Flask、Pymongo 和 Mongoengine - ImportError：无法导入名称“app”

Question

我正在 python 3 上使用 mongoengine 作为 mongodb orm 运行烧瓶应用程序。

我在通用配置文件中配置mongo连接如下：

MONGODB_SETTINGS = {
    'db': "dbname",
    'host': "myhost",
    'port': "27017",
    # 'username': 'xxxxxx',
    # 'password': 'xxxxxx'
}

我正在创建我的 mongoengine 实例：db = MongoEngine(app)

但是，在我的 model.py 中，如果我不包含隐式连接命令，它不会获取参数，它会尝试连接到我配置的主机的本地主机。

所以我添加连接尝试使用配置参数如下：

from app.engine import app
connect(db=app.config['MONGODB_SETTINGS']['db'], host=app.config['MONGODB_SETTINGS']['host'])

class Module(Document):
    identifier = StringField()
    path = StringField()
    description = StringField()
    name = StringField()
    method = StringField()
    meta = {'collection': 'modules'}
    ...

我得到了这个例外：

[2019-01-08 14:56:51 +0000] [8] [INFO] Starting gunicorn 19.9.0
[2019-01-08 14:56:51 +0000] [8] [INFO] Listening at: https://0.0.0.0:5000 (8)
[2019-01-08 14:56:51 +0000] [8] [INFO] Using worker: eventlet
[2019-01-08 14:56:51 +0000] [10] [INFO] Booting worker with pid: 10
[2019-01-08 14:56:51 +0000] [10] [ERROR] Exception in worker process
Traceback (most recent call last):
  File "/app/env/lib/python3.6/site-packages/gunicorn/arbiter.py", line 583, in spawn_worker
    worker.init_process()
  File "/app/env/lib/python3.6/site-packages/gunicorn/workers/geventlet.py", line 102, in init_process
    super(EventletWorker, self).init_process()
  File "/app/env/lib/python3.6/site-packages/gunicorn/workers/base.py", line 129, in init_process
    self.load_wsgi()
  File "/app/env/lib/python3.6/site-packages/gunicorn/workers/base.py", line 138, in load_wsgi
    self.wsgi = self.app.wsgi()
  File "/app/env/lib/python3.6/site-packages/gunicorn/app/base.py", line 67, in wsgi
    self.callable = self.load()
  File "/app/env/lib/python3.6/site-packages/gunicorn/app/wsgiapp.py", line 52, in load
    return self.load_wsgiapp()
  File "/app/env/lib/python3.6/site-packages/gunicorn/app/wsgiapp.py", line 41, in load_wsgiapp
    return util.import_app(self.app_uri)
  File "/app/env/lib/python3.6/site-packages/gunicorn/util.py", line 350, in import_app
    __import__(module)
  File "/app/engine.py", line 10, in <module>
    from app.controllers.modules import modules
  File "/app/controllers/modules.py", line 8, in <module>
    from app.domain.model import DownloadPending
  File "/app/domain/model.py", line 1, in <module>
    from app.engine import app
ImportError: cannot import name 'app'
[2019-01-08 14:56:51 +0000] [10] [INFO] Worker exiting (pid: 10)
[2019-01-08 14:56:51 +0000] [8] [INFO] Shutting down: Master
[2019-01-08 14:56:51 +0000] [8] [INFO] Reason: Worker failed to boot.

除此之外，我还有一个服务，它直接使用 pymongo 聚合将数据存储在动态命名的集合中，因此我必须再次在该服务中包含 mongo 参数和连接命令。

我想知道是否有任何方法可以在所有情况下重用配置文件中的 mongo 参数。

更新 这是app.engine代码（主要py）：

import logging
import os
from datetime import date, timedelta

from celery.schedules import crontab
from flask import Flask
from flask import request

from app.controllers.auth import auth
from app.controllers.modules import modules
from app.controllers.companies import companies
from app.service.services import ModuleService
from flask_jwt_extended import (
    JWTManager, jwt_required
)
from flask_cors import CORS
from flask_socketio import SocketIO

from celery import Celery

import eventlet

from app.utils.JSONEncoder import JSONEncoder
from flask_mongoengine import MongoEngine


eventlet.monkey_patch()

logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)


def create_app(config_name):
    _app = Flask(__name__)
    _app.config.from_pyfile('config.py', silent=True)
    return _app


def make_celery(_app):
    celery = Celery(
        _app.import_name,
        backend=_app.config['CELERY_RESULT_BACKEND'],
        broker=_app.config['CELERY_BROKER_URL']
    )
    celery.conf.update(_app.config)

    class ContextTask(celery.Task):
        def __call__(self, *args, **kwargs):
            with _app.app_context():
                return self.run(*args, **kwargs)

    celery.Task = ContextTask
    return celery


app = create_app('profile')
# app = create_app('config')

db = MongoEngine(app, config={
    'db': "dbname",
    'host': "myhost",
    'port': 27017,
})

CORS(app)

UPLOAD_FOLDER = '/app/import'

app.config['SECRET_KEY'] = 'xxxxxxxxxxxxxxxxxxxxx'
app.config['UPLOAD_FOLDER'] = UPLOAD_FOLDER

app.config.update(
    CELERY_BROKER_URL='redis://redis:6379/0',
    CELERY_RESULT_BACKEND='redis://redis:6379/1',
)

celery = make_celery(app)
socketio = SocketIO(app, message_queue='redis://redis:6379/2')

"""
Services initialization
"""
modules_service = ModuleService()

jwt = JWTManager(app)


@celery.task()
def do(module_name, json_input):
    (..........)


app.register_blueprint(companies)
app.register_blueprint(modules)
app.register_blueprint(auth)

if __name__ == "__main__":
    socketio.run(host='0.0.0.0', threaded=True)

这里的最佳做法是什么？

感谢您的帮助

谢谢。

Answer 1

感谢@Danila Ganchar

我必须重构整个代码，以避免循环依赖冲突和导入顺序问题。 还将数据库连接外部化到另一个类，使用 Mongoengine 的 connect() 命令而不是使用 mongoengine 烧瓶扩展。

现在一切正常。 谢谢！