Id like to go forward and fix this issue by reverting to using the in-built emonhub.log.
1. I would amend emonhub/service/emonhub.service at emon-pi · openenergymonitor/emonhub · GitHub to include the --logfile parameter
ExecStart=/usr/share/emonhub/emonhub.py --config-file=/home/pi/data/emonhub.conf --logfile=/var/log/emonhub/emonhub.log
2. I would update rc.local for the stretch image to setup the emonhub log directory emonpi/stretch/rc.local at master · openenergymonitor/emonpi · GitHub
3. I would update the emonhub update script to create the emonhub log directory to avoid the need for a system restart during the update emonpi/update/emonhub.sh at master · openenergymonitor/emonpi · GitHub
4. Update the emonhub log viewer UI to use /var/log/emonhub/emonhub.log
I think I would prefer to do this than just disabling the systemd service installation, it would also fix existing systems that have already run an update. Would you be happy if I proceed with the above @pb66 @borpin?
The rc.local mod is of course temporary, to be replaced with our non rc.local requirements as part of the new emonSD image & scripts in development.
Im not sure if I need to make any logrotate modifications yet to fix this on existing systems.