memcache won't cache codejail executions

[nedbat]

Hi Ned,

Something I ran into while setting up the load test:

Django's memcache backend seems to accept only certain keys. When I try using safe_exec with spaces or newlines, it raises "MemcachedKeyCharacterError: Control characters not allowed" which causes LoncapaProblem to re-raise the exception in init()

For example, this key causes the exception:
"safe_exec -613400940 \ndef check_func(expect, answer_given):\n return {'ok': answer_given == expect, 'msg': 'Message text'}\n [(u'seed', -613400940)]"

The tests we have for capa mock out the cache, and the local dev settings don't use memcache, which is why they've been passing.

-- Will

[nedbat]

Sorry folks, this was an issue in edX LMS code that calls codejail, not in codejail itself.