InvalidRequestError lors de l'importation d'un modèle Flask dans le shell Flask

Question

Lorsque j'essaie d'importer un modèle dans mon shell Flask, j'obtiens une requête InvalidRequestError.

Il semble qu'il est lié à mon projet init .py, illustré ci-dessous. Lorsque je supprime from . import models dans ce fichier, je peux importer mes modèles dans mon flacon sans aucun problème. Le problème est que j'ai besoin de cette "importation" pour exécuter ma migration de base de données ...

Quelqu'un peut-il aider?

$ flask shell 

Python 3.6.2 |Continuum Analytics, Inc.| (default, Jul 20 2017, 13:51:32) 
[GCC 4.4.7 20120313 (Red Hat 4.4.7-1)] on linux 
IPython: 6.2.0 
App: audiolabeling 
Instance: /home/jul/dev/audiolabeling/instance 
In [1]: from models import TagType 
--------------------------------------------------------------------------- 
InvalidRequestError      Traceback (most recent call last) 
<ipython-input-1-ebb7905a9c4e> in <module>() 
----> 1 from models import TagType 

~/dev/audiolabeling/audiolabeling/models.py in <module>() 
    13 
    14 
---> 15 class TagType(db.Model): 
    16 
    17  id = db.Column(db.Integer, primary_key=True) 

~/.miniconda3/envs/audiolabeling/lib/python3.6/site-packages/flask_sqlalchemy/__init__.py in __init__(self, name, bases, d) 
    600  def __init__(self, name, bases, d): 
    601   bind_key = d.pop('__bind_key__', None) or getattr(self, '__bind_key__', None) 
--> 602   DeclarativeMeta.__init__(self, name, bases, d) 
    603 
    604   if bind_key is not None and hasattr(self, '__table__'): 

~/.miniconda3/envs/audiolabeling/lib/python3.6/site-packages/sqlalchemy/ext/declarative/api.py in __init__(cls, classname, bases, dict_) 
    62  def __init__(cls, classname, bases, dict_): 
    63   if '_decl_class_registry' not in cls.__dict__: 
---> 64    _as_declarative(cls, classname, cls.__dict__) 
    65   type.__init__(cls, classname, bases, dict_) 
    66 

~/.miniconda3/envs/audiolabeling/lib/python3.6/site-packages/sqlalchemy/ext/declarative/base.py in _as_declarative(cls, classname, dict_) 
    86   return 
    87 
---> 88  _MapperConfig.setup_mapping(cls, classname, dict_) 
    89 
    90 

~/.miniconda3/envs/audiolabeling/lib/python3.6/site-packages/sqlalchemy/ext/declarative/base.py in setup_mapping(cls, cls_, classname, dict_) 
    101   else: 
    102    cfg_cls = _MapperConfig 
--> 103   cfg_cls(cls_, classname, dict_) 
    104 
    105  def __init__(self, cls_, classname, dict_): 

~/.miniconda3/envs/audiolabeling/lib/python3.6/site-packages/sqlalchemy/ext/declarative/base.py in __init__(self, cls_, classname, dict_) 
    129   self._extract_declared_columns() 
    130 
--> 131   self._setup_table() 
    132 
    133   self._setup_inheritance() 

~/.miniconda3/envs/audiolabeling/lib/python3.6/site-packages/sqlalchemy/ext/declarative/base.py in _setup_table(self) 
    393      tablename, cls.metadata, 
    394      *(tuple(declared_columns) + tuple(args)), 
--> 395      **table_kw) 
    396   else: 
    397    table = cls.__table__ 

~/.miniconda3/envs/audiolabeling/lib/python3.6/site-packages/sqlalchemy/sql/schema.py in __new__(cls, *args, **kw) 
    419      "to redefine " 
    420      "options and columns on an " 
--> 421      "existing Table object." % key) 
    422    table = metadata.tables[key] 
    423    if extend_existing: 

InvalidRequestError: Table 'tag_type' is already defined for this MetaData instance. Specify 'extend_existing=True' to redefine options and columns on an existing Table object. 

models.py

from audiolabeling import db 
import enum 


class FeedBackType(enum.Enum): 
    NONE = "none" 
    HIDDENIMAGE = "hiddenImage" 


class VisualizationType(enum.Enum): 
    WAVEFORM = "waveform" 
    SPECTROGRAM = "spectrogram" 


class TagType(db.Model): 

    id = db.Column(db.Integer, primary_key=True) 
    name = db.Column(db.String, unique=True) 
    annotationtags = db.relationship('AnnotationTag', 
            backref='tagtype', 
            lazy='dynamic') 

    def __repr__(self): 
     return '<id {}>'.format(self.id) 


class Task(db.Model): 

    id = db.Column(db.Integer, primary_key=True) 
    feedback = db.Column(db.Enum(FeedBackType)) 
    annotationtags = db.relationship('AnnotationTag', 
            backref='task', 
            lazy='dynamic') 
    name = db.Column(db.String, unique=True) 

    def __repr__(self): 
     return '<id {}>'.format(self.id) 


class AnnotationTag(db.Model): 

    id = db.Column(db.Integer, primary_key=True) 
    tagtype_id = db.Column(db.Integer, db.ForeignKey(TagType.id)) 
    task_id = db.Column(db.Integer, db.ForeignKey(Task.id)) 
    name = db.Column(db.String, unique=True) 
    annotations = db.relationship('Annotation', 
            backref='annotationtag', 
            lazy='dynamic') 

    def __repr__(self): 
     return '<id {}>'.format(self.id) 


class Audio(db.Model): 

    id = db.Column(db.Integer, primary_key=True) 
    url = db.Column(db.String, unique=True) 
    tagtype_id = db.Column(db.Integer, db.ForeignKey(TagType.id)) 
    task_id = db.Column(db.Integer, db.ForeignKey(Task.id)) 
    name = db.Column(db.String, unique=True) 
    annotations = db.relationship('Annotation', 
            backref='audio', 
            lazy='dynamic') 

    def __repr__(self): 
     return '<id {}>'.format(self.id) 


class Annotation(db.Model): 

    id = db.Column(db.Integer, primary_key=True) 
    annotationtag_id = db.Column(db.Integer, db.ForeignKey(AnnotationTag.id)) 
    audio_id = db.Column(db.Integer, db.ForeignKey('audio.id')) 

    def __repr__(self): 
     return '<id {}>'.format(self.id) 

.py initialisation

from flask import Flask 
from flask_sqlalchemy import SQLAlchemy 
from flask_migrate import Migrate 


app = Flask(__name__, instance_relative_config=True) 
app.config.from_pyfile('flask.cfg') 


db = SQLAlchemy(app) 
migrate = Migrate(app, db) 

from . import models # OK IF I REMOVE THIS 
from . import views 

Answer 1

Voir this question sur GitHub. C'est le même problème que le vôtre et a à voir avec la version SQLAlchemy.