If a soft deactivated user had a subscription double-toggled without
any new messages being sent in between, add_missing_messages might
incorrectly process those two subscription changes in the wrong order.
Fortunately, the failure mode was usually to throw this exception:
django.db.utils.IntegrityError: duplicate key value violates unique
constraint "zerver_usermessage_user_profile_id_message_id_4936d0df_uniq"
DETAIL: Key (user_profile_id, message_id)=(4, 57) already exists.
Our unit tests actually had this precise setup some fraction of the
time, because a bit of the test setup code subscribed+unsubscribed the
target user without sending any messages in between, resulting in a
test failure something like 50% of the time.
The original exception was hard to reproduce reliably originally
(resulting in an extremely annoying nondetermnistic test failure), but
is easily reproducible by changing the "id" to "-id" in this change to
always mis-order the processing of those RealmAuditLog events.
Previously, our soft-deactivation logic incorrectly did not filter the
set of stream subscription changes to look at to only include the
target stream.
This could result in unspecified buggy behavior.
Break will do the same thing as continue here, as each iteration will
have the same result, and it's also worth explaining why this isn't
one layer up in the loop setup.
When soft deactivation is run for in "auto" mode (no emails are
specified and all users inactive for specified number of days are
deactivated), catch-up is also run in the "auto" mode if
AUTO_CATCH_UP_SOFT_DEACTIVATED_USERS is True.
Automatically catching up soft-deactivated users periodically would
ensure a good user experience for returning users, but on some servers
we may want to turn off this option to save on some disk space.
Fixes#8858, at least for the default configuration, by eliminating
the situation where there are a very large number of messages to recover.
A user who has been soft deactivated for a long time might have 10Ks of message
history that was "soft deactivated". It might take a minute or more to add
UserMessage rows for all of these messages, causing timeouts. So, we paginate
the creation of these UserMessage rows.
The previous logic for soft deactivation ended up doing a giant
transaction in the case that there were thousands of users to
deactivate; this was messy and potentially buggy.
The batched transactions were useful for RealmAuditLog management,
however. So the right solution is to do reasonably sized batches
(e.g. 100 users).
We should still short-circuit the iteration in
`add_missing_messages` if the unsubscription was the last
thing to happen to the user before unsubscription and
soft deactivation.
The name `create_logger` suggests something much bigger than what this
function actually does -- the logger doesn't any more or less exist
after the function is called than before. Its one real function is to
send logs to a specific file.
So, pull out that logic to an appropriately-named function just for
it. We already use `logging.getLogger` in a number of places to
simply get a logger by name, and the old `create_logger` callsites can
do the same.
This is already the loglevel we set on the root logger, so this has no
effect -- except in tests, where `test_settings.py` attempts to set
some of these same loggers to higher loglevels. Because the
`create_logger` call generally runs after we've configured settings,
it clobbers that effect.
The code in `test_settings.py` that tries to suppress logs only works
because it also sets `propagate=False`, which has nothing to do with
loglevels but does cause logs at this logger (and descendants) to be
dropped completely unless we've configured handlers for this logger
(or one of its relevant descendants.)
This commits adds new helper functions which are:
* get_users_for_soft_deactivation(): This function can be used to
fetch a list of human users which pass the criteria of minimum
inactivity period (in days) passed as a parameter to the function.
* do_soft_activate_users(): Given a list of users this function
reactivates them and help them catch up with the missing message
rows for them in the UserMessage table.
This function will help us in creating undisturbed experience for
returning soft deactivated users.
Tweaked by tabbott to fix minor performance and clarity issues.