运行flask app时出现“flask.cli.NoAppException”

Question

我对python开发相当陌生，对flask一无所知，我被分配了一个使用flask开发的项目。经过几周的工作，我现在能够解决所有的依赖关系和项目现在编译成功。但当我使用flask run运行项目，然后在浏览器中输入url时，它抛出“flask.cli.NoAppException”。我怎么能像这样运行我的项目呢。

>

设置FLASK_APP=init.py

设置FLASK_ENV=开发

烧瓶运行

• 服务烧瓶应用程序init.py（延迟加载）
• 环境：发展
• 调试模式：开启
• 重新启动stat
• 调试器已激活！
• 调试器引脚：202-733-235
• 运行在http://127.0.0.1:5000/（按CTRLC退出）

这是回溯

"FLASK_APP=myappnam:name to specify one.
Traceback (most recent call last)

    File "C:\Program Files\Python38\Lib\site-packages\flask\_compat.py", line 39, in reraise

    raise value

    File "C:\Program Files\Python38\Lib\site-packages\flask\cli.py", line 97, in find_best_app

    raise NoAppException(

    flask.cli.NoAppException: Failed to find Flask application or factory in module "myappnam". Use "FLASK_APP=myappnam:name to specify one.

The debugger caught an exception in your WSGI application. You can now look at the traceback which led to the error.

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这是我的--init--。py文件

import os
import logging
import gevent
import datetime
import rollbar

from gevent.queue import Queue
from gevent.event import AsyncResult
import zmq.green as zmq

from werkzeug.contrib.fixers import ProxyFix

# Greens the postgress connector
try:
    import psycogreen.gevent
    psycogreen.gevent.patch_psycopg()
except ImportError:
    pass

from rauth.service import OAuth2Service

from flask import Flask, Request
from flask_sqlalchemy import SQLAlchemy
from flask_bcrypt import Bcrypt
from flask_login import LoginManager, current_user
from flask_assets import Environment
from flask_uploads import UploadSet, configure_uploads, IMAGES

from app.util import setup_logging
from app.exceptions import TimeoutError, BackendError
import app.exceptions


flask_app = None

# Have to use an actor pattern because we cannot allow more than one request to
# be pending at a time.
class Backend(gevent.Greenlet):
    def __init__(self):
        super(Backend, self).__init__()

        self.inbox = Queue()
        self.zmq_context = zmq.Context()
        self.zmq_socket = None
        self.init_socket()

    def init_socket(self):
        zmq_socket = self.zmq_socket
        if zmq_socket is not None:
            zmq_socket.close(0)

        zmq_socket = self.zmq_context.socket(zmq.REQ)
        zmq_socket.connect(flask_app.config["SERVER_ZMQ_URI"])
        self.zmq_socket = zmq_socket

    def process(self, request):
        zmq_socket = self.zmq_socket

        poller = zmq.Poller()
        poller.register(zmq_socket, zmq.POLLIN)

        zmq_socket.send_json({
            "command": request["command"],
            "arguments": request["arguments"]
        })
        sockets = dict(poller.poll(10 * 1000))

        if zmq_socket not in sockets:
            self.init_socket()
            result = request["result"]
            result.set_exception(TimeoutError("The request to the backend timed out."))
            return

        received = zmq_socket.recv_json()

        result = request["result"]
        if received["success"]:
            result.set(received["result"])
        else:
            result.set_exception(BackendError(received["result"]))

    def _run(self):
        while True:
            self.process(self.inbox.get())            

    def send(self, command, **kwargs):
        result = AsyncResult()
        self.inbox.put({
            "command": command,
            "arguments": kwargs,
            "result": result
        })
        return result.get()


class RollbarRequest(Request):
    @property
    def rollbar_person(self):
        if current_user.is_anonymous:
            return {
                "id": 0, 
                "username": "anonymous"
            }
        return {
            "id": current_user.id,
            "username": current_user.name,
            "email": current_user.email_address
        }


def create_app(*args, **kwargs):
    global flask_app
    global l

    app_mode = os.environ.get("APP_MODE")

    assert app_mode is not None, "APP_MODE environment variable must be set"

    flask_app = Flask(__name__)
    flask_app.request_class = RollbarRequest
    flask_app.config.from_object("config.mode_{}".format(app_mode))
    flask_app.config["APP_MODE"] = app_mode

    setup_logging(flask_app.config["LOGGING_LEVEL"])

    l = logging.getLogger(__name__)
    l.info("starting in mode {}".format(app_mode))

    if not flask_app.config["DEBUG"]:
        rollbar.init(
            flask_app.config["ROLLBAR_API_KEY"],
            app_mode,
            allow_logging_basic_config=False
        )

    flask_app.jinja_env.globals.update(
        current_year=lambda: datetime.datetime.now().year
    )

    # Have to do this so that redirects work in proxy mode behind NGINX.
    if not flask_app.debug:
        flask_app.wsgi_app = ProxyFix(flask_app.wsgi_app)

    flask_app.db = SQLAlchemy(flask_app)

    flask_app.bcrypt = Bcrypt(flask_app)
    flask_app.assets = Environment(flask_app)

    flask_app.images = UploadSet("images", IMAGES)
    configure_uploads(flask_app, flask_app.images)

    flask_app.photos = UploadSet("photos", IMAGES)
    configure_uploads(flask_app, flask_app.photos)

    login_manager = LoginManager()
    login_manager.login_view = "signin"
    login_manager.login_message_category = "alert"  # Need newer release of Flask-Login for this to work.
    login_manager.init_app(flask_app)

    flask_app.facebook = OAuth2Service(
        name="facebook",
        base_url="https://graph.facebook.com/v2.8/",
        client_id=flask_app.config["FACEBOOK_CLIENT_ID"],
        client_secret=flask_app.config["FACEBOOK_CLIENT_SECRET"]
    )

    from app import views
    from app import models
    from app import commands

    flask_app.backend = Backend()
    flask_app.backend.start()

    app.exceptions.register(flask_app)

    return flask_app

Answer 1

在您的create_app函数中，您可能不想使用全局关键字来延迟应用程序的初始化。

在您提供的示例中，从未调用创建应用程序函数，因此从未创建应用程序实例。更常见的做法是使用如下创建应用程序功能：

def create_app():
    app = flask.Flask(__name__)
    # do some setup
    return app

app = create_app()

应用程序实例也应称为app，而不是flask\u app。当然，你可以随意调用它，但默认情况下，flask会查找app。指定您自己的更改。pytoFLASK\u APP=\uu init\uu:FLASK\u APP