Ron Grabowski created LOG4J2-2986:
-------------------------------------
Summary: Allow stacktrace pattern converters to specify a starting
point to ignore redundant framework stack elements
Key: LOG4J2-2986
URL: https://issues.apache.org/jira/browse/LOG4J2-2986
Project: Log4j 2
Issue Type: Improvement
Components: Layouts
Reporter: Ron Grabowski
Stack traces from applications in well-known environments can be reduced by
removing certain bottom components of the stack such as the web container and
core framework. For example every exception thrown from an application running
on the fictional Acme framework hosted in Tomcat might produce a stack trace
like this:
{code:java}
at
example.internal.acme.parser.AcmeMethodInfo$AcmeMethodCallHandler.handleCall(AcmeMethodInfo.java:275)
at
example.xml.ws.DefaultWsiInvocationHandler.invoke(DefaultWsiInvocationHandler.java:56)
at
example.internal.xml.ws.server.WebservicesServletBase.doPost(WebservicesServletBase.java:500)
at
example.internal.xml.ws.server.WebservicesServletBase.doPost(WebservicesServletBase.java:402)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:650)
at
example.internal.xml.ws.server.WebservicesServletBase.service(WebservicesServletBase.java:1080)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at
org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
at
org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
at
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:505)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:169)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:956)
at
org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:436)
at
org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1078)
at
org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:625)
at
org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
at
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at
org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:745)
{code}
When shipping logs to a log aggregation tool the stack trace could be greatly
reduced (sometimes more than 50%) by omitting the unhelpful duplicate code that
appears with each exception.
Its not always possible to catch and re-throw with a reduced stack.
The exception patterns on this page allow some filtering but I don't want to
filter out the entire _org.apache_ or _example.internal_ packages. The depth
parameter seems to start from the top:
[https://logging.apache.org/log4j/log4j-2.0/manual/layouts.html]
{code:java}
rException["none"|"short"|"full"|depth],[filters(packages)}
{code}
I briefly scanned the code and couldn't tell if depth supported negative
numbers. A negative depth could indicate how many lines from the bottom should
be skipped. From the example above the value would be "depth=-27". A alternate
(better?) way to express a starting point would be to list what to start with.
This example removes the web container noise and starts the stack trace closer
to meaningful code:
{code}
startWith=javax.servlet.http.HttpServlet.service
{code}
This syntax expresses a slightly more accurate starting point and allows for
more than one starting point:
{code}
startWith=example.internal.acme.parser.AcmeMethodInfo$AcmeMethodCallHandler.handleCall,javax.servlet.http.HttpServlet.service
{code}
Another example of the syntax:
{code:xml}
<properties>
<property
name="startWith">example.internal.acme.parser.AcmeMethodInfo$AcmeMethodCallHandler.handleCall,javax.servlet.http.HttpServlet.service</property>
</properties>
<PatternLayout pattern="%m%xEx{startWith(${startWith})}%n"/>
{code}
I don't know if this should be implemented with simple string manipulation
(regex, substring, etc) or actually inspecting each StackTraceElement.
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