The post_init cache-flushing behavior in the original alert words
migration was subtly wrong; while it may have passed tests, it didn't
have the right ordering for unlikely races.
We use post_save rather than post_init hooks precisely because they
ensure that we flush the cache after we know the database has been
updated and any future reads from the database will have the latest
state.
Previously, alert words were case-insensitive in practice, by which I
mean the Markdown logic had always been case-insensitive; but the data
model was not, so you could create "duplicate" alert words with the
same words in different cases. We fix this inconsistency by making
the database model case-insensitive.
I'd prefer to be using the Postgres `citext` extension to have
postgres take care of case-insensitive logic for us, but that requires
installing a postgres extension as root on the postgres server, which
is a pain and perhaps not worth the effort to arrange given that we
can achieve our goals with transaction when adding alert words.
We take advantage of the migrate_alert_words migration we're already
doing for all users to effect this transition.
Fixes#12563.
Previously, alert words were a JSON list of strings stored in a
TextField on user_profile. That hacky model reflected the fact that
they were an early prototype feature.
This commit migrates from that to a separate table, 'AlertWord'. The
new AlertWord has user_profile, word, id and realm(denormalization so
we can provide a nice index for fetching all the alert words in a
realm).
This transition requires moving the logic for flushing the Alert Words
caches to their own independent feature.
Note that this commit should not be cherry-picked without the
following commit, which fixes case-sensitivity issues with Alert Words.
Generated by `pyupgrade --py3-plus --keep-percent-format` on all our
Python code except `zthumbor` and `zulip-ec2-configure-interfaces`,
followed by manual indentation fixes.
Signed-off-by: Anders Kaseorg <anders@zulipchat.com>
Previous cleanups (mostly the removals of Python __future__ imports)
were done in a way that introduced leading newlines. Delete leading
newlines from all files, except static/assets/zulip-emoji/NOTICE,
which is a verbatim copy of the Apache 2.0 license.
Signed-off-by: Anders Kaseorg <anders@zulipchat.com>
This commit leverages the ahocorasick algorithm to build a set of user_ids
that have their alert_words present in the message. It runs in linear time
of the order of length of the input message as opposed to number of
alert_words. This is after building a ahocorasick Automaton which runs
in O(number of alert_words in entire realm) which is usually cached.
This removes from our cache a moderate amount of totally useless alert
word data corresponding to users who don't have any alert words.
Thanks to @dbiollo for the suggestion!
We want to avoid opening a DB connection in the markdown thread
as its DB connection might live for a long time
(imported from commit 7700b2ca793ee5e9add7f071b92f22a4bf576b3d)
We found that since bugdown processes are threaded, the cost of
doing a db query in a markdown processor is quite high---each
thread must start up a new db connection including a SSL handshake
etc. We should strive to keep our rendering pipeline free of mandatory
DB queries.
(imported from commit 555066bd03da6c681b74ce6137acc264eb41c55d)
Anders Kaseorg
Tim Abbott
Abhishek-Balaji
Anders Kaseorg
Bennet Sunder
Aditya Bansal
rht
Robert Hönig
Eklavya Sharma
Tim Abbott
Ashish
Tim Abbott
Luke Faraone
Leo Franchi