Occasional urlopen error upon login after authenticating to CAS

[toddplank@…]

Occasionally during login I receive an error after authenticating to CAS. When I first connect to Trac as a guest, the site works normally. Then after clicking login, I authenticate to CAS, and when I'm returned to Trac, I receive the error below. When one user receives the error, everyone trying to login at that time also receives the error. After a short period (15-20 min) the error stops appearing and I can login normally.

After authenticating to CAS, I arrive on the following URI:

​http://code.hpm.saint-gobain.com/trac/login?ticket=ST-190755-WOhru9u9VI4pb1LIijvI-05EA9FB4-1AA5-F4B3-83F5-33D66F6ACE15

The error I receive is:

Traceback (most recent call last):
  File "D:\applications\python25\lib\site-packages\trac-0.11.2.1-py2.5.egg\trac\web\api.py", line 367, in send_error
    'text/html')
  File "D:\applications\python25\lib\site-packages\trac-0.11.2.1-py2.5.egg\trac\web\chrome.py", line 688, in render_template
    data = self.populate_data(req, data)
  File "D:\applications\python25\lib\site-packages\trac-0.11.2.1-py2.5.egg\trac\web\chrome.py", line 596, in populate_data
    d['chrome'].update(req.chrome)
  File "D:\applications\python25\lib\site-packages\trac-0.11.2.1-py2.5.egg\trac\web\api.py", line 194, in __getattr__
    value = self.callbacks[name](self)
  File "D:\applications\python25\lib\site-packages\trac-0.11.2.1-py2.5.egg\trac\web\chrome.py", line 464, in prepare_request
    for category, name, text in contributor.get_navigation_items(req):
  File "D:\applications\python25\lib\site-packages\trac-0.11.2.1-py2.5.egg\trac\ticket\web_ui.py", line 162, in get_navigation_items
    if 'TICKET_CREATE' in req.perm:
  File "D:\applications\python25\lib\site-packages\trac-0.11.2.1-py2.5.egg\trac\web\api.py", line 194, in __getattr__
    value = self.callbacks[name](self)
  File "D:\applications\python25\lib\site-packages\trac-0.11.2.1-py2.5.egg\trac\web\main.py", line 261, in _get_perm
    return PermissionCache(self.env, self.authenticate(req))
  File "D:\applications\python25\lib\site-packages\trac-0.11.2.1-py2.5.egg\trac\web\main.py", line 132, in authenticate
    authname = authenticator.authenticate(req)
  File "d:\clients\trac\plugins\traccas-1.0-py2.5.egg\traccas\traccas.py", line 34, in authenticate
    valid, user = self.cas.validate_ticket(req.abs_href.login(), ticket)
  File "d:\clients\trac\plugins\traccas-1.0-py2.5.egg\traccas\pycas.py", line 41, in validate_ticket
    f = urllib2.urlopen(self.validate_url(service, ticket))
  File "D:\applications\python25\lib\urllib2.py", line 124, in urlopen
    return _opener.open(url, data)
  File "D:\applications\python25\lib\urllib2.py", line 381, in open
    response = self._open(req, data)
  File "D:\applications\python25\lib\urllib2.py", line 399, in _open
    '_open', req)
  File "D:\applications\python25\lib\urllib2.py", line 360, in _call_chain
    result = func(*args)
  File "D:\applications\python25\lib\urllib2.py", line 1115, in https_open
    return self.do_open(httplib.HTTPSConnection, req)
  File "D:\applications\python25\lib\urllib2.py", line 1082, in do_open
    raise URLError(err)
URLError: <urlopen error (11001, 'getaddrinfo failed')>

[Noah Kantrowitz]

Check the DNS settings on the Trac server, sounds like it periodically can't resolve the hostname of the CAS server to verify the ticket.

[anonymous]

Bingo. That was it. Thank you for that idea.