- Add a sleep filter

CHANGELOG

@@ -21,6 +21,8 @@
     tagging events on failure. (#328, patch by Neil Prosser)
   - new: uaparser: parses user agent strings in to structured data based on
     BrowserScope data (#347, patch by Dan Everton)
+  - new: sleep: sleeps a given amount of time before passing the event.
+    Useful for rate limiting or replay simulation.
 
   ## outputs
   - fix bug in mongo output that would fail to load bson_java support

lib/logstash/filters/sleep.rb

@@ -0,0 +1,43 @@
+require "logstash/filters/base"
+require "logstash/namespace"
+
+# Sleep a given amount of time. This will cause logstash
+# to stall for the given amount of time. This is useful
+# for rate limiting, etc.
+class LogStash::Filters::Sleep < LogStash::Filters::Base
+  config_name "sleep"
+  plugin_status "experimental"
+
+  # The length of time to sleep, in seconds, for every event.
+  #
+  # This can be a number (eg, 0.5), or a string (eg, "%{foo}") 
+  # The second form (string with a field value) is useful if
+  # you have an attribute of your event that you want to use
+  # to indicate the amount of time to sleep.
+  #
+  # Example:
+  #
+  #     filter {
+  #       sleep {
+  #         # Sleep 1 second for every event.
+  #         duration => "1"
+  #       }
+  #     }
+  config :duration, :validate => :string, :required => true
+
+  public
+  def register
+    # nothing to do
+  end # def register
+
+  public
+  def filter(event)
+    return unless filter?(event)
+
+    case @duration
+      when Fixnum, Float; sleep(@duration)
+      else; sleep(event.sprintf(@duration).to_f)
+    end
+    filter_matched(event)
+  end # def filter
+end