Factor out the repeated pattern of taking a lock, or immediately
aborting with a message if it cannot be acquired. The exit code in
that situation is changed to be exit code 1, rather than the successful
0; we are likely missing new work since that process started.
We move the lockfiles to a common directory under `/srv/zulip-locks`
rather than muddy up `/home/zulip/deployments`.
This commit adds a 'skip-delay' option to the
'send_zulip_update_announcements' management command.
It will be useful for self-hosted servers after 9.0 upgrade to
avoid the 24 hour delay to receive update messages after group
DM is sent to the admins.
One can run the management command with the --skip-delay flag
to immediately send the update messages.
This commit adds a management command that will run regularly
as a cron job to send zulip updates to realms based on their
current and latest zulip_update_announcements_level.
For realms with:
* level = None: Send a group DM to admins notifying them about
this new feature & suggestion to set the stream accordingly.
* level = 0:
* If stream is still not configured, wait for a week
before setting their level to latest level. They will
miss updates until their configure the stream.
* If stream is configured, send updates.
* level > 0: Send one message/update per level & increase
the level by 1 till the latest level.
Fixes#28604.