[
http://jira.dspace.org/jira/browse/DS-605?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=11690#action_11690
]
Sands Fish commented on DS-605:
-------------------------------
All, I have determined the source of this, what we've been calling the "White
Screen Of Death (WSOD)" issue. We have been seeing this at least 3 times a
day, have been running a script to detect it and automatically restart Tomcat,
and it has been the source of some grief for us.
I was able to reproduce it by stressing one of our test servers with a
malformed packager URL. (I'm not clear on whether stressing a URL that throws
an exception is a contributor to the cause, or if any heavy concurrent access
to DSpace URLs would cause it.) Once I had the condition reproducible, I was
able to put a debugger on the instance and dig deeper.
The cause, as it turns out, is an issue we already knew about. The Cocoon NPE
Error: [
http://jira.dspace.org/jira/browse/DS-253?page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel
]
This was just another manifestation of this same issue, but the root cause was
masked because of poor (non-existant) logging in the DSpaceCocoonServletFilter
class. The code that handles exceptions during invocation of the doFilter
method of this class was swallowing any exceptions and not reporting anything...
// Send the real request or the resumed request off to
// cocoon....
// if force ssl is on and the user has authenticated and the
request is not secure redirect to https
if
((ConfigurationManager.getBooleanProperty("xmlui.force.ssl")) &&
(realRequest.getSession().getAttribute("dspace.current.user.id")!=null) &&
(!realRequest.isSecure())) {
StringBuffer location = new StringBuffer("https://";);
location.append(ConfigurationManager.getProperty("dspace.hostname")).append(realRequest.getContextPath()).append(realRequest.getServletPath()).append(
realRequest.getQueryString() == null ? ""
: ("?" + realRequest.getQueryString()));
realResponse.sendRedirect(location.toString());
}
arg2.doFilter(realRequest, realResponse);
} catch (Throwable t) {
ContextUtil.abortContext(realRequest);
// <-- here's where we lost the evidence
} finally {
// Close out the DSpace context no matter what.
ContextUtil.completeContext(realRequest);
}
Once in the debugger, I could halt execution and dig out the stack trace, which
is exactly the same one listed in the Cocoon issue.
I will note that any critical Cocoon exception would be lost to us at this
point, but due to the fact that the webapp has to be restarted to recover once
this state is reached, I feel fairly certain that this is the issue that has
been causing persistent WSOD issues in 1.6.
After reproducing this issue multiple times with the same method on our test
system, I am currently stressing the same server with the modified Cocoon
dependency referenced in the Cocoon ticket and have not yet seen the condition
recur. (crossing my fingers)
I'm also developing a patched DSpaceCocoonServletFilter that will better report
and handle error conditions. I identified a number of other bugs during my
research of this issue and will be submitting them as separate issues.
Let me know if there are any questions.
> Blank screen on XMLUI Dspace 1.6.0
> ----------------------------------
>
> Key: DS-605
> URL: http://jira.dspace.org/jira/browse/DS-605
> Project: DSpace 1.x
> Issue Type: Bug
> Components: XMLUI
> Affects Versions: 1.6.0
> Environment: apache-tomcat-6.0.18
> jdk1.6.0_13
> Debian GNU Linux 5.0
> Reporter: Antero Neto
> Priority: Critical
> Fix For: 1.7.0
>
>
> The interface of Dspce XMLUI shows a blank screen and I need to reboot Tomcat.
> JSPUI The interface is not affected by the issue. It happens sporadically.
> I'm using version 1.6.0 of DSpace. I use a theme based on the theme
> "Reference" which comes in DSpace.
> Below, some log information that may be related.
> 2010-06-09 00:07:00,741 ERROR cocoon.handled - Could not read resource
> cocoon://DRI/2/handle/xxxx/xxx/workflow
> at <map:serialize type="xml"> -
> resource://aspects/Statistics/sitemap.xmap:70:31
> at <map:transform type="Navigation"> -
> resource://aspects/Statistics/sitemap.xmap:38:55
> at <map:generate> - resource://aspects/Statistics/sitemap.xmap:33:19
> ...
> org.apache.cocoon.ProcessingException: Could not read resource
> cocoon://DRI/2/handle/xxxx/xxx/workflow
> at <map:serialize type="xml"> -
> resource://aspects/Statistics/sitemap.xmap:70:31
> at <map:transform type="Navigation"> -
> resource://aspects/Statistics/sitemap.xmap:38:55
> at <map:generate> - resource://aspects/Statistics/sitemap.xmap:33:19
> ...
> Caused by: java.lang.NullPointerException
> at
> org.apache.cocoon.components.source.impl.SitemapSource.init(SitemapSource.java:292)
> at
> org.apache.cocoon.components.source.impl.SitemapSource.<init>(SitemapSource.java:148)
> at
> org.apache.cocoon.components.source.impl.SitemapSourceFactory.getSource(SitemapSourceFactory.java:62)
> at
> org.apache.cocoon.components.source.CocoonSourceResolver.resolveURI(CocoonSourceResolver.java:153)
> at
> org.apache.cocoon.components.source.CocoonSourceResolver.resolveURI(CocoonSourceResolver.java:183)
> at
> org.apache.cocoon.generation.FileGenerator.setup(FileGenerator.java:99)
> at
> org.dspace.app.xmlui.cocoon.AspectGenerator.setup(AspectGenerator.java:112)
> at sun.reflect.GeneratedMethodAccessor57.invoke(Unknown Source)
> at
> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
> at java.lang.reflect.Method.invoke(Method.java:597)
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