Deferred database initialization for flask-peewee.db.Database

app.py

from flask import Flask
from db import db

def create_app(config_obj)
    app = Flask('tets')
    app.config.fromobj(config_obj)  # db configured in `config_obj`
    db.init_app(app)

db.py

from flask_peewee.db import Database
from peewee import Model


class DeferredDatabase(Database):
    def __init__(self, app=None):
        if app:
            super(DeferredDatabase, self).__init__(app)
        else:
            class BaseModel(Model):
                pass
            self.Model = BaseModel

    def init_app(self, app):
        self.app = app

        self.load_database()
        self.register_handlers()

        class Meta:
            database = self.database

        self.Model.Meta = Meta
     
        
db = DeferredDatabase()

models.py

# database engine irrelevant model definitions
# i.e., you can define models before connecting to the database
from db import db


class User(db.Model):
    class Meta:
        db_table = 'test_user'
    name = CharField()