Using the Default Log4j 2-Based Logging System

Logi Report uses SLF4J with Apache Log4j 2 by default. This logging system has the following significant benefits:

• Easy to configure and manage.
• Compatible with your application that also uses the Log4j 2 libraries.
• Can be configured to output the log information of different modules separately or to output them all together.

Configuring Logs

To configure the behavior of Logi Report's default logging system, perform either of the following:

• Use the LogConfig.properties file in the <designer_install_root>\bin directory.
• Use command options at command-line startup.
  
  • -vDebug
    Set engine file's log level to INFO.
  • -vError
    Set engine file's log level to ERROR.
  • -log[:<file>]
    Output message to the specified file using the -vDebug level.

• Any settings made using the command options override the log level setting in LogConfig.properties. To log on console when using the -vDebug or -vError option, you need to configure the appender in LogConfig.properties first.
• The use of the following conversion characters results in slow generation of caller class or location information: %C, %F, %L, and %M. You should avoid using them unless execution speed is not an issue. For more information about conversion pattern, see the comments in LogConfig.properties.

Configuring Output Log Appenders

The default logging system of Logi Report provides certain appenders to which you can output the log content. By default, the output file is in the <designer_install_root>\logs directory. For example:

• RollingFile
• DailyRollingFile
• Console

All the log categories use one appender by default, which is RollingFile. You can also define different output appenders or files for different log categories in LogConfig.properties. For example, to add another log appender, Console, you can edit LogConfig.properties as follows:

appenders=, RollingFile, Console
...
appender.console.type=Console
appender.console.name=STDOUT
appender.console.layout.type=PatternLayout
appender.console.layout.pattern=%m[%p][%C]%n
...

Setting the Log Level

Logi Report's default logging system supports the following log levels, which are sorted according to the amount of the logged information, from the least to the most.

• OFF
  No information logs.
• ERROR
  The ERROR level specifies error events that may allow the application to continue running, such as failing to load a report, failing to find a catalog file, failing to parse a parameter, and failing to create DB buffer. It also specifies severe error events that presumably lead the application to abort, for example, failing to read the valid key, and exceptions that result in feature incomplete.
• WARN
  The WARN level specifies potentially harmful situations, such as failing to find the resource, or having found invalid query or formula with grammar error when loading a catalog.
  
• INFO
  The INFO level specifies an outline of program workflow, and dump global variables, including a single thread, multiple threads, the time for when to begin to fetch data, and success in exporting to the specified result format.
• DEBUG
  The DEBUG level specifies informational messages that highlight the application progress at a coarse-grained level, and important local variables, such as query, parameter, formula value used when running reports, connection information, and SQL statement.
• TRACE
  The TRACE level specifies fine-grained informational events most useful in tracing an application, such as the report structure dump or the result set dump.

You can specify the log level appropriately to get the most helpful log information. If you want to log the least amount of information, you can set the level to ERROR; if you want to log the most amount of information, set the level to TRACE. Setting the level to the highest could affect system performance and disk usage.

Applying Another Logging Framework

You can easily migrate to another logging framework in Designer, by replacing the Log4j 2 libraries with the specific libraries of the logging framework.

After changing the default logging framework Logi Report applies, you should use the corresponding libraries of the new logging framework when you call the Logi Report Java APIs.

Using SimpleLogger

To log using SLF4J's SimpleLogger in Designer, remove the three Log4j 2 libraries: log4j-api, log4j-core, and log4j-slf4j-impl in <designer_install_root>\lib, and add the two libraries of SimpleLogger, slf4j-api and slf4j-simple to the directory, for example, add slf4j-api-1.7.36.jar and slf4j-simple-1.7.36.jar.

You can configure the behavior of SimpleLogger by creating the simplelogger.properties configuration file and adding this file to the slf4j-simple library. For more information about SimpleLogger, go to https://www.slf4j.org/api/org/slf4j/simple/SimpleLogger.html. If you do not add the configuration file, Designer outputs the log to LogiReport.out.log in <designer_install_root>\logs by default, and you can use the -Dorg.slf4j.simpleLogger.defaultLogLevel option at command-line startup to specify the log level to be trace, debug, info, warn, error, or off.

Using JUL (java.util.logging)

To log using SLF4J with JUL in Designer, remove the three Log4j 2 libraries: log4j-api, log4j-core, and log4j-slf4j-impl in <designer install_root>\lib, and add the JDK logging library slf4j-jdk14 to the directory, for example, add slf4j-jdk14-1.7.36.jar.

You can configure the behavior of JUL using its default configuration file $JAVAHOME\jre\lib\logging.properties. You can also create your own configuration file, and then use the -Djava.util.logging.config.file JVM option to add the file to the CLASSPATH environment variable of Designer's startup file JReport.bat in <designer_install_root>\bin, for example:

...-classpath "%CLASSPATH%" -Dreporthome="%REPORTHOME%" -Djava.util.logging.config.file="C:\LogiReport\Designer\mylog.properties" -Djreport.url.encoding="UTF-8"...

For more information about JUL, go to https://docs.oracle.com/javase/8/docs/technotes/guides/logging/index.html.

Using Logevents

To log using SLF4J with Logevents in Designer, remove the three Log4j 2 libraries: log4j-api, log4j-core, and log4j-slf4j-impl in <designer_install_root>\lib, and add the two libraries of Logevents, slf4j-api and logevents to the directory, for example, add slf4j-api-1.7.36.jar and logevents-0.3.4.jar.

You can configure the behavior of Logevents by creating the logevents.properties configuration file in <designer_install_root>\bin, and then using the -Dlogevents.driectory JVM option to add this file to the CLASSPATH environment variable of Designer's startup file JReport.bat in the same directory, for example:

...-classpath "%CLASSPATH%" -Dreporthome="%REPORTHOME%" -Dlogevents.directory="C://LogiReport//Designer//logevents.properties" -Djreport.url.encoding="UTF-8"...

If you do not add the configuration file, Designer outputs the log to LogiReport.out.log in <designer_install_root>\logs by default.

For more information about Logevents, go to https://github.com/jhannes/logevents/blob/main/MANUAL.md.

Using Log4j

To log using SLF4J with Log4j in Designer, remove the three Log4j 2 libraries: log4j-api, log4j-core, and log4j-slf4j-impl in <designer_install_root>\lib, and add the three libraries of Log4j, log4j, slf4j-log4j12, and slf4j-api to the directory, for example, add log4j-1.2.17.jar, slf4j-log4j12-1.7.25.jar, and slf4j-api-1.7.36.jar.

You can configure the behavior of Log4j by creating a configuration file, and then using the -Dlog4j.configuration JVM option to add this file to the CLASSPATH environment variable of Designer's startup file JReport.bat in <designer_install_root>\bin, for example:

...-classpath "%CLASSPATH%" -Dreporthome="%REPORTHOME%" -Dlog4j.configuration="file:\C:\LogiReport\Designer\log4j.properties" -Djreport.url.encoding="UTF-8"...

For more information about Log4j, go to https://logging.apache.org/log4j/1.2/manual.html.

Using reload4j

To log using SLF4J with reload4j in Designer, remove the three Log4j 2 libraries: log4j-api, log4j-core, and log4j-slf4j-impl in <designer_install_root>\lib, and add the two libraries of reload4j, reload4j and slf4j-reload4j to the directory, for example, add reload4j-1.2.18.3.jar and slf4j-reload4j-1.7.36.jar.

You can perform log configuration for reload4j using the same method as you do for Log4j. For more information about reload4j, go to https://reload4j.qos.ch/.

Using logback

To log using SLF4J with logback in Designer, remove the three Log4j 2 libraries: log4j-api, log4j-core, and log4j-slf4j-impl in <designer_install_root>\lib, and add the two libraries of logback, logback-classic and logback-core to the directory, for example, add logback-classic-1.2.11.jar and logback-core-1.2.11.jar.

You can configure the behavior of logback by creating a configuration file, and then using the -Dlogback.configurationFile JVM option to add this file to the CLASSPATH environment variable of Designer's startup file JReport.bat in <designer_install_root>\bin, for example:

...-classpath "%CLASSPATH%" -Dreporthome="%REPORTHOME%" -Dlogback.configurationFile="file:\C:\LogiReport\Designer\logback.xml" -Djreport.url.encoding="UTF-8"...

For more information about logback, go to https://logback.qos.ch/documentation.html.