[jboss-as7-dev] Add Notification support to the domain management API

[David M. Lloyd]

I don't see notifications as a bidirectional thing.  I look at it this way:

sync:
   C: "Please send me notifications regarding /foo=bar to id=123"
   S: "OK, will do"
   C: "Please send me notifications regarding /baz=zap to id=123"
   S: "There is no such resource, sorry"
   ...

In the meantime, you have:
async:
   C: "Notifications for id=123"
   S: "/foo=bar changed ..."
   S: "/foo=bar changed ..."
   ...
   (connection broken - cell phone went into a tunnel)
   C: "Notifications for id=123"
   S: "/foo=bar changed ..."
   ...

It seems a very clean mapping, cleaner than web sockets tbh, and a sight 
simpler architecturally.

I do not see async notifications as a good solution for long-running 
operations since those are essentially synchronous.  I'd rather see a 
server-side solution for that (even the outliers like restarting a 
server).  Trying to make these asynchronous is sort of the path of most 
resistance, in that we're borrowing complexity we do not need.

On 02/27/2013 01:43 PM, Heiko Braun wrote:
> SSE are asynchronous, but unidirectional. Whereas websockets are
> asynchronous and bidirectional.
>
> Enabling push through SSE,  clients could use a combination of
> request/response for the main communication (i.e. execution of
> operations, reading the model contents, etc) and SSE for the notifications .
>
> Using websockets we could move all client communication to one paradigm.
> But do we need it?
>
> Currently have cases where clients keep polling for system state changes
> (i.e. server restart, deployments, etc). Typically the things that take
> some time to complete. So I am wondering if these cases could benefit
> from an asynchronous bidirectional communication channel. But I guess
> this depends on how the DC processes management operations and if
> asynchronous responses would fit into the picture.
>
>
> /Heiko
>
>
> On Feb 26, 2013, at 6:37 PM, David M. Lloyd <david.lloyd at redhat.com
> <mailto:david.lloyd at redhat.com>> wrote:
>
>> I don't know, it seems like overkill.  I think
>> http://html5doctor.com/server-sent-events/is probably a better option
>> than web sockets or polling as it is supported in the browser with a
>> simple API and doesn't require a lot of complex server-side support.
>


-- 
- DML