Do not import aldryn_search outside PostIndex in search_indexes.py

Description

We’re not using aldryn_search at all, but we’re using django-haystack in order to index elements of our websites. We had installed djangocms_blog.

Haystack allows to exclude Indexes with its EXCLUDED_INDEXES paremeter, but it only excludes the content of the Index class.

The problem here is that you include aldryn_search submodules outside the PostIndex, and so when I prevent your search_indexes.py from being used by haystack using "EXCLUDED_INDEXES": ["djangocms_blog.search_indexes.PostIndex"],, it always try to import aldryn_search, even without using your PostIndex at all.

https://github.com/nephila/djangocms-blog/blob/99ab6a1be8a930972d9712321a17ac67a2354bab/djangocms_blog/search_indexes.py#L1-L2

Steps to reproduce

• Do not install aldryn_search.
• Try to index something on the project using django-haystack, but not djangocms_blog (thanks to "EXCLUDED_INDEXES": ["djangocms_blog.search_indexes.PostIndex"],).
• Exception:

  File "[...]djangocms_blog/search_indexes.py", line 4, in <module>
     from aldryn_search.helpers import get_plugin_index_data
  ModuleNotFoundError: No module named 'aldryn_search'
  

Expected solution

Move lines aldryn_search imports in search_indexes.py inside the class: https://github.com/nephila/djangocms-blog/blob/99ab6a1be8a930972d9712321a17ac67a2354bab/djangocms_blog/search_indexes.py#L11

[yakky]

@corentinbettiol definitely nothing wrong! Thanks for reviewing it, I amended the documentation as suggested

[corentinbettiol]

@yakky Done. I think it’s my first review, I don’t really know if I did anything wrong.