Add service to query controller for eta of submission and to check if name is unique

lms/djangoapps/open_ended_grading/controller_query_service.py

+import json
+import logging
+import requests
+from requests.exceptions import RequestException, ConnectionError, HTTPError
+import sys
+from grading_service import GradingService
+from grading_service import GradingServiceError
+
+from django.conf import settings
+from django.http import HttpResponse, Http404
+
+log = logging.getLogger(__name__)
+
+class ControllerQueryService(GradingService):
+    """
+    Interface to staff grading backend.
+    """
+    def __init__(self, config):
+        super(ControllerQuery, self).__init__(config)
+        self.check_eta_url = self.url + '/get_submission_eta/'
+        self.is_unique_url = self.url + '/is_name_unique/'
+
+    def check_if_name_is_unique(self, location, problem_id, course_id):
+        params = {
+            'course_id': course_id,
+            'location' : location,
+            'problem_id' : problem_id
+        }
+        response = self.get(self.is_unique_url, params)
+        return response
+
+    def check_for_eta(self, location):
+        params = {
+            'location' : location,
+        }
+        response = self.get(self.check_eta_url, params)
+        return response