Re: [PATCH RFC] logger: add support for --loglevel-prefix when logging stdin

[Dennis H Jensen <dennis.h.jensen@siemens.com>]

On Tue, 2013-05-14 at 10:07 +0200, Karel Zak wrote:
> Hi Dennis,
> 
> On Mon, May 13, 2013 at 11:57:18PM +0200, Dennis H Jensen wrote:
> > This patch adds a new option to logger that will make it look for a
> > loglevel prefix <[0-7]> at the beginning of every line.
> > 
> > If a loglevel is found logger will log the message using the found
> > loglevel combined with the facility specified by --priority. When no
> > loglevel is found the default level provided by the --priority option
> > will be used.
> 
> I have doubts if this is a good idea. 
> 
> It seems that you're trying to introduce a new meaning of the <n>
> convention.  The <n> in the syslog API is not only log level, it's
> ((lev & LOG_PRIMASK) | (fac & LOG_FACMASK)) -- bottom 3 bits are the
> priority and the top 28 bits are the facility).
>  
> 
> It would be better to follow this already existing convention. It means 
> to use something like
> 
>     --prio-prefix
> 
> and use the <n> number as whole priority number. The result will be
> command line interface with pretty simple semantic.

I wanted the <n> convention but only provide the level, but you are
right, it would be best to provide the whole API.

> 
> The problem is that <n> encoding is not user friendly, but I guess we
> should be able to explain all in the logger man page (for example in
> an EXAMPLE section). For example user.debug:
> 
>     LOG_USER=$((1<<3))
>     LOG_DEBUG=7
>     echo $(( $LOG_USER & 0x03f8 | $LOG_DEBUG & 0x07 ))
> 
> to get the number in shell.

maybe I will add a shiny example to the man page :)

> 
> > --- a/misc-utils/logger.c
> > +++ b/misc-utils/logger.c
> > @@ -64,6 +64,10 @@ enum {
> >  	ALL_TYPES = TYPE_UDP | TYPE_TCP
> >  };
> >  
> > +enum {
> > +	ARG_LOGLEVEL_PREFIX = 0x100
> 
>  We usually use OPT_* and CHAR_MAX, for example:
> 
>         OPT_PRIO_PREFIX = CHAR_MAX + 1
> 
> 

I will resend a new version of the patch..

//Dennis