- add metrics to file output

lib/logstash/outputs/file.rb

@@ -46,6 +46,9 @@ class LogStash::Outputs::File < LogStash::Outputs::Base
     @last_stale_cleanup_cycle = now
     flush_interval = @flush_interval.to_i
     @stale_cleanup_interval = 10
+    @metric_flushes = @logger.metrics.timer(self, "flushes")
+    @metric_write_delay = @logger.metrics.timer(self, "write-delay")
+    @metric_write_bytes = @logger.metrics.histogram(self, "write-bytes")
   end # def register
 
   public
@@ -58,10 +61,16 @@ class LogStash::Outputs::File < LogStash::Outputs::Base
     # TODO(sissel): Check if we should rotate the file.
 
     if @message_format
-      fd.write(event.sprintf(@message_format) + "\n")
+      output = event.sprintf(@message_format) + "\n"
     else
-      fd.write(event.to_json + "\n")
+      output = event.to_json
     end
+
+    @metric_write_delay.time do
+      fd.puts(output)
+    end
+    @metric_write_bytes.record(output.size)
+
     flush(fd)
     close_stale_files
   end # def receive
@@ -84,7 +93,9 @@ class LogStash::Outputs::File < LogStash::Outputs::Base
     if flush_interval > 0
       flush_pending_files
     else
-      fd.flush
+      @metric_flushes.time do
+        fd.flush
+      end
     end
   end
 
@@ -94,7 +105,9 @@ class LogStash::Outputs::File < LogStash::Outputs::Base
     @logger.debug("Starting flush cycle")
     @files.each do |path, fd|
       @logger.debug("Flushing file", :path => path, :fd => fd)
-      fd.flush
+      @metric_flushes.time do
+        fd.flush
+      end
     end
     @last_flush_cycle = Time.now
   end