- make SIGHUP configure logging again (causes the logfile to be

reopened)

lib/logstash/agent.rb

@@ -96,6 +96,11 @@ class LogStash::Agent < Clamp::Command
       pipeline.shutdown
     end
 
+    Stud::trap("HUP") do
+      @logger.info(I18n.t("logstash.agent.sighup"))
+      configure_logging(log_file)
+    end
+
     # TODO(sissel): Get pipeline completion status.
     pipeline.run
     return 0
@@ -201,7 +206,8 @@ class LogStash::Agent < Clamp::Command
       end
 
       puts "Sending all output to #{path}."
-      @logger.subscribe(file)
+      @logger.unsubscribe(@logger_subscription) if @logger_subscription
+      @logger_subscription = @logger.subscribe(file)
     else
       @logger.subscribe(STDOUT)
     end

locales/en.yml

@@ -50,6 +50,8 @@ en:
         For more information on plugin statuses, see
         http://logstash.net/docs/%{LOGSTASH_VERSION}/plugin_status
     agent:
+      sighup: >-
+        SIGHUP received.
       missing-configuration: >-
         No configuration file was specified. Perhaps you forgot to provide
         the '-f yourlogstash.conf' flag?