logging-log4j-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Ralph Goers (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (LOG4J2-1094) Multi thread initialization problem
Date Wed, 27 Apr 2016 05:41:13 GMT

    [ https://issues.apache.org/jira/browse/LOG4J2-1094?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15259589#comment-15259589
] 

Ralph Goers commented on LOG4J2-1094:
-------------------------------------

SLF4J solves this problem by having "substitute loggers". In our case, the problem is that
the LoggerContext is created with a DefaultConfiguration.  The default configuration only
logs errors and above to the console, which may not match the user's configuration.  A possible
solution for this would be to have the default configuration send the events to a ListAppender
and then have a step that republishes those events once the user's configuration is started.

> Multi thread initialization problem
> -----------------------------------
>
>                 Key: LOG4J2-1094
>                 URL: https://issues.apache.org/jira/browse/LOG4J2-1094
>             Project: Log4j 2
>          Issue Type: Bug
>    Affects Versions: 2.3
>            Reporter: Luca Burgazzoli
>
> I wrote a very simple example which has a behaviour I do not expect:
> If I call LogManager.getLogger(..) from two threads, only one of the loggers logs what
I'd expect but if I add an additional call to LogManager.getLogger(..) before the threads
are started, I see what I'd expect so it looks like there is a problem in multi threaded initialization.
> You can find the code and the configuration here:
> - https://github.com/lburgazzoli/lb-chronicle/blob/master/chronicle-examples/chronicle-logger-log4j2/src/main/java/com.github.lburgazzoli.openhft.examples.chronicle.logger.log4j2/MtLogging.java
> - https://github.com/lburgazzoli/lb-chronicle/blob/master/chronicle-examples/chronicle-logger-log4j2/src/main/resources/log4j2.xml
> {code}
> public class MtLogging {
>     public static void main(final String[] args) throws Exception {
>         //LogManager.getLogger("main");
>         Thread th1 = new Thread(() -> {
>             final String name = "thread-1";
>             final Logger log = LogManager.getLogger(name);
>             System.out.println("write " + name);
>             log.info("message");
>             System.out.println("done " + name);
>         });
>         Thread th2 = new Thread(() -> {
>             final String name = "thread-2";
>             final Logger log = LogManager.getLogger(name);
>             System.out.println("write " + name);
>             log.info("message");
>             System.out.println("done " + name);
>         });
>         th1.start();
>         th2.start();
>         th1.join();
>         th2.join();
>     }
> }
> {code}
> {code}
> <?xml version="1.0" encoding="UTF-8"?>
> <configuration>
>     <appenders>
>         <Console name="STDOUT" target="SYSTEM_OUT">
>             <PatternLayout pattern="[TEST] [%-5p] %c - %m%n%throwable{none}"/>
>         </Console>
>     </appenders>
>     <loggers>
>         <root level="all">
>             <appender-ref ref="STDOUT"/>
>         </root>
>     </loggers>
> </configuration>
> {code}
> The code above will show:
> {noformat}
>     write thread-1
>     done thread-1 
>     write thread-2
>     [TEST] [INFO ] thread-2 - message
>     done thread-2
> {noformat}
> Any call to LogManager makes it succeed (the problem no longer occurs):
> {code}
>     LogManager.getContext(false);
>     th1.start();
>     th2.start();
>     th1.join();
>     th2.join();
> {code}
> New output:
> {noformat}
>     write thread-2
>     write thread-1
>     [TEST] [INFO ] thread-2 - message
>    done thread-2
>    [TEST] [INFO ] thread-1 - message
>    done thread-1
> {noformat}
> The funny thing is that the first thread to arrive is initialized with ERROR level instead
of the ALL that is given to root. In other words it seems that the config has not loaded



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)

---------------------------------------------------------------------
To unsubscribe, e-mail: log4j-dev-unsubscribe@logging.apache.org
For additional commands, e-mail: log4j-dev-help@logging.apache.org


Mime
View raw message