Configuring Logging

There are three main components in log4j as Loggers, Appenders, and Layouts. You can change these parameters both globally and individually, at run time. Follow the steps below to configure logging properties using the management console.

1. Log in to the product's management console and select Configure > Logging.  
    
    

2. The Logging Configuration page appears as follows:
   
   It has the following configuration options:

   Configuration Option	Description
   Persist All Configuration Changes	Allows you to persist all modifications, which will be available even after the server restarts.
   Global Log4J Configuration	This section allows you to assign a single log level and log pattern to all loggers. Log Level : Severity of the message. Reflects a minimum level for the logger. You can view the hierarchy of levels. Log Pattern : Defines the output format of the log file. This is the layout pattern that describes the log message format. Restore Defaults button allows to overwrite the Registry with the logging configurations specified in log4j.properties file.
   Configure Log4J appenders	This section allows you to configure appenders individually. Log4j allows logging requests to print to multiple destinations. These output destinations are called Appenders. You can attach several appenders to one logger. Name : The name of an appender. Following log appenders are configured by default: CARBON_CONSOLE - Logs to the console when the server is running. CARBON_LOGFILE - Writes the logs to AS_HOME/repository/logs/wso2carbon.log. CARBON _MEMORY CARBON_SYS_LOG - Allows separation of the software that generates messages from the system that stores them and the software that reports and analyzes them. CARBON_TRACE_LOGFILE   Log pattern - Defines the output format of the log file. Sys Log Host - The IP address of the system log server. The syslog server is a dedicated log server for many applications. It runs in a particular TCP port in a separate machine, which can be identified by an IP address. Facility - The log message type sent to the system log server. Threshold - Filters log entries based on their level. For example, threshold set to "WARN" will allow log entry to pass into appender if its level is "WARN," "ERROR" or "FATAL," other entries will be discarded. This is the minimum log level at which you can log a message. The available categories of logs you can view are: TRACE - Designates fine-grained informational events than the DEBUG. DEBUG - Designates fine-grained informational events that are most useful to debug an application. INFO - Designates informational messages that highlight the progress of the application at coarse-grained level. WARN - Designates potentially harmful situations. ERROR - Designates error events that might still allow the application to continue running. FATAL - Designates very severe error events that will presumably lead the application to abort.
   Configure Log4J Loggers	A Logger is an object used to log messages for a specific system or application component. Loggers are normally named, using a hierarchical dot-separated namespace and have a "child-parent" relationship. For example, the logger named "root.sv" is a parent of the logger named "root.sv.sf" and a child of "root." When the server starts for the first time, all the loggers initially listed in the log4j.properties file appear on the logger name list. This section allows you to browse through all these loggers, define a log level and switch on/off additivity to any of them. After editing, the logging properties are read only from the database. Logger - The name of a logger. Parent Logger - The name of a parent logger. Level - Allows to select level (threshold) from the drop-down menu. After you specify the level for a certain logger, a log request for that logger will only be enabled if its level is equal or higher to the logger’s one. If a given logger is not assigned a level, then it inherits one from its closest ancestor with an assigned level. Refer to hierarchy of levels above.   Additivity - Allows to inherit all the appenders of the parent Logger if set as True. In this section, loggers can be filtered by the first characters (use the Starts With button) or by a combination of characters (use the Contains button). For example, to receive data service level debug logs, search by the name "dataservice" and set the loggers to DEBUG using either the management console. Their logger level of dataservice logs is set to INFO by default. You can also set them using the log4j.properties file, but changing through the UI does not require a server restart.