Systemd unit file

[sm8ps]

I have been struggling literally for years with the Nextcloud client not recognizing changes in external storage. The first and only useful information about a working solution I found in the Nextcloud forum but it is lacking a systemd unit file for non-Docker set-ups. I have cobbled one together that I want to share. It is functional in Nextcloud 24 on Ubuntu 20.04. This is my first try at such a thing and comments as well as suggestions are welcome. I include the full source code here in order to facilitate the discussion.

The start script launches files_external:notify for each mount ID present. It does not change fs.inotify.max_user_watches which might be necessary if the total number of folders being watched is greater than 8192. That could be scripted as well but I do not have need for it now. A manual work-around is to set that value in /etc/sysctl.conf.

/etc/systemd/system/nextcloud-files-inotify.service (-rw-r--r-- 1 root root)

[Unit]
Description=Files-inotify launcher for local external storage one Nextcloud
After=network.target mysql.service
Requires=mysql.service
[Service]
Type=forking
User=www-data
Group=www-data
WorkingDirectory=/var/www/nextcloud
ExecStart=/usr/local/bin/nextcloud-files-external-notify.start
ExecStop=/usr/local/bin/nextcloud-files-external-notify.stop
Nice=19
Restart=always
[Install]
WantedBy=multi-user.target

/usr/local/bin/nextcloud-files-external-notify.start (-rwxr--r-- 1 www-data www-data)

for i in $(/usr/bin/php /var/www/nextcloud/occ files_external:list --output=json | jq '.[].mount_id')
do
        /usr/bin/php /var/www/nextcloud/occ files_external:notify -n $i &  
done

/usr/local/bin/nextcloud-files-external-notify.stop (-rwxr--r-- 1 www-data www-data)

pkill -f '/usr/bin/php /var/www/nextcloud/occ files_external:notify -n [0-9]+'

[sm8ps]

I am having issues with this set-up. Eventually one of the processes started in the background (one for each mount ID) crashes.

Aug 24 10:08:33 lxcNextCloud201806 nextcloud-files-external-notify.start[63557]: An unhandled exception has been thrown:
Aug 24 10:08:33 lxcNextCloud201806 nextcloud-files-external-notify.start[63557]: Error: Call to undefined method OC\DB\ConnectionAdapter::isConnected() in /var/www/nextcloud/apps/files_external/lib/Command/Notif>
Aug 24 10:08:33 lxcNextCloud201806 nextcloud-files-external-notify.start[63557]: Stack trace:
Aug 24 10:08:33 lxcNextCloud201806 nextcloud-files-external-notify.start[63557]: #0 /var/www/nextcloud/apps/files_external/lib/Command/Notify.php(225): OCA\Files_External\Command\Notify->reconnectToDatabase()
Aug 24 10:08:33 lxcNextCloud201806 nextcloud-files-external-notify.start[63557]: #1 /var/www/nextcloud/apps/files_external/lib/Command/Notify.php(205): OCA\Files_External\Command\Notify->markParentAsOutdated()
Aug 24 10:08:33 lxcNextCloud201806 nextcloud-files-external-notify.start[63557]: #2 /var/www/nextcloud/apps/files_inotify/lib/Storage/NotifyHandler.php(238): OCA\Files_External\Command\Notify->OCA\Files_External>
Aug 24 10:08:33 lxcNextCloud201806 nextcloud-files-external-notify.start[63557]: #3 /var/www/nextcloud/apps/files_external/lib/Command/Notify.php(206): OCA\Files_INotify\Storage\NotifyHandler->listen()
Aug 24 10:08:33 lxcNextCloud201806 nextcloud-files-external-notify.start[63557]: #4 /var/www/nextcloud/3rdparty/symfony/console/Command/Command.php(255): OCA\Files_External\Command\Notify->execute()
Aug 24 10:08:33 lxcNextCloud201806 nextcloud-files-external-notify.start[63557]: #5 /var/www/nextcloud/core/Command/Base.php(168): Symfony\Component\Console\Command\Command->run()
Aug 24 10:08:33 lxcNextCloud201806 nextcloud-files-external-notify.start[63557]: #6 /var/www/nextcloud/3rdparty/symfony/console/Application.php(1009): OC\Core\Command\Base->run()
Aug 24 10:08:33 lxcNextCloud201806 nextcloud-files-external-notify.start[63557]: #7 /var/www/nextcloud/3rdparty/symfony/console/Application.php(273): Symfony\Component\Console\Application->doRunCommand()
Aug 24 10:08:33 lxcNextCloud201806 nextcloud-files-external-notify.start[63557]: #8 /var/www/nextcloud/3rdparty/symfony/console/Application.php(149): Symfony\Component\Console\Application->doRun()
Aug 24 10:08:33 lxcNextCloud201806 nextcloud-files-external-notify.start[63557]: #9 /var/www/nextcloud/lib/private/Console/Application.php(211): Symfony\Component\Console\Application->run()
Aug 24 10:08:33 lxcNextCloud201806 nextcloud-files-external-notify.start[63557]: #10 /var/www/nextcloud/console.php(100): OC\Console\Application->run()
Aug 24 10:08:33 lxcNextCloud201806 nextcloud-files-external-notify.start[63557]: #11 /var/www/nextcloud/occ(11): require_once('/var/www/nextcl...')

When using the start script as above, this would happen regularly immediately after launching the script. I then added sleep 1 after the invocation of files_external:notify -n which cured the symptom for about 20 hours but then the error happened. Unfortunately, Systemd does not seem to notice it as failure and does not restart the service. -- Any suggestions much appreciated!

[sm8ps]

In case anyone cares, my work-around to the above issue consists in calling '/bin/systemctl restart' hourly on the service file from /etc/contab. No crashes have been observed as by journalctl.

[sm8ps]

I just wanted to confirm that this work-around seems to be working, indeed! No crash has been observed over the 25 days that it has been in action.

[nursoda]

Here's my first poor man's version of a systemd file on my Arch Linux server:

[Unit]
Description=files_inotify watcher for ONE_SPECIFIC_DIRECTORY on MY_SERVER
After=network.target mariadb.service nginx.service php-fpm.service redis.service
Requires=mariadb.service nginx.service php-fpm.service redis.service

[Service]
User=http
WorkingDirectory=/PATH_TO_MY_CLOUD
ExecCondition=/usr/bin/php -f /PATH_TO_MY_CLOUD/occ status -e
ExecStart=/usr/bin/php -f PATH_TO_MY_CLOUD/occ files_external:notify -v ID_OF_THE_EXTERNAL_STORAGE
Nice=19
Restart=always

[Install]
WantedBy=multi-user.target

I expect this to be more robust due to Restart=always. It should be possible to use systemd Unit templates, and some script to actually derive service instances for each external ID from that.