Paths not registering when using Flask factory pattern

[petargyurov]

This is a really frustrating issue, briefly mentioned in #62 . When using the factory pattern to create an app, path registration does not work.

Consider this folder structure:

myproject
├──  myapp
│    ├── __init__.py
│    └──  example
│         ├── __init__.py
│         └──  endpoints.py
├──  venv 
└──  app.py

myapp/__init__.py

from flask import Flask
from flask_rebar import Rebar

rebar = Rebar()
registry = rebar.create_handler_registry()

def create_app():
  app = Flask(__name__)
  rebar.init_app(app)
  return app

myapp/example/endpoints.py

from myapp import registry
from flask_rebar import ResponseSchema
from marshmallow import fields

class TodoSchema(ResponseSchema):
    id = fields.Integer()

@registry.handles(
   rule='/todos/<id>',
   method='GET',
   response_body_schema=TodoSchema()  # for versions <= 1.7.0, use marshal_schema
)
def get_todo(id):
    return {'id': id}

app.py

from myapp import create_app

app = create_app()

if __name__ == '__main__':
	app.run()

The path /todos/<id> does not get registered.

Workaround (?)

So this is clearly some sort of import issue. I have tried creating the registry in various places but I wasn't having much luck. A weird workaround is to re-import the registry inside create_app:

from flask import Flask
from flask_rebar import Rebar

rebar = Rebar()
registry = rebar.create_handler_registry()

def create_app():
  app = Flask(__name__)
  from myapp.example.endpoints import registry  # important to import it BEFORE initialising rebar with the app
  rebar.init_app(app)
  return app

This is a nasty solution - not actually sure why it works - I need to follow up the import order to figure out exactly what is going on. Would you have to import multuple times if you had more modules (i.e.: if there was an example2 module) ?

[petargyurov]

Okay, it seems you could do from myapp.example.endpoints import get_todo instead, which then makes it similar to how you register views with Flask (see here)

I guess that isn't too bad. However, the fact that you have to do it before calling init_app is undesired.

I wonder if you could replicate Flask's registration behaviour when using Blueprints to avoid this?