ref_pull_grader.py

import time
import logging
import json
import urllib2
import xqueue_util as util
import settings
import urlparse
import project_urls

log = logging.getLogger(__name__)

QUEUE_NAME = settings.QUEUE_NAME

def each_cycle():
    print('[*]Logging in to xqueue')
    session = util.xqueue_login()
    success_length, queue_length = get_queue_length(QUEUE_NAME, session)
    if success_length and queue_length > 0:
        success_get, queue_item = get_from_queue(QUEUE_NAME, session)
        print(queue_item)
        success_parse, content = util.parse_xobject(queue_item, QUEUE_NAME)
        if success_get and success_parse:
            grade(content)
            content_header = json.loads(content['xqueue_header'])
            content_body = json.loads(content['xqueue_body'])
            xqueue_header, xqueue_body = util.create_xqueue_header_and_body(content_header['submission_id'], content_header['submission_key'], True, 1, '<p><emph>Good Job!</emph></p>', 'reference_dummy_grader')
            (success, msg) = util.post_results_to_xqueue(session, json.dumps(xqueue_header), json.dumps(xqueue_body),)
            if success:
                print("successfully posted result back to xqueue")



def grade(content):
    print(content)
    body = json.loads(content['xqueue_body'])
    student_info = json.loads(body.get('student_info', '{}'))
    email = student_info.get('student_email', '')
    print("submitted by email: " + email)
    files = json.loads(content['xqueue_files'])
    for (filename, fileurl) in files.iteritems():
        response = urllib2.urlopen(fileurl)
        with open(filename, 'w') as f:
            f.write(response.read())
        f.close()
        response.close()

def get_from_queue(queue_name,xqueue_session):
    """
        Get a single submission from xqueue
        """
    try:
        success, response = util._http_get(xqueue_session,
                                           urlparse.urljoin(settings.XQUEUE_INTERFACE['url'], project_urls.XqueueURLs.get_submission),
                                           {'queue_name': queue_name})
    except Exception as err:
        return False, "Error getting response: {0}".format(err)
    
    return success, response



def get_queue_length(queue_name,xqueue_session):
    """
        Returns the length of the queue
        """
    try:
        success, response = util._http_get(xqueue_session,
                                           urlparse.urljoin(settings.XQUEUE_INTERFACE['url'], project_urls.XqueueURLs.get_queuelen),
                                           {'queue_name': queue_name})
        
        if not success:
            return False,"Invalid return code in reply"
    
    except Exception as e:
        log.critical("Unable to get queue length: {0}".format(e))
        return False, "Unable to get queue length."
    
    return True, response

try:
    logging.basicConfig()
    while True:
        each_cycle()
        time.sleep(2)
except KeyboardInterrupt:
    print '^C received, shutting down'