导入错误：“没有名为“*does*exis的模块”

Question

当我开始金字塔服务时，我得到了这个堆栈跟踪：

% python $(which pserve) ../etc/development.ini
Traceback (most recent call last):
  File "/home/hughdbrown/.local/bin/pserve", line 9, in <module>
    load_entry_point('pyramid==1.5', 'console_scripts', 'pserve')()
  File "/home/hughdbrown/.virtualenvs/ponder/local/lib/python2.7/site-packages/pyramid-1.5-py2.7.egg/pyramid/scripts/pserve.py", line 51, in main
    return command.run()
  File "/home/hughdbrown/.virtualenvs/ponder/local/lib/python2.7/site-packages/pyramid-1.5-py2.7.egg/pyramid/scripts/pserve.py", line 316, in run
    global_conf=vars)
  File "/home/hughdbrown/.virtualenvs/ponder/local/lib/python2.7/site-packages/pyramid-1.5-py2.7.egg/pyramid/scripts/pserve.py", line 340, in loadapp
    return loadapp(app_spec, name=name, relative_to=relative_to, **kw)
  File "/home/hughdbrown/.virtualenvs/ponder/lib/python2.7/site-packages/PasteDeploy-1.5.2-py2.7.egg/paste/deploy/loadwsgi.py", line 247, in loadapp
    return loadobj(APP, uri, name=name, **kw)
  File "/home/hughdbrown/.virtualenvs/ponder/lib/python2.7/site-packages/PasteDeploy-1.5.2-py2.7.egg/paste/deploy/loadwsgi.py", line 271, in loadobj
    global_conf=global_conf)
  File "/home/hughdbrown/.virtualenvs/ponder/lib/python2.7/site-packages/PasteDeploy-1.5.2-py2.7.egg/paste/deploy/loadwsgi.py", line 296, in loadcontext
    global_conf=global_conf)
  File "/home/hughdbrown/.virtualenvs/ponder/lib/python2.7/site-packages/PasteDeploy-1.5.2-py2.7.egg/paste/deploy/loadwsgi.py", line 320, in _loadconfig
    return loader.get_context(object_type, name, global_conf)
  File "/home/hughdbrown/.virtualenvs/ponder/lib/python2.7/site-packages/PasteDeploy-1.5.2-py2.7.egg/paste/deploy/loadwsgi.py", line 454, in get_context
    section)
  File "/home/hughdbrown/.virtualenvs/ponder/lib/python2.7/site-packages/PasteDeploy-1.5.2-py2.7.egg/paste/deploy/loadwsgi.py", line 476, in _context_from_use
    object_type, name=use, global_conf=global_conf)
  File "/home/hughdbrown/.virtualenvs/ponder/lib/python2.7/site-packages/PasteDeploy-1.5.2-py2.7.egg/paste/deploy/loadwsgi.py", line 406, in get_context
    global_conf=global_conf)
  File "/home/hughdbrown/.virtualenvs/ponder/lib/python2.7/site-packages/PasteDeploy-1.5.2-py2.7.egg/paste/deploy/loadwsgi.py", line 296, in loadcontext
    global_conf=global_conf)
  File "/home/hughdbrown/.virtualenvs/ponder/lib/python2.7/site-packages/PasteDeploy-1.5.2-py2.7.egg/paste/deploy/loadwsgi.py", line 337, in _loadfunc
    return loader.get_context(object_type, name, global_conf)
  File "/home/hughdbrown/.virtualenvs/ponder/lib/python2.7/site-packages/PasteDeploy-1.5.2-py2.7.egg/paste/deploy/loadwsgi.py", line 681, in get_context
    obj = lookup_object(self.spec)
  File "/home/hughdbrown/.virtualenvs/ponder/lib/python2.7/site-packages/PasteDeploy-1.5.2-py2.7.egg/paste/deploy/util.py", line 68, in lookup_object
    module = __import__(parts)
  File "/home/hughdbrown/.virtualenvs/ponder/local/lib/python2.7/site-packages/ponder-0.0.40-py2.7.egg/ponder/server/__init__.py", line 10, in <module>
    from ponder.server.views import Endpoints, route
ImportError: No module named views

这在python REPL中工作得很好：

% python
Python 2.7.5+ (default, Feb 27 2014, 19:37:08) 
[GCC 4.8.1] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> from ponder.server.views import Endpoints, route
>>> 

从命令行导入：

% python -c "from ponder.server.views import Endpoints, route"

简略的tree输出显示了我正在使用的内容：

% tree
├── __init__.py
├── ponder
│   ├── __init__.py
│   ├── server
│   │   ├── __init__.py
│   │   └── views
│   │       ├── environment_templates.py
│   │       ├── groups.py
│   │       ├── __init__.py
│   │       ├── instances.py
│   │       ├── tasks.py
│   │       └── users.py

我的PYTHONPATH设置为此树的根：

% echo $PYTHONPATH
/home/hughdbrown/workspace/ept/ponder/lib

我在一个使用Python2.7的virtualenv中运行这个。我今天断断续续地做这个，但我不知道问题在哪里。首先，__init__.py对于前面的一些导入似乎没问题：

from .database import get_db
from .config import parser
from .views import Endpoints, route

（我把最后一行改为绝对导入。不走运。）

我尝试过的事情：

1. 重建virtualenv

2. 设置PYTHONPATH

3. 在代码中使用绝对路径

4. Looking for circular imports

对于如何调试此错误的进一步建议，我持开放态度。

---

所以我犯的错误是只看源代码树。问题实际上是在运行时环境中，在我的virtualenv中。当我看那里时，我发现没有安装所需的文件。问题的根源是setup.py。

Answer 1

我也遇到了同样的问题，我通过在python文件的顶部添加以下代码解决了这个问题：

import sys
import os

sys.path.append(os.path.dirname(os.path.dirname(os.path.dirname(__file__))))

os.path.dirname的重复次数取决于文件位于项目层次结构的位置。例如，在我的例子中，项目根目录向上三层。

Answer 2

我通常的技巧是在发生导入问题的实际上下文中简单地打印sys.path。在您的情况下，似乎打印的位置在/home/hughdbrown/.local/bin/pserve。然后在路径显示的位置检查目录文件。。

你首先要做的是：

import sys

在python 2中使用print表达式：

print sys.path

或者在python 3中使用print函数：

print(sys.path)

Answer 3

我把PYTHONPATH设置为'.'，这就解决了我的问题。

export PYTHONPATH='.'

对于一行代码，您可以很容易地：

PYTHONPATH='.' your_python_script

这些命令应该在终端中运行