Retry on failures (database locking).

TNL-5091

lms/djangoapps/verified_track_content/tasks.py

@@ -15,8 +15,8 @@ from openedx.core.djangoapps.course_groups.cohorts import (
 LOGGER = get_task_logger(__name__)
 
 
-@task()
-def sync_cohort_with_mode(course_id, user_id, verified_cohort_name, default_cohort_name):
+@task(bind=True, default_retry_delay=60, max_retries=4)
+def sync_cohort_with_mode(self, course_id, user_id, verified_cohort_name, default_cohort_name):
     """
     If the learner's mode does not match their assigned cohort, move the learner into the correct cohort.
     It is assumed that this task is only initiated for courses that are using the
@@ -26,28 +26,35 @@ def sync_cohort_with_mode(course_id, user_id, verified_cohort_name, default_coho
     """
     course_key = CourseKey.from_string(course_id)
     user = User.objects.get(id=user_id)
-    enrollment = CourseEnrollment.get_enrollment(user, course_key)
-    # Note that this will enroll the user in the default cohort on initial enrollment.
-    # That's good because it will force creation of the default cohort if necessary.
-    current_cohort = get_cohort(user, course_key)
-    verified_cohort = get_cohort_by_name(course_key, verified_cohort_name)
+    try:
+        enrollment = CourseEnrollment.get_enrollment(user, course_key)
+        # Note that this will enroll the user in the default cohort on initial enrollment.
+        # That's good because it will force creation of the default cohort if necessary.
+        current_cohort = get_cohort(user, course_key)
+        verified_cohort = get_cohort_by_name(course_key, verified_cohort_name)
 
-    if enrollment.mode == CourseMode.VERIFIED and (current_cohort.id != verified_cohort.id):
-        LOGGER.info(
-            "MOVING_TO_VERIFIED: Moving user '%s' to the verified cohort '%s' for course '%s'",
-            user.username, verified_cohort.name, course_id
-        )
-        add_user_to_cohort(verified_cohort, user.username)
-    elif enrollment.mode != CourseMode.VERIFIED and current_cohort.id == verified_cohort.id:
-        default_cohort = get_cohort_by_name(course_key, default_cohort_name)
-        LOGGER.info(
-            "MOVING_TO_DEFAULT: Moving user '%s' to the default cohort '%s' for course '%s'",
-            user.username, default_cohort.name, course_id
-        )
-        add_user_to_cohort(default_cohort, user.username)
-    else:
-        LOGGER.info(
-            "NO_ACTION_NECESSARY: No action necessary for user '%s' in course '%s' and enrollment mode '%s'. "
-            "The user is already in cohort '%s'.",
-            user.username, course_id, enrollment.mode, current_cohort.name
+        if enrollment.mode == CourseMode.VERIFIED and (current_cohort.id != verified_cohort.id):
+            LOGGER.info(
+                "MOVING_TO_VERIFIED: Moving user '%s' to the verified cohort '%s' for course '%s'",
+                user.username, verified_cohort.name, course_id
+            )
+            add_user_to_cohort(verified_cohort, user.username)
+        elif enrollment.mode != CourseMode.VERIFIED and current_cohort.id == verified_cohort.id:
+            default_cohort = get_cohort_by_name(course_key, default_cohort_name)
+            LOGGER.info(
+                "MOVING_TO_DEFAULT: Moving user '%s' to the default cohort '%s' for course '%s'",
+                user.username, default_cohort.name, course_id
+            )
+            add_user_to_cohort(default_cohort, user.username)
+        else:
+            LOGGER.info(
+                "NO_ACTION_NECESSARY: No action necessary for user '%s' in course '%s' and enrollment mode '%s'. "
+                "The user is already in cohort '%s'.",
+                user.username, course_id, enrollment.mode, current_cohort.name
+            )
+    except Exception as exc:
+        LOGGER.warning(
+            "SYNC_COHORT_WITH_MODE_RETRY: Exception encountered for course '%s' and user '%s': %s",
+            course_id, user.username, unicode(exc)
         )
+        raise self.retry(exc=exc)