Second pass at nautobot.apps exports

[lampwins]

As a Patti the Plugin Developer, I want the most relevant items from the core codebase to be exported for official use in the nautobot.apps namespace, so I know I am using a blessed interface and so that my imports are consolidated.

I will know this is complete when the core team takes a fresh pass over the core code base to decern items that should reasonably be exported to the apps namespace. The goal will be to export the broadest set of features, leaving only those things that the team has a strong, justifiable reason for not exporting, out of the apps namespace. Obviously if an item is positively known to be currently used by an app, it should be included, but the point of this story is to use good judgement to include things that are either not positively known, or that may reasonably be used in the future.

The app developer and migration documentation should also be updated to clarify the state and purpose of the apps namespace.

There has been some discussion about including models in the namespace and it was not entirely clear if that would pose challenges with FKs or migrations. Unless we feel confident at this time that those issues are resolved, models will be the primary exception to the namespace exports and the docs will clearly spell this out. Model dependent items, such as Choice classes will remain with models and my preference for the docs would be to push app developers to import those items from the model's module to simplify things for app developers.

[lampwins]

Hey team! Please add your planning poker estimate with Zenhub @glennmatthews @gsnider2195 @HanlinMiao @jathanism @timizuoebideri1

[bryanculver]

As discussed in standup:

Look through Core and Extras and export all functions and classes unless there is a significant reason it should not be exported in apps (ex: Models).

[gsnider2195]

After the first pass through core/extras I'm seeing this warning on Nautobot startup:

nautobot-nautobot-1       | 16:25:31.292 WARNING nautobot.core.graphql.utils utils.py        get_filtering_args_from_filterset() :
nautobot-nautobot-1       |   Filter "_custom_field_data" on NamespaceFilterSet is not GraphQL safe, and will be omitted

We'll need to keep in mind that this may be changing the order that modules are being loaded which may be the cause of the above error.

edit:

This was a result of importing nautobot.core.graphql.schema_init

[itdependsnetworks]

In theory nothing is calling nautobot.apps EXCEPT a plugin, so the key imports (e.g. ConstanceConfigItem, NautobotAppConfig) should ensure the application is ready before importing anything else or simply ensure the app is ready (maybe nautobot_database_ready?) before any other import in the nautobot.apps directory.