val|
+    config_param :keys, default: [] do |val|
       val.split(',')
     end
     desc 'Tag of the output events.'
-    config_param :tag, :string, :default => nil
+    config_param :tag, :string, default: nil
     desc 'The key to use as the event tag instead of the value in the event record. '
-    config_param :tag_key, :string, :default => nil
+    config_param :tag_key, :string, default: nil
     desc 'The key to use as the event time instead of the value in the event record.'
-    config_param :time_key, :string, :default => nil
+    config_param :time_key, :string, default: nil
     desc 'The format of the event time used for the time_key parameter.'
-    config_param :time_format, :string, :default => nil
+    config_param :time_format, :string, default: nil
     desc 'The interval time between periodic program runs.'
-    config_param :run_interval, :time, :default => nil
+    config_param :run_interval, :time, default: nil
 
     def configure(conf)
       super
@@ -136,7 +136,7 @@ def run_periodic
           Process.waitpid(io.pid)
           sleep @run_interval
         rescue
-          log.error "exec failed to run or shutdown child process", :error => $!.to_s, :error_class => $!.class.to_s
+          log.error "exec failed to run or shutdown child process", error: $!.to_s, error_class: $!.class.to_s
           log.warn_backtrace $!.backtrace
         end
       end
@@ -163,7 +163,7 @@ def on_message(record, parsed_time = nil)
 
       router.emit(tag, time, record)
     rescue => e
-      log.error "exec failed to emit", :error => e.to_s, :error_class => e.class.to_s, :tag => tag, :record => Yajl.dump(record)
+      log.error "exec failed to emit", error: e.to_s, error_class: e.class.to_s, tag: tag, record: Yajl.dump(record)
     end
   end
 end
diff --git a/lib/fluent/plugin/in_forward.rb b/lib/fluent/plugin/in_forward.rb
index ce91d0fe02..c9d6d51a20 100644
--- a/lib/fluent/plugin/in_forward.rb
+++ b/lib/fluent/plugin/in_forward.rb
@@ -24,22 +24,22 @@ def initialize
     end
 
     desc 'The port to listen to.'
-    config_param :port, :integer, :default => DEFAULT_LISTEN_PORT
+    config_param :port, :integer, default: DEFAULT_LISTEN_PORT
     desc 'The bind address to listen to.'
-    config_param :bind, :string, :default => '0.0.0.0'
-    config_param :backlog, :integer, :default => nil
+    config_param :bind, :string, default: '0.0.0.0'
+    config_param :backlog, :integer, default: nil
     # SO_LINGER 0 to send RST rather than FIN to avoid lots of connections sitting in TIME_WAIT at src
     desc 'The timeout time used to set linger option.'
-    config_param :linger_timeout, :integer, :default => 0
+    config_param :linger_timeout, :integer, default: 0
     # This option is for Cool.io's loop wait timeout to avoid loop stuck at shutdown. Almost users don't need to change this value.
-    config_param :blocking_timeout, :time, :default => 0.5
+    config_param :blocking_timeout, :time, default: 0.5
 
     desc 'Log warning if received chunk size is larger than this value.'
-    config_param :chunk_size_warn_limit, :size, :default => nil
+    config_param :chunk_size_warn_limit, :size, default: nil
     desc 'Received chunk is dropped if it is larger than this value.'
-    config_param :chunk_size_limit, :size, :default => nil
+    config_param :chunk_size_limit, :size, default: nil
     desc 'Skip an event if incoming event is invalid.'
-    config_param :skip_invalid_event, :bool, :default => false
+    config_param :skip_invalid_event, :bool, default: false
 
     def configure(conf)
       super
@@ -97,7 +97,7 @@ def listen
     def run
       @loop.run(@blocking_timeout)
     rescue => e
-      log.error "unexpected error", :error => e, :error_class => e.class
+      log.error "unexpected error", error: e, error_class: e.class
       log.error_backtrace
     end
 
@@ -265,7 +265,7 @@ def on_read_json(data)
         @chunk_counter += data.bytesize
         @y << data
       rescue => e
-        @log.error "forward error", :error => e, :error_class => e.class
+        @log.error "forward error", error: e, error_class: e.class
         @log.error_backtrace
         close
       end
@@ -278,7 +278,7 @@ def on_read_msgpack(data)
           @chunk_counter = 0
         end
       rescue => e
-        @log.error "forward error", :error => e, :error_class => e.class
+        @log.error "forward error", error: e, error_class: e.class
         @log.error_backtrace
         close
       end
diff --git a/lib/fluent/plugin/in_gc_stat.rb b/lib/fluent/plugin/in_gc_stat.rb
index e68297b138..e0dbfdea41 100644
--- a/lib/fluent/plugin/in_gc_stat.rb
+++ b/lib/fluent/plugin/in_gc_stat.rb
@@ -22,7 +22,7 @@ def initialize
       super
     end
 
-    config_param :emit_interval, :time, :default => 60
+    config_param :emit_interval, :time, default: 60
     config_param :tag, :string
 
     class TimerWatcher < Coolio::TimerWatcher
@@ -61,7 +61,7 @@ def shutdown
     def run
       @loop.run
     rescue
-      log.error "unexpected error", :error=>$!.to_s
+      log.error "unexpected error", error: $!.to_s
       log.error_backtrace
     end
 
diff --git a/lib/fluent/plugin/in_http.rb b/lib/fluent/plugin/in_http.rb
index a44ce0b3fd..255a5c5fe3 100644
--- a/lib/fluent/plugin/in_http.rb
+++ b/lib/fluent/plugin/in_http.rb
@@ -31,25 +31,25 @@ def initialize
     EMPTY_GIF_IMAGE = "GIF89a\u0001\u0000\u0001\u0000\x80\xFF\u0000\xFF\xFF\xFF\u0000\u0000\u0000,\u0000\u0000\u0000\u0000\u0001\u0000\u0001\u0000\u0000\u0002\u0002D\u0001\u0000;".force_encoding("UTF-8")
 
     desc 'The port to listen to.'
-    config_param :port, :integer, :default => 9880
+    config_param :port, :integer, default: 9880
     desc 'The bind address to listen to.'
-    config_param :bind, :string, :default => '0.0.0.0'
+    config_param :bind, :string, default: '0.0.0.0'
     desc 'The size limit of the POSTed element. Default is 32MB.'
-    config_param :body_size_limit, :size, :default => 32*1024*1024  # TODO default
+    config_param :body_size_limit, :size, default: 32*1024*1024  # TODO default
     desc 'The timeout limit for keeping the connection alive.'
-    config_param :keepalive_timeout, :time, :default => 10   # TODO default
-    config_param :backlog, :integer, :default => nil
+    config_param :keepalive_timeout, :time, default: 10   # TODO default
+    config_param :backlog, :integer, default: nil
     desc 'Add HTTP_ prefix headers to the record.'
-    config_param :add_http_headers, :bool, :default => false
+    config_param :add_http_headers, :bool, default: false
     desc 'Add REMOTE_ADDR header to the record.'
-    config_param :add_remote_addr, :bool, :default => false
+    config_param :add_remote_addr, :bool, default: false
     desc 'The format of the HTTP body.'
-    config_param :format, :string, :default => 'default'
-    config_param :blocking_timeout, :time, :default => 0.5
+    config_param :format, :string, default: 'default'
+    config_param :blocking_timeout, :time, default: 0.5
     desc 'Set a white list of domains that can do CORS (Cross-Origin Resource Sharing)'
-    config_param :cors_allow_origins, :array, :default => nil
+    config_param :cors_allow_origins, :array, default: nil
     desc 'Respond with empty gif image of 1x1 pixel.'
-    config_param :respond_with_empty_img, :bool, :default => false
+    config_param :respond_with_empty_img, :bool, default: false
 
     def configure(conf)
       super
@@ -121,7 +121,7 @@ def shutdown
     def run
       @loop.run(@blocking_timeout)
     rescue
-      log.error "unexpected error", :error=>$!.to_s
+      log.error "unexpected error", error: $!.to_s
       log.error_backtrace
     end
 
@@ -254,7 +254,7 @@ def on_read(data)
         @idle = 0
         @parser << data
       rescue
-        @log.warn "unexpected error", :error=>$!.to_s
+        @log.warn "unexpected error", error: $!.to_s
         @log.warn_backtrace
         close
       end
diff --git a/lib/fluent/plugin/in_monitor_agent.rb b/lib/fluent/plugin/in_monitor_agent.rb
index 18b3cd4d82..9ec0a5a1d7 100644
--- a/lib/fluent/plugin/in_monitor_agent.rb
+++ b/lib/fluent/plugin/in_monitor_agent.rb
@@ -25,10 +25,10 @@ def initialize
       super
     end
 
-    config_param :bind, :string, :default => '0.0.0.0'
-    config_param :port, :integer, :default => 24220
-    config_param :tag, :string, :default => nil
-    config_param :emit_interval, :time, :default => 60
+    config_param :bind, :string, default: '0.0.0.0'
+    config_param :port, :integer, default: 24220
+    config_param :tag, :string, default: nil
+    config_param :emit_interval, :time, default: 60
 
     class MonitorServlet < WEBrick::HTTPServlet::AbstractServlet
       def initialize(server, agent)
@@ -234,10 +234,10 @@ def on_timer
     def start
       log.debug "listening monitoring http server on http://#{@bind}:#{@port}/api/plugins"
       @srv = WEBrick::HTTPServer.new({
-          :BindAddress => @bind,
-          :Port => @port,
-          :Logger => WEBrick::Log.new(STDERR, WEBrick::Log::FATAL),
-          :AccessLog => [],
+          BindAddress: @bind,
+          Port: @port,
+          Logger: WEBrick::Log.new(STDERR, WEBrick::Log::FATAL),
+          AccessLog: [],
         })
       @srv.mount('/api/plugins', LTSVMonitorServlet, self)
       @srv.mount('/api/plugins.json', JSONMonitorServlet, self)
@@ -250,7 +250,7 @@ def start
         log.debug "tag parameter is specified. Emit plugins info to '#{@tag}'"
 
         @loop = Coolio::Loop.new
-        opts = {:with_config => false}
+        opts = {with_config: false}
         timer = TimerWatcher.new(@emit_interval, log) {
           es = MultiEventStream.new
           now = Engine.now
@@ -267,7 +267,7 @@ def start
     def run
       @loop.run
     rescue => e
-      log.error "unexpected error", :error => e.to_s
+      log.error "unexpected error", error: e.to_s
       log.error_backtrace
     end
 
diff --git a/lib/fluent/plugin/in_object_space.rb b/lib/fluent/plugin/in_object_space.rb
index 8f2f3dbdea..d29e90905d 100644
--- a/lib/fluent/plugin/in_object_space.rb
+++ b/lib/fluent/plugin/in_object_space.rb
@@ -22,9 +22,9 @@ def initialize
       super
     end
 
-    config_param :emit_interval, :time, :default => 60
+    config_param :emit_interval, :time, default: 60
     config_param :tag, :string
-    config_param :top, :integer, :default => 15
+    config_param :top, :integer, default: 15
 
     class TimerWatcher < Coolio::TimerWatcher
       def initialize(interval, repeat, log, &callback)
@@ -62,7 +62,7 @@ def shutdown
     def run
       @loop.run
     rescue
-      log.error "unexpected error", :error=>$!.to_s
+      log.error "unexpected error", error: $!.to_s
       log.error_backtrace
     end
 
@@ -110,7 +110,7 @@ def on_timer
 
       router.emit(@tag, now, record)
     rescue => e
-      log.error "object space failed to emit", :error => e.to_s, :error_class => e.class.to_s, :tag => @tag, :record => Yajl.dump(record)
+      log.error "object space failed to emit", error: e.to_s, error_class: e.class.to_s, tag: @tag, record: Yajl.dump(record)
     end
   end
 end
diff --git a/lib/fluent/plugin/in_stream.rb b/lib/fluent/plugin/in_stream.rb
index a14b76efe1..d2f9c030aa 100644
--- a/lib/fluent/plugin/in_stream.rb
+++ b/lib/fluent/plugin/in_stream.rb
@@ -17,7 +17,7 @@
 module Fluent
   # obsolete
   class StreamInput < Input
-    config_param :blocking_timeout, :time, :default => 0.5
+    config_param :blocking_timeout, :time, default: 0.5
 
     def initialize
       require 'socket'
@@ -45,7 +45,7 @@ def shutdown
     def run
       @loop.run(@blocking_timeout)
     rescue
-      log.error "unexpected error", :error=>$!.to_s
+      log.error "unexpected error", error: $!.to_s
       log.error_backtrace
     end
 
@@ -142,7 +142,7 @@ def on_read(data)
       def on_read_json(data)
         @y << data
       rescue
-        @log.error "unexpected error", :error=>$!.to_s
+        @log.error "unexpected error", error: $!.to_s
         @log.error_backtrace
         close
       end
@@ -150,7 +150,7 @@ def on_read_json(data)
       def on_read_msgpack(data)
         @u.feed_each(data, &@on_message)
       rescue
-        @log.error "unexpected error", :error=>$!.to_s
+        @log.error "unexpected error", error: $!.to_s
         @log.error_backtrace
         close
       end
@@ -165,9 +165,9 @@ class UnixInput < StreamInput
     Plugin.register_input('unix', self)
 
     desc 'The path to your Unix Domain Socket.'
-    config_param :path, :string, :default => DEFAULT_SOCKET_PATH
+    config_param :path, :string, default: DEFAULT_SOCKET_PATH
     desc 'The backlog of Unix Domain Socket.'
-    config_param :backlog, :integer, :default => nil
+    config_param :backlog, :integer, default: nil
 
     def configure(conf)
       super
diff --git a/lib/fluent/plugin/in_syslog.rb b/lib/fluent/plugin/in_syslog.rb
index 0ec6148562..fc7d5e2b9d 100644
--- a/lib/fluent/plugin/in_syslog.rb
+++ b/lib/fluent/plugin/in_syslog.rb
@@ -65,13 +65,13 @@ def initialize
     end
 
     desc 'The port to listen to.'
-    config_param :port, :integer, :default => 5140
+    config_param :port, :integer, default: 5140
     desc 'The bind address to listen to.'
-    config_param :bind, :string, :default => '0.0.0.0'
+    config_param :bind, :string, default: '0.0.0.0'
     desc 'The prefix of the tag. The tag itself is generated by the tag prefix, facility level, and priority.'
     config_param :tag, :string
     desc 'The transport protocol used to receive logs.(udp, tcp)'
-    config_param :protocol_type, :default => :udp do |val|
+    config_param :protocol_type, default: :udp do |val|
       case val.downcase
       when 'tcp'
         :tcp
@@ -82,10 +82,10 @@ def initialize
       end
     end
     desc 'If true, add source host to event record.'
-    config_param :include_source_host, :bool, :default => false
+    config_param :include_source_host, :bool, default: false
     desc 'Specify key of source host when include_source_host is true.'
-    config_param :source_host_key, :string, :default => 'source_host'.freeze
-    config_param :blocking_timeout, :time, :default => 0.5
+    config_param :source_host_key, :string, default: 'source_host'.freeze
+    config_param :blocking_timeout, :time, default: 0.5
 
     def configure(conf)
       super
@@ -125,7 +125,7 @@ def shutdown
     def run
       @loop.run(@blocking_timeout)
     rescue
-      log.error "unexpected error", :error=>$!.to_s
+      log.error "unexpected error", error: $!.to_s
       log.error_backtrace
     end
 
@@ -150,14 +150,14 @@ def receive_data_parser(data, addr)
         emit(pri, time, record)
       }
     rescue => e
-      log.error data.dump, :error => e.to_s
+      log.error data.dump, error: e.to_s
       log.error_backtrace
     end
 
     def receive_data(data, addr)
       @parser.parse(data) { |time, record|
         unless time && record
-          log.warn "invalid syslog message", :data => data
+          log.warn "invalid syslog message", data: data
           return
         end
 
@@ -166,7 +166,7 @@ def receive_data(data, addr)
         emit(pri, time, record)
       }
     rescue => e
-      log.error data.dump, :error => e.to_s
+      log.error data.dump, error: e.to_s
       log.error_backtrace
     end
 
@@ -192,7 +192,7 @@ def emit(pri, time, record)
 
       router.emit(tag, time, record)
     rescue => e
-      log.error "syslog failed to emit", :error => e.to_s, :error_class => e.class.to_s, :tag => tag, :record => Yajl.dump(record)
+      log.error "syslog failed to emit", error: e.to_s, error_class: e.class.to_s, tag: tag, record: Yajl.dump(record)
     end
   end
 end
diff --git a/lib/fluent/plugin/in_tail.rb b/lib/fluent/plugin/in_tail.rb
index c25239810d..fc8c51ac47 100644
--- a/lib/fluent/plugin/in_tail.rb
+++ b/lib/fluent/plugin/in_tail.rb
@@ -29,19 +29,19 @@ def initialize
     desc 'The tag of the event.'
     config_param :tag, :string
     desc 'The paths to exclude the files from watcher list.'
-    config_param :exclude_path, :array, :default => []
+    config_param :exclude_path, :array, default: []
     desc 'Specify interval to keep reference to old file when rotate a file.'
-    config_param :rotate_wait, :time, :default => 5
+    config_param :rotate_wait, :time, default: 5
     desc 'Fluentd will record the position it last read into this file.'
-    config_param :pos_file, :string, :default => nil
+    config_param :pos_file, :string, default: nil
     desc 'Start to read the logs from the head of file, not bottom.'
-    config_param :read_from_head, :bool, :default => false
+    config_param :read_from_head, :bool, default: false
     desc 'The interval of refreshing the list of watch file.'
-    config_param :refresh_interval, :time, :default => 60
+    config_param :refresh_interval, :time, default: 60
     desc 'The number of reading lines at each IO.'
-    config_param :read_lines_limit, :integer, :default => 1000
+    config_param :read_lines_limit, :integer, default: 1000
     desc 'The interval of flushing the buffer for multiline format'
-    config_param :multiline_flush_interval, :time, :default => nil
+    config_param :multiline_flush_interval, :time, default: nil
 
     attr_reader :paths
 
@@ -232,7 +232,7 @@ def flush_buffer(tw)
     def run
       @loop.run
     rescue
-      log.error "unexpected error", :error=>$!.to_s
+      log.error "unexpected error", error: $!.to_s
       log.error_backtrace
     end
 
@@ -263,7 +263,7 @@ def convert_line_to_event(line, es)
           end
         }
       rescue => e
-        log.warn line.dump, :error => e.to_s
+        log.warn line.dump, error: e.to_s
         log.debug_backtrace(e.backtrace)
       end
     end
diff --git a/lib/fluent/plugin/in_tcp.rb b/lib/fluent/plugin/in_tcp.rb
index 5993d95052..df02c5ecbf 100644
--- a/lib/fluent/plugin/in_tcp.rb
+++ b/lib/fluent/plugin/in_tcp.rb
@@ -22,7 +22,7 @@ class TcpInput < SocketUtil::BaseInput
 
     config_set_default :port, 5170
     desc 'The payload is read up to this character.'
-    config_param :delimiter, :string, :default => "\n" # syslog family add "\n" to each message and this seems only way to split messages in tcp stream
+    config_param :delimiter, :string, default: "\n" # syslog family add "\n" to each message and this seems only way to split messages in tcp stream
 
     def listen(callback)
       log.info "listening tcp socket on #{@bind}:#{@port}"
diff --git a/lib/fluent/plugin/in_udp.rb b/lib/fluent/plugin/in_udp.rb
index d07ef6cc86..5fe9dd90e8 100644
--- a/lib/fluent/plugin/in_udp.rb
+++ b/lib/fluent/plugin/in_udp.rb
@@ -21,7 +21,7 @@ class UdpInput < SocketUtil::BaseInput
     Plugin.register_input('udp', self)
 
     config_set_default :port, 5160
-    config_param :body_size_limit, :size, :default => 4096
+    config_param :body_size_limit, :size, default: 4096
 
     def listen(callback)
       log.info "listening udp socket on #{@bind}:#{@port}"
diff --git a/lib/fluent/plugin/out_copy.rb b/lib/fluent/plugin/out_copy.rb
index 6a0ec95086..de43630589 100644
--- a/lib/fluent/plugin/out_copy.rb
+++ b/lib/fluent/plugin/out_copy.rb
@@ -19,7 +19,7 @@ class CopyOutput < MultiOutput
     Plugin.register_output('copy', self)
 
     desc 'If true, pass different record to each `store` plugin.'
-    config_param :deep_copy, :bool, :default => false
+    config_param :deep_copy, :bool, default: false
 
     def initialize
       super
diff --git a/lib/fluent/plugin/out_exec.rb b/lib/fluent/plugin/out_exec.rb
index cdf4ee496a..2062afda51 100644
--- a/lib/fluent/plugin/out_exec.rb
+++ b/lib/fluent/plugin/out_exec.rb
@@ -29,17 +29,17 @@ def initialize
     desc 'The command (program) to execute. The exec plugin passes the path of a TSV file as the last argumen'
     config_param :command, :string
     desc 'Specify the comma-separated keys when using the tsv format.'
-    config_param :keys, :default => [] do |val|
+    config_param :keys, default: [] do |val|
       val.split(',')
     end
     desc 'The name of the key to use as the event tag. This replaces the value in the event record.'
-    config_param :tag_key, :string, :default => nil
+    config_param :tag_key, :string, default: nil
     desc 'The name of the key to use as the event time. This replaces the the value in the event record.'
-    config_param :time_key, :string, :default => nil
+    config_param :time_key, :string, default: nil
     desc 'The format for event time used when the time_key parameter is specified. The default is UNIX time (integer).'
-    config_param :time_format, :string, :default => nil
+    config_param :time_format, :string, default: nil
     desc "The format used to map the incoming events to the program input. (#{ExecUtil::SUPPORTED_FORMAT.keys.join(',')})"
-    config_param :format, :default => :tsv do |val|
+    config_param :format, default: :tsv do |val|
       f = ExecUtil::SUPPORTED_FORMAT[val]
       raise ConfigError, "Unsupported format '#{val}'" unless f
       f
diff --git a/lib/fluent/plugin/out_exec_filter.rb b/lib/fluent/plugin/out_exec_filter.rb
index 261a7571c1..46021c37bc 100644
--- a/lib/fluent/plugin/out_exec_filter.rb
+++ b/lib/fluent/plugin/out_exec_filter.rb
@@ -28,61 +28,61 @@ def initialize
     desc 'The command (program) to execute.'
     config_param :command, :string
 
-    config_param :remove_prefix, :string, :default => nil
-    config_param :add_prefix, :string, :default => nil
+    config_param :remove_prefix, :string, default: nil
+    config_param :add_prefix, :string, default: nil
 
     desc "The format used to map the incoming event to the program input.(#{ExecUtil::SUPPORTED_FORMAT.keys.join(',')})"
-    config_param :in_format, :default => :tsv do |val|
+    config_param :in_format, default: :tsv do |val|
       f = ExecUtil::SUPPORTED_FORMAT[val]
       raise ConfigError, "Unsupported in_format '#{val}'" unless f
       f
     end
     desc 'Specify comma-separated values for tsv format.'
-    config_param :in_keys, :default => [] do |val|
+    config_param :in_keys, default: [] do |val|
       val.split(',')
     end
     desc 'The name of the key to use as the event tag.'
-    config_param :in_tag_key, :default => nil
+    config_param :in_tag_key, default: nil
     desc 'The name of the key to use as the event time.'
-    config_param :in_time_key, :default => nil
+    config_param :in_time_key, default: nil
     desc 'The format for event time used when the in_time_key parameter is specified.(Defauls is UNIX time)'
-    config_param :in_time_format, :default => nil
+    config_param :in_time_format, default: nil
 
     desc "The format used to process the program output.(#{ExecUtil::SUPPORTED_FORMAT.keys.join(',')})"
-    config_param :out_format, :default => :tsv do |val|
+    config_param :out_format, default: :tsv do |val|
       f = ExecUtil::SUPPORTED_FORMAT[val]
       raise ConfigError, "Unsupported out_format '#{val}'" unless f
       f
     end
     desc 'Specify comma-separated values for tsv format.'
-    config_param :out_keys, :default => [] do |val|  # for tsv format
+    config_param :out_keys, default: [] do |val|  # for tsv format
       val.split(',')
     end
     desc 'The name of the key to use as the event tag.'
-    config_param :out_tag_key, :default => nil
+    config_param :out_tag_key, default: nil
     desc 'The name of the key to use as the event time.'
-    config_param :out_time_key, :default => nil
+    config_param :out_time_key, default: nil
     desc 'The format for event time used when the in_time_key parameter is specified.(Defauls is UNIX time)'
-    config_param :out_time_format, :default => nil
+    config_param :out_time_format, default: nil
 
-    config_param :tag, :string, :default => nil
+    config_param :tag, :string, default: nil
 
-    config_param :time_key, :string, :default => nil
-    config_param :time_format, :string, :default => nil
+    config_param :time_key, :string, default: nil
+    config_param :time_format, :string, default: nil
 
     desc 'If true, use localtime with in_time_format.'
-    config_param :localtime, :bool, :default => true
+    config_param :localtime, :bool, default: true
     desc 'If true, use timezone with in_time_format.'
-    config_param :timezone, :string, :default => nil
+    config_param :timezone, :string, default: nil
     desc 'The number of spawned process for command.'
-    config_param :num_children, :integer, :default => 1
+    config_param :num_children, :integer, default: 1
 
     desc 'Respawn command when command exit.'
     # nil, 'none' or 0: no respawn, 'inf' or -1: infinite times, positive integer: try to respawn specified times only
-    config_param :child_respawn, :string, :default => nil
+    config_param :child_respawn, :string, default: nil
 
     # 0: output logs for all of messages to emit
-    config_param :suppress_error_log_interval, :time, :default => 0
+    config_param :suppress_error_log_interval, :time, default: 0
 
     config_set_default :flush_interval, 1
 
@@ -306,7 +306,7 @@ def write(chunk)
           chunk.write_to(@io)
         rescue Errno::EPIPE => e
           # Broken pipe (child process unexpectedly exited)
-          @log.warn "exec_filter Broken pipe, child process maybe exited.", :command => @command
+          @log.warn "exec_filter Broken pipe, child process maybe exited.", command: @command
           if try_respawn
             retry # retry chunk#write_to with child respawned
           else
@@ -329,19 +329,19 @@ def try_respawn
 
           @respawns -= 1 if @respawns > 0
         end
-        @log.warn "exec_filter child process successfully respawned.", :command => @command, :respawns => @respawns
+        @log.warn "exec_filter child process successfully respawned.", command: @command, respawns: @respawns
         true
       end
 
       def run
         @parser.call(@io)
       rescue
-        @log.error "exec_filter thread unexpectedly failed with an error.", :command=>@command, :error=>$!.to_s
+        @log.error "exec_filter thread unexpectedly failed with an error.", command: @command, error: $!.to_s
         @log.warn_backtrace $!.backtrace
       ensure
         pid, stat = Process.waitpid2(@pid)
         unless @finished
-          @log.error "exec_filter process unexpectedly exited.", :command=>@command, :ecode=>stat.to_i
+          @log.error "exec_filter process unexpectedly exited.", command: @command, ecode: stat.to_i
           unless @respawns == 0
             @log.warn "exec_filter child process will respawn for next input data (respawns #{@respawns})."
           end
@@ -369,7 +369,7 @@ def on_message(record)
       router.emit(tag, time, record)
     rescue
       if @suppress_error_log_interval == 0 || Time.now.to_i > @next_log_time
-        log.error "exec_filter failed to emit", :error=>$!.to_s, :error_class=>$!.class.to_s, :record=>Yajl.dump(record)
+        log.error "exec_filter failed to emit", error: $!.to_s, error_class: $!.class.to_s, record: Yajl.dump(record)
         log.warn_backtrace $!.backtrace
         @next_log_time = Time.now.to_i + @suppress_error_log_interval
       end
diff --git a/lib/fluent/plugin/out_file.rb b/lib/fluent/plugin/out_file.rb
index d5ba98ee14..08e355cd5c 100644
--- a/lib/fluent/plugin/out_file.rb
+++ b/lib/fluent/plugin/out_file.rb
@@ -26,11 +26,11 @@ class FileOutput < TimeSlicedOutput
     desc "The Path of the file."
     config_param :path, :string
     desc "The format of the file content. The default is out_file."
-    config_param :format, :string, :default => 'out_file'
+    config_param :format, :string, default: 'out_file'
     desc "The flushed chunk is appended to existence file or not."
-    config_param :append, :bool, :default => false
+    config_param :append, :bool, default: false
     desc "Compress flushed file."
-    config_param :compress, :default => nil do |val|
+    config_param :compress, default: nil do |val|
       c = SUPPORTED_COMPRESS[val]
       unless c
         raise ConfigError, "Unsupported compression algorithm '#{val}'"
@@ -38,7 +38,7 @@ class FileOutput < TimeSlicedOutput
       c
     end
     desc "Create symlink to temporary buffered file when buffer_type is file."
-    config_param :symlink_path, :string, :default => nil
+    config_param :symlink_path, :string, default: nil
 
     def initialize
       require 'zlib'
@@ -84,7 +84,7 @@ def format(tag, time, record)
 
     def write(chunk)
       path = generate_path(chunk.key)
-      FileUtils.mkdir_p File.dirname(path), :mode => DEFAULT_DIR_PERMISSION
+      FileUtils.mkdir_p File.dirname(path), mode: DEFAULT_DIR_PERMISSION
 
       case @compress
       when nil
diff --git a/lib/fluent/plugin/out_forward.rb b/lib/fluent/plugin/out_forward.rb
index 9e85b84cce..3063b8caa6 100644
--- a/lib/fluent/plugin/out_forward.rb
+++ b/lib/fluent/plugin/out_forward.rb
@@ -37,9 +37,9 @@ def initialize
     end
 
     desc 'The timeout time when sending event logs.'
-    config_param :send_timeout, :time, :default => 60
+    config_param :send_timeout, :time, default: 60
     desc 'The transport protocol to use for heartbeats.(udp,tcp,none)'
-    config_param :heartbeat_type, :default => :udp do |val|
+    config_param :heartbeat_type, default: :udp do |val|
       case val.downcase
       when 'tcp'
         :tcp
@@ -52,34 +52,34 @@ def initialize
       end
     end
     desc 'The interval of the heartbeat packer.'
-    config_param :heartbeat_interval, :time, :default => 1
+    config_param :heartbeat_interval, :time, default: 1
     desc 'The wait time before accepting a server fault recovery.'
-    config_param :recover_wait, :time, :default => 10
+    config_param :recover_wait, :time, default: 10
     desc 'The hard timeout used to detect server failure.'
-    config_param :hard_timeout, :time, :default => 60
+    config_param :hard_timeout, :time, default: 60
     desc 'Set TTL to expire DNS cache in seconds.'
-    config_param :expire_dns_cache, :time, :default => nil  # 0 means disable cache
+    config_param :expire_dns_cache, :time, default: nil  # 0 means disable cache
     desc 'The threshold parameter used to detect server faults.'
-    config_param :phi_threshold, :integer, :default => 16
+    config_param :phi_threshold, :integer, default: 16
     desc 'Use the "Phi accrual failure detector" to detect server failure.'
-    config_param :phi_failure_detector, :bool, :default => true
+    config_param :phi_failure_detector, :bool, default: true
 
     # if any options added that requires extended forward api, fix @extend_internal_protocol
 
     desc 'Change the protocol to at-least-once.'
-    config_param :require_ack_response, :bool, :default => false  # require in_forward to respond with ack
+    config_param :require_ack_response, :bool, default: false  # require in_forward to respond with ack
     desc 'This option is used when require_ack_response is true.'
-    config_param :ack_response_timeout, :time, :default => 190  # 0 means do not wait for ack responses
+    config_param :ack_response_timeout, :time, default: 190  # 0 means do not wait for ack responses
     # Linux default tcp_syn_retries is 5 (in many environment)
     # 3 + 6 + 12 + 24 + 48 + 96 -> 189 (sec)
     desc 'Enable client-side DNS round robin.'
-    config_param :dns_round_robin, :bool, :default => false # heartbeat_type 'udp' is not available for this
+    config_param :dns_round_robin, :bool, default: false # heartbeat_type 'udp' is not available for this
 
     attr_reader :nodes
 
     # backward compatibility
-    config_param :port, :integer, :default => DEFAULT_LISTEN_PORT
-    config_param :host, :string, :default => nil
+    config_param :port, :integer, default: DEFAULT_LISTEN_PORT
+    config_param :host, :string, default: nil
 
     attr_accessor :extend_internal_protocol
 
@@ -138,7 +138,7 @@ def configure(conf)
         else
           @nodes << Node.new(log, node_conf)
         end
-        log.info "adding forwarding server '#{name}'", :host=>host, :port=>port, :weight=>weight, :plugin_id=>plugin_id
+        log.info "adding forwarding server '#{name}'", host: host, port: port, weight: weight, plugin_id: plugin_id
       }
 
       if @nodes.empty?
@@ -184,7 +184,7 @@ def shutdown
     def run
       @loop.run if @loop
     rescue
-      log.error "unexpected error", :error=>$!.to_s
+      log.error "unexpected error", error: $!.to_s
       log.error_backtrace
     end
 
@@ -229,13 +229,13 @@ def rebuild_weight_array
           lost_weight += n.weight
         end
       }
-      log.debug "rebuilding weight array", :lost_weight=>lost_weight
+      log.debug "rebuilding weight array", lost_weight: lost_weight
 
       if lost_weight > 0
         standby_nodes.each {|n|
           if n.available?
             regular_nodes << n
-            log.warn "using standby node #{n.host}:#{n.port}", :weight=>n.weight
+            log.warn "using standby node #{n.host}:#{n.port}", weight: n.weight
             lost_weight -= n.weight
             break if lost_weight <= 0
           end
@@ -399,7 +399,7 @@ def on_timer
           end
         rescue Errno::EAGAIN, Errno::EWOULDBLOCK, Errno::EINTR, Errno::ECONNREFUSED
           # TODO log
-          log.debug "failed to send heartbeat packet to #{n.host}:#{n.port}", :error=>$!.to_s
+          log.debug "failed to send heartbeat packet to #{n.host}:#{n.port}", error: $!.to_s
         end
       }
     end
@@ -511,7 +511,7 @@ def tick
         end
 
         if @failure.hard_timeout?(now)
-          @log.warn "detached forwarding server '#{@name}'", :host=>@host, :port=>@port, :hard_timeout=>true
+          @log.warn "detached forwarding server '#{@name}'", host: @host, port: @port, hard_timeout: true
           @available = false
           @resolved_host = nil  # expire cached host
           @failure.clear
@@ -522,7 +522,7 @@ def tick
           phi = @failure.phi(now)
           #$log.trace "phi '#{@name}'", :host=>@host, :port=>@port, :phi=>phi
           if phi > @conf.phi_threshold
-            @log.warn "detached forwarding server '#{@name}'", :host=>@host, :port=>@port, :phi=>phi
+            @log.warn "detached forwarding server '#{@name}'", host: @host, port: @port, phi: phi
             @available = false
             @resolved_host = nil  # expire cached host
             @failure.clear
@@ -538,7 +538,7 @@ def heartbeat(detect=true)
         #@log.trace "heartbeat from '#{@name}'", :host=>@host, :port=>@port, :available=>@available, :sample_size=>@failure.sample_size
         if detect && !@available && @failure.sample_size > @conf.recover_sample_size
           @available = true
-          @log.warn "recovered forwarding server '#{@name}'", :host=>@host, :port=>@port
+          @log.warn "recovered forwarding server '#{@name}'", host: @host, port: @port
           return true
         else
           return nil
diff --git a/lib/fluent/plugin/out_stdout.rb b/lib/fluent/plugin/out_stdout.rb
index eb289217c2..fbaa700622 100644
--- a/lib/fluent/plugin/out_stdout.rb
+++ b/lib/fluent/plugin/out_stdout.rb
@@ -19,7 +19,7 @@ class StdoutOutput < Output
     Plugin.register_output('stdout', self)
 
     desc 'Output format.(json,hash)'
-    config_param :output_type, :default => 'json'
+    config_param :output_type, default: 'json'
 
     def configure(conf)
       super
diff --git a/lib/fluent/plugin/out_stream.rb b/lib/fluent/plugin/out_stream.rb
index 41db049c6d..2ee222010b 100644
--- a/lib/fluent/plugin/out_stream.rb
+++ b/lib/fluent/plugin/out_stream.rb
@@ -23,7 +23,7 @@ def initialize
       super
     end
 
-    config_param :send_timeout, :time, :default => 60
+    config_param :send_timeout, :time, default: 60
 
     def configure(conf)
       super
@@ -91,7 +91,7 @@ def initialize
       $log.warn "see 'forward' section in http://docs.fluentd.org/ for the high-availability configuration."
     end
 
-    config_param :port, :integer, :default => DEFAULT_LISTEN_PORT
+    config_param :port, :integer, default: DEFAULT_LISTEN_PORT
     config_param :host, :string
 
     def configure(conf)
diff --git a/lib/fluent/plugin/socket_util.rb b/lib/fluent/plugin/socket_util.rb
index 0f1e1496a7..7b9829e879 100644
--- a/lib/fluent/plugin/socket_util.rb
+++ b/lib/fluent/plugin/socket_util.rb
@@ -43,7 +43,7 @@ def on_readable
         msg.chomp!
         @callback.call(msg, addr)
       rescue => e
-        @log.error "unexpected error", :error => e, :error_class => e.class
+        @log.error "unexpected error", error: e, error_class: e.class
       end
     end
 
@@ -79,7 +79,7 @@ def on_read(data)
         end
         @buffer.slice!(0, pos) if pos > 0
       rescue => e
-        @log.error "unexpected error", :error => e, :error_class => e.class
+        @log.error "unexpected error", error: e, error_class: e.class
         close
       end
 
@@ -99,12 +99,12 @@ def initialize
       desc 'The format of the payload.'
       config_param :format, :string
       desc 'The port to listen to.'
-      config_param :port, :integer, :default => 5150
+      config_param :port, :integer, default: 5150
       desc 'The bind address to listen to.'
-      config_param :bind, :string, :default => '0.0.0.0'
+      config_param :bind, :string, default: '0.0.0.0'
       desc "The field name of the client's hostname."
-      config_param :source_host_key, :string, :default => nil
-      config_param :blocking_timeout, :time, :default => 0.5
+      config_param :source_host_key, :string, default: nil
+      config_param :blocking_timeout, :time, default: 0.5
 
       def configure(conf)
         super
@@ -130,7 +130,7 @@ def shutdown
       def run
         @loop.run(@blocking_timeout)
       rescue => e
-        log.error "unexpected error", :error => e, :error_class => e.class
+        log.error "unexpected error", error: e, error_class: e.class
         log.error_backtrace
       end
 
@@ -147,7 +147,7 @@ def on_message(msg, addr)
           router.emit(@tag, time, record)
         }
       rescue => e
-        log.error msg.dump, :error => e, :error_class => e.class, :host => addr[3]
+        log.error msg.dump, error: e, error_class: e.class, host: addr[3]
         log.error_backtrace
       end
     end
diff --git a/lib/fluent/process.rb b/lib/fluent/process.rb
index 6130e472a4..d2f87a0351 100644
--- a/lib/fluent/process.rb
+++ b/lib/fluent/process.rb
@@ -149,12 +149,12 @@ def output_forward_main(opr, target)
         begin
           target.emit(tag, es, NullOutputChain.instance)
         rescue
-          $log.warn "failed to emit", :error=>$!.to_s, :pid=>Process.pid
+          $log.warn "failed to emit", error: $!.to_s, pid: Process.pid
           $log.warn_backtrace
         end
       }
     rescue
-      $log.error "error on output process forwarding thread", :error=>$!.to_s, :pid=>Process.pid
+      $log.error "error on output process forwarding thread", error: $!.to_s, pid: Process.pid
       $log.error_backtrace
       raise
     end
@@ -165,12 +165,12 @@ def input_forward_main(ipr, pid)
         begin
           Engine.emit_stream(tag, es)
         rescue
-          $log.warn "failed to emit", :error=>$!.to_s, :pid=>Process.pid
+          $log.warn "failed to emit", error: $!.to_s, pid: Process.pid
           $log.warn_backtrace
         end
       }
     rescue
-      $log.error "error on input process forwarding thread", :error=>$!.to_s, :pid=>Process.pid
+      $log.error "error on input process forwarding thread", error: $!.to_s, pid: Process.pid
       $log.error_backtrace
       raise
     end
@@ -264,7 +264,7 @@ def run
           end
         end
       rescue
-        $log.error "error on forwerder thread", :error=>$!.to_s
+        $log.error "error on forwerder thread", error: $!.to_s
         $log.error_backtrace
         raise
       end
@@ -302,7 +302,7 @@ def detach_process_impl(num, &block)
 
         if pid
           # parent process
-          $log.info "detached process", :class=>self.class, :pid=>pid
+          $log.info "detached process", class: self.class, pid: pid
           children << [pid, forward_thread]
           next
         end
@@ -332,7 +332,7 @@ def detach_process_impl(num, &block)
           on_exit_process(i)
           exit! 0
         ensure
-          $log.error "unknown error while shutting down this child process", :error=>$!.to_s, :pid=>Process.pid
+          $log.error "unknown error while shutting down this child process", error: $!.to_s, pid: Process.pid
           $log.error_backtrace
         end
 
@@ -353,7 +353,7 @@ def detach_process_impl(num, &block)
               pair[0] = nil
             end
           rescue
-            $log.error "unknown error while shutting down remote child process", :error=>$!.to_s
+            $log.error "unknown error while shutting down remote child process", error: $!.to_s
             $log.error_backtrace
           end
         }
diff --git a/lib/fluent/root_agent.rb b/lib/fluent/root_agent.rb
index a0851c78b7..58462ef478 100644
--- a/lib/fluent/root_agent.rb
+++ b/lib/fluent/root_agent.rb
@@ -121,7 +121,7 @@ def shutdown
             log.info "shutting down input", type: Plugin.lookup_name_from_class(i.class), plugin_id: i.plugin_id
             i.shutdown
           rescue => e
-            log.warn "unexpected error while shutting down input plugin", :plugin => i.class, :plugin_id => i.plugin_id, :error_class => e.class, :error => e
+            log.warn "unexpected error while shutting down input plugin", plugin: i.class, plugin_id: i.plugin_id, error_class: e.class, error: e
             log.warn_backtrace
           end
         end
@@ -168,7 +168,7 @@ def find_label(label_name)
     end
 
     def emit_error_event(tag, time, record, error)
-      error_info = {:error_class => error.class, :error => error.to_s, :tag => tag, :time => time}
+      error_info = {error_class: error.class, error: error.to_s, tag: tag, time: time}
       if @error_collector
         # A record is not included in the logs because <@ERROR> handles it. This warn is for the notification
         log.warn "send an error event to @ERROR:", error_info
@@ -180,7 +180,7 @@ def emit_error_event(tag, time, record, error)
     end
 
     def handle_emits_error(tag, es, error)
-      error_info = {:error_class => error.class, :error => error.to_s, :tag => tag}
+      error_info = {error_class: error.class, error: error.to_s, tag: tag}
       if @error_collector
         log.warn "send an error event stream to @ERROR:", error_info
         @error_collector.emit_stream(tag, es)
@@ -209,14 +209,14 @@ def initialize(root_agent)
       end
 
       def emit_error_event(tag, time, record, error)
-        error_info = {:error_class => error.class, :error => error.to_s, :tag => tag, :time => time, :record => record}
+        error_info = {error_class: error.class, error: error.to_s, tag: tag, time: time, record: record}
         log.warn "dump an error event in @ERROR:", error_info
       end
 
       def handle_emits_error(tag, es, e)
         now = Engine.now
         if @suppress_emit_error_log_interval.zero? || now > @next_emit_error_log_time
-          log.warn "emit transaction failed in @ERROR:", :error_class => e.class, :error => e, :tag => tag
+          log.warn "emit transaction failed in @ERROR:", error_class: e.class, error: e, tag: tag
           log.warn_backtrace
           @next_emit_error_log_time = now + @suppress_emit_error_log_interval
         end
diff --git a/lib/fluent/rpc.rb b/lib/fluent/rpc.rb
index 752e7f0727..2c7e70a16c 100644
--- a/lib/fluent/rpc.rb
+++ b/lib/fluent/rpc.rb
@@ -26,10 +26,10 @@ def initialize(endpoint, log)
         @log = log
 
         @server = WEBrick::HTTPServer.new(
-          :BindAddress => @bind,
-          :Port => @port,
-          :Logger => WEBrick::Log.new(STDERR, WEBrick::Log::FATAL),
-          :AccessLog => [],
+          BindAddress: @bind,
+          Port: @port,
+          Logger: WEBrick::Log.new(STDERR, WEBrick::Log::FATAL),
+          AccessLog: [],
         )
       end
 
@@ -43,7 +43,7 @@ def mount_proc(path, &block)
           begin
             code, header, response = block.call(req, res)
           rescue => e
-            @log.warn "failed to handle RPC request", :path => path, :error => e.to_s
+            @log.warn "failed to handle RPC request", path: path, error: e.to_s
             @log.warn_backtrace e.backtrace
 
             code = 500
diff --git a/lib/fluent/supervisor.rb b/lib/fluent/supervisor.rb
index 10299ba3ea..ce5a364f4a 100644
--- a/lib/fluent/supervisor.rb
+++ b/lib/fluent/supervisor.rb
@@ -80,20 +80,20 @@ def level=(level)
 
     def self.default_options
       {
-        :config_path => Fluent::DEFAULT_CONFIG_PATH,
-        :plugin_dirs => [Fluent::DEFAULT_PLUGIN_DIR],
-        :log_level => Fluent::Log::LEVEL_INFO,
-        :log_path => nil,
-        :daemonize => nil,
-        :libs => [],
-        :setup_path => nil,
-        :chuser => nil,
-        :chgroup => nil,
-        :suppress_interval => 0,
-        :suppress_repeated_stacktrace => true,
-        :without_source => false,
-        :use_v1_config => true,
-        :supervise => true,
+        config_path: Fluent::DEFAULT_CONFIG_PATH,
+        plugin_dirs: [Fluent::DEFAULT_PLUGIN_DIR],
+        log_level: Fluent::Log::LEVEL_INFO,
+        log_path: nil,
+        daemonize: nil,
+        libs: [],
+        setup_path: nil,
+        chuser: nil,
+        chgroup: nil,
+        suppress_interval: 0,
+        suppress_repeated_stacktrace: true,
+        without_source: false,
+        use_v1_config: true,
+        supervise: true,
       }
     end
 
@@ -118,7 +118,7 @@ def initialize(opt)
       @suppress_config_dump = opt[:suppress_config_dump]
       @without_source = opt[:without_source]
 
-      log_opts = {:suppress_repeated_stacktrace => opt[:suppress_repeated_stacktrace]}
+      log_opts = {suppress_repeated_stacktrace: opt[:suppress_repeated_stacktrace]}
       @log = LoggerInitializer.new(@log_path, @log_level, @chuser, @chgroup, log_opts)
       @finished = false
       @main_pid = nil
@@ -337,7 +337,7 @@ def supervise(&block)
       @main_pid = nil
       ecode = $?.to_i
 
-      $log.info "process finished", :code=>ecode
+      $log.info "process finished", code: ecode
 
       if !@finished && Time.now - start_time < 1
         $log.warn "process died within 1 second. exit."
@@ -352,20 +352,20 @@ def main_process(&block)
         block.call
 
       rescue Fluent::ConfigError
-        $log.error "config error", :file=>@config_path, :error=>$!.to_s
+        $log.error "config error", file: @config_path, error: $!.to_s
         $log.debug_backtrace
         unless @log.stdout?
           console = Fluent::Log.new(STDOUT, @log_level).enable_debug
-          console.error "config error", :file=>@config_path, :error=>$!.to_s
+          console.error "config error", file: @config_path, error: $!.to_s
           console.debug_backtrace
         end
 
       rescue
-        $log.error "unexpected error", :error=>$!.to_s
+        $log.error "unexpected error", error: $!.to_s
         $log.error_backtrace
         unless @log.stdout?
           console = Fluent::Log.new(STDOUT, @log_level).enable_debug
-          console.error "unexpected error", :error=>$!.to_s
+          console.error "unexpected error", error: $!.to_s
           console.error_backtrace
         end
       end
@@ -454,7 +454,7 @@ def supervisor_get_dump_config_handler
     end
 
     def read_config
-      $log.info "reading config file", :path => @config_path
+      $log.info "reading config file", path: @config_path
       @config_fname = File.basename(@config_path)
       @config_basedir = File.dirname(@config_path)
       @config_data = File.read(@config_path)
@@ -469,16 +469,16 @@ def read_config
     class SystemConfig
       include Configurable
 
-      config_param :log_level, :default => nil do |level|
+      config_param :log_level, default: nil do |level|
         Log.str_to_level(level)
       end
-      config_param :suppress_repeated_stacktrace, :bool, :default => nil
-      config_param :emit_error_log_interval, :time, :default => nil
-      config_param :suppress_config_dump, :bool, :default => nil
-      config_param :without_source, :bool, :default => nil
-      config_param :rpc_endpoint, :string, :default => nil
-      config_param :enable_get_dump, :bool, :default => nil
-      config_param :process_name, :default => nil
+      config_param :suppress_repeated_stacktrace, :bool, default: nil
+      config_param :emit_error_log_interval, :time, default: nil
+      config_param :suppress_config_dump, :bool, default: nil
+      config_param :without_source, :bool, default: nil
+      config_param :rpc_endpoint, :string, default: nil
+      config_param :enable_get_dump, :bool, default: nil
+      config_param :process_name, default: nil
 
       def initialize(conf)
         super()
diff --git a/test/config/test_configurable.rb b/test/config/test_configurable.rb
index 14d509216a..d09c40c5a6 100644
--- a/test/config/test_configurable.rb
+++ b/test/config/test_configurable.rb
@@ -7,14 +7,14 @@ module ConfigurableSpec
   class Base1
     include Fluent::Configurable
 
-    config_param :node, :string, :default => "node"
-    config_param :flag1, :bool, :default => false
-    config_param :flag2, :bool, :default => true
+    config_param :node, :string, default: "node"
+    config_param :flag1, :bool, default: false
+    config_param :flag2, :bool, default: true
 
     config_param :name1, :string
     config_param :name2, :string
-    config_param :name3, :string, :default => "base1"
-    config_param :name4, :string, :default => "base1"
+    config_param :name3, :string, default: "base1"
+    config_param :name4, :string, default: "base1"
 
     config_param :opt1, :enum, list: [:foo, :bar, :baz]
     config_param :opt2, :enum, list: [:foo, :bar, :baz], default: :foo
@@ -29,7 +29,7 @@ class Base2 < Base1
     config_set_default :name4, "base2"
     config_set_default :opt1, :bar
     config_param :name5, :string
-    config_param :name6, :string, :default => "base2"
+    config_param :name6, :string, default: "base2"
     config_param :opt3, :enum, list: [:a, :b]
 
     def get_all
@@ -41,7 +41,7 @@ def get_all
   class Base3 < Base2
     config_set_default :opt3, :a
     config_section :node do
-      config_param :name, :string, :default => "node"
+      config_param :name, :string, default: "node"
       config_param :type, :string
     end
     config_section :branch, required: true, multi: true do
@@ -65,8 +65,8 @@ class Base4 < Base2
     config_set_default :opt3, :a
     config_section :node, param_name: :nodes do
       config_argument :num, :integer
-      config_param :name, :string, :default => "node"
-      config_param :type, :string, :default => "b4"
+      config_param :name, :string, default: "node"
+      config_param :type, :string, default: "b4"
     end
     config_section :description1, required: false, multi: false do
       config_argument :note, :string, default: "desc1"
@@ -151,11 +151,11 @@ class Example5
     include Fluent::Configurable
 
     config_param :normal_param, :string
-    config_param :secret_param, :string, :secret => true
+    config_param :secret_param, :string, secret: true
 
     config_section :section  do
       config_param :normal_param2, :string
-      config_param :secret_param2, :string, :secret => true
+      config_param :secret_param2, :string, secret: true
     end
   end
 end
diff --git a/test/config/test_configure_proxy.rb b/test/config/test_configure_proxy.rb
index b46d85a710..63ee5c7809 100644
--- a/test/config/test_configure_proxy.rb
+++ b/test/config/test_configure_proxy.rb
@@ -127,7 +127,7 @@ class TestConfigureProxy < ::Test::Unit::TestCase
         test 'does not permit description specification twice' do
           @proxy.desc("description1")
           assert_raise(ArgumentError) do
-            @proxy.config_param(:name, :string, :desc => "description2")
+            @proxy.config_param(:name, :string, desc: "description2")
           end
         end
       end
diff --git a/test/plugin/test_filter_record_transformer.rb b/test/plugin/test_filter_record_transformer.rb
index 957d2dc645..94746196e0 100644
--- a/test/plugin/test_filter_record_transformer.rb
+++ b/test/plugin/test_filter_record_transformer.rb
@@ -351,41 +351,41 @@ def emit(config, msgs = [''])
           { "source" => nil },
         ]
         expected_results = [
-          { :single      => "string",
-            :multiple    => "stringstring",
-            :with_prefix => "prefix-string",
-            :with_suffix => "string-suffix",
-            :with_quote  => %Q{source[""]} },
-          { :single      => 123.to_s,
-            :multiple    => "#{123.to_s}#{123.to_s}",
-            :with_prefix => "prefix-#{123.to_s}",
-            :with_suffix => "#{123.to_s}-suffix",
-            :with_quote  => %Q{source[""]} },
-          { :single      => [1, 2].to_s,
-            :multiple    => "#{[1, 2].to_s}#{[1, 2].to_s}",
-            :with_prefix => "prefix-#{[1, 2].to_s}",
-            :with_suffix => "#{[1, 2].to_s}-suffix",
-            :with_quote  => %Q{source[""]} },
-          { :single      => {a:1, b:2}.to_s,
-            :multiple    => "#{{a:1, b:2}.to_s}#{{a:1, b:2}.to_s}",
-            :with_prefix => "prefix-#{{a:1, b:2}.to_s}",
-            :with_suffix => "#{{a:1, b:2}.to_s}-suffix",
-            :with_quote  => %Q{source[""]} },
-          { :single      => nil.to_s,
-            :multiple    => "#{nil.to_s}#{nil.to_s}",
-            :with_prefix => "prefix-#{nil.to_s}",
-            :with_suffix => "#{nil.to_s}-suffix",
-            :with_quote  => %Q{source[""]} },
+          { single: "string",
+            multiple: "stringstring",
+            with_prefix: "prefix-string",
+            with_suffix: "string-suffix",
+            with_quote: %Q{source[""]} },
+          { single: 123.to_s,
+            multiple: "#{123.to_s}#{123.to_s}",
+            with_prefix: "prefix-#{123.to_s}",
+            with_suffix: "#{123.to_s}-suffix",
+            with_quote: %Q{source[""]} },
+          { single: [1, 2].to_s,
+            multiple: "#{[1, 2].to_s}#{[1, 2].to_s}",
+            with_prefix: "prefix-#{[1, 2].to_s}",
+            with_suffix: "#{[1, 2].to_s}-suffix",
+            with_quote: %Q{source[""]} },
+          { single: {a:1, b:2}.to_s,
+            multiple: "#{{a:1, b:2}.to_s}#{{a:1, b:2}.to_s}",
+            with_prefix: "prefix-#{{a:1, b:2}.to_s}",
+            with_suffix: "#{{a:1, b:2}.to_s}-suffix",
+            with_quote: %Q{source[""]} },
+          { single: nil.to_s,
+            multiple: "#{nil.to_s}#{nil.to_s}",
+            with_prefix: "prefix-#{nil.to_s}",
+            with_suffix: "#{nil.to_s}-suffix",
+            with_quote: %Q{source[""]} },
         ]
         actual_results = []
         es = emit(config, msgs)
         es.each_with_index do |(t, r), i|
           actual_results << {
-            :single      => r["single"],
-            :multiple    => r["multiple"],
-            :with_prefix => r["with_prefix"],
-            :with_suffix => r["with_suffix"],
-            :with_quote  => r["with_quote"],
+            single: r["single"],
+            multiple: r["multiple"],
+            with_prefix: r["with_prefix"],
+            with_suffix: r["with_suffix"],
+            with_quote: r["with_quote"],
           }
         end
         assert_equal(expected_results, actual_results)
@@ -410,35 +410,35 @@ def emit(config, msgs = [''])
           { "source" => nil },
         ]
         expected_results = [
-          { :single      => "string",
-            :multiple    => "stringstring",
-            :with_prefix => "prefix-string",
-            :with_suffix => "string-suffix" },
-          { :single      => 123,
-            :multiple    => "#{123.to_s}#{123.to_s}",
-            :with_prefix => "prefix-#{123.to_s}",
-            :with_suffix => "#{123.to_s}-suffix" },
-          { :single      => [1, 2],
-            :multiple    => "#{[1, 2].to_s}#{[1, 2].to_s}",
-            :with_prefix => "prefix-#{[1, 2].to_s}",
-            :with_suffix => "#{[1, 2].to_s}-suffix" },
-          { :single      => {a:1, b:2},
-            :multiple    => "#{{a:1, b:2}.to_s}#{{a:1, b:2}.to_s}",
-            :with_prefix => "prefix-#{{a:1, b:2}.to_s}",
-            :with_suffix => "#{{a:1, b:2}.to_s}-suffix" },
-          { :single      => nil,
-            :multiple    => "#{nil.to_s}#{nil.to_s}",
-            :with_prefix => "prefix-#{nil.to_s}",
-            :with_suffix => "#{nil.to_s}-suffix" },
+          { single: "string",
+            multiple: "stringstring",
+            with_prefix: "prefix-string",
+            with_suffix: "string-suffix" },
+          { single: 123,
+            multiple: "#{123.to_s}#{123.to_s}",
+            with_prefix: "prefix-#{123.to_s}",
+            with_suffix: "#{123.to_s}-suffix" },
+          { single: [1, 2],
+            multiple: "#{[1, 2].to_s}#{[1, 2].to_s}",
+            with_prefix: "prefix-#{[1, 2].to_s}",
+            with_suffix: "#{[1, 2].to_s}-suffix" },
+          { single: {a:1, b:2},
+            multiple: "#{{a:1, b:2}.to_s}#{{a:1, b:2}.to_s}",
+            with_prefix: "prefix-#{{a:1, b:2}.to_s}",
+            with_suffix: "#{{a:1, b:2}.to_s}-suffix" },
+          { single: nil,
+            multiple: "#{nil.to_s}#{nil.to_s}",
+            with_prefix: "prefix-#{nil.to_s}",
+            with_suffix: "#{nil.to_s}-suffix" },
         ]
         actual_results = []
         es = emit(config, msgs)
         es.each_with_index do |(t, r), i|
           actual_results << {
-            :single      => r["single"],
-            :multiple    => r["multiple"],
-            :with_prefix => r["with_prefix"],
-            :with_suffix => r["with_suffix"],
+            single: r["single"],
+            multiple: r["multiple"],
+            with_prefix: r["with_prefix"],
+            with_suffix: r["with_suffix"],
           }
         end
         assert_equal(expected_results, actual_results)
diff --git a/test/test_config.rb b/test/test_config.rb
index 3b7d495154..e245519203 100644
--- a/test/test_config.rb
+++ b/test/test_config.rb
@@ -159,8 +159,8 @@ def write_config(path, data)
   def test_inline
     prepare_config 
     opts = {
-      :config_path => "#{TMP_DIR}/config_test_1.conf",
-      :inline_config => "<source>\n  type http\n  port 2222\n </source>"
+      config_path: "#{TMP_DIR}/config_test_1.conf",
+      inline_config: "<source>\n  type http\n  port 2222\n </source>"
     }
     assert_nothing_raised do
       Fluent::Supervisor.new(opts)