Added new method to retrieve the course runs for a course based on UUID

This method will retrieve the Course Run information from the Discovery
service based on a Courses UUID.

[LEARNER-3160]

openedx/core/djangoapps/catalog/migrations/0005_catalogintegration_long_term_cache_ttl.py

+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('catalog', '0004_auto_20170616_0618'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='catalogintegration',
+            name='long_term_cache_ttl',
+            field=models.PositiveIntegerField(default=86400, help_text='Specified in seconds (defaults to 86400s, 24hr). In some cases the cache does needs to be refreshed less frequently. Enable long term caching of API responses by setting this to a value greater than 0.', verbose_name='Long Term Cache Time To Live'),
+        ),
+    ]

openedx/core/djangoapps/catalog/models.py

@@ -29,6 +29,15 @@ class CatalogIntegration(ConfigurationModel):
         )
     )
 
+    long_term_cache_ttl = models.PositiveIntegerField(
+        verbose_name=_('Long Term Cache Time To Live'),
+        default=86400,
+        help_text=_(
+            'Specified in seconds (defaults to 86400s, 24hr). In some cases the cache does needs to be refreshed '
+            'less frequently. Enable long term caching of API responses by setting this to a value greater than 0.'
+        )
+    )
+
     service_username = models.CharField(
         max_length=100,
         default='lms_catalog_service_user',

openedx/core/djangoapps/catalog/tests/test_utils.py

@@ -11,10 +11,11 @@ from student.tests.factories import UserFactory
 
 from openedx.core.djangoapps.catalog.cache import PROGRAM_CACHE_KEY_TPL, SITE_PROGRAM_UUIDS_CACHE_KEY_TPL
 from openedx.core.djangoapps.catalog.models import CatalogIntegration
-from openedx.core.djangoapps.catalog.tests.factories import CourseRunFactory, ProgramFactory, ProgramTypeFactory
+from openedx.core.djangoapps.catalog.tests.factories import CourseFactory, CourseRunFactory, ProgramFactory, ProgramTypeFactory
 from openedx.core.djangoapps.catalog.tests.mixins import CatalogIntegrationMixin
 from openedx.core.djangoapps.catalog.utils import (
     get_course_runs,
+    get_course_runs_for_course,
     get_course_run_details,
     get_currency_data,
     get_program_types,
@@ -330,6 +331,18 @@ class TestGetCourseRuns(CatalogIntegrationMixin, TestCase):
         self.assert_contract(mock_get_edx_api_data.call_args)
         self.assertEqual(data, catalog_course_runs)
 
+    def test_get_course_runs_by_course(self, mock_get_edx_api_data):
+        """
+        Test retrievals of run from a Course.
+        """
+        catalog_course_runs = CourseRunFactory.create_batch(10)
+        catalog_course = CourseFactory(course_runs=catalog_course_runs)
+        mock_get_edx_api_data.return_value = catalog_course
+
+        data = get_course_runs_for_course(course_uuid=str(catalog_course['uuid']))
+        self.assertTrue(mock_get_edx_api_data.called)
+        self.assertEqual(data, catalog_course_runs)
+
 
 @skip_unless_lms
 @mock.patch(UTILS_MODULE + '.get_edx_api_data')

openedx/core/djangoapps/catalog/utils.py

@@ -210,6 +210,38 @@ def get_course_runs():
     return course_runs
 
 
+def get_course_runs_for_course(course_uuid):
+    catalog_integration = CatalogIntegration.current()
+
+    if catalog_integration.is_enabled():
+        try:
+            user = catalog_integration.get_service_user()
+        except ObjectDoesNotExist:
+            logger.error(
+                'Catalog service user with username [%s] does not exist. Course runs will not be retrieved.',
+                catalog_integration.service_username,
+            )
+            return []
+
+        api = create_catalog_api_client(user)
+        cache_key = '{base}.course.{uuid}.course_runs'.format(
+            base=catalog_integration.CACHE_KEY,
+            uuid=course_uuid
+        )
+        data = get_edx_api_data(
+            catalog_integration,
+            'courses',
+            resource_id=course_uuid,
+            api=api,
+            cache_key=cache_key if catalog_integration.is_cache_enabled else None,
+            long_term_cache=True
+        )
+
+        return data.get('course_runs', [])
+    else:
+        return []
+
+
 def get_course_run_details(course_run_key, fields):
     """
     Retrieve information about the course run with the given id

openedx/core/lib/edx_api_utils.py

@@ -24,7 +24,7 @@ def get_fields(fields, response):
 
 
 def get_edx_api_data(api_config, resource, api, resource_id=None, querystring=None, cache_key=None, many=True,
-                     traverse_pagination=True, fields=None):
+                     traverse_pagination=True, fields=None, long_term_cache=False):
     """GET data from an edX REST API.
 
     DRY utility for handling caching and pagination.
@@ -42,6 +42,7 @@ def get_edx_api_data(api_config, resource, api, resource_id=None, querystring=No
         many (bool): Whether the resource requested is a collection of objects, or a single object.
             If false, an empty dict will be returned in cases of failure rather than the default empty list.
         traverse_pagination (bool): Whether to traverse pagination or return paginated response..
+        long_term_cache (bool): Whether to use the long term cache ttl or the standard cache ttl
 
     Returns:
         Data returned by the API. When hitting a list endpoint, extracts "results" (list of dict)
@@ -81,7 +82,10 @@ def get_edx_api_data(api_config, resource, api, resource_id=None, querystring=No
 
     if cache_key:
         zdata = zpickle(results)
-        cache.set(cache_key, zdata, api_config.cache_ttl)
+        cache_ttl = api_config.cache_ttl
+        if long_term_cache:
+            cache_ttl = api_config.long_term_cache_ttl
+        cache.set(cache_key, zdata, cache_ttl)
 
     return results