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edx-platform/lms/djangoapps/instructor_task/tasks_helper.py

456 lines
21 KiB
Python

"""
This file contains tasks that are designed to perform background operations on the
running state of a course.
"""
import json
from time import time
from celery import Task, current_task
from celery.utils.log import get_task_logger
from celery.states import SUCCESS, FAILURE
from django.contrib.auth.models import User
from django.db import transaction, reset_queries
from dogapi import dog_stats_api
from xmodule.modulestore.django import modulestore
from track.views import task_track
from courseware.models import StudentModule
from courseware.model_data import FieldDataCache
from courseware.module_render import get_module_for_descriptor_internal
from instructor_task.models import InstructorTask, PROGRESS
# define different loggers for use within tasks and on client side
TASK_LOG = get_task_logger(__name__)
# define value to use when no task_id is provided:
UNKNOWN_TASK_ID = 'unknown-task_id'
# define values for update functions to use to return status to perform_module_state_update
UPDATE_STATUS_SUCCEEDED = 'succeeded'
UPDATE_STATUS_FAILED = 'failed'
UPDATE_STATUS_SKIPPED = 'skipped'
class BaseInstructorTask(Task):
"""
Base task class for use with InstructorTask models.
Permits updating information about task in corresponding InstructorTask for monitoring purposes.
Assumes that the entry_id of the InstructorTask model is the first argument to the task.
"""
abstract = True
def on_success(self, task_progress, task_id, args, kwargs):
"""
Update InstructorTask object corresponding to this task with info about success.
Updates task_output and task_state. But it shouldn't actually do anything
if the task is only creating subtasks to actually do the work.
"""
TASK_LOG.info('Task success returned: %r' % (self.request, ))
# We should be able to find the InstructorTask object to update
# based on the task_id here, without having to dig into the
# original args to the task. On the other hand, the entry_id
# is the first value passed to all such args, so we'll use that.
# And we assume that it exists, else we would already have had a failure.
entry_id = args[0]
entry = InstructorTask.objects.get(pk=entry_id)
# Check to see if any subtasks had been defined as part of this task.
# If not, then we know that we're done. (If so, let the subtasks
# handle updating task_state themselves.)
if len(entry.subtasks) == 0:
entry.task_output = InstructorTask.create_output_for_success(task_progress)
entry.task_state = SUCCESS
entry.save_now()
def on_failure(self, exc, task_id, args, kwargs, einfo):
"""
Update InstructorTask object corresponding to this task with info about failure.
Fetches and updates exception and traceback information on failure.
"""
TASK_LOG.info('Task failure returned: %r' % (self.request, ))
entry_id = args[0]
try:
entry = InstructorTask.objects.get(pk=entry_id)
except InstructorTask.DoesNotExist:
# if the InstructorTask object does not exist, then there's no point
# trying to update it.
pass
else:
TASK_LOG.warning("background task (%s) failed: %s %s", task_id, einfo.exception, einfo.traceback)
entry.task_output = InstructorTask.create_output_for_failure(einfo.exception, einfo.traceback)
entry.task_state = FAILURE
entry.save_now()
def on_retry(self, exc, task_id, args, kwargs, einfo):
# We don't expect this to be called for top-level tasks, at the moment....
# If it were, not sure what kind of status to report for it.
# But it would be good to know that it's being called, so at least log it.
TASK_LOG.info('Task retry returned: %r' % (self.request, ))
class UpdateProblemModuleStateError(Exception):
"""
Error signaling a fatal condition while updating problem modules.
Used when the current module cannot be processed and no more
modules should be attempted.
"""
pass
def _get_current_task():
"""Stub to make it easier to test without actually running Celery"""
return current_task
def perform_module_state_update(update_fcn, filter_fcn, _entry_id, course_id, task_input, action_name):
"""
Performs generic update by visiting StudentModule instances with the update_fcn provided.
StudentModule instances are those that match the specified `course_id` and `module_state_key`.
If `student_identifier` is not None, it is used as an additional filter to limit the modules to those belonging
to that student. If `student_identifier` is None, performs update on modules for all students on the specified problem.
If a `filter_fcn` is not None, it is applied to the query that has been constructed. It takes one
argument, which is the query being filtered, and returns the filtered version of the query.
The `update_fcn` is called on each StudentModule that passes the resulting filtering.
It is passed three arguments: the module_descriptor for the module pointed to by the
module_state_key, the particular StudentModule to update, and the xmodule_instance_args being
passed through. If the value returned by the update function evaluates to a boolean True,
the update is successful; False indicates the update on the particular student module failed.
A raised exception indicates a fatal condition -- that no other student modules should be considered.
The return value is a dict containing the task's results, with the following keys:
'attempted': number of attempts made
'succeeded': number of attempts that "succeeded"
'skipped': number of attempts that "skipped"
'failed': number of attempts that "failed"
'total': number of possible updates to attempt
'action_name': user-visible verb to use in status messages. Should be past-tense.
Pass-through of input `action_name`.
'duration_ms': how long the task has (or had) been running.
Because this is run internal to a task, it does not catch exceptions. These are allowed to pass up to the
next level, so that it can set the failure modes and capture the error trace in the InstructorTask and the
result object.
"""
# get start time for task:
start_time = time()
module_state_key = task_input.get('problem_url')
student_identifier = task_input.get('student')
# find the problem descriptor:
module_descriptor = modulestore().get_instance(course_id, module_state_key)
# find the module in question
modules_to_update = StudentModule.objects.filter(course_id=course_id,
module_state_key=module_state_key)
# give the option of updating an individual student. If not specified,
# then updates all students who have responded to a problem so far
student = None
if student_identifier is not None:
# if an identifier is supplied, then look for the student,
# and let it throw an exception if none is found.
if "@" in student_identifier:
student = User.objects.get(email=student_identifier)
elif student_identifier is not None:
student = User.objects.get(username=student_identifier)
if student is not None:
modules_to_update = modules_to_update.filter(student_id=student.id)
if filter_fcn is not None:
modules_to_update = filter_fcn(modules_to_update)
# perform the main loop
num_attempted = 0
num_succeeded = 0
num_skipped = 0
num_failed = 0
num_total = modules_to_update.count()
def get_task_progress():
"""Return a dict containing info about current task"""
current_time = time()
progress = {'action_name': action_name,
'attempted': num_attempted,
'succeeded': num_succeeded,
'skipped': num_skipped,
'failed': num_failed,
'total': num_total,
'duration_ms': int((current_time - start_time) * 1000),
}
return progress
task_progress = get_task_progress()
_get_current_task().update_state(state=PROGRESS, meta=task_progress)
for module_to_update in modules_to_update:
num_attempted += 1
# There is no try here: if there's an error, we let it throw, and the task will
# be marked as FAILED, with a stack trace.
with dog_stats_api.timer('instructor_tasks.module.time.step', tags=['action:{name}'.format(name=action_name)]):
update_status = update_fcn(module_descriptor, module_to_update)
if update_status == UPDATE_STATUS_SUCCEEDED:
# If the update_fcn returns true, then it performed some kind of work.
# Logging of failures is left to the update_fcn itself.
num_succeeded += 1
elif update_status == UPDATE_STATUS_FAILED:
num_failed += 1
elif update_status == UPDATE_STATUS_SKIPPED:
num_skipped += 1
else:
raise UpdateProblemModuleStateError("Unexpected update_status returned: {}".format(update_status))
# update task status:
task_progress = get_task_progress()
_get_current_task().update_state(state=PROGRESS, meta=task_progress)
return task_progress
def run_main_task(entry_id, task_fcn, action_name):
"""
Applies the `task_fcn` to the arguments defined in `entry_id` InstructorTask.
TODO: UPDATE THIS DOCSTRING
(IT's not just visiting StudentModule instances....)
Performs generic update by visiting StudentModule instances with the update_fcn provided.
The `entry_id` is the primary key for the InstructorTask entry representing the task. This function
updates the entry on success and failure of the perform_module_state_update function it
wraps. It is setting the entry's value for task_state based on what Celery would set it to once
the task returns to Celery: FAILURE if an exception is encountered, and SUCCESS if it returns normally.
Other arguments are pass-throughs to perform_module_state_update, and documented there.
If no exceptions are raised, a dict containing the task's result is returned, with the following keys:
'attempted': number of attempts made
'succeeded': number of attempts that "succeeded"
'skipped': number of attempts that "skipped"
'failed': number of attempts that "failed"
'total': number of possible subtasks to attempt
'action_name': user-visible verb to use in status messages. Should be past-tense.
Pass-through of input `action_name`.
'duration_ms': how long the task has (or had) been running.
Before returning, this is also JSON-serialized and stored in the task_output column of the InstructorTask entry.
If an exception is raised internally, it is caught and recorded in the InstructorTask entry.
This is also a JSON-serialized dict, stored in the task_output column, containing the following keys:
'exception': type of exception object
'message': error message from exception object
'traceback': traceback information (truncated if necessary)
Once the exception is caught, it is raised again and allowed to pass up to the
task-running level, so that it can also set the failure modes and capture the error trace in the
result object that Celery creates.
"""
# get the InstructorTask to be updated. If this fails, then let the exception return to Celery.
# There's no point in catching it here.
entry = InstructorTask.objects.get(pk=entry_id)
# get inputs to use in this task from the entry:
task_id = entry.task_id
course_id = entry.course_id
task_input = json.loads(entry.task_input)
# construct log message:
# TODO: generalize this beyond just problem and student, so it includes email_id and to_option.
# Can we just loop over all keys and output them all? Just print the task_input dict itself?
module_state_key = task_input.get('problem_url')
fmt = 'task "{task_id}": course "{course_id}" problem "{state_key}"'
task_info_string = fmt.format(task_id=task_id, course_id=course_id, state_key=module_state_key)
TASK_LOG.info('Starting update (nothing %s yet): %s', action_name, task_info_string)
# Check that the task_id submitted in the InstructorTask matches the current task
# that is running.
request_task_id = _get_current_task().request.id
if task_id != request_task_id:
fmt = 'Requested task did not match actual task "{actual_id}": {task_info}'
message = fmt.format(actual_id=request_task_id, task_info=task_info_string)
TASK_LOG.error(message)
raise UpdateProblemModuleStateError(message)
# Now do the work:
with dog_stats_api.timer('instructor_tasks.time.overall', tags=['action:{name}'.format(name=action_name)]):
task_progress = task_fcn(entry_id, course_id, task_input, action_name)
# Release any queries that the connection has been hanging onto:
reset_queries()
# log and exit, returning task_progress info as task result:
TASK_LOG.info('Finishing %s: final: %s', task_info_string, task_progress)
return task_progress
def _get_task_id_from_xmodule_args(xmodule_instance_args):
"""Gets task_id from `xmodule_instance_args` dict, or returns default value if missing."""
return xmodule_instance_args.get('task_id', UNKNOWN_TASK_ID) if xmodule_instance_args is not None else UNKNOWN_TASK_ID
def _get_xqueue_callback_url_prefix(xmodule_instance_args):
"""
"""
return xmodule_instance_args.get('xqueue_callback_url_prefix', '') if xmodule_instance_args is not None else ''
def _get_track_function_for_task(student, xmodule_instance_args=None, source_page='x_module_task'):
"""
Make a tracking function that logs what happened.
For insertion into ModuleSystem, and used by CapaModule, which will
provide the event_type (as string) and event (as dict) as arguments.
The request_info and task_info (and page) are provided here.
"""
# get request-related tracking information from args passthrough, and supplement with task-specific
# information:
request_info = xmodule_instance_args.get('request_info', {}) if xmodule_instance_args is not None else {}
task_info = {'student': student.username, 'task_id': _get_task_id_from_xmodule_args(xmodule_instance_args)}
return lambda event_type, event: task_track(request_info, task_info, event_type, event, page=source_page)
def _get_module_instance_for_task(course_id, student, module_descriptor, xmodule_instance_args=None,
grade_bucket_type=None):
"""
Fetches a StudentModule instance for a given `course_id`, `student` object, and `module_descriptor`.
`xmodule_instance_args` is used to provide information for creating a track function and an XQueue callback.
These are passed, along with `grade_bucket_type`, to get_module_for_descriptor_internal, which sidesteps
the need for a Request object when instantiating an xmodule instance.
"""
# reconstitute the problem's corresponding XModule:
field_data_cache = FieldDataCache.cache_for_descriptor_descendents(course_id, student, module_descriptor)
# get request-related tracking information from args passthrough, and supplement with task-specific
# information:
request_info = xmodule_instance_args.get('request_info', {}) if xmodule_instance_args is not None else {}
task_info = {"student": student.username, "task_id": _get_task_id_from_xmodule_args(xmodule_instance_args)}
def make_track_function():
'''
Make a tracking function that logs what happened.
For insertion into ModuleSystem, and used by CapaModule, which will
provide the event_type (as string) and event (as dict) as arguments.
The request_info and task_info (and page) are provided here.
'''
return lambda event_type, event: task_track(request_info, task_info, event_type, event, page='x_module_task')
xqueue_callback_url_prefix = xmodule_instance_args.get('xqueue_callback_url_prefix', '') \
if xmodule_instance_args is not None else ''
return get_module_for_descriptor_internal(student, module_descriptor, field_data_cache, course_id,
make_track_function(), xqueue_callback_url_prefix,
grade_bucket_type=grade_bucket_type)
@transaction.autocommit
def rescore_problem_module_state(xmodule_instance_args, module_descriptor, student_module):
'''
Takes an XModule descriptor and a corresponding StudentModule object, and
performs rescoring on the student's problem submission.
Throws exceptions if the rescoring is fatal and should be aborted if in a loop.
In particular, raises UpdateProblemModuleStateError if module fails to instantiate,
or if the module doesn't support rescoring.
Returns True if problem was successfully rescored for the given student, and False
if problem encountered some kind of error in rescoring.
'''
# unpack the StudentModule:
course_id = student_module.course_id
student = student_module.student
module_state_key = student_module.module_state_key
instance = _get_module_instance_for_task(course_id, student, module_descriptor, xmodule_instance_args, grade_bucket_type='rescore')
if instance is None:
# Either permissions just changed, or someone is trying to be clever
# and load something they shouldn't have access to.
msg = "No module {loc} for student {student}--access denied?".format(loc=module_state_key,
student=student)
TASK_LOG.debug(msg)
raise UpdateProblemModuleStateError(msg)
if not hasattr(instance, 'rescore_problem'):
# This should also not happen, since it should be already checked in the caller,
# but check here to be sure.
msg = "Specified problem does not support rescoring."
raise UpdateProblemModuleStateError(msg)
result = instance.rescore_problem()
instance.save()
if 'success' not in result:
# don't consider these fatal, but false means that the individual call didn't complete:
TASK_LOG.warning(u"error processing rescore call for course {course}, problem {loc} and student {student}: "
"unexpected response {msg}".format(msg=result, course=course_id, loc=module_state_key, student=student))
return UPDATE_STATUS_FAILED
elif result['success'] not in ['correct', 'incorrect']:
TASK_LOG.warning(u"error processing rescore call for course {course}, problem {loc} and student {student}: "
"{msg}".format(msg=result['success'], course=course_id, loc=module_state_key, student=student))
return UPDATE_STATUS_FAILED
else:
TASK_LOG.debug(u"successfully processed rescore call for course {course}, problem {loc} and student {student}: "
"{msg}".format(msg=result['success'], course=course_id, loc=module_state_key, student=student))
return UPDATE_STATUS_SUCCEEDED
@transaction.autocommit
def reset_attempts_module_state(xmodule_instance_args, _module_descriptor, student_module):
"""
Resets problem attempts to zero for specified `student_module`.
Returns a status of UPDATE_STATUS_SUCCEEDED if a problem has non-zero attempts
that are being reset, and UPDATE_STATUS_SKIPPED otherwise.
"""
update_status = UPDATE_STATUS_SKIPPED
problem_state = json.loads(student_module.state) if student_module.state else {}
if 'attempts' in problem_state:
old_number_of_attempts = problem_state["attempts"]
if old_number_of_attempts > 0:
problem_state["attempts"] = 0
# convert back to json and save
student_module.state = json.dumps(problem_state)
student_module.save()
# get request-related tracking information from args passthrough,
# and supplement with task-specific information:
track_function = _get_track_function_for_task(student_module.student, xmodule_instance_args)
event_info = {"old_attempts": old_number_of_attempts, "new_attempts": 0}
track_function('problem_reset_attempts', event_info)
update_status = UPDATE_STATUS_SUCCEEDED
return update_status
@transaction.autocommit
def delete_problem_module_state(xmodule_instance_args, _module_descriptor, student_module):
"""
Delete the StudentModule entry.
Always returns UPDATE_STATUS_SUCCEEDED, indicating success, if it doesn't raise an exception due to database error.
"""
student_module.delete()
# get request-related tracking information from args passthrough,
# and supplement with task-specific information:
track_function = _get_track_function_for_task(student_module.student, xmodule_instance_args)
track_function('problem_delete_state', {})
return UPDATE_STATUS_SUCCEEDED