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My API is being built to allow developers to extend it's functionality. My plan is to do this by providing an "extensions" directory where they can drop in Blueprints and they will be dynamically loaded. This is the code I am utilizing to import (modifed from this tutorial )

from flask import Flask
import pkgutil
import sys
app = Flask(__name__)
EXTENSIONS_DIR = "extensions"
modules = pkgutil.iter_modules(path=[EXTENSIONS_DIR])
for loader, mod_name, ispkg in modules: 
    if mod_name not in sys.modules:
        # It imports fine
        loaded_mod = __import__(EXTENSIONS_DIR+"."+mod_name+"."+mod_name, fromlist=[mod_name])
        # It does not register
        app.register_blueprint(loaded_mod)
This is the directory layout of my project. The extensions directory is where developers drop in their expanded functionality.
/root
    /extensions
        /extension1
            __init__.py
            extension1.py
        /extension2
            __init__.py
            extension2.py
    simple_example.py
The problem is that I get this error and am not sure what it is telling me.
>python simple_example.py
Traceback (most recent call last):
  File "simple_example.py", line 14, in <module>
    app.register_blueprint(loaded_mod)
  File "C:\Python27\lib\site-packages\flask\app.py", line 62, in wrapper_func
    return f(self, *args, **kwargs)
  File "C:\Python27\lib\site-packages\flask\app.py", line 880, in register_blueprint
    if blueprint.name in self.blueprints:
AttributeError: 'module' object has no attribute 'name'
A simple extension looks like this
from flask import Blueprint
extension1 = Blueprint('extension1', __name__)
@extension1.route("/my_route")
def treasure_list():
    return "list of objects"
How do I solve the AttributeError in a way that allows my app.register_blueprint call to succeed?
You are trying to register the module and not the contained Blueprint object.
You'll need to introspect the module to find Blueprint instances instead:
if mod_name not in sys.modules:
    loaded_mod = __import__(EXTENSIONS_DIR+"."+mod_name+"."+mod_name, fromlist=[mod_name])
    for obj in vars(loaded_mod).values():
        if isinstance(obj, Blueprint):
            app.register_blueprint(obj)
                I'm getting a very similar error, except I'm just trying to import a very basic blueprint without any of that fancyness.
– David Crook
                Aug 20, 2016 at 16:46
                @DavidCrook: it basically means you are trying to register something that is not an actual Blueprint instance. Make sure you pass in the right object.
– Martijn Pieters
                Aug 20, 2016 at 18:13
                I am new to Blueprints and I am getting the same error. Could this error arise because I am using the exactly the same name for both blueprint and folder where blueprint is located? Also where do I put above-mentioned piece of code to pass the blueprint object? I have run.py file that imports import app as app, and then in lower level folder init.py where I import all blueprints in the following way: from app.i_statement import income_statement, and register all blueprints import lines of code as such: app.register_blueprint(i_statement).
– user3151858
                Mar 8, 2019 at 9:06
                @user3151858: income_statement itself is not a blueprint object. I don't know what kind of object it is so I can't really help more there.
– Martijn Pieters
                Mar 8, 2019 at 11:08
                Thanks for this.  I was registering the module but not the blueprint object inside the module.
– Kenny Pyatt
                May 10, 2022 at 14:51
I have also experienced the same effect in a project. The origin of the problem was an incorrect import of the blueprint file.
Make sure the import statement imports the real blueprint and not the module on which it is defined.
In other words, you may be doing
from .blueprint import blueprint
while you meant
from .blueprint.blueprint import blueprint
As a side recommendation, name the module on which the blueprint is defined with a different name than the blueprint itself, in order to clarify the import. An example:
from .blueprint.views import blueprint
I got an error saying AttributeError: 'Blueprint' object has no attribute 'register_blueprint'
For this I simply uninstalled Flask using pip uninstall flask
and then installed flask[async] pip install flask[async]
Changing the flask version will help. I was using Flask==1.1.2 and changing to Flask==2.0.2 resolves the error.

pip install Flask==2.0.2
        
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