Review of Jose Armando Garcia Sancio's std.log
Robert Jacques
sandford at jhu.edu
Tue Mar 6 09:32:07 PST 2012
On Tue, 06 Mar 2012 11:01:19 -0600, Jose Armando Garcia
<jsancio at gmail.com> wrote:
> On Wed, Feb 29, 2012 at 4:13 PM, Richard van Scheijen <dlang at mesadu.net>
> wrote:
>> When logging the severity level should convey a certain insight that the
>> developer has about the code. This can be done with a 3 bit field. These
>> are: known-cause, known-effect and breaks-flow.
>>
>> This creates the following matrix:
>>
>> KC KE BF Severity
>> =================
>> 1 1 0 Trace
>> 0 1 0 Info
>> 1 0 0 Notice
>> 0 0 0 Warning
>> 1 1 1 Error
>> 0 1 1 Critical
>> 1 0 1 Severe
>> 0 0 1 Fatal
>>
>> A known cause is when the developer knows why a log event is made.
>> e.g.: if
>> you cannot open a file, you do not know why.
>> A known effect is when he/she knows what happens after. Basically, you
>> can
>> tell if it is a catch-all by this flag.
>>
>> When a severity should only be handled by a debugger, the normal debug
>> statement should be used. This is in essence a 4th bit.
>>
>> I hope this helpful in the search for a good level system.
>>
>
> Interesting observation on logging. I like your theoretical
> observation and explanation. To me the most important thing is
> usability and unfortunately people are used to log levels as a order
> concept. Meaning error is higher severity than info so if I am logging
> info events I should probably also log error events.
>
> If we go with a mechanism like the one you describe above there is no
> order so the configuration is a little more complicated or verbose I
> should say. Instead of saying we should log everything "greater" than
> warning the user needs to say that they want to log known-cause,
> known-effect, breaks-flow events. This mean that there are 27 (= 3^3)
> configuration combinations. To implement this we need 3 configuration
> nobs with 3 values (on, off, both).
>
> Thoughts?
> -Jose
There are only 8 possible configurations and they are nicely ordered in
terms of severity. So I don't see this as a problem. Also, if you went
with a combinatorial approach, shouldn't it be 2^8 = 256, not 3^3 = 27
values?
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