I’m using MongoEngine in a flask 2.0.3 application. I want to overwrite the CRUD method in one MongoEngine model class. So I created a function to annotate the model class.

    def customize():
        def inner(cls):
            cls.delete = MethodCustomizer.delete(cls.delete)
            cls.modify = MethodCustomizer.modify(cls.modify)
            cls.reload = MethodCustomizer.reload(cls.reload)
            cls.save = MethodCustomizer.save(cls.save)
            cls.update = MethodCustomizer.update(cls.update)
            return cls
        return inner

    @customize()
    class MwSection(Document):
        ...

This same model and class decorator work as expected in other applications such as stackstorm server, flask-restful (Flask==0.12.2, Flask-RESTful==0.3.6, flask-mongoengine==0.9.5), standalone python script; but not in flask 2.0.3 with flask-mongoengine==1.0.0.

As long as the model class is decorated, the docker container for the flask app will get into an endless restarting loop.