Newbie questions

Tue Sep 1 00:34:16 EDT 2009

Hi Iain,

Sorry for getting back to you so late.  Long story short, I applaud
your achievement in such a short term and appreciate your contribution
to the community.  Also, please stay tuned for the next round of
documentation update. :)

Cheers and best regards,
Trustin

On Thu, 20 Aug 2009 18:12:51 +0900 (KST)
Iain McGinniss <iainmcgin at gmail.com> wrote:
> Hi Trustin,
> 
> I fully intend to get the reusable chunks of what I have written  
> packaged up and contributed to netty, and perhaps become an active  
> contributor to the project. For the last 3 months I have had the  
> luxury of being paid to write open source software, by OneDrum
> (www.onedrum.com ). I have been fixing a number of issues in the JXTA
> peer to peer framework, mostly performance analysis and optimisation.
> I have had a big impact on the project in my time working on it, and
> the last major piece of work to be delivered (today or tomorrow,
> eek!) is a complete replacement for both the TCP and HTTP transports
> that are used. I've rewritten both using Netty - it's been a
> challenge, but I've made it in the end.
> 
> The HTTP tunnel I have written is full duplex and does not require a  
> servlet container for the server end, in contrast to the existing
> HTTP tunnel that ships in Netty 3.x. It does this by using two
> physical connections per tunnel much like the "comet" comms strategy
> that has become so popular for rich internet applications. I had
> originally planned to do full duplex using a single connection with
> request pipelining and chunking to keep the overhead as low as
> possible, but this unfortunately does not work with most HTTP
> proxies, which do not relay pipelined requests (they consume them
> from the client, then dispatch them in the normal request-response
> half duplex fashion to the server).
> 
> I still have some work to do around connection closing, to make sure  
> the virtual tunnel connection on client and server behaves exactly  
> like a normal netty channel in terms of the events fired and  
> behaviour. The server end was a particular challenge, especially
> since the requests for a particular tunnel could arrive across
> multiple connections over a period of time, with proxies closing
> connections or potentially reusing connections for multiple clients.
> I also need to verify that my usage patterns do not raise red flags
> with common proxies and firewalls.
> 
> Tomorrow is my last day working full time on JXTA, so I will need to  
> package up everything I've got by tomorrow. I'll send out my HTTP  
> tunnel code, regard it as experimental and only partially tested.
> From October onwards I will be working part time on JXTA and most
> likely Netty as well, so if someone else in the community does not
> pick it up I will polish up what I have and get it ready for
> inclusion in the official Netty build.
> 
> Overall, my experience with Netty has been quite positive - the API
> is quite clearly documented. I do however feel there needs to be
> more examples of common usage patterns - in my tunnel code, I feel
> that in a number of places I have had to make up an approach based on
> my own instincts, without any real feel for how this will affect the  
> performance of behaviour of Netty as a whole. An example would be  
> capturing close events and deferring sending them downstream until  
> some other key behaviour has occurred, such as sending a close  
> handshake to the server. I have had to dip into the implementations
> of the Nio channels a number of times to verify my assumptions on
> how they behave, so perhaps a more comprehensive breakdown of the
> typical event flow and lifecycle of a netty channel would be useful.
> 
> Anyway, if I do not have time to submit what I have done directly
> here before tomorrow evening, I will submit it next month.
> 
> Iain
> 
> 
> On 20 Aug 2009, at 08:42, 이희승 (Trustin Lee) wrote:
> 
> > Thanks Iain for sharing your work.  I think it looks fine although I
> > didn't run it by myself.  I hope Bozo loves your contribution. :)
> >
> > You might want to include your work into Netty 3.2.  WDYT?
> >
> > Cheers,
> > Trustin
> >
> > On 08/18/2009 06:46 PM, Iain McGinniss wrote:
> >> Hi Bozo,
> >>
> >> I'll take a quick stab at this. I've attached something like what  
> >> you're
> >> looking for, but beware: I've not tested this, I've just written it
> >> based on my current understanding of netty. Would be useful to
> >> have it
> >> reviewed by others in the community to see if it is a sensible  
> >> pattern.
> >> The alternative would be to use a WriteTimeoutHandler in your  
> >> pipeline,
> >> but I do not think this fits the requirements here as it will not
> >> trigger an exception if writes are being continuously issued, but  
> >> never
> >> completing (due to a slow connection).
> >>
> >> Iain
> >>
> >>
> >>
> >> On 18 Aug 2009, at 10:11, Bozo Juretic wrote:
> >>
> >>> 이희승 (Trustin Lee) wrote:
> >>>> You could use org.jboss.netty.util.HashedWheelTimer and schedule
> >>>> a timeout for each request, cancel the scheduled timeout when a
> >>>> corresponding response is received, and handle the timeout if no
> >>>> response was received.
> >>>>
> >>> Trustin,
> >>>
> >>> first of all thank you for your kind response. Is it possible
> >>> that you
> >>> give me a small (pseudo)code example or a pointer to existing
> >>> code to
> >>> see how this can be practically done? I understand the
> >>> principle, but am
> >>> all too new to netty to do it.
> >>>
> >>> Thank you,
> >>>
> >>> Bozo
> >>> _______________________________________________
> >>> netty-users mailing list
> >>> netty-users at lists.jboss.org
> >>> https://lists.jboss.org/mailman/listinfo/netty-users
> >>
> >>
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> 
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-- 
Trustin Lee, http://gleamynode.net/