add trace log to track event size expansion

CHANGELOG.md

@@ -1,3 +1,6 @@
+## 3.1.10
+  - Added trace log to track event size expansion [#49](https://github.com/logstash-plugins/logstash-filter-split/pull/49)
+
 ## 3.1.9
   - [DOC] Added introductory statement to clarify purpose of the plugin [#43](https://github.com/logstash-plugins/logstash-filter-split/pull/43)
 

lib/logstash/filters/split.rb

@@ -81,19 +81,31 @@ def filter(event)
 
     # set event_target to @field if not configured
     event_target = @target.nil? ? @field : @target
-
+    split_bytes = 0
+    logger.trace? && logger.trace("Event being split into #{splits.size} events")
+
     splits.each do |value|
       next if value.nil? || (value.is_a?(String) && value.empty?)
-      @logger.debug? && @logger.debug("Split event", :value => value, :field => @field)
 
       event_split = event.clone
       event_split.set(event_target, value)
       filter_matched(event_split)
 
+      logger.trace? && split_bytes += event_split.to_json.size
+
       # Push this new event onto the stack at the LogStash::FilterWorker
       yield event_split
     end
 
+
+    if logger.trace?
+      original_bytes = event.to_json.size
+      logger.trace("Estimated event size growth after split",
+        :original_bytes => original_bytes,
+        :split_bytes => split_bytes,
+        :growth_ratio => (split_bytes.to_f / original_bytes).round(2))
+    end
+
     # Cancel this event, we'll use the newly generated ones above.
     event.cancel
   end

logstash-filter-split.gemspec

@@ -1,7 +1,7 @@
 Gem::Specification.new do |s|
 
   s.name            = 'logstash-filter-split'
-  s.version         = '3.1.9'
+  s.version         = '3.1.10'
   s.licenses        = ['Apache License (2.0)']
   s.summary         = "Splits multi-line messages into distinct events"
   s.description     = "This gem is a Logstash plugin required to be installed on top of the Logstash core pipeline using $LS_HOME/bin/logstash-plugin install gemname. This gem is not a stand-alone program"