[openstack-dev] Nova extension oddness?

Andrew Bogott abogott at wikimedia.org
Thu Sep 6 13:59:30 UTC 2012

On 9/5/12 4:23 PM, Kevin L. Mitchell wrote:
> On Wed, 2012-09-05 at 14:07 -0700, Joshua Harlow wrote:
>> It seems like its almost like a extension here is a bundle of code that
>> extends multiple parts no?
> That would be a good way of doing it.  However, it's not the way that's
> currently implemented in nova.  Right now, the only thing that can be
> extended by loading a plugin—in the context we're discussing—is the
> osapi itself.
I have added a plugin framework to Folsom which addresses many of the 
concerns in this thread.


There's an attempt on that page to clarify terminology so that we can 
distinguish between plugins, extensions, and drivers.  So far I haven't 
gotten much traction with that, though, and the three terms seem to be 
used interchangeably within OpenStack.

In my world, a plugin (as opposed to an Extension) is loaded via 
entrypoints (thus, does not need to be checked/merged into an OpenStack 
source tree), and provides several sets of hooks for injecting custom 
code into each service.  A plugin may or may not include extensions to 
an API.

My hope is that the plugin framework will become an umbrella for project 
extensibility, but there will need to be a fair bit of planning and 
discussion on this topic.  In the meantime... http://xkcd.com/927/

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