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

From: Gennadiy Rozental (gennadiy.rozental_at_[hidden])
Date: 2005-04-26 13:11:31

>> > 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 am sorry to jump into the middle of discussion, but I wanted to comment on 
that:

>From my experience (and I wrote several logging solutions used in 
production) logging system is required to provide an explicit log level 
support. Any other solution is simply unacceptable. The same applies to 
keyword and category.

> Note that the presence of multiple logs does *not* imply multiple
> files.  You can use a single appender for everything:
>
> add_appender ("*", write_to_file ("app.all.txt"));

Now you have multiple agents writing into the same file. It not only adding 
extra headache with synchronization. Most probably disable any buffering and 
still inconvenient to use.

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

Second that.

Gennadiy