Flask - ImportError: No module named app

Question

First I created __init__.py

from flask import Flask

app = Flask(__name__)

Then in a separate file, in the same directory, run.py

from app import app 

app.run(
    debug = True
)

When I try to run run.py, I get the error

Traceback (most recent call last):
  File "run.py", line 1, in <module>
    from app import app 
ImportError: No module named app

Elisha · Accepted Answer · 2014-07-06T08:29:31.373

46

__init__.py is imported using a directory. if you want to import it as app you should put __init__.py file in directory named app

a better option is just to rename __init__.py to app.py

edited Jul 06 '14 at 08:29

answered Mar 28 '14 at 11:33

Elisha

4,513
4
27
45

6

I renamed the directory to 'app', still getting the same error – onepiece Mar 28 '14 at 11:56
2

don't rename, add a new one and put this file there. (the problem is because `run.py` is also inside the directory) – Elisha Mar 28 '14 at 12:17
but I think that what you really want is to rename the file name to `app.py` – Elisha Mar 28 '14 at 12:18
1

Could you clarify why I need to make a new folder instead of just renaming the current one? – onepiece Mar 28 '14 at 12:22
3

it is better to rename. `__init__.py` is meant for cases that you want a directory with several files to be a one package. – Elisha Mar 28 '14 at 12:30
1

i actually just removed run.py from app folder and placed it outside and run it. It worked but i wonder how it worked? – ashim888 Dec 04 '14 at 06:25

score 17 · Answer 2 · edited Apr 04 '19 at 19:27

17

This is probably an error in flask application's folder structure.
Anyone looking for a simple beginner-friendly structure for the flask project may find this helpful:

   |__movies 
     |__run.py 
     |__app     
        ├── templates
        │   └── index.html
        │   └── signup.html
        └── __init__.py
        └── routes.py

Here 'movies' is the name given for the main application. It contains 'run.py' and a folder called 'app'. 'app' folder contains all necessary flask files such as 'templates' folder, '__init __.py', and 'routes.py'.

Contents of:

run.py:

from app import app

__init__.py:

from flask import Flask

app = Flask(__name__)

from app import routes


app.run(debug=True)

routes.py:

from app import app

@app.route('/')
@app.route('/index')
def index():
    return "Hello, World!"

edited Apr 04 '19 at 19:27

Robert Brisita

4,684
2
33
33

answered Apr 13 '18 at 11:52

Nuhman

1,081
16
20

How do you run `app` from the command line in this case? The docs suggest `export FLASK_APP="movies/app"; run flask` but it does not work; `flask.cli.NoAppException: Could not import "app".` – user5359531 Sep 04 '18 at 19:47
@user5359531 either `export FLASK_APP=main` or `export FLASK_APP=main.py` worked for me with this structure. – andrei13 Jun 08 '20 at 17:27
1

This helps a lot. Somehow, I was trying to do this with an empty `__init__.py`, and what you have put in this file in an `app.py` file, and it was not working. I think I was missing `app.run()` too. – Wok Jan 18 '21 at 15:25
1

This is the solution for me. I kept the run.py inside app folder. Changing its directory solved it. Thanks. – Sadman Amin Apr 13 '21 at 06:45
How do you actually run this app and from what path? `run.py ` – Pavel Fedotov Jan 19 '22 at 12:19

score 7 · Answer 3 · edited Jun 10 '16 at 22:54

7

Your __init__.py file needs to go in the folder named app, not the same directory as the run.py file.

from app import app is looking in the app folder, so the __init__.py file needs to sit in there.

edited Jun 10 '16 at 22:54

B.Mr.W.

17,766
32
107
160

answered Jul 05 '14 at 19:49

Takeshi Patterson

1,055
6
14
29

score 6 · Answer 4 · answered Apr 04 '19 at 19:54

6

Ensure to set your PYTHONPATH to the src/ directory as well. Example export PYTHONPATH="$PYTHONPATH:/path/to/your/src"

answered Apr 04 '19 at 19:54

ckjavi70

138
2
10

Thanks, yes, I'm using flask boilerplate and this what actually helped `export PYTHONPATH="$PYTHONPATH:/var/gx/app"` – Vladimir Stazhilov May 02 '20 at 12:07
in vscode you can put export PYTHONPATH="$PYTHONPATH:/path/to/your/src" to launch.json – Zafer Fatih Koyuncu Oct 03 '20 at 15:25

score 3 · Answer 5 · answered Jul 12 '20 at 12:07

3

Just rename your file to app.py and it will works.

answered Jul 12 '20 at 12:07

joepadz

81
1

score 2 · Answer 6 · answered Jul 23 '20 at 11:46

2

For me, export PYTHONPATH=/path/to/your/src && python app/main.py works

answered Jul 23 '20 at 11:46

Jianping Ding

21
2

score 2 · Answer 7 · answered Aug 19 '21 at 16:55

(In case someone else is lost even after trying other solutions..)

I get the No module named app error only when Debugging, not when Running.

That's because I had set debug=True in my app.py's __main__ (which kindly auto-reloads flask when we save code changes) :

app.run(debug=True)

But if you try to Debug in your IDE now, it gives above error.

Fix : set debug=False

app.run(debug=False)

and it works like a magic ~~trick~~ illusion.

score 1 · Answer 8 · edited Aug 30 '20 at 11:41

1

I solved this as follows -

$export FLASK_APP=run

$flask run

After executing this command. I don't get any error, my app running smoothly.

edited Aug 30 '20 at 11:41

Arghya Sadhu

35,183
9
62
80

answered Aug 30 '20 at 11:09

Parag Kulkarni

11
5

I had a similar issue: ```python -m FLASK_APP='wsgi_app.py' flask shell ``` -- Separating the environment variable worked for me! Thank you! – baumannalexj Aug 07 '21 at 04:11

score 0 · Answer 9 · answered May 13 '22 at 01:40

This may be an isolated case, but for me this was a VS Code issue. The "no module found" error would only happen when debug=True.

In VS Code, you can "Run Python File" or "Debug Python File". I was using debug in VS Code AND I had app.run(debug=True). Once I just ran the file normally in VS Code, the problem went away and Flask debugger is working as expected.

I guess it doesn't like 2 layers of Inception!

Flask - ImportError: No module named app

9 Answers9

Linked