Netty usage in AS5 (shutdown hangs)

[Mike McGrady]

Very helpful.  Thanks

Sent from my iPhone

On Sep 3, 2009, at 7:44 PM, 이희승 (Trustin Lee) <trustin at gmail.com>  
wrote:

> On Wed, 2 Sep 2009 09:46:59 +0900 (KST)
> Bob McWhirter <bmcwhirt at redhat.com> wrote:
>>
>> On Sep 1, 2009, at 7:57 PM, _댄ъŠ_ (Trustin Lee) wrote:
>>> If a ChannelFactory is shared or there are any open connections
>>> left, you must not call releaseExternalResources() as it will
>>> result in resource leak, infinite loop, and so on.
>>
>> Okay, in that case, instead of making the user of ChannelFactory do
>> reference-counting to determine if it's okay to shutdown, can we add
>> a stop() method to it?  This way, when it's undeployed by the MC,
>> it'll be automatically stopped.
>>
>> Otherwise, it seems like it'd be hard to correctly use/shutdown the
>> ChannelFactory in netty.jar's own jboss-beans.xml, particularly if
>> multiple unrelated POJOs are using it to set up unrelated servers.
>>
>> Or should I create and manage my ChannelFactories on a per-server
>> basis?
>
> I think only one factory is enough for more than one servers.
>
> Actually, Netty does a sort of reference counting.
>
> The resources acquired by ChannelFactories (e.g. Selector) are  
> released
> automatically if there is no open channel after about a second.
> Therefore, closing all open connections are just enough and Netty will
> release other internal resources automatically.  However, there is any
> open connection, Netty refuses to shut down.
>
> The problem is that Netty cannot shut down the Executors which was
> specified in the ChannelFactory constructor as it is an 'external'
> resource which might be shared.  Netty can't do reference counting on
> external resources as you know.
>
> Calling releaseExternalResources() simply means shutting down the
> Executors, and therefore you don't need to call
> releaseExternalResources() if you shut down the executor by yourself
> somewhere else.  However, you still need to make sure to close all  
> open
> channels (both server channels and accepted channels) before shutting
> down.
>
> Things could be much simpler if Netty used ThreadFactory, but I'm not
> sure it's a good idea.  I'd love to listen to any good idea for  
> smoother
> shut down procedure.
>
> Thanks for feed back, and will look forward to more ;)
>
> -- 
> Trustin Lee, http://gleamynode.net/
>
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