logging

Discussions related to Visual Prolog
Post Reply
B.Hooijenga
Active Member
Posts: 95
Joined: 11 Jul 2002 23:01

logging

Post by B.Hooijenga » 28 May 2018 12:38

Hello,

I am trying to use the log/package.
In the logdemo program there is the following xml file.


<LogConfigurations>
<LogConfig name="ConfigName0">
<Appenders>
</Appenders>
</LogConfig>
<LogConfig name="ConfigNameMC">
<Appenders>
<Appender name="AppenderName2">
<LogLevel>all</LogLevel>
<Type>fileasync</Type>
<ThreadPriority>low</ThreadPriority>
<!--Target>%TEMP%\ideVault.log</Target-->
<Target>VIP %date{MM-dd} %time{HH.mm}.log</Target>
<PatternLayout>%lineno{4d} %time: %username [%callerClassName::%callerPredicateName] %msg</PatternLayout>
<!--PatternLayout>%time: %msg</PatternLayout-->
<filter>class:entityModel;method:aaa</filter>
</Appender>
<!--Appender name="AppenderName3">
<LogLevel>all</LogLevel>
<Type>dbtable</Type>
<PatternLayout>%userid %proc:%thread %datetime %msg</PatternLayout>
<filter>class:entityModel;method:aaa</filter>
</Appender-->
<Appender name="Appender Console">
<LogLevel>all</LogLevel>
<Type>console</Type>
<PatternLayout>%lineno{4d}. ~red %msglevel{-5s}~normal %time{HH:mm:ss} [%callerclassname::%callerPredicateName] %msg</PatternLayout>
<filter>class:entityModel;method:aaa</filter>
</Appender>

</Appenders>

</LogConfig>
</LogConfigurations>

Making a patternlayout is a problem.
I presume that the characters % { ~ and [ are delimiters.
But when and how are they used?

Kind regards
Ben

User avatar
Thomas Linder Puls
VIP Member
Posts: 2341
Joined: 28 Feb 2000 0:01

Re: logging

Post by Thomas Linder Puls » 30 May 2018 9:21

I agree that there lack some documentation on that matter.

The log tool has two ends:
  • In the main parts of the program you insert calls to log events, by calling logging predicates in the log tool
  • In the other end appenders will append log events to specific logs.
A configuration file describes which appenders to use and how to use them. (You can also deal with appenders directly in the program code, but this is about "external" configuration).

Here is a cleaned version of the configuration from the example (the token coloring is not the best for XML, but anyways):

Code: Select all

<LogConfigurations>     <LogConfig name="ConfigName">         <Appenders>             <Appender name="AppenderName2">                 <LogLevel>all</LogLevel>                 <Type>fileasync</Type>                 <ThreadPriority>low</ThreadPriority>                 <Target>                     VIP  %date{MM-dd} %time{HH.mm}.log                 </Target>                 <PatternLayout>                     %lineno{4d} %time: %username [%callerClassName::%callerPredicateName] %msg                 </PatternLayout>                 <filter>class:entityModel;method:aaa</filter>             </Appender>             <Appender name="Appender Console">                 <LogLevel>all</LogLevel>                 <Type>console</Type>                 <PatternLayout>                     %lineno{4d}. ~red %msglevel{-5s}~normal  %time{HH:mm:ss} [%callerclassname::%callerPredicateName] %msg                 </PatternLayout>                 <filter>class:entityModel;method:aaa</filter>             </Appender>         </Appenders>     </LogConfig> </LogConfigurations>
It configures two appenders AppenderName2 and Appender Console. The first is a "fileasync" appender which will create a log file with a name defined by <Target>; this log file will receive an entry for log events of all levels. Each entry will be formatted using the <PatternLayout>.

This should answer the "when is it used" part of the question.

In the <PatternLayout> you can use %<name> and %<name>{<format>} to format attributes from the event into the log entry. ~red and ~normal can only be used with the console, I think the demo and the names explains what they do.

The possible <name>'s can be found in $(ProDir)\pfc\log\formatter.pro:

Code: Select all

constants     proc = "proc".     thread = "thread".     userid = "userid".     username = "username".     date = "date".     time = "time".     msg = "msg".     msglevel = "msglevel".     newline = "newline".     callerClassName = "callerclassname".     callerPredicateName = "callerpredicatename".     callerCursor = "callercursor".     linenumber = "lineno".     seqnumber = "seqno".     applicationName = "applicationname".
The formatting you will have to "guess and experiment" with at present (or inspect the code of course).
Regards Thomas Linder Puls
PDC

B.Hooijenga
Active Member
Posts: 95
Joined: 11 Jul 2002 23:01

Re: logging

Post by B.Hooijenga » 30 May 2018 10:08

Thank you Thomas,

I will study it further.

Kind regards

Ben

Post Reply