The magic behaviour of 'logging level all LEVEL'

Hi all, A discussion was started during the review of https://gerrit.osmocom.org/10116/. The main idea of this change is to fix the behaviour of 'logging level all LEVEL', but I think it was also mixed with some additional feature, which I would like to discuss here, publicly. First of all, the change introduces a new special logging level 'unset', which allows one to reset a given category (i.e. unset its custom value): !! Initial logging configuration: logging level all error logging level mncc debug logging level pag notice logging level meas debug !! Resetting DMNCC: # logging level mncc unset !! So, now DMNCC has no custom log level, it will use !! the default level (in this example it is 'error'): logging level all error logging level pag notice logging level meas debug This feature looks fine and extremely useful for me. But (among fixing) this change additionally changes the behaviour of a command for setting the default logging category (i.e. 'logging level all LEVEL'): !! Initial logging configuration: logging level all error logging level mncc debug logging level pag notice logging level meas debug !! Changing the default logging level: # logging level all debug !! Ahhh, I've lost my custom levels :( logging level all debug !! What I expected to get: logging level all debug logging level mncc debug logging level pag notice logging level meas debug So, together with changing the default logging category, this command now would also reset all custom settings... I am not sure this is exactly what one need/expect, so I would like to share the following ideas: 1) The category 'all' looks/sounds confusing when it's used in such cases like this: # logging level all debug because one can interpret it like: "set all categories to debug". despite actually (according to the implementation) this is related to the default logging policy. Maybe, we should rename it to 'default'? So, 'logging level all LEVEL' would *set all categories* to a given logging LEVEL, while 'logging level default LEVEL' would only affect the default logging level... 2) Introducing the new command: # logging level unset LEVEL which is intended to assign a given LEVEL to all categories, which have no custom logging level (i.e. have 'unset'), would make the idea of having default logging policy meaningless. Setting logging level(s) for all possible categories (using this command), looks like writing iptables rules for all possible and impossible cases instead of using the DEFAULT policy... 3) The introduced behaviour of resetting all categories to 'unset' could be implemented in a separate function, and can be represented by a separate command: # logging level unset-all The name of this command clearly defines the expected behaviour. Moreover, it doesn't affect the default logging level, which can be still changed by a separate command. As we (me and Pau) have different opinions, or we simply don't understand each other, let's make this discussion public, and let's see what others think about this... With best regards, Vadim Yanitskiy.