Logging

Qlik NPrinting has detailed log files, which let log analysts view events logged by different services. For example, it is possible to follow a request spread into different tasks and joined back to create a response.

When you need to troubleshoot a problem, start by checking rows with errors in the log files. You will usually find useful error messages to help you understand the origin of the issue. You should include the log files in your support requests.

Overview

Log files are saved in %ProgramData%\NPrinting\Logs. They are divided into three families:

  • nprinting_scheduler.log (contains the log of Qlik NPrinting scheduler service)
  • nprinting_webengine.log
  • nprinting_engine.log

When a file becomes too big to be easily managed, Qlik NPrinting creates a new file and adds a progressive integer suffix to the old file. So the file with no suffix is the current file, and the files with suffixes are the older files. A larger suffix indicates older files. For example:

  • \NPrinting\Logs (newest file)
  • \NPrinting\Logs.1
  • \NPrinting\Logs.2 (oldest file)

These files are not rotated on a daily basis. You have to manually delete old files to save disk space. The number of files kept depends on the settings in the following config files:

  • C:\Program files\NPrintingServer\NPrinting\Engine\Qlik.NPrinting.Engine.config (Engine Service)
  • C:\Program files\NPrintingServer\NPrinting\Scheduler\Qlik.NPrinting.Scheduler.config (SchedulerService)
  • C:\Program files\NPrintingServer\NPrinting\Webengine\Qlik.NPrinting.Webengine.config (WebEngine Service)

You can change these settings by editing these strings:

<maxSizeRollBackups value="3" />

<maximumFileSize value="10MB" />

For example: If you change the value of maxSizeRollBackups to 10 in Qlik.NPrinting.Engine.config, Qlik NPrinting will keep 11 files (current file + 10 archived files). If you change the value of maximumFileSize to 20MB, log files will reach double their default maximum size before triggering the creation of a new file.

Note that there are two sections: one for normal log files and one for _dev files (when debug level is enabled). You must customize the appropriate section, or both.

Log files structure

All log files have the following fields:

  • Product Assembly Name
  • Product Version
  • Class Name
  • Timestamp
  • Severity
  • Hostname
  • User name
  • User ID
  • WebEngine Request ID
  • Connection ID
  • Task ID
  • Execution ID
  • Report ID
  • Request ID
  • Transformation ID
  • Message
  • Exception
  • Stacktrace

Log files are tab-separated value files, so they can be imported as tables.

Changing log details level

The log level is set to INFO by default. You can change the log level to DEBUG of a Windows service.

Do the following:

  1. Open the appropriate configuration file with a text editor:
    • C:\Program Files\NPrintingServer\NPrinting\Engine\Qlik.NPrinting.Engine.exe.config
    • C:\Program Files\NPrintingServer\NPrinting\Scheduler\Qlik.NPrinting.Scheduler.exe.config
    • C:\Program Files\NPrintingServer\NPrinting\WebEngine\Qlik.NPrinting.WebEngine.exe.config

    Where C:\Program Files\NPrintingServer is the Qlik NPrinting Server installation path. Adapt it to your installation if necessary.

    If you want to view Qlik NPrinting On-Demand logs, you need to set Qlik.NPrinting.Engine.exe.config to DEBUG.

  2. Search for:

    <root>

    <level value="INFO" />

    <appender-ref ref="LogFileAppender" />

    <!--Uncomment the row below and set the level value above to obtain the logs in the file nprinting_engine_dev.log-->

    <!--<appender-ref ref="LogFileAppenderDev" />-->

    <appender-ref ref="LogFileAppender" />

    </root>

  3. Change level value to "DEBUG":

    <root>

    <level value="DEBUG" />

    <appender-ref ref="LogFileAppender" />

    <!--Uncomment the row below and set the level value above to obtain the logs in the file nprinting_engine_dev.log-->

    <!--<appender-ref ref="LogFileAppenderDev" />-->

    <appender-ref ref="LogFileAppender" />

    </root>

  4. Uncomment: <!--<appender-ref ref="LogFileAppenderDev" />-->

  5. Save the edited files.
  6. Restart the corresponding Windows service.

When you change a log level to DEBUG, a new log file is created. The new log file has the same name as the log file with INFO details level followed by _dev. For example:

  • nprinting_scheduler_dev.log
  • nprinting_webengine_dev.log
  • nprinting_engine_dev.log

The default log files will still be present and will continue to only have INFO level information.

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