Adds a re-usable lockfile_nonblocking helper to context_managers.
Relying on naive `os.mkdir` is not enough especially now that the
successful operation of this command is necessary for push notifications
to work for many servers.
We can't use `lockfile` context manager from
`zerver.lib.context_managers`, because we want the custom behavior of
failing if the lock can't be acquired, instead of waiting.
That's because if an instance of this gets stuck, we don't want to start
queueing up more processes waiting forever whenever the cronjob runs
again and fail->exit is preferrable instead.
Fixes#2665.
Regenerated by tabbott with `lint --fix` after a rebase and change in
parameters.
Note from tabbott: In a few cases, this converts technical debt in the
form of unsorted imports into different technical debt in the form of
our largest files having very long, ugly import sequences at the
start. I expect this change will increase pressure for us to split
those files, which isn't a bad thing.
Signed-off-by: Anders Kaseorg <anders@zulip.com>
Calling open() with mode 'w' or 'a' will create a file if it doesn't exist,
while mode 'r' will cause an exception. This can be easily tested with:
python -c 'open("test.tmp", "w")'
ls test.tmp
This needs to be deployed to both staging and prod at the same
off-peak time (and the schema migration run).
At the time it is deployed, we need to make a few changes directly in
the database:
(1) UPDATE django_content_type set app_label='zerver' where app_label='zephyr';
(2) UPDATE south_migrationhistory set app_name='zerver' where app_name='zephyr';
(imported from commit eb3fd719571740189514ef0b884738cb30df1320)
Anders Kaseorg
Mateusz Mandera
rht
neiljp (Neil Pilgrim)
sylvan1
Nathan Florea
Tim Abbott
Tim Abbott
Tim Abbott