We use the dealer.git library to determine the current revision of
edx-platform at startup time and store that as EDX_PLATFORM_REVISION in
our settings. This can take a surprisingly long time and involve a lot
of disk IO to initialize.
Studio still needs this functionality because it determines its static
asset folder based partly on the hash. This is horrible, because it
means all static assets are invalidated on every release instead of
just the ones that change. But that will be the subject of a different
PR.
Before this commit, we had to do a separate query for every course a
user was enrolled in when determining whether a course was refundable
(if you have a certificate, it isn't). Now the student dashboard will
make a one-time query to grab all of a user's cert-issued courses. This
is indexed, so it should be much faster than grabbing each one
separately.
Pre-load the course overviews attached to CourseEnrollments on the
Student Dashboard, if possible. This will only grab the CourseOverviews
that already exist, and will not generate new ones. Any missing
CourseOverviews fall back to the lazily-created one-at-a-time behavior
they've always had. That's mostly because I wanted to optimize for the
common case in the least invasive way possible, and I don't want to get
caught up in locking issues.
There are a number of Django Signals that are on the modulestore's
SignalHandler class, such as SignalHandler.course_published. These
signals can trigger very expensive processes to occur, such as course
overview or block structures generation. Most of the time, the test
author doesn't care about these side-effects.
This commit does a few things:
* Converts the signals on SignalHandler to be instances of a new
SwitchedSignal class, that allows signal sending to be disabled.
* Creates a SignalIsolationMixin helper similar in spirit to the
CacheIsolationMixin, and adds it to the ModuleStoreIsolationMixin
(and thus to ModuleStoreTestCase and SharedModuleStoreTestCase).
* Converts our various tests to use this new mechanism. In some cases,
this means adjusting query counts downwards because they no longer
have to account for publishing listener actions.
Modulestore generated signals are now muted by default during test runs.
Calls to send() them will result in no-ops. You can choose to enable
specific signals for a given subclass of ModuleStoreTestCase or
SharedModuleStoreTestCase by specifying an ENABLED_SIGNALS class
attribute, like the following example:
from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
class MyPublishTestCase(ModuleStoreTestCase):
ENABLED_SIGNALS = ['course_published', 'pre_publish']
You should take great care when disabling signals outside of a
ModuleStoreTestCase or SharedModuleStoreTestCase, since they can leak
out into other tests. Be sure to always clean up, and never disable
signals outside of testing. Because signals are essentially process
globals, it can have a lot of unpleasant side-effects if we start
mucking around with them during live requests.
Overall, this change has cut the total test execution time for
edx-platform by a bit over a third, though we still spend a lot in
pre-test setup during our test builds.
[PERF-413]
The RLIMIT_NPROC limit is per-user so simultaneous student submissions
pile up and overflow the limit. Setting this environment variable will
prevent spawning any threads (the 1 means only have one threads, the
already existing main thread).
