On a Nexus 5 running 5.1.1, I have the DS Photo from Synology set to do automatic background uploading of new photos/videos that show up to my NAS. Normally works great. The app includes a setting for whether to upload only over wifi or to upload over both wifi and cellular.
The one problem is that the phone uses cellular data via a hotspot, so while the phone sees it as just another wifi network, I really want it to be treated like cellular.
Even though I went into settings -> data usage -> network restrictions and marked the hotspot as 'metered usage', the DS Photo app still uploads new videos over it. I'm guessing DS Photo would need to change to actively check this 'metered usage' flag and behave differently.
The 'best' fix would be to somehow have that hotspot's wifi connection treated like cellular across all apps. Since DS Photo already has the 'wifi-only' support, that would be sufficient for this scenario.
Lacking that capability, I'm trying to figure out how I can make it so that one app isn't allowed to talk over that one wifi connection.
I tried Tasker, but it appeared to only trigger the profile of an app when it was the foreground app. It would disable fine if I actively switched to the DS Photo app, but if it was just starting an upload in the background like normal, Tasker didn't didn't prevent it.
I also tried the approach from this answer and had it disable Auto-Sync when connected to that particular wifi network, but the DS Photo app still uploaded even though Tasker had disabled Auto-Sync :(