带有create_app，SQLAlchemy和Celery的Flask

时间：2014-08-18 09:32:22

标签： flask celery flask-sqlalchemy

我真的很难为Flask，SQLAlchemy和Celery进行正确的设置。我已经广泛搜索并尝试了不同的方法，似乎没有什么工作。要么我错过了应用程序上下文，要么无法运行工作程序，或者存在其他一些问题。结构非常通用，因此我可以构建更大的应用程序。

我正在使用：Flask 0.10.1，SQLAlchemy 1.0，Celery 3.1.13，我目前的设置如下：

应用程序/ __初始化__。PY 

#Empty

应用程序/ config.py 

import os
basedir = os.path.abspath(os.path.dirname(__file__))

class Config:

    @staticmethod
    def init_app(app):
        pass

class LocalConfig(Config):
    DEBUG = True
    SQLALCHEMY_DATABASE_URI = r"sqlite:///" + os.path.join(basedir, 
                                 "data-dev.sqlite")
    CELERY_BROKER_URL = 'amqp://guest:guest@localhost:5672//'


config = {
    "local": LocalConfig}

应用程序/ exstensions.py 

from flask.ext.sqlalchemy import SQLAlchemy
from celery import Celery

db = SQLAlchemy()
celery = Celery()

应用程序/ factory.py 

from extensions import db, celery
from flask import Flask
from flask import g
from config import config

def create_before_request(app):
    def before_request():
        g.db = db
    return before_request


def create_app(config_name):
    app = Flask(__name__)
    app.config.from_object(config[config_name])

    db.init_app(app)
    celery.config_from_object(config)

    # Register the blueprints

    # Add the before request handler
    app.before_request(create_before_request(app))
    return app

应用程序/ manage.py 

from factory import create_app

app = create_app("local")

from flask import render_template
from flask import request

@app.route('/test', methods=['POST'])
def task_simple():
    import tasks
    tasks.do_some_stuff.delay()
    return ""

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

应用程序/ models.py 

from extensions import db

class User(db.Model):
    __tablename__ = "user"

    id = db.Column(db.Integer, primary_key=True)
    username = db.Column(db.String(128), unique=True, nullable=False)

应用程序/ tasks.py 

from extensions import celery
from celery.signals import task_prerun
from flask import g, current_app


@task_prerun.connect
def close_session(*args, **kwargs):
    with current_app.app_context():
       # use g.db
       print g

@celery.task()
def do_some_stuff():
    with current_app.app_context():
       # use g.db
       print g

在文件夹app中：

  • 使用以下内容启动开发网络服务器：python.exe manage.py
  • 以celery.exe worker -A tasks
    • 开始工作

我收到一个对我没有任何意义的导入错误。 我应该以不同方式构建应用程序最后，我想我想要一个非常基本的设置，例如将Flask与工厂模式一起使用，可以使用Flask-SQLAlchmey扩展并让一些工作人员需要访问数据库。

非常感谢任何帮助。

启动芹菜工人时会执行回溯。

Traceback (most recent call last):

  File "[PATH]\scripts\celery-script.py", line 9, in <module>
    load_entry_point('celery==3.1.13', 'console_scripts', 'celery')()

  File "[PATH]\lib\site-packages\celery\__main__.py", line 30, in main
    main()

  File "[PATH]\lib\site-packages\celery\bin\celery.py", line 81, in main
    cmd.execute_from_commandline(argv)

  File "[PATH]\lib\site-packages\celery\bin\celery.py", line 769, in execute_from_commandline
    super(CeleryCommand, self).execute_from_commandline(argv)))

  File "[PATH]\lib\site-packages\celery\bin\base.py", line 305, in execute_from_commandline
    argv = self.setup_app_from_commandline(argv)

  File "[PATH]\lib\site-packages\celery\bin\base.py", line 473, in setup_app_from_commandline
    user_preload = tuple(self.app.user_options['preload'] or ())
AttributeError: 'Flask' object has no attribute 'user_options'

更新我根据评论中的建议更改了代码。工作人员现在启动，但在使用http://127.0.0.1:5000/test的get请求进行测试时。我得到以下追溯：

Traceback (most recent call last):
  File "[PATH]\lib\site-packages\celery\app\trace.py", line 230, in trace_task
    args=args, kwargs=kwargs)

  File "[PATH]\lib\site-packages\celery\utils\dispatch\signal.py", line 166, in send
    response = receiver(signal=self, sender=sender, \**named)

  File "[PATH]\app\stackoverflow\tasks.py", line 7, in close_session
    with current_app.app_context():

  File "[PATH]\lib\site-packages\werkzeug\local.py", line 338, in __getattr__
    return getattr(self._get_current_object(), name)

  File "[PATH]\lib\site-packages\werkzeug\local.py", line 297, in _get_current_object
    return self.__local()

  File "[PATH]\lib\site-packages\flask\globals.py", line 34, in _find_app
    raise RuntimeError('working outside of application context')
RuntimeError: working outside of application context exc, exc_info.traceback)))

更新根据Marteen的评论，我更改了代码。当前的工作版本位于：https://gist.github.com/anonymous/fa47834db2f4f3b8b257。 欢迎任何进一步的改进或建议。

2 个答案:

答案 0 :(得分：18)

我关闭了current_app的建议。

您的芹菜对象需要访问应用程序上下文。我在网上找到了一些关于使用工厂函数创建Celery对象的信息。在没有消息代理的情况下测试下面的示例。

#factory.py
from celery import Celery
from config import config

def create_celery_app(app=None):
    app = app or create_app(config)
    celery = Celery(__name__, broker=app.config['CELERY_BROKER_URL'])
    celery.conf.update(app.config)
    TaskBase = celery.Task

    class ContextTask(TaskBase):
        abstract = True

        def __call__(self, *args, **kwargs):
            with app.app_context():
                return TaskBase.__call__(self, *args, **kwargs)

    celery.Task = ContextTask
    return celery

并在tasks.py中：

#tasks.py
from factory import create_celery_app
from celery.signals import task_prerun
from flask import g

celery = create_celery_app()

@task_prerun.connect
def celery_prerun(*args, **kwargs):
    #print g
    with celery.app.app_context():
    #   # use g.db
       print g

@celery.task()
def do_some_stuff():
    with celery.app.app_context():
        # use g.db
        g.user = "test"
        print g.user

一些链接：

Flask pattern for creating a Celery instance with factory function

Application using both application factory and celery

Source for said application's factory.py

Source for application tasks.py

答案 1 :(得分：2)

这是一个解决方案，它适用于烧瓶应用工厂模式，并且还可以使用上下文创建芹菜任务，而无需在任务中明确使用import java.util.*; class Test { static ArrayList<int[][]> list = new ArrayList<int[][]>(); public static void main(String[] args) { int[][] array1 = new int[5][5]; array1[0][4] = 1; list.add(array1); array1 = new int[5][5]; array1[1][2] = 1; list.add(array1); printArray(); } public static void printArray() { for (int i = 0; i < list.size(); i++) { printDim(list.get(i)); } } public static void printDim(int[][] array) { for (int x = 0; x < array.length; x++) { for (int y = 0; y < array[0].length; y++) { System.out.print(array[y][x]+" "); } System.out.println(); } System.out.println("--------"); } } 。在我的应用程序中，获取该app对象同时避免循环导入是非常棘手的，但这解决了它。在撰写本文时，这也适用于最新的芹菜版本4.2。

结构：

app.app_context()

因此repo_name/ manage.py base/ base/__init__.py base/app.py base/runcelery.py base/celeryconfig.py base/utility/celery_util.py base/tasks/workers.py 是此示例中的主要应用程序包。在base我们创建芹菜实例如下：

base/__init__.py

from celery import Celery celery = Celery('base', config_source='base.celeryconfig') 文件包含烧瓶应用工厂base/app.py并记下它包含的create_app：

init_celery(app, celery)

转到from base import celery from base.utility.celery_util import init_celery def create_app(config_obj): """An application factory, as explained here: http://flask.pocoo.org/docs/patterns/appfactories/. :param config_object: The configuration object to use. """ app = Flask('base') app.config.from_object(config_obj) init_celery(app, celery=celery) register_extensions(app) register_blueprints(app) register_errorhandlers(app) register_app_context_processors(app) return app 内容：

base/runcelery.py

接下来，from flask.helpers import get_debug_flag from base.settings import DevConfig, ProdConfig from base import celery from base.app import create_app from base.utility.celery_util import init_celery CONFIG = DevConfig if get_debug_flag() else ProdConfig app = create_app(CONFIG) init_celery(app, celery) 文件（作为示例）：

base/celeryconfig.py

现在在# -*- coding: utf-8 -*- """ Configure Celery. See the configuration guide at -> http://docs.celeryproject.org/en/master/userguide/configuration.html#configuration """ ## Broker settings. broker_url = 'pyamqp://guest:guest@localhost:5672//' broker_heartbeat=0 # List of modules to import when the Celery worker starts. imports = ('base.tasks.workers',) ## Using the database to store task state and results. result_backend = 'rpc' #result_persistent = False accept_content = ['json', 'application/text'] result_serializer = 'json' timezone = "UTC" # define periodic tasks / cron here # beat_schedule = { # 'add-every-10-seconds': { # 'task': 'workers.add_together', # 'schedule': 10.0, # 'args': (16, 16) # }, # } 文件中定义init_celery：

base/utility/celery_util.py

# -*- coding: utf-8 -*- def init_celery(app, celery): """Add flask app context to celery.Task""" TaskBase = celery.Task class ContextTask(TaskBase): abstract = True def __call__(self, *args, **kwargs): with app.app_context(): return TaskBase.__call__(self, *args, **kwargs) celery.Task = ContextTask 中的工人：

base/tasks/workers.py

然后，您需要在from base import celery as celery_app from flask_security.utils import config_value, send_mail from base.bp.users.models.user_models import User @celery_app.task def send_welcome_email(email, user_id, confirmation_link): """Background task to send a welcome email with flask-security's mail. You don't need to use with app.app_context() as Task has app context. """ user = User.query.filter_by(id=user_id).first() print(f'sending user {user} a welcome email') send_mail(config_value('EMAIL_SUBJECT_REGISTER'), email, 'welcome', user=user, confirmation_link=confirmation_link) @celery_app.task def do_some_stuff(): print(g) 文件夹中的两个不同的cmd提示中启动芹菜节拍和芹菜工作者。

在一个cmd提示符下执行repo_name和另一个celery -A base.runcelery:celery beat。

然后，执行需要烧瓶上下文的任务。应该工作。

相关问题
最新问题