Unable to connect to external services from App Engine development server with urlfetch or urllib2

Question

The following code works in the Python interactive shell:

import urllib2
result = urllib2.urlopen("http://www.google.com/")

and gives a 200 result.

If I run the same code in an AppEngine app running locally with the development server, it fails with the following error:

URLError: <urlopen error An error occured while connecting to the server:
Unable to fetch  URL: http://www.google.com/ 
Error: [Errno 11004] getaddrinfo failed>`

I've tried using the urlfetch library directly:

from google.appengine.api import urlfetch
result = urlfetch.fetch("http://www.google.com")

and this also fails (which makes sense, as I believe urllib2 within AppEngine calls URLFetch internally?)

I can clearly access the URL from my local machine - so what's happening?

UPDATE: the relevant stack trace:

File "c:\dev\repos\stackoverflow\main.py", line 40, in get_latest_comments
result = urlfetch.fetch("http://www.google.com")

File "C:\Program Files (x86)\Google\google_appengine\google\appengine\api\urlfetch.py", line 266, in fetch
return rpc.get_result()

File "C:\Program Files (x86)\Google\google_appengine\google\appengine\api\apiproxy_stub_map.py", line 604, in get_result
return self.__get_result_hook(self)

File "C:\Program Files (x86)\Google\google_appengine\google\appengine\api\urlfetch.py", line 397, in _get_fetch_result
raise DownloadError("Unable to fetch URL: " + url + error_detail)

DownloadError: Unable to fetch URL: http://www.google.com Error: [Errno 11004] getaddrinfo failed

Answer 1

DO you have a proxy configured with environment variables? The dev_appserver clears all env vars.