Extending the Grizzly HTTP Runtime part III: Gathering Monster's Statistics

So far we were able to build a WebServer based on Grizzly and add JMX Support to it. Now it is time to gather statistics of what’s happening inside the monster’ stomach.

Part I was about building synchronous and asynchronous Web Server using Grizzly Http Engine, part II demonstrated how to add JMX support and track what’s happening. Let’s re-use the example we used in part II:

 47         GrizzlyWebServer ws = new GrizzlyWebServer(path);
 48         ServletAdapter sa = new ServletAdapter();
 49         sa.setRootFolder("/Path/To/Exploded/War/File");
 50         sa.setServlet(new MyServlet());
 51         sa.setContextPath("/myServlet");
 52         ws.addGrizzlyAdapter(sa);
 53 
 54         ServletAdapter sa2 = new ServletAdapter();
 55         sa2.setRootFolder("/Path/To/Exploded/War2/File");
 56         sa2.setServlet(new MySecondServlet());
 57         sa2.setContextPath("/mySecondServlet");
 58         ws.addGrizzlyAdapter(sa2);
 59 
 60         ws.enableJMX(new Management() {
 61 
 62             public void registerComponent(Object bean, ObjectName oname, String type)
 63                     throws Exception {
 64                 Registry.getRegistry().registerComponent(bean, oname, type);
 65             }
 66 
 67             public void unregisterComponent(ObjectName oname) throws Exception {
 68                 Registry.getRegistry().
 69                         unregisterComponent(oname);
 70             }
 71         });
 72         ws.start();

There are two way to add statistics. First, you can just enable it using JMX and click on enableMonitoring button:

Then start doing request, and you can use jconsole to see the statistics:

Programmatically, you can enable statistics by just doing:

     56         GrizzlyWebServer ws = new GrizzlyWebServer(path);
     57         ws.enableJMX(new Management() {
     58 
     59             public void registerComponent(Object bean, ObjectName oname, String type)
     60                     throws Exception{
     61                 Registry.getRegistry().registerComponent(bean,oname,type);
     62             }
     63 
     64             public void unregisterComponent(ObjectName oname) throws Exception{
     65                 Registry.getRegistry().
     66                         unregisterComponent(oname);
     67             }
     68         });
     69 
     70         final Statistics stats = ws.getStatistics();
     71         stats.startGatheringStatistics();

The key method is GrizzlWebServer.getStatistics(). From the Statistics instance, you can start and stop gathering statistics. Below is an example that use a simple scheduler to output data on the console:

     45     // Simple scheduler that will outpot stats every 5 seconds.
     46     private static ScheduledThreadPoolExecutor ste =
     47             new ScheduledThreadPoolExecutor(1);
     48 
     49     public static void main( String args[] ) throws Exception {
     50         String path = args[0];
     51         if (args[0] == null || path == null){
     52             System.out.println("Invalid static resource path");
     53             System.exit(-1);
     54         }
     55 
     56         GrizzlyWebServer ws = new GrizzlyWebServer(path);
     57         ws.enableJMX(new Management() {
     58 
     59             public void registerComponent(Object bean, ObjectName oname, String type)
     60                     throws Exception{
     61                 Registry.getRegistry().registerComponent(bean,oname,type);
     62             }
     63 
     64             public void unregisterComponent(ObjectName oname) throws Exception{
     65                 Registry.getRegistry().
     66                         unregisterComponent(oname);
     67             }
     68         });
     69 
     70         final Statistics stats = ws.getStatistics();
     71         stats.startGatheringStatistics();
     72 
     73         ste.scheduleAtFixedRate(new Runnable() {
     74             public void run() {
     75                 System.out.println("Current connected users: " +
     76                         stats.getKeepAliveStatistics().getCountConnections());
     77                 System.out.println("How many requests since startup:" +
     78                         stats.getRequestStatistics().getRequestCount());
     79                 System.out.println("How many connection we queued because of all" +
     80                         "thread were busy: " +
     81                         stats.getThreadPoolStatistics().getCountQueued());
     82                 return;
     83             }
     84         }, 0, 10,TimeUnit.SECONDS);
     85         System.out.println("Grizzly WebServer listening on port 8080");
     86         ws.start();
     87     }

Another easy things with the monster! You can download the above example from here (bundled as an OSGi bundle if you like OSGi). Next time I will explore ways to write AsyncFilter, which was partially covered in part 1.

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