Code review comment for lp:~michihenning/apparmor-easyprof-ubuntu/new-thumbnailer-methods

The clients don’t specify the values. The values live in gsettings. Some of the values are relevant to the client-side library, such as whether to write additional trace. The problem is that confined apps cannot read gsettings. So, the only solution is to have the server provide those config values that are relevant to the client side over DBus. The client only has read-only access to the values, and can read only those values that the server provides.

The values need to change when we have to debug things and for performance tuning. Without this, we can’t just tell someone “change this gsetting, and send us the log”, for example. It also makes it much easier for us to diagnose problems caused by misbehaving applications because, with trace on the client side, we can correlate the interchange of messages between the application and the thumbnailer. (And we can't leave the trace on permanently because that would hopelessly spam the application log.)