Develop Reference

App Engine + Django: ImportError: No module named django.core.wsgi

I'm deploying a simple Django app to Google App Engine. How can I fix the following?
Traceback (most recent call last):
File "/base/data/home/runtimes/python27/python27_lib/versions/1/google/appengine/runtime/wsgi.py", line 240, in Handle
handler = _config_handle.add_wsgi_middleware(self._LoadHandler())
File "/base/data/home/runtimes/python27/python27_lib/versions/1/google/appengine/runtime/wsgi.py", line 299, in _LoadHandler
handler, path, err = LoadObject(self._handler)
File "/base/data/home/runtimes/python27/python27_lib/versions/1/google/appengine/runtime/wsgi.py", line 96, in LoadObject
__import__(cumulative_path)
File "/base/data/home/apps/.../20171104t152156.405293023907909181/mysite/wsgi.py", line 12, in <module>
from django.core.wsgi import get_wsgi_application
ImportError: No module named django.core.wsgi

You're getting the ImportError because Django is not in your sys.path.
If you want to use one of the built-in Django versions from the App Engine SDK, simply add this to your app.yaml (it's not necessary to install the Django library separately):
libraries:
- name: django
version: "1.4"
Update:
If you want to include your own Django version with your app (eg. to use a recent version > 1.5), don't add the above line and instead install the library directly into your project's root directory:
$ cd myapp/
$ pip install django -t .

PyCharm debugger fails with AttributeError

I cannot debug a Flask application in PyCharm. The application should run on port 5000: app.run(host="10.1.0.17", port=5000, debug=True). The console output is:
C:\Python\python.exe "C:\Program Files (x86)\JetBrains\PyCharm 145.597.11\helpers\pydev\pydevd.py" --multiproc --qt-support --client 127.0.0.1 --port 10498 --file "D:/TGM/SMS/SMS/Back .v2/wsgi.py"
pydev debugger: process 4108 is connecting
Could not connect to 127.0.0.1: 10499
Traceback (most recent call last):
File "C:\Program Files (x86)\JetBrains\PyCharm 145.597.11\helpers\pydev\pydevd.py", line 1523, in <module>
debugger.connect(host, port)
File "C:\Program Files (x86)\JetBrains\PyCharm 145.597.11\helpers\pydev\pydevd.py", line 317, in connect
self.initialize_network(s)
File "C:\Program Files (x86)\JetBrains\PyCharm 145.597.11\helpers\pydev\pydevd.py", line 304, in initialize_network
self.writer = WriterThread(sock)
File "C:\Program Files (x86)\JetBrains\PyCharm 145.597.11\helpers\pydev\_pydevd_bundle\pydevd_comm.py", line 392, in __init__
self.cmdQueue = _queue.Queue()
AttributeError: module 'queue' has no attribute 'Queue'
Process finished with exit code -1
I am using Python 3.5.1. What could be wrong?

The pydev debugger uses the same Pythonpath as the project you are trying to debug.
If you have any modules or packages with names of standard modules or packages, the pydev debugger might load your module instead of the standard module.
You probably have a module called queue in your projects directories, which causes this issue, since the python standard library also includes a module with that name.
try renaming your module, or changing your PYTHONPATH
PyCharm has the option to not include the projects root/source roots in the PYTHONPATH in Run > Edit Configurations. This could fix your problem, although you might need to fix some import statements in your project, if any of your import statements relied on this setting.

Module not found when debugging

I am running a Python client using PyCharm. If I just run it, PyCharm simply calls:
C:\Python27\python.exe E:/faf/client/src
and everything is fine.
These are my settings:
If I want to debug it, PyCharm calls:
C:\Python27\python.exe "C:\Program Files (x86)\JetBrains\PyCharm Community Edition 5.0.2\helpers\pydev\pydevd.py" --multiproc --qt-support --client 127.0.0.1 --port 52948 --file E:/faf/client/src
and the result is that the modules which are in fact there cannot be included
pydev debugger: process 5092 is connecting
Connected to pydev debugger (build 143.1184)
Traceback (most recent call last):
File "C:\Program Files (x86)\JetBrains\PyCharm Community Edition 5.0.2\helpers\pydev\pydevd.py", line 2407, in <module>
globals = debugger.run(setup['file'], None, None, is_module)
File "C:\Program Files (x86)\JetBrains\PyCharm Community Edition 5.0.2\helpers\pydev\pydevd.py", line 1798, in run
launch(file, globals, locals) # execute the script
File "E:/faf/client/src\__main__.py", line 29, in <module>
import config
ImportError: No module named config
What do I have to do to be able to debug this thing?

I had to click on the src directory and add it as source folder (Mark Directory As -> Source Root). No apparent thing changed like e.g. the way the python command got called.
So if you have a similar looking problem try to do the same.

I resolved this issue for myself by adding an init.py in the folder of the module I was trying to import.

App Engine Python won't start

I don't know what changed, but suddenly none of my Python App Engine projects will start on my PC. They start on my MacBook just fine, so there's something about the installation on my PC that's messed up. I've tried going back to 1.8.8, but that doesn't work. I've also tried using a fresh Python installation, but that didn't work. I've even tried using port 8080 (I usually use port 80, as I run the app launcher as admin).
This is what shows up in the error log when I click start on one of my projects:
2014-02-05 10:42:24 Running command: "['c:\\users\\jonathan\\appdata\\local\\enthought\\canopy\\user\\scripts\\pythonw.exe', 'C:\\Program Files (x86)\\Google\\google_appengine\\dev_appserver.py', '--skip_sdk_update_check=yes', '--port=80', '--admin_port=8000', 'C:\\Users\\jonathan\\My Repositories\\my-project']"
Traceback (most recent call last):
File "C:\Program Files (x86)\Google\google_appengine\dev_appserver.py", line 197, in <module>
_run_file(__file__, globals())
File "C:\Program Files (x86)\Google\google_appengine\dev_appserver.py", line 193, in _run_file
execfile(script_path, globals_)
File "C:\Program Files (x86)\Google\google_appengine\google\appengine\tools\devappserver2\devappserver2.py", line 32, in <module>
from google.appengine.tools.devappserver2.admin import admin_server
File "C:\Program Files (x86)\Google\google_appengine\google\appengine\tools\devappserver2\admin\admin_server.py", line 29, in <module>
from google.appengine.tools.devappserver2.admin import console
File "C:\Program Files (x86)\Google\google_appengine\google\appengine\tools\devappserver2\admin\console.py", line 22, in <module>
from google.appengine.tools.devappserver2 import module
File "C:\Program Files (x86)\Google\google_appengine\google\appengine\tools\devappserver2\module.py", line 69, in <module>
from google.appengine.tools.devappserver2 import wsgi_server
File "C:\Program Files (x86)\Google\google_appengine\google\appengine\tools\devappserver2\wsgi_server.py", line 31, in <module>
from cherrypy import wsgiserver
File "C:\Program Files (x86)\Google\google_appengine\lib\cherrypy\cherrypy\__init__.py", line 278, in <module>
_pydoc._builtin_resolve = _pydoc.resolve
AttributeError: 'module' object has no attribute 'resolve'
2014-02-05 10:42:32 (Process exited with code 1)
Also, I'm using Windows 7 x64. My original installation of Python is from Enthought x64, but I did try using the basic x64 Python as well. As mentioned, I downgraded from 1.8.9 to 1.8.8, to no avail.

From a quick Google search, other users are suggesting it's a bug in pyvenv. Since not very many people are still using CherryPy, and it seems to only manifest itself in whatever CherryPy is doing there, that's probably it.
Bug the gist is that somewhere, only on Windows, you have a pydoc.py file which is being imported instead of the standard library's pydoc file.
So, find the offending pydoc.py file in your import path, and rename it. You can most likely find it by doing something like this:
import pydoc
print pydoc.__file__

Trouble running an application made with PyInstaller, importing GTK--searching nonexistent directories

I am trying to create an executable of my Python application that uses PyGTK to make a GUI. I have a well-established, automated build process using Pyinstaller that has worked for me for a previous application. Suffice it to say that it calls the usual Makespec.py and Build.py with 32-bit Python 2.7, with Pyinstaller configured for 32 bits. The resulting 32-bit application works fine on my machine and another machine running Windows 7 64-bit, but fails on 32-bit Windows XP with this error:
C:\OutNav_0_64\OutNav_0.64>outnav
Traceback (most recent call last):
File "<string>", line 23, in <module>
File "C:\Pyinstaller-1.5\iu.py", line 436, in importHook
File "C:\Pyinstaller-1.5\iu.py", line 521, in doimport
File "C:\Users\462974\Documents\Local Sandbox\tools\utilities\Oni\build\pyi.win32\OutNav\outPYZ1.pyz/gtk", line 40, in
<module>
File "C:\Pyinstaller-1.5\iu.py", line 477, in importHook
File "C:\Pyinstaller-1.5\iu.py", line 495, in doimport
File "C:\Pyinstaller-1.5\iu.py", line 297, in getmod
File "C:\Pyinstaller-1.5\archive.py", line 468, in getmod
File "C:\Pyinstaller-1.5\iu.py", line 109, in getmod
ImportError: DLL load failed: The specified procedure could not be found.
The strange part is, there is no C:\Pyinstaller-1.5 directory on my machine or the one experiencing the error. I have no idea why it is attempting to run code from this nonexistent directory, or what the missing DLL is. Can anyone help me fold PyGTK into my application?
NOTE: The first line of the trace, line 23 in my program, is
import gtk
UPDATE: My manager successfully ran it on 64-bit Windows XP.
UPDATE 2: He was mistaken, it was 64-bit Windows 7. It has the same problem on his Windows XP installation.
Also, on the original machine it failed on, from the directory of the executable, I did this:
>>> import imp
>>> fp = open('gtk._gtk.pyd', 'rb')
>>> mod = imp.load_module('gtk._gtk', fp, 'gtk._gtk.pyd', ('.pyd', 'rb', 3))
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
ImportError: DLL load failed: A dynamic link library (DLL) initialization routine failed.

As far as I can tell, the .pyd file (which is in the format of a .DLL file) generated by pyinstaller on Windows 7 is incompatible with Windows XP. My solution was to simply recreate my build process on a Windows XP machine, which solved it to my satisfaction.