[Fab-user] Fabric setuptools plugin prototype

[Rob Cowie]

Hi Christian,

I haven't figured out how to do diffs with git, so until then...

I've posted a diff to snipplr (http://snipplr.com/view/5340/)

The changes thus far are:

 * Import pkg_resources
 * Addition of an entrypoint mapping (maps application entrypoints  
(strings) to Fabric registries)
 * Addition of a load_plugins() function.
 * load_plugins call in main()

load_plugins() is responsible for using pkg_resources for searching  
sys.path, os.getcwd(), and any additional paths passed for  
"distributions".
A "distribution" is a python module/package/egg identifiable by  
setuptools. From this list of distributions, we can search for  
packages that expose callables registered to our entry points (in this  
case, fabric.operations, fabric.commands, and fabric.strategies).

I'm not convinced that my choice of plugin entry points is a good one.  
It might be better to provide one entry point (say fabric.plugins) and  
have the application code discover what 'type' of callable is made  
available.

Oh... the diff also includes an additional prompt() operation, simply  
because I forgot to remove it! It also includes some extraneous print  
statements, also because I forgot about them.

All that remains is to create a plugin, register entrypoints in  
setup.py, package it as an egg and either install it in the PYTHONPATH  
or drop it into the same directory as the fabfile.

I've attached a stub Subversion plugin. It exposes two functions that  
will be registered as fabric operations; svn_checkout, svn_export.  
Neither does anything except print to stdout.

Your idea of passing the current fabric 'context' to every plugin  
callable is a good one. I haven't implemented this.

Attached is an egg which - with any luck - will make these two  
operations available if you install it.

Rob C

FabricSVN-0.11-py2.5.egg
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