我遇到了模块导入问题。
在 ubuntu 10.10 上使用 python 2.6
我在http://www.jejik.com/articles/2007/02/a_simple_unix_linux_daemon_in_python/有一个子类化守护进程的类。我创建了一个 python 包，其中包含一个模块，该模块包含从 django 项目中导入一些模型的代码。该代码在从类中使用时有效，而不是对守护程序进行子类化。结构看起来像：
my_module
__init__.py
- bin
- cfg
- core
__init__.py
collection.py
daemon.py
ItemRepository 代码：
class ItemRepository(object):
"""This class provides an implementation to retrieve configuration data
from the monocle database
"""
def __init__(self, project_path):
if project_path is not None:
sys.path.append(project_path)
try:
from django.core.management import setup_environ
from someproj import settings
setup_environ(settings)
from someproj.someapp.models import ItemConfiguration
except ImportError:
print "Could not import models from web app. Please ensure the\
PYTHONPATH is configured properly"
def get_scheduled_collectors(self):
"""This method finds and returns all ItemConfiguration objects
that are scheduled to run
"""
logging.info('At the error path: %s' % sys.path)
# query ItemConfigs from database
items = ItemConfiguration.objects.filter(disabled=False) #ERROR OCCURS AT THIS LINE
return [item for item in items if item.scheduled]
守护程序代码（在 /usr/local/bin/testdaemon.py 中）：
import sys
from my_module.core.daemon import Daemon
from my_module.core.collection import ItemRepository
import logging
import time
class TestDaemon(Daemon):
default_conf = '/etc/echodaemon.conf'
section = 'echo'
def run(self):
while True:
logging.info('The echo daemon says hello')
ir = ItemRepository(project_path=self.project_path)
items = ir.get_scheduled_collectors() #TRIGGERS ERROR
logging.info('there are %d scheduled items' % len(items))
time.sleep(1)
if __name__ == '__main__':
TestDaemon().main()
我得到的错误是“NameError：未定义全局名称'my_module'”它通过了导入，但在尝试调用对象上的方法时失败。我假设它与 sys.path / PYTHONPATH 有关，但我知道我的 django 项目在路径上，因为我已经打印出来了。到目前为止，python 文档或 Learning Python 中没有任何帮助。有没有人有任何见解或知道对模块导入的良好参考？
更新：
现在我试图简化问题以使其更容易理解。现在我有一个看起来像这样的目录结构：
/home
/username
/django
/someproj
/web
models.py
/my_module
daemon.py
我已将 /etc/bash.bashrc 中的 $PYTHONPATH 变量设置为“/home/username/django”。
在 testdaemon.py 文件中，导入看起来像：
import logging
from django.core.management import setup_environ
from someproj import settings
setup_environ(settings)
from someproj.web.models import ItemConfiguration
但现在我得到一个 ImportError：没有名为“someproj”的模块。所以我附加了路径。
import sys
sys.path.append('/home/username/django')
import logging
from django.core.management import setup_environ
from someproj import settings
setup_environ(settings)
from someproj.web.models import ItemConfiguration
现在 ImportError 说：没有名为“web”的模块。这是回溯：
Traceback (most recent call last):
File "testdaemon.py", line 77, in <module>
TestDaemon('/tmp/testdaemon.pid').run()
File "testdaemon.py", line 47, in run
scheduled_items = [item for item in ItemConfiguration.objects.filter(disabled=False) if collector.scheduled]
File "/usr/local/lib/python2.6/dist-packages/django/db/models/manager.py", line 141, in filter
return self.get_query_set().filter(*args, **kwargs)
File "/usr/local/lib/python2.6/dist-packages/django/db/models/query.py", line 550, in filter
return self._filter_or_exclude(False, *args, **kwargs)
File "/usr/local/lib/python2.6/dist-packages/django/db/models/query.py", line 568, in _filter_or_exclude
clone.query.add_q(Q(*args, **kwargs))
File "/usr/local/lib/python2.6/dist-packages/django/db/models/sql/query.py", line 1128, in add_q
can_reuse=used_aliases)
File "/usr/local/lib/python2.6/dist-packages/django/db/models/sql/query.py", line 1026, in add_filter
negate=negate, process_extras=process_extras)
File "/usr/local/lib/python2.6/dist-packages/django/db/models/sql/query.py", line 1179, in setup_joins
field, model, direct, m2m = opts.get_field_by_name(name)
File "/usr/local/lib/python2.6/dist-packages/django/db/models/options.py", line 291, in get_field_by_name
cache = self.init_name_map()
File "/usr/local/lib/python2.6/dist-packages/django/db/models/options.py", line 321, in init_name_map
for f, model in self.get_all_related_m2m_objects_with_model():
File "/usr/local/lib/python2.6/dist-packages/django/db/models/options.py", line 396, in get_all_related_m2m_objects_with_model
cache = self._fill_related_many_to_many_cache()
File "/usr/local/lib/python2.6/dist-packages/django/db/models/options.py", line 410, in _fill_related_many_to_many_cache
for klass in get_models():
File "/usr/local/lib/python2.6/dist-packages/django/db/models/loading.py", line 167, in get_models
self._populate()
File "/usr/local/lib/python2.6/dist-packages/django/db/models/loading.py", line 61, in _populate
self.load_app(app_name, True)
File "/usr/local/lib/python2.6/dist-packages/django/db/models/loading.py", line 76, in load_app
app_module = import_module(app_name)
File "/usr/local/lib/python2.6/dist-packages/django/utils/importlib.py", line 35, in import_module
__import__(name)
ImportError: No module named web
因此，从我尝试添加的早期评论开始：
import sys
sys.path.append('/home/username/django')
import logging
from django.core.management import setup_environ
from someproj import settings
setup_environ(settings)
from someproj import web
from someproj.web import models
from someproj.web.models import ItemConfiguration
但这没有帮助。所以我创建了一个非常简单的文件：
#!/usr/bin/python
import logging
import time
import sys
sys.path.append('/home/username/django')
from django.core.management import setup_environ
from someproj import settings
setup_environ(settings)
from someproj.web.models import ItemConfiguration
if __name__ == '__main__':
print sys.path
items = ItemConfiguration.objects.all()
for item in items:
print item
这行得通！这真的只会让我更加困惑。所以现在我在想也许它与守护进程有关。它使用 os.fork() 并且我不确定路径是否仍然设置。这就是我在 /etc/bash.bashrc 文件中设置 $PYTHONPATH 变量的原因。
还有更多见解吗？我真的需要守护进程，我没有太多选择，因为我需要一个长时间运行的进程。