Felix Meschberger created SLING-3915:
----------------------------------------
Summary: Launchpad ControlListener improvement
Key: SLING-3915
URL: https://issues.apache.org/jira/browse/SLING-3915
Project: Sling
Issue Type: Improvement
Components: Launchpad
Affects Versions: Launchpad Base 2.5.2
Reporter: Felix Meschberger
I was involved with a customer report indicating that the ControlListener would
not work. The customer issued a stop command upon which the system should have
shut down. This seems to not have been the case so the customer tried to issue
stop again. This time, though the connection to the control port could be
opened but the command was not answered.
Looking at the situation it looks like the first command issues the shutdown.
But this caused a deadlock. The server side socket was terminating and the
control thread was waiting for sling to shutdown. While waiting for the
shutdown the control thread could of course not accept new commands, even
though TCP/IP connections were being setup.
To prevent such situations I am proposing an extension to the Launchpad
ControlListener which listens on a TCP/IP control port for status and stop
commands:
* Calling stop starts a separate thread to shutdown Sling asynchronously to the
ControlListener thread. After having issued a stop command the ControlListener
will reply "STOPPING" to the status command
* Adding a new "threads" command to have the ControlListener print a thread
dump similar to the JDK jstack command. This includes all threads as well as
dumping potential deadlocks. A new Unit test contains two Thread classes which
provoke deadlocks to show how the thread dumper reports deadlocks.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
