Implementation replacing function

Author: smallcreep

lib/fluent/plugin/filter_record_modifier.rb

@@ -8,28 +8,33 @@ class Plugin::RecordModifierFilter < Plugin::Filter
                  desc: <<-DESC
 Prepare values for filtering in configure phase. Prepared values can be used in <record>.
 You can write any ruby code.
-DESC
+    DESC
     config_param :char_encoding, :string, default: nil,
                  desc: <<-DESC
 Fluentd including some plugins treats the logs as a BINARY by default to forward.
 But an user sometimes processes the logs depends on their requirements,
 e.g. handling char encoding correctly.
 In more detail, please refer this section:
 https://github.com/repeatedly/fluent-plugin-record-modifier#char_encoding.
-DESC
+    DESC
     config_param :remove_keys, :string, default: nil,
                  desc: <<-DESC
 The logs include needless record keys in some cases.
 You can remove it by using `remove_keys` parameter.
 This option is exclusive with `whitelist_keys`.
-DESC
+    DESC
 
     config_param :whitelist_keys, :string, default: nil,
                  desc: <<-DESC
 Specify `whitelist_keys` to remove all unexpected keys and values from events.
 Modified events will have only specified keys (if exist in original events).
 This option is exclusive with `remove_keys`.
-DESC
+    DESC
+
+    config_param :replace, :bool, default: false,
+                 desc: <<-DESC
+Boolean flag to enable replace function. Default is false.
+    DESC
 
     def configure(conf)
       super
@@ -51,13 +56,16 @@ def configure(conf)
               method(:set_encoding)
             end
 
-        (class << self; self; end).module_eval do
+        (
+        class << self;
+          self;
+        end).module_eval do
           define_method(:change_encoding, m)
         end
       end
 
       @has_tag_parts = false
-      conf.elements.select { |element| element.name == 'record' }.each do |element|
+      conf.elements.select {|element| element.name == 'record'}.each do |element|
         element.each_pair do |k, v|
           check_config_placeholders(k, v)
           element.has_key?(k) # to suppress unread configuration warning
@@ -66,6 +74,20 @@ def configure(conf)
         end
       end
 
+      @replace_keys = Array.new
+      if @replace
+        conf.elements.select {|element| element.name == 'replace'}.each do |element|
+          expr = if element['expression'][0] == "/" && element['expression'][-1] == "/"
+                   element['expression'][1..-2]
+                 else
+                   element['expression']
+                 end
+          @replace_keys.push("key" => element['key'],
+                             "expression" => Regexp.new(expr),
+                             "replace" => element['replace'])
+        end
+      end
+
       if @remove_keys and @whitelist_keys
         raise Fluent::ConfigError, "remove_keys and whitelist_keys are exclusive with each other."
       elsif @remove_keys
@@ -81,12 +103,12 @@ def configure(conf)
     def filter(tag, time, record)
       tag_parts = @has_tag_parts ? tag.split('.') : nil
 
-      @map.each_pair { |k, v|
+      @map.each_pair {|k, v|
         record[k] = v.expand(tag, time, record, tag_parts)
       }
 
       if @remove_keys
-        @remove_keys.each { |v|
+        @remove_keys.each {|v|
           record.delete(v)
         }
       elsif @whitelist_keys
@@ -97,8 +119,14 @@ def filter(tag, time, record)
         record = modified
       end
 
+      if @replace && @replace_keys
+        @replace_keys.each {|rep|
+          record[rep['key']] = record[rep['key']].gsub(rep['expression'], rep['replace']) if record.include?(rep['key']) && rep['expression'].match(record[rep['key']])
+        }
+      end
+
       record = change_encoding(record) if @char_encoding
-      record
+      recordk
     end
 
     private
@@ -107,15 +135,15 @@ def set_encoding(value)
       if value.is_a?(String)
         value.force_encoding(@from_enc)
       elsif value.is_a?(Hash)
-        value.each_pair { |k, v|
+        value.each_pair {|k, v|
           if v.frozen? && v.is_a?(String)
             value[k] = set_encoding(v.dup)
           else
             set_encoding(v)
           end
         }
       elsif value.is_a?(Array)
-        value.each { |v| set_encoding(v) }
+        value.each {|v| set_encoding(v)}
       else
         value
       end
@@ -126,15 +154,15 @@ def convert_encoding(value)
         value.force_encoding(@from_enc) if value.encoding == Encoding::BINARY
         value.encode!(@to_enc, @from_enc, :invalid => :replace, :undef => :replace)
       elsif value.is_a?(Hash)
-        value.each_pair { |k, v|
+        value.each_pair {|k, v|
           if v.frozen? && v.is_a?(String)
             value[k] = convert_encoding(v.dup)
           else
             convert_encoding(v)
           end
         }
       elsif value.is_a?(Array)
-        value.each { |v| convert_encoding(v) }
+        value.each {|v| convert_encoding(v)}
       else
         value
       end
@@ -143,7 +171,7 @@ def convert_encoding(value)
     HOSTNAME_PLACEHOLDERS = %W(__HOSTNAME__ ${hostname})
 
     def check_config_placeholders(k, v)
-      HOSTNAME_PLACEHOLDERS.each { |ph|
+      HOSTNAME_PLACEHOLDERS.each {|ph|
         if v.include?(ph)
           raise ConfigError, %!#{ph} placeholder in #{k} is removed. Use "\#{Socket.gethostname}" instead.!
         end
@@ -158,7 +186,10 @@ def initialize(param_key, param_value, prepare_value)
           # Use class_eval with string instead of define_method for performance.
           # It can't share instructions but this is 2x+ faster than define_method in filter case.
           # Refer: http://tenderlovemaking.com/2013/03/03/dynamic_method_definitions.html
-          (class << self; self; end).class_eval <<-EORUBY,  __FILE__, __LINE__ + 1
+          (
+          class << self;
+            self;
+          end).class_eval <<-EORUBY, __FILE__, __LINE__ + 1
             def expand(tag, time, record, tag_parts)
               #{__str_eval_code__}
             end