Templates with session activation

KeithP

Hello,

I have looked at the session activation example and have tried to templatise it. The original is as follows:

<icegrid>

  <application name="Session">

    <node name="localhost">
      <server id="SessionServer" exe="./server" activation="session">
	<adapter name="Hello" endpoints="tcp">
	  <allocatable identity="hello" property="Identity"/>
	</adapter>
      </server>
    </node>

  </application>

</icegrid>

I amended it by following the IceGrid simple example "application_with_template.xml" to give the following:

<icegrid>

  <application name="Session">

    <server-template id="SessionServer">
      <parameter name="index"/>
      <server id="SimpleServer-${index}" exe="./server" activation="session">
        <adapter name="Hello" endpoints="tcp">
          <allocatable identity="hello-${index}" type="::Demo::Hello"/>
        </adapter>
      </server>
    </server-template>

    <node name="localhost">
      <server-instance template="SessionServer" index="1"/>      
    </node>

  </application>

</icegrid>

I start up an icegridnode as in the sessionActivation example and run icegridadmin to apply the above configuration.

When I start the client from sessionActivation it throws an exception "object not registered with registry". I presume it is looking for allocatable object "hello" instead of "hello-${index}". However, I still want the code to look for "hello". Do you know how I can achieve this or have I mis-configured the application?

Thanks,
Keith

benoit

Hi,

You should change:

<allocatable identity="hello-${index}" type="::Demo::Hello"/>

To:

<allocatable identity="hello" type="::Demo::Hello"/>

If you want to register the hello allocatable object instead of hello-${index}. It's not clear to me why you would want to do this however. By using a fixed identity for this object, you won't be able to deploy multiple servers (since only one server instance can register a given well-known object) so using a template here won't be really useful.

If you need additional clarifications on this, could you detail a little more what you are trying to achieve?

Cheers,
Benoit.

KeithP

Hi Benoit,

My aim is to have multiple servers all providing the Hello proxy for multiple clients to be able to use. Ultimately, I may have several icegridnodes each running numerous instances of the SessionServer. I need them each to be allocatable, but if I use "hello-${index}" as their identity, how does the client find a single server that exposes the "hello" proxy? Essentially, I don't want the client to need hard-coding to a particular id, i.e. "hello-1" in order to allocate an object.

Let me know if you require more information.

Thanks,
Keith

benoit

Hi,

Instead of allocating the object by id, your clients should allocate the object by type, see the demo/IceGrid/allocate demo for an example (deployed using with application-multiple.xml).

This way, your client don't need to know the identity of the object. Instead, the IceGrid::Session allocateByType method returns one of the available object.

Cheers,
Benoit.

KeithP

Hi Benoit,

Thanks for the advice.

It's working as I need now.

Keith