Nick, If you want to combine the formatted message string and the stack trace into a single string in your layout then yes, that is one way to do that.
For reference, take a look at the MessagePatternConverter and ThrowablePatternConverter (used by Log4j's PatternLayout): https://github.com/apache/logging-log4j2/tree/master/log4j-core/src/main/java/org/apache/logging/log4j/core/pattern Conceptually the Message and the Throwable are separate parts of the LogEvent. I think what may have caused some confusion is that initially ParameterizedMessage captures message parameters and the Throwable in a single vararg array, but please consider that an implementation detail. Sent from my iPhone > On 6 Nov 2016, at 10:33, Nicholas Duane <[email protected]> wrote: > > Thanks. I have no problem doing that. Just wondering what needs to be done > and how? I guess I was hoping that the logging framework, eg. log4j, handled > combining the message and the exception such that no matter what > appender/layout you used you'd get consistent results. Sounds like that's > not the case. So are you saying I need to combine the message and the > exception myself within our appender/layout? > > > From the code I included below you can see we're doing: > > > String message = logEvent.getMessage().getFormattedMessage(); > > > to get the event's message. Are you saying we should be doing something like > this: > > > StringWriter sw = new StringWriter(); > logEvent.getThrown().printStackTrace(new PrintWriter(sw)); > String exceptionAsString = sw.toString(); > String message = logEvent.getMessage().getFormattedMessage() + "\n" + > exceptionAsString; > > > Thanks, > > Nick > > ________________________________ > From: Remko Popma <[email protected]> > Sent: Saturday, November 5, 2016 9:16 PM > To: Log4J Users List > Subject: Re: looking for source > > The point is that in a custom layout/appender you should get the throwable > from the LogEvent, not from the Message. That is the design that all Layouts > and Appenders follow and should follow. > > The Message object passed to the Layout may no longer have the Throwable. > > Sent from my iPhone > >> On 6 Nov 2016, at 10:01, Nicholas Duane <[email protected]> wrote: >> >> Thanks for the info. Unfortunately I'm not following. If someone can point >> me to the source in question I will certainly look it over. My sample >> outputs the message (%msg) and when the method logger.error(String message, >> Throwable t) is called it seems some code is combining the supplied string >> message with the exception message and stack trace. Just wondering what >> code is doing that as I'm told someone using our appender/layout is not >> seeing the exception. >> >> >> Thanks, >> >> Nick >> >> ________________________________ >> From: Remko Popma <[email protected]> >> Sent: Friday, November 4, 2016 9:58 PM >> To: Log4J Users List >> Subject: Re: looking for source >> >> The Throwable is initially captured in the Message (usually >> ParameterizedMessage or its garbage-free equivalent), but is later >> transferred to the LogEvent. >> >> By the time the LogEvent reaches the Layout, the Message instance may be a >> different Object than the one that originally held the Throwable. >> >> The Layout should get the Throwable from the LogEvent, not from the Message. >> >> Remko >> >> Sent from my iPhone >> >>> On 5 Nov 2016, at 7:50,Nicholas Duane <[email protected]> wrote: >>> >>> Thanks for the replies. Let me ask a more pointed question now as >>> rummaging through the source will probably take me hours. I'm curious >>> about the overloads with the throwable, for instance: >>> >>> >>> logger.error("some message", <some throwable>); >>> >>> >>> What's the expected behavior? Meaning, what is the logging framework going >>> to do with the message and the exception? I know the message is usually >>> output via the message property in the pattern layout. But what happens >>> with the throwable? Is there some code responsible for constructing a >>> message which combines the supplied message with the throwable exception >>> message and callstack? >>> >>> >>> I wrote the following simple java sample: >>> >>> >>> import org.apache.logging.log4j.Logger; >>> import org.apache.logging.log4j.LogManager; >>> >>> public class Test >>> { >>> private static final Logger logger = LogManager.getLogger(Test.class); >>> >>> public static void main(String[] args) >>> { >>> logger.info("entered main"); >>> try >>> { >>> throw(new IllegalArgumentException("bad argument")); >>> } >>> catch(Throwable t) >>> { >>> logger.error("caught exception", t); >>> } >>> logger.info("exiting main"); >>> } >>> } >>> >>> >>> Here is the log4j2.xml file: >>> >>> >>> <?xml version="1.0" encoding="UTF-8"?> >>> <Configuration status="WARN"> >>> <Appenders> >>> <Console name="Console" > >>> <PatternLayout pattern="%d{HH:mm:ss.SSS} [%t] %-5level %logger{36} >>> \ >>> - %msg%n"/> >>> </Console> >>> </Appenders> >>> <Loggers> >>> <Root level="info"> >>> <AppenderRef ref="Console"/> >>> </Root> >>> </Loggers> >>> </Configuration> >>> >>> >>> Here is the output to the console when I run the sample: >>> >>> >>> [nick@thinkpad log4j]$ java Test >>> 16:37:57.681 [main] INFO Test - entered main >>> 16:37:57.683 [main] ERROR Test - caught exception >>> java.lang.IllegalArgumentException: bad argument >>> at Test.main(Test.java:13) [log4j/:?] >>> 16:37:57.689 [main] INFO Test - exiting main >>> >>> >>> So there does seem to be some code which is combining the message with the >>> exception. Just wondering where that happens. Now onto my specific >>> problem. We've got someone saying that when they use the error() method >>> which takes a string message and an throwable the exception information is >>> not making it to our central repository. We have written our own appender >>> and our own layout. Here is a snippet from our appender: >>> >>> >>> String serializedEvent = (String) getLayout().toSerializable(logEvent); >>> >>> Here is a snippet from our layout: >>> >>> >>> String message = logEvent.getMessage().getFormattedMessage(); >>> >>> >>> It seems the message above does not include any exception info. What are >>> we doing wrong? >>> >>> >>> Thanks, >>> >>> Nick >>> >>> ________________________________ >>> From: Remko Popma <[email protected]> >>> Sent: Friday, November 4, 2016 10:42 AM >>> To: Log4J Users List >>> Subject: Re: looking for source >>> >>> Sure. Start in AbstractLogger in the API module: >>> https://github.com/apache/logging-log4j2/blob/master/log4j-api/src/main/java/org/apache/logging/log4j/spi/AbstractLogger.java > [https://avatars1.githubusercontent.com/u/47359?v=3&s=400]<https://github.com/apache/logging-log4j2/blob/master/log4j-api/src/main/java/org/apache/logging/log4j/spi/AbstractLogger.java> > > apache/logging-log4j2<https://github.com/apache/logging-log4j2/blob/master/log4j-api/src/main/java/org/apache/logging/log4j/spi/AbstractLogger.java> > github.com > logging-log4j2 - Mirror of Apache Logging Log4J2 > > >> [https://avatars1.githubusercontent.com/u/47359?v=3&s=400]<https://github.com/apache/logging-log4j2/blob/master/log4j-api/src/main/java/org/apache/logging/log4j/spi/AbstractLogger.java> >> >> apache/logging-log4j2<https://github.com/apache/logging-log4j2/blob/master/log4j-api/src/main/java/org/apache/logging/log4j/spi/AbstractLogger.java> >> github.com >> logging-log4j2 - Mirror of Apache Logging Log4J2 >> >> >>> >>> and at some point you probably also want to look at the concrete subclass >>> Logger in the core module: >>> https://github.com/apache/logging-log4j2/blob/master/log4j-core/src/main/java/org/apache/logging/log4j/core/Logger.java >> [https://avatars1.githubusercontent.com/u/47359?v=3&s=400]<https://github.com/apache/logging-log4j2/blob/master/log4j-core/src/main/java/org/apache/logging/log4j/core/Logger.java> >> >> apache/logging-log4j2<https://github.com/apache/logging-log4j2/blob/master/log4j-core/src/main/java/org/apache/logging/log4j/core/Logger.java> >> github.com >> logging-log4j2 - Mirror of Apache Logging Log4J2 >> >> >>> >>> Hope this helps to get you started. >>> >>> It may be easier to use an IDE and check out the whole project >>> (https://logging.apache.org/log4j/2.x/source-repository.html). > Log4j – Source Repository - Apache Log4j > 2<https://logging.apache.org/log4j/2.x/source-repository.html> > logging.apache.org > Access from Behind a Firewall. Refer to the documentation of the SCM used for > more information about access behind a firewall. > > >> Log4j - Source Repository - Apache Log4j >> 2<https://logging.apache.org/log4j/2.x/source-repository.html> > Log4j – Source Repository - Apache Log4j > 2<https://logging.apache.org/log4j/2.x/source-repository.html> > logging.apache.org > Access from Behind a Firewall. Refer to the documentation of the SCM used for > more information about access behind a firewall. > > >> logging.apache.org >> Access from Behind a Firewall. Refer to the documentation of the SCM used >> for more information about access behind a firewall. >> >> >>> Log4j - Source Repository - Apache Log4j >>> 2<https://logging.apache.org/log4j/2.x/source-repository.html> > Log4j – Source Repository - Apache Log4j > 2<https://logging.apache.org/log4j/2.x/source-repository.html> > logging.apache.org > Access from Behind a Firewall. Refer to the documentation of the SCM used for > more information about access behind a firewall. > > >> Log4j - Source Repository - Apache Log4j >> 2<https://logging.apache.org/log4j/2.x/source-repository.html> > Log4j – Source Repository - Apache Log4j > 2<https://logging.apache.org/log4j/2.x/source-repository.html> > logging.apache.org > Access from Behind a Firewall. Refer to the documentation of the SCM used for > more information about access behind a firewall. > > >> logging.apache.org >> Access from Behind a Firewall. Refer to the documentation of the SCM used >> for more information about access behind a firewall. >> >> >>> logging.apache.org >>> Access from Behind a Firewall. Refer to the documentation of the SCM used >>> for more information about access behind a firewall. >>> >>> >>> >>> Enjoy! >>> Remko >>> >>> Sent from my iPhone >>> >>>> On 4 Nov 2016, at 23:29, Nicholas Duane <[email protected]> wrote: >>>> >>>> I'm not that familiar with java and java conventions, package names, etc. >>>> I'm trying to find the source for log4j2's implementation of >>>> logger.error(String, Throwable);. Can someone point me to that? I was >>>> looking around here: >>>> >>>> >>>> https://git-wip-us.apache.org/repos/asf?p=logging-log4j2.git;a=tree;hb=refs/heads/master >>>> >>>> >>>> But couldn't seem to find what I was looking for. >>>> >>>> >>>> Thanks, >>>> >>>> Nick >> >> --------------------------------------------------------------------- >> To unsubscribe, e-mail: [email protected] >> For additional commands, e-mail: [email protected] >> > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [email protected] > For additional commands, e-mail: [email protected] >
