openshift：Perhaps your account does not have write access to this directory? You can change the cac

添加了pymongo之后重新部署程序，openshift 出现如下错误

 File "/var/lib/openshift/0f9c019e8890400bb48af288d0307389/app-root/runtime/repo//diy/runapp.py", line 5, in <module>
    from application import Application
  File "/var/lib/openshift/0f9c019e8890400bb48af288d0307389/app-root/runtime/repo/diy/application.py", line 7, in <module>
    import dbhelper
  File "/var/lib/openshift/0f9c019e8890400bb48af288d0307389/app-root/runtime/repo/diy/dbhelper/__init__.py", line 5, in <module>
    from dbhelper import *
  File "/var/lib/openshift/0f9c019e8890400bb48af288d0307389/app-root/runtime/repo/diy/dbhelper/dbhelper.py", line 4, in <module>
    from pymongo import MongoClient
  File "build/bdist.linux-x86_64/egg/pymongo/__init__.py", line 61, in <module>
  File "build/bdist.linux-x86_64/egg/pymongo/connection.py", line 39, in <module>
  File "build/bdist.linux-x86_64/egg/pymongo/mongo_client.py", line 44, in <module>
  File "build/bdist.linux-x86_64/egg/bson/__init__.py", line 41, in <module>
  File "build/bdist.linux-x86_64/egg/bson/_cbson.py", line 7, in <module>
  File "build/bdist.linux-x86_64/egg/bson/_cbson.py", line 4, in __bootstrap__
  File "build/bdist.linux-x86_64/egg/pkg_resources.py", line 882, in resource_filename
    The exception instance that caused extraction to fail
  File "build/bdist.linux-x86_64/egg/pkg_resources.py", line 1351, in get_resource_filename
    
  File "build/bdist.linux-x86_64/egg/pkg_resources.py", line 1373, in _extract_resource
    # Convert a zipfile subpath into an egg-relative path part list
  File "build/bdist.linux-x86_64/egg/pkg_resources.py", line 962, in get_cache_path
    
  File "build/bdist.linux-x86_64/egg/pkg_resources.py", line 928, in extraction_error
    
pkg_resources.ExtractionError: Can't extract file(s) to egg cache


The following error occurred while trying to extract file(s) to the Python egg
cache:


  [Errno 13] Permission denied: '/var/lib/openshift/0f9c019e8890400bb48af288d0307389/.python-eggs'


The Python egg cache directory is currently set to:


  /var/lib/openshift/0f9c019e8890400bb48af288d0307389/.python-eggs


Perhaps your account does not have write access to this directory?  You can
change the cache directory by setting the PYTHON_EGG_CACHE environment
variable to point to an accessible directory.

分析原因是访问了某个不被允许的目录，由于使用的virtenv管理包，在openshift启动的时候已经设置了这项的值：

here = os.path.dirname(os.path.abspath(__file__))
os.environ['PYTHON_EGG_CACHE'] = os.path.join(here, '..', 'misc/virtenv/lib/python2.7/site-packages')
virtualenv = os.path.join(here, '..', 'misc/virtenv/bin/activate_this.py')
execfile(virtualenv, dict(__file__=virtualenv))

最后原因是需要在引用某些模块之前设置这个变量：

#!/usr/bin/env python
#-*- coding:utf-8 -*-
from setting import *
import os

here = os.path.dirname(os.path.abspath(__file__))
os.environ['PYTHON_EGG_CACHE'] = os.path.join(here, '..', 'misc/virtenv/lib/python2.7/site-packages')
virtualenv = os.path.join(here, '..', 'misc/virtenv/bin/activate_this.py')
execfile(virtualenv, dict(__file__=virtualenv))

from application import Application
import tornado.options
import tornado.httpserver
import tornado.ioloop

将后面的模块导入改下顺序就可以了。