Logging

Web app will log four outputs as follows.

Log
File name
Content
App log app.log Logging of Web application.
Developers output the log here.  See below about output method.
Access log access.log Logging access from the browser.
Including access to a static file.
TreeFrog log treefrog.log Logging of the TreeFrog system.
Since it is the log that the system output, when an error occurs, some information may be available here. 
Query log query.log Query log issued to the database.  Specify the file name in the file value of SqlQueryLog in the configuration file.
When stopping the output, empty it.  Because there is overhead when the log is outputting, it is a good idea to stop the output when you operate a formal Web application.

  

Output of the Application Log

The application log is used for logging Web application. Use the following method if you want to output the application log.

  • tFatal()
  • tError()
  • tWarn()
  • tInfo()
  • tDebug()
  • tTrace()

Arguments that can be passed are the same as the printf-format of  format string and a variable number.  For example, like this.

 tError("Invalid Parameter : value : %d", value);

 
Then, the following log will be output to the log/app.log file.

 2011-04-01 21:06:04 ERROR [12345678] Invalid Parameter : value : -1

 
Line feed code is not required at the end of the format string.

Changing Log Layout

It is possible to change the layout of the log output, by setting FileLogger.Layout parameters in the configuration file logger.ini.

# Specify the layout of FileLogger.
#  %d : date-time
#  %p : priority (lowercase)
#  %P : priority (uppercase)
#  %t : thread ID (dec)
#  %T : thread ID (hex)
#  %i : PID (dec)
#  %I : PID (hex)
#  %m : log message
#  %n : newline code
FileLogger.Layout="%d %5P [%t] %m%n"

 
The date and time when the log was generated is inserted as indicated by the '%d' in the log layout.  
The date format is specified in the FileLogger.DateTimeFormat parameter.  The format that can be specified is the same value to the argument of QDateTime::toString().  Please refer to the Qt document for further detail. 

# Specify the date-time format of FileLogger, see also QDateTime
# class reference.
FileLogger.DateTimeFormat="yyyy-MM-dd hh:mm:ss"

 

Changing the Logging Level

You can set log output level at the following parameter in logger.ini.

# Outputs the logs of equal or higher priority than this.
FileLogger.Threshold=debug

 
In this example, the log level is higher than debug.

  
  In brief: Output the debug log (necessary for development) using the tDebug() function.

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