Make log_level entry in rebar.app work again

[richcarl]

The log_level app setting had become ignored during refactorings of old. This makes it take effect again and syncs its standard setting with that of with rebar_log:default_level(). We add rebar_log:atom_to_level/1 to avoid exposing the level numbers used internally.

[vkatsuba]

It looks like that it can be simplify like:

Suggested change

	try
	{ok, L} = application:get_env(rebar, log_level),
	rebar_log:atom_to_level(L)
	catch
	_:_ -> rebar_log:default_level()
	end;
	rebar_log:atom_to_level(application:get_env(rebar, log_level, info));

[richcarl]

It looks like that it can be simplify like:

No, even if you call get_env(rebar, log_level, rebar_log:default_level()) so that this code does not hardcode the info value, someone may still put an invalid value in the configuration, and in that case I also want to substitute the default rather than failing to start.

[vkatsuba]

For this case you can change logic in to_level function:

atom_to_level(Level) ->
    case Level of
        error -> ?ERROR_LEVEL;
        warn  -> ?WARN_LEVEL;
        debug -> ?DEBUG_LEVEL;
        diagnostic -> ?DIAGNOSTIC_LEVEL;
        _ -> ?INFO_LEVEL
    end.

[richcarl]

Yes, but that is also not appropriate. The conversion function should work on defined levels only.

[vkatsuba]

But you doing totally same in catch block - if set incorrect value and it will crashed over missing matching - then use default value - default value is ?INFO_LEVEL based on the code.

[richcarl]

But you doing totally same in catch block - if set incorrect value and it will crashed over missing matching - then use default value - default value is ?INFO_LEVEL based on the code.

Those modules and functions have very different areas of responsibility.

[tsloughter]

I think that was meant to be removed from rebar.app since you'd change it in config or environment and not by rebuilding rebar3.

Not that this isn't an ok change since its not like it hurts to have I guess.

[richcarl]

I think that was meant to be removed from rebar.app since you'd change it in config or environment and not by rebuilding rebar3.

Yeah, I thought about dropping it, but it's a nice and easy way to rebuild rebar with your default level of choice. Also, the only other way to change the level currently is by setting env variables like DEBUG or QUIET.