Where can I find a working example of how to remotely invoke an OSGi service contained within Eclipse Virgo?

Question

Can anyone point to a step-by-step tutorial on how to configure a remotely-accessible service contained within Eclipse Virgo 3.0x? I know that standards exist, etc., but I can find NO example which does not seem to contain a bunch of hand waving instead of specific steps along with working code/configurations to download. I don't care if the example uses Apache CXF, Eclipse ECF, or just about anything else. What I want is the equivalent of RMI in that both the transport and wire protocol are abstracted away behind what appears to both client and server-side developers as just plain Java (with some liberties taken).

Which bundles must be deployed into Virgo to support remoting? What Spring-ish configuration settings work? What jars must be on the client-side classpath? Etc, etc.?

Answer 1

I played around with Apache CXF DOSGI and got it working quite easily.

• Download CXF single bundle distribution from here - I used 1.3.0.

• Unzip Virgo (I used the kernel distribution for simplicity), copy CXF bundle to pickup, and start Virgo:

  $ bin/startup.sh
  [2012-04-04 14:17:33.011] startup-tracker              <KE0001I> Kernel starting. 
  [2012-04-04 14:17:36.135] startup-tracker              <KE0002I> Kernel started. 
  ...
  [2012-04-04 14:17:38.561] sync Event Dispatcher Thread <UR0001I> User region ready. 
  [2012-04-04 14:17:39.565] fs-watcher                   <HD0001I> Hot deployer processing 'INITIAL' event for file 'cxf-dosgi-ri-singlebundle-distribution-1.3.jar'. 
  [2012-04-04 14:17:40.060] fs-watcher                   <DE0000I> Installing bundle 'cxf-dosgi-ri-singlebundle-distribution' version '1.3.0'. 
  [2012-04-04 14:17:40.570] fs-watcher                   <DE0001I> Installed bundle 'cxf-dosgi-ri-singlebundle-distribution' version '1.3.0'. 
  [2012-04-04 14:17:40.593] fs-watcher                   <DE0004I> Starting bundle 'cxf-dosgi-ri-singlebundle-distribution' version '1.3.0'. 
  [2012-04-04 14:17:43.498] start-signalling-1           <DE0005I> Started bundle 'cxf-dosgi-ri-singlebundle-distribution' version '1.3.0'.
  

• Install and run ZooKeeper server according to these instructions - I used 3.4.3. See also the ZooKeeper instructions including how to create a configuration file.

• Create a file org.apache.cxf.dosgi.discovery.zookeeper.properties containing:

  zookeeper.host = 127.0.0.1
  

  and copy to pickup:

  [2012-04-04 14:29:51.385] fs-watcher                   <HD0001I> Hot deployer processing 'CREATED' event for file 'org.apache.cxf.dosgi.discovery.zookeeper.properties'. 
  [2012-04-04 14:29:51.417] fs-watcher                   <DE0000I> Installing configuration 'org.apache.cxf.dosgi.discovery.zookeeper' version '0.0.0'. 
  [2012-04-04 14:29:51.428] fs-watcher                   <DE0001I> Installed configuration 'org.apache.cxf.dosgi.discovery.zookeeper' version '0.0.0'. 
  [2012-04-04 14:29:51.434] fs-watcher                   <DE0004I> Starting configuration 'org.apache.cxf.dosgi.discovery.zookeeper' version '0.0.0'. 
  [2012-04-04 14:29:51.439] fs-watcher                   <DE0005I> Started configuration 'org.apache.cxf.dosgi.discovery.zookeeper' version '0.0.0'. 
  

• Unzip another copy of Virgo kernel,copy the CXF bundle and org.apache.cxf.dosgi.discovery.zookeeper.properties into pickup, and start with a different JMX port:

  $ bin/startup.sh -jmxport 9876
  

  That's it, but to check that it's working, the remaining steps run the greeter sample...

• Install/start the greeter interface and implementation bundles into the first Virgo instance. The simplest way is to copy the interface bundle to repository/usr and then copy the implementation bundle to pickup.

• Install/start the greeter interface and client bundles into the second Virgo instance. The simplest way is to copy the interface bundle to repository/usr and then copy the client bundle to pickup.

• When the "Invoke Remote Greeter Service" window appears, enter a string (e.g. "foo") into the Name field and click "Invoke".

• The first Virgo instance shows the following trace log messages (in serviceability/logs/log.log):

  Invoking: greetMe(foo)
  

• The second Virgo instance shows the following trace log messages:

  [2012-04-05 14:14:56.766] INFO  Thread-29                    System.out                                                        *** Invoking greeter *** 
  [2012-04-05 14:14:56.970] INFO  Thread-29                    System.out                                                        greetMe("foo") returns: 
  [2012-04-05 14:14:56.971] INFO  Thread-29                    System.out                                                          Hola foo 
  [2012-04-05 14:14:56.971] INFO  Thread-29                    System.out                                                          Bonjour foo 
  [2012-04-05 14:14:56.972] INFO  Thread-29                    System.out                                                          Hoi foo 
  [2012-04-05 14:14:56.972] INFO  Thread-29                    System.out                                                          Hello foo 
  [2012-04-05 14:14:56.972] INFO  Thread-29                    System.out                                                        *** Opening greeter client dialog *** 
  

• Look in the service registry of the second Virgo instance.

  osgi> vsh:service examine 245
  
  Properties:
      endpoint.id:
          http://localhost:9090/greeter
      objectClass:
          org.apache.cxf.dosgi.samples.greeter.GreeterService
      service.id:
          245
      service.imported:
          true
      service.imported.configs:
          org.apache.cxf.ws
  
  Publisher: cxf-dosgi-ri-singlebundle-distribution 1.3.0 [84]
  
  Consumer(s):
      cxf-dosgi-ri-samples-greeter-client 1.2.0 [86]
  

  A remote GreeterService has been published in the service registry.

Answer 2

This may not be precisely what you are looking for, but I have every reason to believe that the instructions in the Remote Services chapter in Enterprise OSGi in Action should work with Virgo.