def get_group_info_for_cohort(cohort, use_cached=False):
"""
Get the ids of the group and partition to which this cohort has been linked
as a tuple of (int, int).
If the cohort has not been linked to any group/partition, both values in the
tuple will be None.
The partition group info is cached for the duration of a request. Pass
use_cached=True to use the cached value instead of fetching from the
database.
"""
cache = RequestCache("cohorts.get_group_info_for_cohort").data
cache_key = str(cohort.id)
if use_cached and cache_key in cache:
return cache[cache_key]
cache.pop(cache_key, None)
try:
partition_group = CourseUserGroupPartitionGroup.objects.get(course_user_group=cohort)
return cache.setdefault(cache_key, (partition_group.group_id, partition_group.partition_id))
except CourseUserGroupPartitionGroup.DoesNotExist:
pass
return cache.setdefault(cache_key, (None, None))
def get_group_info_for_cohort(cohort, use_cached=False):
"""
Get the ids of the group and partition to which this cohort has been linked
as a tuple of (int, int).
If the cohort has not been linked to any group/partition, both values in the
tuple will be None.
The partition group info is cached for the duration of a request. Pass
use_cached=True to use the cached value instead of fetching from the
database.
"""
cache = RequestCache(u"cohorts.get_group_info_for_cohort").data
cache_key = six.text_type(cohort.id)
if use_cached and cache_key in cache:
return cache[cache_key]
cache.pop(cache_key, None)
try:
partition_group = CourseUserGroupPartitionGroup.objects.get(course_user_group=cohort)
return cache.setdefault(cache_key, (partition_group.group_id, partition_group.partition_id))
except CourseUserGroupPartitionGroup.DoesNotExist:
pass
return cache.setdefault(cache_key, (None, None))
def get_cohort(user, course_key, assign=True, use_cached=False):
"""
Returns the user's cohort for the specified course.
The cohort for the user is cached for the duration of a request. Pass
use_cached=True to use the cached value instead of fetching from the
database.
Arguments:
user: a Django User object.
course_key: CourseKey
assign (bool): if False then we don't assign a group to user
use_cached (bool): Whether to use the cached value or fetch from database.
Returns:
A CourseUserGroup object if the course is cohorted and the User has a
cohort, else None.
Raises:
ValueError if the CourseKey doesn't exist.
"""
if user is None or user.is_anonymous:
return None
cache = RequestCache(COHORT_CACHE_NAMESPACE).data
cache_key = _cohort_cache_key(user.id, course_key)
if use_cached and cache_key in cache:
return cache[cache_key]
cache.pop(cache_key, None)
# First check whether the course is cohorted (users shouldn't be in a cohort
# in non-cohorted courses, but settings can change after course starts)
if not is_course_cohorted(course_key):
return cache.setdefault(cache_key, None)
# If course is cohorted, check if the user already has a cohort.
try:
membership = CohortMembership.objects.get(
course_id=course_key,
user_id=user.id,
)
return cache.setdefault(cache_key, membership.course_user_group)
except CohortMembership.DoesNotExist:
# Didn't find the group. If we do not want to assign, return here.
if not assign:
# Do not cache the cohort here, because in the next call assign
# may be True, and we will have to assign the user a cohort.
return None
# Otherwise assign the user a cohort.
try:
# If learner has been pre-registered in a cohort, get that cohort. Otherwise assign to a random cohort.
course_user_group = None
for assignment in UnregisteredLearnerCohortAssignments.objects.filter(email=user.email, course_id=course_key):
course_user_group = assignment.course_user_group
assignment.delete()
break
else:
course_user_group = get_random_cohort(course_key)
add_user_to_cohort(course_user_group, user)
return course_user_group
except ValueError:
# user already in cohort
return course_user_group
except IntegrityError as integrity_error:
# An IntegrityError is raised when multiple workers attempt to
# create the same row in one of the cohort model entries:
# CourseCohort, CohortMembership.
log.info(
"HANDLING_INTEGRITY_ERROR: IntegrityError encountered for course '%s' and user '%s': %s",
course_key, user.id, str(integrity_error)
)
return get_cohort(user, course_key, assign, use_cached)
def get_cohort(user, course_key, assign=True, use_cached=False):
"""
Returns the user's cohort for the specified course.
The cohort for the user is cached for the duration of a request. Pass
use_cached=True to use the cached value instead of fetching from the
database.
Arguments:
user: a Django User object.
course_key: CourseKey
assign (bool): if False then we don't assign a group to user
use_cached (bool): Whether to use the cached value or fetch from database.
Returns:
A CourseUserGroup object if the course is cohorted and the User has a
cohort, else None.
Raises:
ValueError if the CourseKey doesn't exist.
"""
if user.is_anonymous:
return None
cache = RequestCache(COHORT_CACHE_NAMESPACE).data
cache_key = _cohort_cache_key(user.id, course_key)
if use_cached and cache_key in cache:
return cache[cache_key]
cache.pop(cache_key, None)
# First check whether the course is cohorted (users shouldn't be in a cohort
# in non-cohorted courses, but settings can change after course starts)
if not is_course_cohorted(course_key):
return cache.setdefault(cache_key, None)
# If course is cohorted, check if the user already has a cohort.
try:
membership = CohortMembership.objects.get(
course_id=course_key,
user_id=user.id,
)
return cache.setdefault(cache_key, membership.course_user_group)
except CohortMembership.DoesNotExist:
# Didn't find the group. If we do not want to assign, return here.
if not assign:
# Do not cache the cohort here, because in the next call assign
# may be True, and we will have to assign the user a cohort.
return None
# Otherwise assign the user a cohort.
try:
# If learner has been pre-registered in a cohort, get that cohort. Otherwise assign to a random cohort.
course_user_group = None
for assignment in UnregisteredLearnerCohortAssignments.objects.filter(email=user.email, course_id=course_key):
course_user_group = assignment.course_user_group
assignment.delete()
break
else:
course_user_group = get_random_cohort(course_key)
add_user_to_cohort(course_user_group, user)
return course_user_group
except ValueError:
# user already in cohort
return course_user_group
except IntegrityError as integrity_error:
# An IntegrityError is raised when multiple workers attempt to
# create the same row in one of the cohort model entries:
# CourseCohort, CohortMembership.
log.info(
u"HANDLING_INTEGRITY_ERROR: IntegrityError encountered for course '%s' and user '%s': %s",
course_key, user.id, six.text_type(integrity_error)
)
return get_cohort(user, course_key, assign, use_cached)
