Open Stack

Geoff, do you expect all of our users to write all of their messaging
code in Python?

oslo.messaging is a _python_ library.

Zaqar is a service with a REST API -- accessible to any application.

As Zane's sarcastic reply implied, these are as related as sharks are
to tornados. Could they be combined? Yes [1]. But the only result would be
dead people and sharks strewn about the landscape.

[1] http://www.imdb.com/title/tt2724064/

Excerpts from Geoff O'Callaghan's message of 2014-09-20 01:17:45 -0700:
> Hi all,
> I'm just trying to understand the messaging strategy in openstack.    It
> seems we have at least 2 messaging layers.
> 
> Oslo.messaging and zaqar,  Can someone explain to me why there are two?
> To quote from the zaqar faq :
> ---------
> How does Zaqar compare to oslo.messaging?
> 
> oslo.messsaging is an RPC library used throughout OpenStack to manage
> distributed commands by sending messages through different messaging
> layers. Oslo Messaging was originally developed as an abstraction over
> AMQP, but has since added support for ZeroMQ.
> 
> As opposed to Oslo Messaging, Zaqar is a messaging service for the over and
> under cloud. As a service, it is meant to be consumed by using libraries
> for different languages. Zaqar currently supports 1 protocol (HTTP) and
> sits on top of other existing technologies (MongoDB as of version 1.0).
> --------
> It seems to my casual view that we could have one and scale that and use it
> for SQS style messages, internal messaging (which could include logging)
> all managed by message schemas and QoS.  This would give a very robust and
> flexible system for endpoints to consume.
> 
> Is there a plan to consolidate?
> 
> Rgds
> Geoff