Re: [logback-user] Filtering stacktraces by evaluating packages

5 Dec 2011

      I've done something very similar to this here:
https://github.com/Mahoney/lidalia-logging/

Basically using the decorator pattern around Events.

Specifically look at EventTransformingAppender and StackTraceCleanser, and have a look at src/main/resources/logback.xml to see how to configure it.  It's currently very specific to getting rid of Groovy noise, but it would be trivial to generalise it to get rid of other frames.

----- Original Message -----
...
From: "Christopher BROWN" <brown@reflexe.fr>
To: "LogBack Users list" <logback-user@qos.ch>
Sent: Monday, 5 December, 2011 11:44:25 AM
Subject: [logback-user] Filtering stacktraces by evaluating packages
Hello,
I would like to simplify stacktraces when errors occur in an
application. For example, with a hypothetical stack such as:
com.xyz.Wombat.doSomething
javax.servlet.http.HttpServlet.service
org.appserver.JspCompiler.handleJsp
org.appserver.ServletEngine.handleServlet
java.lang.Thread.run
...going down from top-to-bottom, I'd like to detect that line
"org.appserver.JspCompiler.handleJsp" has been found, and exclude it
-- and all subsequent "lower down" stack frames -- from logging
output.
Looking at http://logback.qos.ch/manual/layouts.html#Evaluators I
assume it must be possible with EventEvaluator because of the syntax
%xEx{evaluator-n} but I can't find an example. Furthermore, as I set
up LogBack programmatically (and not via XML or any of bundled
"configurator"), I'd be happiest if I could be directed towards an
API-based example.
If it's of any use, here are two methods extracted from the class that
I use to configure LogBack (incomplete but should help see what I'm
trying to do, and how):
private synchronized boolean maybeInitialize(final Logger logger,
String pattern)
{
// will throw ClassCastException if our configuration is incorrect (or
accessed from wrong classloader)
// that's OK, it's what should happen...
final ch.qos.logback.classic.Logger impl =
(ch.qos.logback.classic.Logger)logger;
// if there's an appender, then the logger seems to have been
configured
Iterator<Appender<ILoggingEvent>> it = impl.iteratorForAppenders();
if (it.hasNext())
{
return false;
}
String logFileName = impl.getName();
if (logFileName.startsWith(LOG_FILE_STDPREFIX) && logFileName.length()
...
LOG_FILE_STDPREFIX.length())
{
logFileName = logFileName.substring(LOG_FILE_STDPREFIX.length());
}
logFileName += LOG_FILE_EXTENSION;
Appender<ILoggingEvent> appender;
if (CONFIG_VALUE_ROLL_TYPE_DATE.equals(_rollType))
{
appender = createRollByDateFileAppender(logFileName, pattern != null ?
pattern : PATTERN_FOR_DATE);
}
else if (CONFIG_VALUE_ROLL_TYPE_SIZE.equals(_rollType))
{
appender = createRollBySizeFileAppender(logFileName, pattern);
}
else
{
appender = createFileAppender(logFileName, pattern);
}
appender.start();
impl.addAppender(appender);
impl.setLevel(_level);
impl.setAdditive(false);
return true;
}
private synchronized boolean maybeInitialize(final Logger logger,
String pattern)
{
// will throw ClassCastException if our configuration is incorrect (or
accessed from wrong classloader)
// that's OK, it's what should happen...
final ch.qos.logback.classic.Logger impl =
(ch.qos.logback.classic.Logger)logger;
// if there's an appender, then the logger seems to have been
configured
Iterator<Appender<ILoggingEvent>> it = impl.iteratorForAppenders();
if (it.hasNext())
{
return false;
}
String logFileName = impl.getName();
if (logFileName.startsWith(LOG_FILE_STDPREFIX) && logFileName.length()
...
LOG_FILE_STDPREFIX.length())
{
logFileName = logFileName.substring(LOG_FILE_STDPREFIX.length());
}
logFileName += LOG_FILE_EXTENSION;
Appender<ILoggingEvent> appender;
if (CONFIG_VALUE_ROLL_TYPE_DATE.equals(_rollType))
{
appender = createRollByDateFileAppender(logFileName, pattern != null ?
pattern : PATTERN_FOR_DATE);
}
else if (CONFIG_VALUE_ROLL_TYPE_SIZE.equals(_rollType))
{
appender = createRollBySizeFileAppender(logFileName, pattern);
}
else
{
appender = createFileAppender(logFileName, pattern);
}
appender.start();
impl.addAppender(appender);
impl.setLevel(_level);
impl.setAdditive(false);
return true;
}
Thanks,
Christopher
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Re: [logback-user] Filtering stacktraces by evaluating packages

Robert Elliot