Re: [openstack-dev] [oslo.messaging] Can RPCClient.call() be used with a subset of servers?

2015-02-09 Thread Doug Hellmann


On Mon, Feb 9, 2015, at 02:40 PM, Gravel, Julie Chongcharoen wrote:
 Hello,
 I want to use oslo.messaging.RPCClient.call() to invoke a
 method on multiple servers, but not all of them. Can this
 be done and how? I read the code documentation (client.py
 and target.py). I only saw either the call used for one
 server at a time, or for all of them using the fanout
 param. Neither options is exactly what I want.
 Any response/explanation would be highly appreciated.

This isn't a pattern that has come up before. Before we talk about
adding it, I'd like to understand more about your use case. How do you
know which servers should receive the call, for example? And are you
actually calling and expecting a response, or do you just need to send a
message to those servers?

Doug

 
 Regards,
 Julie Gravel
 
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Re: [openstack-dev] [oslo.messaging] Can RPCClient.call() be used with a subset of servers?

2015-02-09 Thread Russell Bryant
On 02/09/2015 04:04 PM, Doug Hellmann wrote:
 
 
 On Mon, Feb 9, 2015, at 02:40 PM, Gravel, Julie Chongcharoen wrote:
 Hello,
 I want to use oslo.messaging.RPCClient.call() to invoke a
 method on multiple servers, but not all of them. Can this
 be done and how? I read the code documentation (client.py
 and target.py). I only saw either the call used for one
 server at a time, or for all of them using the fanout
 param. Neither options is exactly what I want.
 Any response/explanation would be highly appreciated.
 
 This isn't a pattern that has come up before. Before we talk about
 adding it, I'd like to understand more about your use case. How do you
 know which servers should receive the call, for example? And are you
 actually calling and expecting a response, or do you just need to send a
 message to those servers?

If no response is needed, you might be able to use whatever is done for
notifications.  Notifications are sent out to a topic, and N servers may
be subscribed to receive those notifications.  IIRC, that isn't done
through the RPC classes, but would result in the pattern desired here.

-- 
Russell Bryant

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Re: [openstack-dev] [oslo.messaging] Can RPCClient.call() be used with a subset of servers?

2015-02-09 Thread Denis Makogon
On Monday, February 9, 2015, Gravel, Julie Chongcharoen julie.gra...@hp.com
wrote:

  Hello,

 I want to use oslo.messaging.RPCClient.call() to invoke a
 method on multiple servers, but not all of them. Can this be done and how?
 I read the code documentation (client.py and target.py). I only saw either
 the call used for one server at a time, or for all of them using the fanout
 param. Neither options is exactly what I want.

 Any response/explanation would be highly appreciated.



Hello, I would say that there's no need to have such ability since since
oslo.messaging is unaware of your servers, so everything you need is to
write your own code to accomplish your mission. Even if you want to execute
call procedures at the same time you can parallelize your code. Would that
work for you?



 Regards,

 Julie Gravel




Kind regards,
DenisM.
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