[jboss-jira] [JBoss JIRA] (WFCORE-3210) Wildfly module isolation not working consistently

Nuno Godinho de Matos (JIRA) issues at jboss.org
Tue Aug 29 14:49:00 EDT 2017


    [ https://issues.jboss.org/browse/WFCORE-3210?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13455626#comment-13455626 ] 

Nuno Godinho de Matos commented on WFCORE-3210:
-----------------------------------------------

And answer your final question. 

I do not know how I can make myself any clearer.
No we have absolutely no intention of having log4j configuration per deployment. Not at all. No war, or ear we produce will ever contain a lo4j property configuration.
We configure the logging at the logging subsytem leveling such a way that all applications deployed are using the one and only global configuration.

Deployed applications limit themselves to use logging APIs.
The logging goes to the wildfly logmanager.
The logmanager calls our jul to log4j der.
And our jul to log4j appender calls the pure log4j implementation that is configured just the way we want it with the appenders we like and have implemented.

I hope this description is clear.

And I hope as well that you do not tell me that I am trying to do is not possible because with my limited internal knowledge of wildly I can already that what I am trying to do is definitely possible based on the module architecture. 100 % possible. It just requires one simple trivial elements to be in place. And that is the module of our jul to log4j apprentder to be isolated from the jboss log4j implementation. And this simply has to be possible. I cannot believe for one second that this is not supposed to be possible.

> Wildfly module isolation not working consistently
> -------------------------------------------------
>
>                 Key: WFCORE-3210
>                 URL: https://issues.jboss.org/browse/WFCORE-3210
>             Project: WildFly Core
>          Issue Type: Bug
>          Components: Logging, Modules
>    Affects Versions: 2.2.0.Final
>            Reporter: Nuno Godinho de Matos
>
> There is an underministic bug on the module layer of wildfly, whereby the boot logic of the application server is not ensured to give the appropriate module isolation - which can lead to unexpected boot classpath problems.
> An example of this phenomena is given on the wildfly forum thread:
> https://developer.jboss.org/thread/275839
> In this example, we have the logging subsystem setup to use a custome handler.
> The custom handler wishes to have acces to the JUL extension classes on the org.jboss.logmanger module, but wishes to do have no relationship with the org.apache.log4j packages associated to the wildfly org.jboss.log4j module.
> What we see in this example is that an application gets from wildfly mixed behavior.
> Most of the time, during boot, the processes works without problem, where the custom handler runs isolated from the undersired log4j libraries within wildfly.
> But other times the application boot procedure will not go smoothly with the custom handler having processes routing JUL LogRecords events into the bundled log4j because the application server has loaded some of the classes that exist the org.jboss.log4j module.
> And as we know when the same class is loaded by different class loaders, then that class that orinates from class loader A cannot be assigned to the corresponding class of class loader B, even if the classes are exactly the same.
> This is not an isolated issue.
> There are also open issues on the wildfly forum reporting on startup problems on the logging subsystme where sometimes the LogManager class had not yet been loaded, and sometimes this issue goes away.
> This is an indication of some deep issue engrained into the module loading, where the module isolation behavior is not ensured to work all the time and that the boot procedure is not deterministically reliable. 
> It should not be that the application server some time starts successfully and others not.
> Booting wildfly should always result in the same outcode.
> Problems of this nature with class loading problems should either always happen if the configuration is not done properly or never happen if the configuration is proper.
> In the case of thread:
> https://developer.jboss.org/thread/275839
> Our belief is that the configuration is doing all it possible can to request the necessary module isolation from base packages and the outcome where log4j class load problems take place should never be allowed to happen.
> Many thanks.



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