如何在Apache2上使用WSGI部署Flask时解决导入错误

Question

我在用wsgi把一个flask应用部署到apache2上时遇到了问题。我把错误日志和配置文件都贴在下面了。我尝试过移动文件、重命名等等，但都出现了内部服务器错误。我不明白为什么会出现导入错误。任何建议或意见都非常感谢！

这是我的apache错误日志

[Sun Sep 12 20:47:59 2010] [error] [client] mod_wsgi (pid=9753): Target WSGI script '/sites/flaskfirst/wsgi.py' cannot be loaded as Python module.
[Sun Sep 12 20:47:59 2010] [error] [client] mod_wsgi (pid=9753): Exception occurred processing WSGI script '/sites/flaskfirst/wsgi.py'.
[Sun Sep 12 20:47:59 2010] [error] [client] Traceback (most recent call last):
[Sun Sep 12 20:47:59 2010] [error] [client]   File "/sites/flaskfirst/wsgi.py", line 1, in <module>
[Sun Sep 12 20:47:59 2010] [error] [client]     from app import app as application
[Sun Sep 12 20:47:59 2010] [error] [client] ImportError: No module named app

wsgi.py文件内容

# This is wsgi.py
from app import app as application

app.py文件内容

# This is app.py
from flask import Flask, render_template
import settings

app = Flask(__name__)
app.debug = settings.DEBUG

from views.homepage import *
from views.events import *
from views.submit import *
from views.feed import *

if __name__ == "__main__":
    app.run()

这里是目录结构的基本情况，给你一个大概念。

/flaskfirst/
    /static/
    /templates/
    /views/
    __init__.py
    app.py
    wsgi.py

这是apache的虚拟主机配置文件

<VirtualHost *:80>
        ServerAdmin sreustle@gmail.com
        ServerName crath.org
        DocumentRoot /sites/flaskfirst

        # WSGI Settings
        WSGIScriptAlias / /sites/flaskfirst/wsgi.py
        WSGIDaemonProcess flaskfirst user=sreustle group=general processes=1 threads=10
        WSGIProcessGroup flaskfirst

        # Static Directories
        Alias /static /sites/flaskfirst/static/
        <Location "/static">
                SetHandler None
        </Location>

</VirtualHost>

Answer 1

我用了你的方法让它正常工作了，但它在sys.path里一直重复添加路径（你可以试着打印出来看看是不是这样），所以我做了一点小修改：

import sys
flaskfirst = "/sites/flaskfirst"
if not flaskfirst in sys.path:
    sys.path.insert(0, flaskfirst)

from app import app
application = app

这样的话，它就只会被添加一次了。

Answer 2

感谢zarf和damjan在irc.freenode.org的#pocoo频道，他们帮我解决了这个问题。问题出在Python的路径设置不正确。我们通过使用下面的wsgi.py文件来修复这个问题。

import sys
sys.path.insert(0, "/sites/flaskfirst")

from app import app
application = app