Re: [boost] Logging Library -- Formal Review Request

From: Jody Hagins (jody-boost-011304_at_[hidden])
Date: 2005-04-26 11:39:35

On Tue, 26 Apr 2005 12:16:03 -0400
Caleb Epstein <caleb.epstein_at_[hidden]> wrote:

> I think John's approach to having multiple log "levels" is to just use
> a separate log for each one (e.g. you might have logs called trace,
> debug, warning, info, and fatal).  Logs are either enabled or
> disabled; there is no "level" or above-some-threshold-type checking as
> with some other common implementations.

Unfortunately, you lose relativity in logs, which is very important in
diagnosing failures.  Suppose a problem occurs that gets logged to the
"fatal" log.  Really, to find out all surrounding context, you need to
merge all logs.  Unless there is a common sequence number or something
like that, you have no way of really knowing what sequence of events led
to the problem since they are scattered about in a number of logs.  You
can make good guesses, but in large that handle multiple requests at the
same time, it becomes very difficult.

I'd prefer a common log, which records levels.

I also think the concept of multiple log variables is important in large
systems, where different subsystems may have different log levels (e.g,
turn on all logging for new subsystems, and only critical logging for
other subsystems).