Apache + WSGI运行Flask，获取Python ImportError：“无法导入名称…”或“未命名模块…”

Question

Hello dear SO users and welcome to my first ever SO question,

I am currently looking to deploy a Flask application using Apache and mod_wsgi . Everything was coded with Python 3.4 so I had to follow several tutorials / questions to get mod_wsgi working with my version of Python (because apt-get install gets you the 3.4 version which is Python 2.7 compatible, you have to compile it after getting it with pip in a Python 3 virtualenv for it to be the 4.x version).

The Apache server error.log shows Apache/2.4.10 (Debian) mod_wsgi/4.4.13 Python/3.4.2 configured so this seems to be working fine.

My problem lies in the importation of the application in the .wsgi file . Tutorials such as this one usually do from FlaskApp import app as application considering their file tree, and this works as intended with a minimal application, I tried it without any problem.

My application is a little more complicated and uses a manage.py file to run on localhost, which may be part of the problem once trying to deploy on Apache.

From what I have found on countless SO Questions and other sites' questions, this most likely comes from:

• A permission problem (if the user executing the current script doesn't have reading right on the script he's looking to import)
• A sys.path problem (if the top-level folder is not in the sys.path , Python 3 cannot see it)

Mainly out of frustration, I ended up using chmod 744 LongAppName in /var/www/ resulting in drwxrwxr-x rights. My file tree is the following:

drwxrwxr-x LongAppName
    drwxr-xr-x LongAppName
        drwxr--r-- ShorterAppName
            -rw-r--r-- app.py
            -rw-r--r-- commands.py
            -rw-r--r-- __init__.py
            drwxr--r-- static
            drwxr--r-- templates
            <irrelevant files>
        -rw-r--r-- __init__.py
        -rw-r--r-- manage.py
        drwxr-xr-x venv
        <more irrelevent files>
    -rwxr-xr-x longappname.wsgi

So for the first possible fix, permissions seem fine to me. Regarding the second one, I'm printing sys.path in the .wsgi file and it outpouts ['/var/www/LongAppName', <among others>] which shows that the top-level folder is in the sys.path .

My longappname.wsgi is as follows:

#!/var/www/LongAppName/LongAppName/venv/bin/python3
import os, sys, logging
#Doing some prints to check if we're in the venv and such.
PROJECT_DIR = '/var/www/LongAppName/'
if PROJECT_DIR not in sys.path:
    sys.path.insert(0, PROJECT_DIR)

def execfile(filename):
    globals = dict( __file__ = filename )
    exec( open(filename).read(), globals )

activate_this = os.path.join( PROJECT_DIR+'LongAppName/', 'venv/bin', 'activate_this.py' )
execfile( ativate_this )
#Printing sys.path and sys.executable here
logging.basicConfig(stream=sys.stderr)

from LongAppName.ShorterAppName.app import manager as application
#The previous line changed a lot, I tried importing app, changing the path but this one was the first one I wrote.

Python can't seem to find LongAppName.ShorterAppName.app and I don't know why.

From the number of attempts I have made to test different alternatives to the code I wrote in the first place, I'm starting to lose track of what was good and what might cause the problem so I require your help to figure this out.

Thanks in advance!

Answer 1

Some of your directory permissions are now suspect. You have:

    drwxr--r-- ShorterAppName

Better to be using:

    drwxr-xr-x ShorterAppName

Same for static and templates.

What we really need to see is the exact Python exception details with traceback from the Apache error logs.