Errors flood when restarting Ubuntu with Laravel Horizon

Do your get your log files or your Slack channel flooded with such errors when you restart your Ubuntu server where you are hosting Laravel application?

production.ERROR: Error while reading line from the server. [tcp://127.0.0.1:6379] {"exception":"[object] (Predis\Connection\ConnectionException(code: 0): Error while reading line from the server.

or

production.ERROR: Connection refused [tcp://127.0.0.1:6379] {"exception":"[object] (Predis\Connection\ConnectionException(code: 111): Connection refused [tcp://127.0.0.1:6379]

If yes, you are probably running Redis (opens new window), Laravel Horizon (opens new window) and Supervisor (opens new window) on this machine.

The issue

The issue is at the order of shutting down of dependent softwares or simply said Laravel Horizon depends on the Redis server being available, but it gets shut down before Supervisor and respectively Laravel Horizon. Fortunately the fix is pretty simple.

The fix

You should let systemd (opens new window) knows that Supervisor depends on the Redis service being available. When you do that the system restart command will first halt Supervisor and then Redis. You have to edit the supervisor.service file:

sudo nano /etc/systemd/system/multi-user.target.wants/supervisor.service

For the [Unit] section you will see After=network.target line. Add redis.service on the same line like this:

[Unit]
...
After=network.target redis.service

Save the file by pressing Ctrl + x and then y to confirm the edit and Enter to exit the editor.

Then make sure to restart the Supervisor service and you should be good to go.

sudo service supervisor restart

The next time you restart the server Supervisor and Laravel Horizon will get shut down before the Redis server and you will not see the same errors anymore.