bc30addfb9
fixing unit tests fixing merge error fixing xqueue submission issue with unicode url (trial 0.1) fixing fotmats as commented upon removing yaml file language selection Unicode changes to support QRF removed unnecessary pass in modulestore/init.py fixing merge error fixing fotmats as commented upon removing yaml file language selection fixing pep8 violations - fixing pylint violations pylint violation fixing line spaces and formats ignore pylint E1101 remove empty line fixing pylint violations pep8 violations bulk mail unicode/decode fix migration error fix pep8 just to push again more unicode/decode Final changes to comments and error messages.
131 lines
3.8 KiB
Python
131 lines
3.8 KiB
Python
#
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# LMS Interface to external queueing system (xqueue)
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#
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import hashlib
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import json
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import logging
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import requests
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log = logging.getLogger(__name__)
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dateformat = '%Y%m%d%H%M%S'
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def make_hashkey(seed):
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"""
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Generate a string key by hashing
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"""
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h = hashlib.md5()
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h.update(str(seed))
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return h.hexdigest()
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def make_xheader(lms_callback_url, lms_key, queue_name):
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"""
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Generate header for delivery and reply of queue request.
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Xqueue header is a JSON-serialized dict:
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{ 'lms_callback_url': url to which xqueue will return the request (string),
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'lms_key': secret key used by LMS to protect its state (string),
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'queue_name': designate a specific queue within xqueue server, e.g. 'MITx-6.00x' (string)
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}
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"""
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return json.dumps({
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'lms_callback_url': lms_callback_url,
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'lms_key': lms_key,
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'queue_name': queue_name
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})
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def parse_xreply(xreply):
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"""
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Parse the reply from xqueue. Messages are JSON-serialized dict:
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{ 'return_code': 0 (success), 1 (fail)
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'content': Message from xqueue (string)
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}
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"""
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try:
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xreply = json.loads(xreply)
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except ValueError, err:
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log.error(err)
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return (1, 'unexpected reply from server')
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return_code = xreply['return_code']
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content = xreply['content']
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return (return_code, content)
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class XQueueInterface(object):
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"""
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Interface to the external grading system
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"""
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def __init__(self, url, django_auth, requests_auth=None):
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self.url = unicode(url)
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self.auth = django_auth
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self.session = requests.Session()
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self.session.auth = requests_auth
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def send_to_queue(self, header, body, files_to_upload=None):
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"""
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Submit a request to xqueue.
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header: JSON-serialized dict in the format described in 'xqueue_interface.make_xheader'
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body: Serialized data for the receipient behind the queueing service. The operation of
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xqueue is agnostic to the contents of 'body'
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files_to_upload: List of file objects to be uploaded to xqueue along with queue request
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Returns (error_code, msg) where error_code != 0 indicates an error
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"""
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# Attempt to send to queue
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(error, msg) = self._send_to_queue(header, body, files_to_upload)
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# Log in, then try again
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if error and (msg == 'login_required'):
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(error, content) = self._login()
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if error != 0:
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# when the login fails
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log.debug("Failed to login to queue: %s", content)
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return (error, content)
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if files_to_upload is not None:
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# Need to rewind file pointers
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for f in files_to_upload:
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f.seek(0)
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(error, msg) = self._send_to_queue(header, body, files_to_upload)
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return (error, msg)
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def _login(self):
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payload = {
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'username': self.auth['username'],
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'password': self.auth['password']
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}
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return self._http_post(self.url + '/xqueue/login/', payload)
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def _send_to_queue(self, header, body, files_to_upload):
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payload = {
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'xqueue_header': header,
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'xqueue_body': body
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}
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files = {}
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if files_to_upload is not None:
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for f in files_to_upload:
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files.update({f.name: f})
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return self._http_post(self.url + '/xqueue/submit/', payload, files=files)
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def _http_post(self, url, data, files=None):
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try:
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r = self.session.post(url, data=data, files=files)
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except requests.exceptions.ConnectionError, err:
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log.error(err)
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return (1, 'cannot connect to server')
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if r.status_code not in [200]:
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return (1, 'unexpected HTTP status code [%d]' % r.status_code)
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return parse_xreply(r.text)
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