[Opensim-dev] Event Queue

[Frisby, Adam]

I've suggested on a few occasions to move it into ClientStack - that's where this belongs.

EventQueue messages should be sent/received the exact same way that UDP ones are.

SendXYZMessage() on ClientStack, and OnXYZRecieved events also on clientstack.

Adam

> -----Original Message-----
> From: opensim-dev-bounces at lists.berlios.de [mailto:opensim-dev-
> bounces at lists.berlios.de] On Behalf Of Cristina Videira Lopes
> Sent: Wednesday, 3 December 2008 9:40 AM
> To: opensim-dev at lists.berlios.de
> Subject: [Opensim-dev] Event Queue
>
> Apologies in advance for bringing up everyone's favorite hate topic,
> but
> having spent most of yesterday tracking TP/crossing problems (again), I
> can't help but bringing this up to a wider audience. I know everyone
> hates the EQ. As it stands, there are several broken elements with the
> EQ in OpenSim, beyond the obvious bugs caused by its management. I'm
> just wondering if there is something here that I'm completely missing,
> or if this is really this bad:
>
> 1) It's implemented as an optional region module (!!!), configurable in
> OpenSim.ini (!!!). That explains why, for example, I could not
> reproduce
> crashes that other people have reported with older viewers. It turns
> out
> that those people are not just using older viewers; they are using
> OpenSim servers configured with EventQueue=false. A complete
> miscommunication.
>
> 2) It's implemented as an optional region module -- the sequel. It is
> being considered a [optional] part of the Region Environment, something
> a region may or may not do. I'm afraid, this is the incorrect model.
> The
> server side doesn't have any choice on this, if it wants to interact
> with the current version of the LL viewer. The EQ should be hand-in-
> hand
> with LLClientView. After all, it's the new channel of communications
> between a server and the LL viewer. Things that used to go over UDP are
> now sent via the EQ, period, no choice. Region Environment should be
> completely oblivious to that change. As it is now, this pattern occurs
> all over Region Environment classes:
>
>             IEventQueue eq =
> [scene.]RequestModuleInterface<IEventQueue>();
>             if (eq != null)
>             {
>                 // send the event over EQ
>             }
>             else
>             {
>                 // call the right IClientAPI method to send the event
> [over UDP]
>             }
>
> This is infecting the server side with things that should be purely
> client side. It's a horrendous way of getting at the question "what
> version of the LL viewer are you supporting in your region?". If there
> is such a thing as a wrong question to ask, this is one of them. If we
> want to support viewers with older communication stacks, then let's
> make
> that explicit in OpenSim and subclass LLClientView for the N previous
> versions of the LL viewer's communications stack. Region Environment,
> and the whole of the OpenSim framework, should be insulated from that
> mess, that's what the IClientAPI is there for. No OpenSim.ini
> configuration variables, other than the already existing one:
> clientstack_plugin="OpenSim.Region.ClientStack.LindenUDP.dll"
>
> What will happen when Rex comes along? ... what version of the LL
> viewer
> is that based on? ...
>
> Sorry for venting! I'm just sending this out to find the answer to
> these
> three questions:
>
> a) Am I missing something?
>
> b) Are there any objections to placing EQ under
> OpenSim.Region.ClientStack.LindenUDP? (besides that name now being
> somewhat incorrect)
>
> c) Should OpenSim be backwards compatible with viewers forked off from
> older LL viewers *for the specific aspect of communications*? If so,
> what design pattern should be used?, subclassing or alternative code
> paths inside methods?
>
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