RFC: Approach to support loading of extensions

[jcfr]

Approach below are not exclusive

(1) Use namespace filepath returned by extension python package

import ndx_my_extension

from pynwb import load_namespaces

load_namespaces(ndx_my_extension.namespace_filepath)

(2) systematic installation of spec files as datafiles

Instead of setting package_data, the spec files could be listed as data_files always installed under a directory called ndx_specs

(3) Use entrypoint to register extensions

Add support for entrypoints allowing to automatically register the ndx python extension after its installation.

pynwb will need to be updated to support the following:

• listing installed extensions using a pynwb functions (e.g pnwb.list_registered_namespaces())
• implement a function named pynwb.load_registered_namespaces()
• automatic loading of registered namespaces on import. Do we want that ? @oruebel @bendichter

automatic loading of registered namespaces on import. Do we want that ?

To support both cases: automatic loading and explicit loading of extension. The following could be done:

pip install pynwb[extension_autoload]

By installing the extra [extension_autoload], pynwb would load the namespace of all installed extensions on import.

suggested path forward

As first step, I suggest to go with (1), it will:

• not prevent from implementing (2) and/or (3)
• nicely abstract the location of the spec files

[oruebel]

@ajtritt @rly thoughts?

[rly]

I also like starting with option 1. Even better if we have a function load_extension(package_name).