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Bug 7970 - Eventing: clarify role of event source
Summary: Eventing: clarify role of event source
Status: CLOSED REMIND
Alias: None
Product: WS-Resource Access
Classification: Unclassified
Component: Eventing (show other bugs)
Version: FPWD
Hardware: PC Windows XP
: P2 normal
Target Milestone: ---
Assignee: Doug Davis
QA Contact: notifications mailing list for WS Resource Access
URL: http://lists.w3.org/Archives/Public/p...
Whiteboard:
Keywords: externalComments
Depends on:
Blocks:
 
Reported: 2009-10-19 15:07 UTC by Doug Davis
Modified: 2009-12-08 22:19 UTC (History)
0 users

See Also:


Attachments
A proposal to issue 7970 (10.78 KB, application/pdf)
2009-10-29 21:33 UTC, Wu Chou
Details
This is a revised (v.2) version proposal to issue 7970 (10.58 KB, application/pdf)
2009-10-30 20:31 UTC, Wu Chou
Details

Description Doug Davis 2009-10-19 15:07:46 UTC
(from a note conversation with Antoine Mensch)
Eventing currently defines an Event Source as:
    A Web service that sends notifications and accepts requests
    to create subscriptions. 

This isn't quite accurate. An Event Source does accept requests to
create subscriptions, but who actually sends out the notifications
is an implementation detail.  For example, the endpoint that accepts
the Subscribe() could be very different from the endpoints/components
that actually send out the notifications - it could just be acting as
a sort of proxy/manager.

Proposal:
Modify the defn to read:

    A Web service that accepts requests to create subscriptions.

If we don't want to lose the tie-in with notifications, perhaps something
like this:

   A Web service that accepts requests to create subscriptions for
   a certain set of notification that might be generated.
Comment 1 Doug Davis 2009-10-20 20:48:25 UTC
for proposal 2: s/notification/notifications/
Comment 2 Wu Chou 2009-10-29 21:33:24 UTC
Created attachment 777 [details]
A proposal to issue 7970

A proposal to issue 7970 that can support the existing as well as the clustering deployment model.
 
Use case: In some data center or high volume event processor, events may be delivered from a special event dispatcher or from a pool of high speed event dispatchers, not necessarily from the event source endpoint. 
 
Rationale and benefits: 1) Event dispatcher pools can be shared by all event sources to improve the event dispatch throughput. 2) These event dispatchers can be on high speed links (IP addresses) as part of the infrastructure. 3) There is no need to implement a http client event dispatch for every single event source. For example, there might be 10,000 individual event sources on the platform, but only 10 high speed event dispatchers. 4) For some resource limited devices, the resource hungry event dispatcher may reside in a separate but more resourceful environment from the event source.
 
The attached proposal supports this clustering deployment model . In addition, by making the event dispatcher explicit, it supports the pull-model in event delivery and IP-blocking as in current model.
Comment 3 Wu Chou 2009-10-30 20:31:02 UTC
Created attachment 778 [details]
This is a revised (v.2) version proposal to issue 7970 

Tthe last paragraph of the previous proposal is removed to address an issue with pull-model event delivery. - Wu Chou
Comment 5 Doug Davis 2009-11-03 22:38:28 UTC
Another sentence that would need to be changed:
--
As described previously, event sources transmit events to event sinks as SOAP messages called "Notifications".
--
to
--
As described previously, events are transmitted to event sinks as SOAP messages
called "Notifications".
--
Comment 6 Robert Freund 2009-11-05 14:10:53 UTC
from external reviewer point 3
Comment 7 Doug Davis 2009-11-06 18:33:23 UTC
Latest proposal:
http://lists.w3.org/Archives/Public/public-ws-resource-access/2009Nov/0022.html

plus:

change:
--
As described previously, event sources transmit events to event sinks as SOAP
messages called "Notifications".
--
to
--
As described previously, events are transmitted to event sinks as SOAP messages
called "Notifications".
--


plus:
change:
--
Event Source 
A Web service that accepts requests to create subscriptions.
--
to
--
Event Source 
A Web service that accepts requests to create subscriptions for the subscriber to receive certain type of notifications.
--
Comment 8 Doug Davis 2009-11-06 18:43:13 UTC
amended:
- - - - - -
Event Source 
A Web service that accepts requests to create subscriptions. Notifications MAY be sent by any endpoint including the event source. 

Notification 
A message sent to indicate that an event, or events, have occurred. 
- - - - - - - 
Comment 9 Robert Freund 2009-11-06 18:44:38 UTC
resolved with the combination of comments 7 and 8