refs #6 and refs #7 - Python packaging

[benoitbryon]

refs #6 and refs #7 : introduced Python packaging and several eggs:

• thumbnailer.core
• thumbnailer.engines.images
• thumbnailer.engines.documents

Updated INSTALL procedure.

[benoitbryon]

@Natim can you give feedback about current state of 7-python-packages branch? I wonder whether we should merge it now or later. Because we may require additional work before merge or create new issues...

pip install thumbnailer.* doesn't work

pip install git+https://github.com/Natim/Thumbnailer@7-python-packages#egg=thumbnailer.core doesn't work. It seems that pip looks for a setup.py file at repository root. But currently we can't do that because we host several eggs. I guess the best solution would be to create one repository for each egg, i.e. 3 repositories, one per directory in src/ folder.

Documentation covers 3 packages

Should be: each package has its own documentation. And optionally we could use Sphinx's intersphinx extension as a glue.

Development covers 3 packages

We should be able to develop only one package at a time, i.e. install a dev environment with images engines but without documents engine. We should be able to develop only thumbnailer.core, i.e. have a fake engine that we use in tests.

[benoitbryon]

My personal choice would be: create new tickets then merge.

[Natim]

Oh, I see your message after merging, I review the code and it seamed ok for me.

[Natim]

Maybe one setup is en enough to install the three packages. I don't think it is a good idea to create three repository. If it is pluggable it will allow other project to create other engines. But we can provide some in this repository.

[benoitbryon]

Maybe I'm wrong, but I think we cannot declare more than one egg in a setup.py. 1 setup.py <=> 1 egg

But, since your merged, let's discuss all points in issues ;)