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javajettyjmxservlet-filtersmanaged-bean

Jetty: How to configure DoSFilter parameters using JMX

I have set up a DoSFilter for my webapp and have deployed it in Jetty. Things works nicely. However I occasionally want to change the Filter configuration. To do that I always have to change the web.xml and redeploy the webapps which is rather inconvenient. I would want to do this dynamically instead.

I learned that I can configure QoSFilter and DoSFilter using JMX since they are exposed as MBeans inside Jetty. I am having trouble in doing the same.

So far, I have been able to do the following:

  1. Configure jetty to enable jmx and jmxremote. I was successful in connecting to jetty jvm using jconsole.
  2. In my deployment descriptor, I've a filter defined as follows

<filter> <filter-name>DoSFilter</filter-name> <filter-class>org.eclipse.jetty.servlets.DoSFilter</filter-class> <init-param> <param-name>maxRequestsPerSec</param-name> <param-value>2</param-value> </init-param> <init-param> <param-name>requestPort</param-name> <param-value>true</param-value> </init-param> <init-param> <param-name>maxRequestMs</param-name> <param-value>600000</param-value> </init-param> <init-param> <param-name>excludePatterns</param-name> <param-value>/healthCheck</param-value> </init-param> <init-param> <param-name>managedAttr</param-name> <param-value>true</param-value> </init-param> </filter>

The managedAttr param is set to true so that this filter is added to the ServletContext thereby exposing it as a MBean.

3 I've also added a context param asking jetty to make DoSFilter as a MBean as follows

<context-param> <param-name>org.eclipse.jetty.server.context.ManagedAttributes</param-name> <param-value>DoSFilter</param-value> </context-param>

Now this works, but not the way I want it to. When I open Jconsole and go to the MBeans tab I can see the DoSFilter under org.eclipse.jetty.servlets.DoSFilter.

When I move down the tree, however, I can only see metadata information of that MBean. There are no attributes or operations attached to that MBean and I can't change anything.

Please advise. Am I doing anything wrong here?

My webapp is a spring application and there is only one servlet defined

<servlet> <servlet-name>capture</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <load-on-startup>1</load-on-startup> </servlet>

Thanks

UPDATE: I tried configuring this in Embedded Jetty and things seem to work fine. But I still can't get this to work in a standalone deployment.

Following is how I tested embedded Server 

public static void main(String[] args) throws Exception {
        Server server = new Server();
        Connector connector = new ServerConnector(server);
        server.addConnector(connector);
        MBeanServer mbeanServer = ManagementFactory.getPlatformMBeanServer();
        MBeanContainer mbeanContainer = new MBeanContainer(mbeanServer);
        server.addBean(mbeanContainer);

  WebAppContext context = new WebAppContext(server,"/home/neo/ideaprojects/helloworld/src/main/webapp/", "/");


        DoSFilter filter = new DoSFilter();
        FilterHolder holder = new FilterHolder(filter);
        String name = "DosFilter";
        holder.setName(name);
        holder.setInitParameter("managedAttr", "true");

        context.setInitParameter(ServletContextHandler.MANAGED_ATTRIBUTES, name);
        context.addFilter(holder, "/*", EnumSet.of(DispatcherType.FORWARD));
        // ----------------------------------------

        server.start();
        server.join();
    }

Updated 

I see the following debug logs in jetty standalone mode
2014-04-05 20:18:32.834:DBUG:oejj.MBeanContainer:main: beanAdded o.e.j.w.WebAppContext@ace3c1b{/,file:/tmp/jetty-0.0.0.0-8080-ROOT.war-_-any-6506776307143437350.dir/webapp/,STARTING}{/ROOT.war}->org.eclipse.jetty.servlets.DoSFilter@6d4d63ba
2014-04-05 20:18:32.835:DBUG:oejj.ObjectMBean:main: ObjectMbean: mbeanFor org.eclipse.jetty.servlets.DoSFilter@6d4d63ba mClass=class org.eclipse.jetty.jmx.ObjectMBean
2014-04-05 20:18:32.835:DBUG:oejj.ObjectMBean:main: mbeanFor org.eclipse.jetty.servlets.DoSFilter@6d4d63ba is org.eclipse.jetty.jmx.ObjectMBean@34bb5def
2014-04-05 20:18:32.835:DBUG:oejj.ObjectMBean:main: No MBean Influence for DoSFilter
2014-04-05 20:18:32.835:DBUG:oejj.ObjectMBean:main: No MBean Influence for Object
2014-04-05 20:18:32.836:DBUG:oejj.ObjectMBean:main: No MBean Influence for Filter
2014-04-05 20:18:32.836:DBUG:oejj.ObjectMBean:main: Influence Count: 3
2014-04-05 20:18:32.836:DBUG:oejj.ObjectMBean:main: No @ManagedObject declared on class org.eclipse.jetty.servlets.DoSFilter
2014-04-05 20:18:32.836:DBUG:oejj.ObjectMBean:main: Influenced by: org.eclipse.jetty.servlets.DoSFilter
2014-04-05 20:18:32.836:DBUG:oejj.ObjectMBean:main: Annotations not found for: org.eclipse.jetty.servlets.DoSFilter
2014-04-05 20:18:32.836:DBUG:oejj.ObjectMBean:main: Influenced by: java.lang.Object
2014-04-05 20:18:32.836:DBUG:oejj.ObjectMBean:main: Annotations not found for: java.lang.Object
2014-04-05 20:18:32.836:DBUG:oejj.ObjectMBean:main: Influenced by: javax.servlet.Filter
2014-04-05 20:18:32.836:DBUG:oejj.ObjectMBean:main: Annotations not found for: javax.servlet.Filter
2014-04-05 20:18:32.836:DBUG:oejj.MBeanContainer:main: Registered org.eclipse.jetty.servlets:context=ROOT,type=dosfilter,id=0
Solution

  • I found the issue. The issue was with the jars I believe. I extended the DOSFilter to replace some headers before the check so I had to include the servlets jar in my webapp. I had a whole bunch of other jetty-*.jar in my WEB-INF/lib folder as well(for some other debug purporse) which somehow were creating conflicts. The webapp was a maven project so I added provided to all jetty based modules in my webapp so that these jars don't get packed into my deployable war. This solved the problem.