From ab9130d528b8618ec890e71a97adf866a8232fdf Mon Sep 17 00:00:00 2001
From: Athish Pranav D <athishanna@gmail.com>
Date: Thu, 29 Aug 2024 11:54:01 +0530
Subject: [PATCH] Transition filter_parser from single record to stream

Signed-off-by: Athish Pranav D <athishanna@gmail.com>
---
 lib/fluent/plugin/filter_parser.rb | 78 ++++++++++--------------------
 1 file changed, 26 insertions(+), 52 deletions(-)

diff --git a/lib/fluent/plugin/filter_parser.rb b/lib/fluent/plugin/filter_parser.rb
index 6998a38286..b65c17f5d4 100644
--- a/lib/fluent/plugin/filter_parser.rb
+++ b/lib/fluent/plugin/filter_parser.rb
@@ -54,29 +54,32 @@ def configure(conf)
       @parser = parser_create
     end
 
-    FAILED_RESULT = [nil, nil].freeze # reduce allocation cost
     REPLACE_CHAR = '?'.freeze
 
-    def filter_with_time(tag, time, record)
-      raw_value = @accessor.call(record)
-      if raw_value.nil?
-        if @emit_invalid_record_to_error
-          router.emit_error_event(tag, time, record, ArgumentError.new("#{@key_name} does not exist"))
-        end
-        if @reserve_data
-          return time, handle_parsed(tag, record, time, {})
-        else
-          return FAILED_RESULT
+    def filter_stream(tag, es)
+      new_es = Fluent::MultiEventStream.new
+      es.each do |time, record|
+        begin
+          raw_value = @accessor.call(record)
+          if raw_value.nil?
+            new_es.add(time, handle_parsed(tag, record, time, {})) if @reserve_data
+            raise ArgumentError, "#{@key_name} does not exist"
+          else
+            filter_one_record(tag, time, record, raw_value) do |result_time, result_record|
+              new_es.add(result_time, result_record)
+            end
+          end
+        rescue => e
+          router.emit_error_event(tag, time, record, e) if @emit_invalid_record_to_error
         end
       end
-      begin
-        # Note: https://github.com/fluent/fluentd/issues/4100
-        # If the parser returns multiple records from one raw_value,
-        # this returns only the first one record.
-        # This should be fixed in the future version.
-        result_time = nil
-        result_record = nil
+      new_es
+    end
+
+    private
 
+    def filter_one_record(tag, time, record, raw_value)
+      begin
         @parser.parse(raw_value) do |t, values|
           if values
             t = if @reserve_time
@@ -85,38 +88,15 @@ def filter_with_time(tag, time, record)
                   t.nil? ? time : t
                 end
             @accessor.delete(record) if @remove_key_name_field
-            r = handle_parsed(tag, record, t, values)
-
-            if result_record.nil?
-              result_time = t
-              result_record = r
-            else
-              if @emit_invalid_record_to_error
-                router.emit_error_event(tag, t, r, Fluent::Plugin::Parser::ParserError.new(
-                  "Could not emit the event. The parser returned multiple results, but currently filter_parser plugin only returns the first parsed result. Raw data: '#{raw_value}'"
-                ))
-              end
-            end
           else
-            if @emit_invalid_record_to_error
-              router.emit_error_event(tag, time, record, Fluent::Plugin::Parser::ParserError.new("pattern not matched with data '#{raw_value}'"))
-            end
-
+            router.emit_error_event(tag, time, record, Fluent::Plugin::Parser::ParserError.new("pattern not matched with data '#{raw_value}'")) if @emit_invalid_record_to_error
             next unless @reserve_data
-            next unless result_record.nil?
-
-            result_time = time
-            result_record = handle_parsed(tag, record, time, {})
+            t = time
+            values = {}
           end
+          yield(t, handle_parsed(tag, record, t, values))
         end
 
-        return result_time, result_record
-      rescue Fluent::Plugin::Parser::ParserError => e
-        if @emit_invalid_record_to_error
-          raise e
-        else
-          return FAILED_RESULT
-        end
       rescue ArgumentError => e
         raise unless @replace_invalid_sequence
         raise unless e.message.index("invalid byte sequence in") == 0
@@ -124,16 +104,10 @@ def filter_with_time(tag, time, record)
         raw_value = raw_value.scrub(REPLACE_CHAR)
         retry
       rescue => e
-        if @emit_invalid_record_to_error
-          raise Fluent::Plugin::Parser::ParserError, "parse failed #{e.message}"
-        else
-          return FAILED_RESULT
-        end
+        raise Fluent::Plugin::Parser::ParserError, "parse failed #{e.message}"
       end
     end
 
-    private
-
     def handle_parsed(tag, record, t, values)
       if values && @inject_key_prefix
         values = Hash[values.map { |k, v| [@inject_key_prefix + k, v] }]