Can't import LoginManager() in Flask

Question

I am using Flask BluePrint in my applications and have to main parts: 1. Admin and 2. Public. When I try to import the loginManager to my views.py file I get the error ImportError: cannot import name lm my folder structure is like: ``` ~/LargeApplication |-- run.py |-- config.py |__ /env # Virtual Environment |__ /app # Application Module |-- __init__.py |-- models.py |-- /admin |-- __init__.py |-- views.py |__ /templates |-- .. |__ .. |__ . ``` I do initialize the LoginManager() in __ init__ .py file /app/__ init__ .py ``` from flask.ext.login import LoginManager lm = LoginManager() lm.init_app(app) lm.login_view = 'login' ``` and when I try to import lm in /app/admin/views.py ``` from app import lm ``` it raises ImportError. ``` ImportError: cannot import name lm ``` Can you please tell what might be the issue?

Accepted Answer

You probably have a circular import. This is fine, but you need to take into account that you'll be working with modules that haven't yet completed all top-level instructions.

If you have code like:

```
from flask.ext.login import LoginManager
from app.admin import admin_blueprint

lm = LoginManager()
lm.init_app(app)
lm.login_view = 'login'
```

then `app.admin` will be imported before the `lm = LoginManager()` line has executed; any code in `app.admin` that then tries to address `app.lm` will fail.

Move blueprint imports down your module and `lm` will have been created already:

```
from flask.ext.login import LoginManager

lm = LoginManager()
lm.init_app(app)
lm.login_view = 'login'

from app.admin import admin_blueprint
```

See the Circular Imports note in the 'Larger Applications' documentation section of the Flask manual.

Can't import LoginManager() in Flask

Solution

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