I have built is a simple web app with Flask and Python, which I intend to upload to Heroku.
When starting my app locally, with the following script:
#!venv/bin/python
from app import app
app.run(debug = True)
I get this error message:
Traceback (most recent call last):
File "./run.py", line 2, in <module>
from app import app, mail
File "/home/ricardo/personalSite/app/__init__.py", line 3, in <module>
from app import index
File "/home/ricardo/personalSite/app/index.py", line 6, in <module>
from emails import send_email
File "/home/ricardo/personalSite/app/emails.py", line 2, in <module>
from app import app, mail
ImportError: cannot import name mail
So, it cannot import mail.
Inside the app directory I have this __init__.py, here is were I create the Mail object that is ginving me trouble to import:
from flask import Flask
app = Flask(__name__)
from app import index
from flask.ext.mail import Mail
mail = Mail(app)
And this is the file emails.py where I call the send_mail function:
from flask.ext.mail import Message
from app import app, mail
from flask import render_template
from config import ADMINS
from decorators import async
So, according to the error message, the error is in this file, in the from app import app, mail.
What is the problem? Why can't it import mail?
Update:
This is my directory listing:
persSite\
venv\
<virtual environment files>
app\
static\
templates\
__init__.py
index.py
emails.py
decorators.oy
tmp\
run.py
You have a circular dependency. You have to realize what Python is doing when it imports a file.
Whenever Python imports a file, Python looks to see if the file has already started being imported before. Thus, if module A imports module B which imports module A, then Python will do the following:
Start running module A.
When module A tries to import module B, temporarily stop running module A, and start running module B.
When module B then tries to import module A, then Python will NOT continue running module A to completion; instead, module B will only be able to import from module A the attributes that were already defined there before module B started running.
Here is app/__init__.py, which is the first file to be imported.
from flask import Flask
app = Flask(__name__)
from app import index # <-- See note below.
from flask.ext.mail import Mail
mail = Mail(app)
When this file is imported, it is just Python running the script. Any global attribute created becomes part of the attributes of the module. So, by the time you hit the third line, the attributes 'Flask' and 'app' have been defined. However, when you hit the third line, Python begins trying to import index from app. So, it starts running the app/index.py file.
This, of course, looks like the following:
from flask.ext.mail import Message
from app import app, mail # <-- Error here
from flask import render_template
from config import ADMINS
from decorators import async
Remember, when this Python file is being imported, you have thus far only defined Flask and app in the app module. Therefore, trying to import mail will not work.
So, you need to rearrange your code so that if app.index relies on an attribute in app, that app defines that attribute before attempting to import app.index.
This is probably the problem:
from app import app, mail
In the file 'app/emails.py' the import is from the current module, not a nested app module. Try:
from . import app, mail
If it doesn't work, you should update your question with a more detailed directory listing.
Related
My goal is to import code into three separate Flask servers. It's not going well. I am on python 3.10.4. I have read perhaps 10 different posts that say things like "put a __init__.py file in your folders" which I have done.
For context I'm not exactly new to Python but I've never learned the importing/module system properly.
I have three Flask servers that run scraping operations on different (but similar) websites. I need them to be separate for various reasons. Anyway, all three need to run the same procedure of getting an IP for a proxy from my proxy provider. For this I have some code:
# we don't need the details here so I snip it to save space
def get_proxy_ip(choice):
r = requests.get(download_list, headers={"Authorization": "Token " + token})
selected_proxy_ip = r.json()["results"][choice]["proxy_address"]
selected_proxy_port = r.json()["results"][choice]["port"]
print(selected_proxy_ip)
return selected_proxy_ip, selected_proxy_port
I want to use this function across all 3 of my Flask servers. Here are some various ways I've tried to import the code into one of the Flask servers:
scrapers/rentCanada/app.py
import requests
from flask import Flask, request, make_response
print("cats")
app = Flask(__name__)
print(__name__, __package__)
# from ..shared.ipgetter import get_proxy_ip
# from ..shared.checker import check_public_ip
# from scrapers.shared.ipgetter import get_proxy_ip
# from scrapers.shared.checker import check_public_ip
import shared.ipgetter as ipgetter
import shared.checker as checker
None of them work.
import shared.ipgetter as ipgetter yields:
cats
__main__ None
Traceback (most recent call last):
File "/home/rlm/Code/canadaAps/scrapers/rentCanada/app.py", line 10, in <module>
import shared.ipgetter as ipgetter
ModuleNotFoundError: No module named 'shared'
ModuleNotFoundError: No module named 'scrapers' yields: ModuleNotFoundError: No module named 'scrapers'
from ..shared.ipgetter import get_proxy_ip yields: ImportError: attempted relative import with no known parent package
At this point you need to see my folder structure.
/scrapers
..__init__.py
..setup.py
../rentCanada
.....__init__.py
.....app.py
../rentFaster
.....__init__.py
.....app.py
../rentSeeker
.....__init__.py
.....app.py
../shared
.....__init__.py
.....ipgetter.py
.....checker.py
I need to be able to use any of the app.py files as entry points.
I also tried setup.py with this:
from setuptools import setup, find_packages
setup(
name = 'tools',
packages = find_packages(),
)
followed by python setup.py install but that didn't make a "tools" import available in app.py like I wanted.
As a final note I suspect someone will tell me to use a blueprint. To me those look like a tool I'd use if I was adding a route. I'm not sure they're right for a simple function, but maybe I'm wrong.
My solution for now is to run Flask with python rentCanada/app.py from the /scrapers folder and use this code
import sys
from pathlib import Path
sys.path.append(str(Path(__file__).parent.parent)) # necessary so util folder is available
import requests
from flask import Flask, request, make_response
print("cats")
app = Flask(__name__)
print(__name__, __package__)
from util.ipgetter import get_proxy_ip
from util.checker import check_public_ip
So the program appends the app.py file folder's parent folder to the path. That makes the util folder (which used to be shared but had a naming conflict) available within the app.py file.
The Following is my code hierarchy.
I am trying to create a package for my project, "UIGenerator" but it is giving me following error.
traceback (most recent call last):
File "run.py", line 1, in <module>
from UIGenerator import app
File "/Users/______/Desktop/UIGenerator/UIGenerator/__init__.py", line 2, in <module>
from site.routes import site
ModuleNotFoundError: No module named 'site.routes'; 'site' is not a package
Here is the code for run.py =>
from UIGenerator import app
#app.route('/')
def test_connection():
return "<h1>Connected<h1>"
if __name__ == '__main__':
app.run(debug=True)
There is nothing in site =>__init__.py file and in site=>routes.py, I have some sample code to test-
from flask import Blueprint
site = Blueprint('site', __name__)
#site.route('/site')
def site():
return "this is test for site package"
The following is my code for the UIGenerator's init.py file =>
from flask import Flask
from site.routes import site
def getApp():
app = Flask(__name__)
app.register_blueprint(site)
return app
app = getApp()
Can anyone give me any clue, please.
One way to fix this is to build a Python package with you files, like outlined here. This will be better in the long run if you want to scale this project up, and will allow you to declare things in init
That being said, I think you can get your setup working by moving this chunk of code
def getApp():
app = Flask(__name__)
app.register_blueprint(site)
return app
app = getApp()
to the run.py file for the time being.
So, here is what I found out from a different post. In my site=>routes, I declared a global blueprint with the name, site and later I created a site() function which somehow masked my site blueprint. If I just renamed the site method name, it works.
In my main.py have the below code:
app.config.from_object('config.DevelopmentConfig')
In another module I used import main and then used main.app.config['KEY'] to get a parameter, but Python interpreter says that it couldn't load the module in main.py because of the import part. How can I access config parameters in another module in Flask?
Your structure is not really clear but by what I can get, import your configuration object and just pass it to app.config.from_object():
from flask import Flask
from <path_to_config_module>.config import DevelopmentConfig
app = Flask('Project')
app.config.from_object(DevelopmentConfig)
if __name__ == "__main__":
application.run(host="0.0.0.0")
if your your config module is in the same directory where your application module is, you can just use :
from .config import DevelopmentConfig
The solution was to put app initialization in another file (e.g: myapp_init_file.py) in the root:
from flask import Flask
app = Flask(__name__)
# Change this on production environment to: config.ProductionConfig
app.config.from_object('config.DevelopmentConfig')
Now to access config parameters I just need to import this module in different files:
from myapp_init_file import app
Now I have access to my config parameters as below:
app.config['url']
The problem was that I had an import loop an could not run my python app. With this solution everything works like a charm. ;-)
I have a Flask application with this error:
ImportError: No module named annotaria, referer: http://ltw1413.web.cs.unibo.it/
So, my root in web server is:
/home/web/ltw1413/html
Inside html folder I have:
One folder named "annotaria
One file .wsgi named "wsgi.wsgi"
My file .wsgi is:
import sys
sys.path.insert(0, '/home/web/ltw1413/html')
from annotaria import app as application
Inside my folder "annotaria" I have:
"Static" folder : inside stylesheet and js
"Templates" folder : inside html
"run.py" : file python where I have my application
run.py is this:
from pydoc import html
from annotaria import app
from flask import Flask, render_template, redirect, request
import json
import urllib2
import urlparse
import re
import string
import os
from SPARQLWrapper import SPARQLWrapper, JSON
from rdflib import Graph, BNode, Literal, Namespace
from time import strftime
import urllib2
import BeautifulSoup
app = Flask(__name__)
#app.route('/')
def index():
return render_template('index.html')
#app.route('/index.html')
def reloader():
return render_template('index.html')
# other app.route()...
if __name__ == '__main__':
app.run(debug=True)
How can I find a solution? Where is my error?
Lots of errors here...
annotaria is not found on path (that is why it says... well.. exactly that).
In your code you also redefine app: you import it from annotaria and then redefine it in app = Flask(...
Others mentioned individual errors, but it would be helpful to understand the big picture. First of all, let's assume the following structure:
/home/web/ltw1413/html
- wsgi.wsgi
- annotaria/
- __init.py__
- run.py
- static/
- templates
Like Klaus mentioned, you need __init__.py to tell Python that annotaria is a valid package. But then your wsgi.wsgi file needs to import the app from the run module:
from annotaria.run import app as application
You also need to remove this unnecessary import from run.py, since you instantiate a new application:
from annotaria import app
Because there is no application to import, you instantiate a new Flask application.
Finally, make sure that the app runs manually before you start deploying it.
I've encountered an issue while trying to access PostgreSQL from heroku python console (first attempt).
First up, I launch python using $ heroku run python
Then I try to load up the db module with >>> from app import db, this action returns:
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
ImportError: No module named app
I have one web dyno running python which has app = Flask(__name__), apart from that, I don't know what other details should I provide in order to shed more light into the issue.
After experimenting with the terminal, it became clear, that there really is no way for it to know what variables do I have in my main.py, so what I did then was load the main parts of the app through the terminal like so:
>>> import os
>>> from flask import Flask, request, session, g, redirect, url_for, abort, render_template, flash
>>> from flask.ext.sqlalchemy import SQLAlchemy
>>> # create the application
>>> app = Flask(__name__)
>>> app.config.from_object(__name__)
>>> app.config['SQLALCHEMY_DATABASE_URI'] = os.environ.get('DATABASE_URL', 'some-url.com')
>>> db = SQLAlchemy(app)
And from then on I was able to access the db object as intended.
EDIT - the issue completely resolved below.
So the reason I was having an error while trying to import my apps code into the python shell was two fold:
The *.py that was the target of my import was not at the root directory, I was telling the shell to look in the wrong place.
Since the *.py I was importing was not named app.py (and I was asking to from app import db), I was also telling the shell to look for the wrong file.
The way to solve this issue was to append the path of my *.py file to the sys.path and instead of from app import db, us from my_filename_without_the_extenssion import db. For a summary, the shell received these instructions:
>>> import sys
>>> sys.path.append('path/to/my/file')
>>> from my_filename_without_the_extenssion import db
>>> # to test if everythings ok
>>> db