Hi

I am posting this to the user forum of Camel to a broader audience.

I have just added Graceful Shutdown to Camel 2.2 (trunk code will be
committed shortly).
https://issues.apache.org/activemq/browse/CAMEL-1483

The wiki page is here
http://cwiki.apache.org/confluence/display/CAMEL/Graceful+Shutdown

I have enabled it by default on trunk, which means the shutdown
process is altered.
You can read all about it on the wiki page.

As its new code I would love feedback and having people giving it a
test run on your systems.

There is one note, the SEDA/VM components uses an internal in memory
queue with pending exchanges to be processed.
The graceful shutdown will take this into account and wait until all
those pending messages have been run to completion.
The progress is logged at INFO level such as shown on the wiki page.

If there are other Camel components which have the same behavior,
please let me know, as I could not remember any other that did.
If so we need to let its consumer implements the ShutdownAware
interface which ensures the graceful shutdown can work with it.

I have set a default timeout of 300 seconds for the hole shutdown
process. During this time any pending and inflight exchanges should be
run to completion.
Camel will of course stop input consumers before hand which ensures no
new messages come into Camel. And therefore its just a matter of
waiting until
all those existing messages runs to completion. If you think this
timeout should have a different default value, then speak up.
What happens if the timeout is hit, then Camel will do a shutdown now,
where it forces all routes to shutdown and shutdown the remainder
services.
This ensures that Camel will not block forever during shutdown.


I have one questions although
======================

We have a batch consumer concept which allows a consumer to batch up a
number of exchanges to be routed.
For example: file, ftp, mail, jpa and others implement this.

The current gracful shutdown behavior is to stop during this batch.
What happens is that lets say there are 23 messages in the batch and
it has completed 7 of those.
Then a shutdown is issued. The batch consumer will complete its
current inprogress, and therefore it has completed 8. There are still
15 left in the batch. What happens
is that it will break and not complete the batch.

Do you think we should offer a configuration which allows the batch
consumers to control their behavior to
- stop as now during a batch
- continue to complete the batch before shutting down




-- 
Claus Ibsen
Apache Camel Committer

Author of Camel in Action: http://www.manning.com/ibsen/
Open Source Integration: http://fusesource.com
Blog: http://davsclaus.blogspot.com/
Twitter: http://twitter.com/davsclaus

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