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WebLogic logging services provide several filtering options that give you the flexibility to determine which messages are written to WebLogic Server log files and standard out, and which are written to the log file and standard out that a client JVM maintains. Most of these filtering features are implementations of the Java Logging APIs, which are available in the java.util.logging package.
The following sections describe how to filter messages that the WebLogic logging services generate:
When WebLogic Server message catalogs and the NonCatalogLogger generate messages, they distribute their messages to a java.util.logging.Logger object. The Logger object publishes the messages to any message handler that has subscribed to the Logger.
WebLogic Server instantiates Logger and Handler objects in three distinct contexts (See Figure 4-1):
Logger object publishes messages that are sent from client applications running in the client JVM.
The following handlers subscribe to the Logger object in a client JVM:
ConsoleHandler, which prints messages from the client JVM to the client’s standard out.
If you use the -Dweblogic.log.StdoutSeverityLevel Java startup option for the client JVM, WebLogic logging services create a filter for this handler that limits the messages that the handler writes to standard out. See
“Writing Messages from a Client Application” in Using WebLogic Logging Services for Application Logging.
FileStreamHandler, which writes messages from the client JVM to the client’s log file.Logger object publishes messages that are sent from subsystems and applications that run on a server instance.
The following handlers subscribe to the server Logger object:
Logger object in addition to a server Logger object. The domain Logger object receives messages from each Managed Server’s Logger object.
The following handler subscribes to the domain Logger object:
When WebLogic Server message catalogs and the NonCatalogLogger generate messages, they convert the message severity to a weblogic.logging.WLLevel object. A WLLevel object can specify any of the following values, from lowest to highest impact:
TRACE, DEBUG, INFO, NOTICE, WARNING, ERROR, CRITICAL, ALERT, EMERGENCY
By default, a Logger object publishes messages of all levels. To set the lowest-level message that a Logger object publishes, you use a simple Logger.setLevel API. When a Logger object receives an incoming message, it checks the message level with the level set by the setLevel API. If the message level is below the Logger level, it returns immediately. If the message level is above the Logger level, the Logger allocates a WLLogRecord object to describe the message.
For example, if you set a Logger object level to WARNING, the Logger object publishes only WARNING, ERROR, CRITICAL, ALERT, or EMERGENCY messages.
To provide more control over the messages that a Logger object publishes, you can also create and set a filter. A filter is a class that compares data in the WLLogRecord object with a set of criteria. The Logger object publishes only the WLLogRecord objects that satisfy the filter criteria. For example, a filter can configure a Logger to publish only messages from the JDBC subsystem. To create a filter, you instantiate a java.util.logging.Filter object and use the Logger.setFilter API to set it for a Logger object.
Instead of (or in addition to) setting the level and a filter for the messages that a Logger object publishes, you can set the level and filters on individual message handlers.
For example, you can specify that a Logger publishes messages that are of the WARNING level or higher. Then you can do the following for each handler:
ConsoleHandler, set a level and filter that selects only ALERT messages from the JDBC, JMS, and EJB subsystems. This causes standard out to display only ALERT messages from the JDBC, JMS, and EJB subsystems.FileStreamHandler, set no additional level or filter criteria. Because the Logger object has been configured to publish only messages of the WARNING level or higher, the log file will contain all messages from all subsystems that are of WARNING severity level or higher.WARNING severity level or higher to the domain-wide message log on the Administration Server.
The Administration Console and WLST provide a way to set the severity level for a Handler object through standard MBean commands. To set the Severity level for a Logger object, you can use the Logger API. You can also set the Severity level for a Logger via the Administrator Console, WLST, or the command line; see Specifying Severity Level for Loggers. To configure Logger and Handler severity level for WLS clients (such as EJB and Web Service clients), you must use the Java Logging API.
To set the severity level for a Logger object, create a class that does the following:
LoggingHelper methods:getClientLogger if the current context is a client JVM.getServerLogger if the current context is a server JVM and you want to retrieve the Logger object that a server uses to manage its local server log.getDomainLogger if the current context is the Administration Server and you want to retrieve the Logger object that manages the domain log.
The LoggerHelper method returns a Logger object. See the Sun API documentation for Logger:
http://java.sun.com/j2se/1.5.0/docs/api/java/util/logging/Logger.html
Logger.setLevel(Level level) method.
To set the level of a WebLogic Server Logger object, you must pass a value that is defined in the weblogic.logging.WLLevel class. WebLogic Server maps the java.util.logging.Level to the appropriate WLLevel. For a list of valid values, see the WLLevel
Javadoc.
To set the severity level for a Handler object using the API, create a class that does the following (See Listing 4-1):
LoggingHelper methods:getClientLogger if the current context is a client JVM.getServerLogger if the current context is a server JVM and you want to retrieve the Logger object that a server uses to manage its local server log.getDomainLogger if the current context is the Administration Server and you want to retrieve the Logger object that manages the domain log.
The LoggerHelper method returns a Logger object. See the Sun API documentation for Logger:
http://java.sun.com/j2se/1.5.0/docs/api/java/util/logging/Logger.html
Logger.getHandlers() method.
The method returns an array of all handlers that are registered with the Logger object.
Handler object for which you want to set a level.
Use Handler.getClass().getName() to determine the type of handler to which the current array index refers.
Handler.setLevel(Level level) method.
To set the level of a WebLogic Server Handler object, you must pass a value that is defined in the weblogic.logging.WLLevel class. WebLogic Server maps the java.util.logging.Level to the appropriate WLLevel. For a list of valid values, see the WLLevel
Javadoc.
import java.util.logging.Logger;
import java.util.logging.Handler;
import weblogic.logging.LoggingHelper;
import weblogic.logging.WLLevel;
public class LogLevel { public static void main(String[] argv) throws Exception {Logger serverlogger = LoggingHelper.getServerLogger();
Handler[] handlerArray = serverlogger.getHandlers();
for (int i=0; i < handlerArray.length; i++) {
Handler h = handlerArray[i];
if(h.getClass().getName().equals
(“weblogic.logging.ConsoleHandler”)){
h.setLevel(WLLevel.ALERT);
}
}
}
}
You can configure the severity level for a Handler object through the LogMBean interface using the Administration Console or the command line:
INFO.C:\>java weblogic.WLST
wls:/offline> connect('username','password')
wls:/mydomain/serverConfig> edit()
wls:/mydomain/edit> startEdit()
wls:/mydomain/edit !> cd("Servers/myserver/Log/myserver")
wls:/mydomain/edit/Servers/myserver/Log/myserver !> cmo.setStdoutSeverity("Info")
wls:/mydomain/edit/Servers/myserver/Log/myserver !> save()
wls:/mydomain/edit/Servers/myserver/Log/myserver !> activate()
For more information about using WLST, see
“Using the WebLogic Scripting Tool” in WebLogic Scripting Tool. For more information about setStdoutSeverity, see LogMBean in the WebLogic Server MBean Reference.
When you set a filter on the Logger object, the filter specifies which messages the object publishes; therefore, the filter affects all handlers that are registered with the Logger object as well. When you set a filter on a handler, the filter affects only the behavior of the specific handler.
The Administration Console and WLST provide a way to set a filter on the Handler object through standard MBean commands. To set a filter on the Logger object, you must use the Logger API. For client-side logging, the only way to set a filter is through using the Java Logging API.
java.util.logging.Filter. See Listing 4-3.
The class must include the Filter.isLoggable method and logic that evaluates incoming messages. If the logic evaluates as true, the isLoggable method enables the Logger object to publish the message.
Logger object is running.Logger object, create a class that does the following:getClientLogger if the current context is a client JVM.getServerLogger if the current context is a server JVM and you want to filter the Logger object that a server uses to manage its local server log.getDomainLogger if the current context is the Administration Server and you want to filter the Logger object that manages the domain server log.Handler object using the API, create a class that does the following:getClientLogger if the current context is a client JVM.getServerLogger if the current context is a server JVM and you want to filter the Logger object that a server uses to manage its local server log.getDomainLogger if the current context is the Administration Server and you want to filter the Logger object that manages the domain server log.Listing 4-3 provides an example class that rejects all messages from the Deployer subsystem.
import java.util.logging.Logger;
import java.util.logging.Filter;
import java.util.logging.LogRecord;
import weblogic.logging.WLLogRecord;
import weblogic.logging.WLLevel;
public class MyFilter implements Filter {
public boolean isLoggable(LogRecord record) {
if (record instanceof WLLogRecord) {
WLLogRecord rec = (WLLogRecord)record;
if (rec.getLoggerName().equals("Deployer")) {
return false;
} else {
return true;
}
} else {
return false;
}
}
}
You can configure a filter for a Handler object through the LogMBean interface using the Administration Console or the command line:
C:\>java weblogic.WLST
wls:/offline> connect('username','password')
wls:/mydomain/serverConfig> edit()
wls:/mydomain/edit> startEdit()
wls:/mydomain/edit !> cmo.createLogFilter('myFilter')
wls:/mydomain/edit !> cd("Servers/myserver/Log/myserver")
wls:/mydomain/edit/Servers/myserver/Log/myserver !> cmo.setDomainLogBroadcastFilter(getMBean('/LogFilters/myFilter'))
wls:/mydomain/edit/Servers/myserver/Log/myserver !> save()
wls:/mydomain/edit/Servers/myserver/Log/myserver !> activate()
For more information about using WLST, see “Using the WebLogic Scripting Tool” in WebLogic Scripting Tool. For more information about setDomainLogBroadcastFilter, see LogMBean in the WebLogic Server MBean Reference.
To filter the messages that each Managed Server publishes to the domain log, you can use the Administration Console (see “Create log filters”) or WLST (see Listing 4-4) to create a log filter for the domain log.
Any Java Logging severity level or filter that you set on the Logger object that manages a server instance’s log file supersedes a domain log filter. For example, if the level of the server Logger object is set to WARNING, a domain log filter will receive only messages of the WARNING level or higher.
You can define a domain log filter which modifies the set of messages that one or more servers send to the domain log. By default, all messages of severity NOTICE or higher are sent.
| Note: | Messages of severity DEBUG are never sent to the domain log, even if you use a filter. |
See “Filter log messages” in the Administration Console Online Help which describes configuring a domain log filter for a WebLogic Server instance using the Administration Console.
The Administration Console and WLST provide a way to set the level for an Appender object through standard MBean commands. To set the level for a Logger object, you can use the Logger API as described in this section, or you can do so from the Administration Console, WLST, or the command line as described in Specifying Severity Level for Loggers.
To set the level for an Appender object using the API, create a class that does the following:
Log4jLoggingHelper methods (See Listing 4-5).logger.getAllAppenders() method.
Enumeration e = logger.getAllAppenders();
The method returns all the appenders that are registered with the Logger object.
app.setThreshold(WLLog4jLevel level) method.
To set the level of a Log4j Appender object, you must pass a value that is defined in the weblogic.logging.log4j.WLLog4jLevel class. WebLogic Server maps the org.apache.log4j.Level to the appropriate WLLevel. For a list of valid values, see the WLLevel
Javadoc.
To set a filter, implement a class that extends org.apache.log4j.Filter and adds the filter to the Appender, invoke the app.addFilter(Filter newFilter) method.
Listing 4-5 provides an example class that does the following:
WARNING level or higher in the server log.INFO level or higher to standard out.INFO messages from the HTTP subsystem.package weblogic.logging.examples;
import java.util.Enumeration;
import org.apache.log4j.AppenderSkeleton;
import org.apache.log4j.Logger;
import org.apache.log4j.spi.Filter;
import org.apache.log4j.spi.LoggingEvent;
import weblogic.logging.LoggerNotAvailableException;
import weblogic.logging.NonCatalogLogger;
import weblogic.logging.Severities;
import weblogic.logging.log4j.AppenderNames;
import weblogic.logging.log4j.Log4jLoggingHelper;
import weblogic.logging.log4j.WLLog4jLevel;
import weblogic.logging.log4j.WLLog4jLogEvent;
/**
* This class sets a level and filter on a Log4j Appender.
*/
public class Log4jFilterExamplesStartup {
public static void main(String[] args) {
try {
System.out.println("Invoked the log4j filter example startup class");
Logger logger = Log4jLoggingHelper.getLog4jServerLogger();
Enumeration e = logger.getAllAppenders();
while (e.hasMoreElements()) {
AppenderSkeleton app = (AppenderSkeleton) e.nextElement();
String name = app.getName();
if (name == null) continue;
if (name.equals(AppenderNames.LOG_FILE_APPENDER)) {
// Set the threshold level of messages going to the log file to WARNING
// This will result in NOTICE, INFO, DEBUG, and TRACE messages being suppressed from going to the server log file
app.setThreshold(WLLog4jLevel.WARN);
System.out.println("Set WARNING level on the log file appender");
} else if (name.equals(AppenderNames.STDOUT_APPENDER)) {
// Set level to INFO on the stdout filter
app.setThreshold(WLLog4jLevel.INFO);
// First clear the existing filters on the appender
app.clearFilters();
// Add a filter to block INFO messages from the HTTP subsystem
app.addFilter(new MyFilter());
}
}// Now test the filter
NonCatalogLogger nc = new NonCatalogLogger("MyFilterTest");
nc.info("INFO messages will not be published to the file but to stdout");
nc.warning("WARNINFG messages will be published to the file and stdout");
} catch(LoggerNotAvailableException lex) {
System.err.println("Log4j logger is not available on this server
}
}
/**
* Deny messages from the HTTP subsystem of level INFO
*/
private static class MyFilter extends Filter {
public int decide(LoggingEvent event) {
if (event instanceof WLLog4jLogEvent) {
WLLog4jLogEvent wlsEvent = (WLLog4jLogEvent)event;
if (wlsEvent.getSubsystem().equals("HTTP")
&& wlsEvent.getSeverity() == Severities.INFO) {
return DENY;
}
}
return ACCEPT;
}
}
}
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