CXF-DOSGI学习笔记(一)-web service暴露

一.cxf-dosgi暴露服务和在zookeeper上注册的过程说明：

 1.有2个地方可以调用TopologyManager  protected void exportService(ServiceReference sref) ：
  a.TopologyManager 初始化
  b.org.apache.cxf.dosgi.topologymanager.ServiceListenerImpl 有服务事件时。
    public void serviceChanged(ServiceEvent event) 
    
  2.调用TopologyManager triggerExport(sref);  
   

 for (final RemoteServiceAdmin remoteServiceAdmin : remoteServiceAdminList) {                            LOG                                .info("TopologyManager: handling remoteServiceAdmin "                                      + remoteServiceAdmin);                            if (exports.containsKey(remoteServiceAdmin)) {                                // already handled by this remoteServiceAdmin                                LOG.info("TopologyManager: already handled by this remoteServiceAdmin -> skipping");                            } else {                                // TODO: additional parameter Map ?                                LOG.info("TopologyManager: exporting ...");                                Collection<ExportRegistration> endpoints = remoteServiceAdmin                                    .exportService(sref, null);                                if (endpoints == null) {                                    // TODO export failed -> What should be done here?                                    LOG.info("TopologyManager: export failed");                                    exports.put(remoteServiceAdmin, null);                                } else {                                    LOG.info("TopologyManager: export sucessful Endpoints:" + endpoints);                                    // enqueue in local list of endpoints                                    exports.put(remoteServiceAdmin, endpoints);                                    // publish to endpoint listeners                                    nofifyListeners(endpoints);                                }                            }                        }

                        
      调用所有的RemoteServiceAdmin来暴露服务remoteServiceAdmin.exportService(sref, null);  
      并通知linstenser有节点变化nofifyListeners(endpoints)，要连zookeeper做节点操作。


     3. 调用RemoteServiceAdminInstance 暴露服务
       

 public List /* ExportRegistration */exportService(ServiceReference ref, Map properties)        throws IllegalArgumentException, UnsupportedOperationException {                 ....          synchronized (exportedServices) {                    List er = rsaCore.exportService(refFinal, propertiesFinal);                    if (er != null)                        exportedServices.addAll(er);                    return er;                }        ......        }        

                                 
     4.调用RemoteServiceAdminCore暴露服务
      根据暴露服务的类型，来选择typehandler来创建web service服务
    

 public List exportService(ServiceReference serviceReference, Map additionalProperties)        throws IllegalArgumentException, UnsupportedOperationException {                ...                ExportRegistrationImpl exportRegistration = exportRegs.get(iface);                ConfigurationTypeHandler handler = getHandler(configurationTypes, serviceProperties,                                                              getHandlerProperties());                Object serviceObject = bctx.getService(serviceReference);                BundleContext callingContext = serviceReference.getBundle().getBundleContext();                if (handler == null) {                    // TODO: publish error event ? not sure                    return Collections.EMPTY_LIST;                }                LOG.info("found handler for " + iface + "  -> " + handler);                String interfaceName = iface;                // this is an extra sanity check, but do we really need it now ?                Class<?> interfaceClass = ClassUtils.getInterfaceClass(serviceObject, interfaceName);                if (interfaceClass != null) {                    handler.createServer(exportRegistration, bctx, callingContext, serviceProperties,                                         interfaceClass, serviceObject);                                        if(exportRegistration.getException()==null){                        LOG.info("created server for interface " + iface);                        exportRegistration.startServiceTracker(bctx);                    }else{                        LOG.warning("server creation for interface " + iface + "  failed!");                        // Fire event happens at the end                    }                                    }

        5.后面的步骤和Apache CXF暴露服务-学习笔记 描述的类似
        
        6.步骤2提到nofifyListeners(endpoints);会连zookeeper,继续看看 TopologyManager
        

protected void nofifyListeners(Collection<ExportRegistration> exportRegistrations) {        try {            // Find all EndpointListeners; They must have the Scope property otherwise they have to be ignored            ServiceReference[] refs = Utils.getEndpointListeners(bctx);            if (refs != null) {                for (ServiceReference sref : refs) {                    notifyListenerOfAddingIfAppropriate(sref, exportRegistrations);                }            }        } catch (InvalidSyntaxException e) {            e.printStackTrace();        }

       7.TopologyManager 获取ServiceListener来处理
      

 protected void notifyListenerOfAddingIfAppropriate(ServiceReference sref,                                                       Collection<ExportRegistration> exportRegistrations) {        // if (sref.getBundle().equals(bctx.getBundle())) {        // LOG        // .info("TopologyManager: notifyListenerOfAddingIfAppropriate() called for own listener -> skipping ");        // return;        // }        EndpointListener epl = (EndpointListener)bctx.getService(sref);        LOG.info("TopologyManager: notifyListenerOfAddingIfAppropriate() ");        try {            List<Filter> filters = Utils.normalizeScope(sref, bctx);            for (ExportRegistration exReg : exportRegistrations) {                // FIXME!!!!!!!!!!!!! There needs to be a better way ?!?!?!                Map props = exReg.getExportReference().getExportedEndpoint().getProperties();                Dictionary d = new Hashtable(props);                for (Filter filter : filters) {                    LOG.info("Matching: " + filter + "  against " + d);                }                for (Filter filter : filters) {                    if (filter.match(d)) {                        LOG.info("Listener mached one of the Endpoints !!!!: " + epl);                        epl                            .endpointAdded(exReg.getExportReference().getExportedEndpoint(), filter                                .toString());                    }                }            }        } catch (InvalidSyntaxException e) {            e.printStackTrace();        }    }

    
        8.org.apache.cxf.dosgi.discovery.zookeeper.EndpointListenerImpl
        连zookeeper创建节点，到此服务暴露完毕。
        
       

 public void endpointAdded(EndpointDescription endpoint, String matchedFilter) {        LOG.info("endpointDescription added: " + endpoint);        if (closed)            return;        synchronized (endpoints) {            if (endpoints.contains(endpoint)) {                // TODO -> Should the published endpoint be updated here ?                return;            }            try {                Collection<String> interfaces = endpoint.getInterfaces();                String endpointKey = getKey(endpoint.getId());                ZooKeeper zk = getZooKeeper();                for (String name : interfaces) {                    String path = Util.getZooKeeperPath(name);                    String fullPath = path + '/' + endpointKey;                    LOG.info("Creating ZooKeeper node: " + fullPath);                    ensurePath(path, zk);                    zk.create(fullPath, getData(endpoint), Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL);                }                endpoints.add(endpoint);            } catch (Exception ex) {                LOG.log(Level.SEVERE, "Exception while processing the addition of a ServicePublication.", ex);            }        }    }

二、暴露服务删除

1.在Bundle stop后，org.apache.cxf.dosgi.topologymanager.ServiceListenerImpl收到ServiceEvent

 

public void serviceChanged(ServiceEvent event) {        LOG.fine("Received ServiceEvent: " + event);        ServiceReference sref = event.getServiceReference();        if (event.getType() == ServiceEvent.REGISTERED) {            LOG.fine("Registered");            if (analyzeService(sref)) {                LOG.info("calling TopologyManager -> registered service");                topManager.exportService(sref);            }        } else if (event.getType() == ServiceEvent.UNREGISTERING) {            topManager.removeService(sref);        }    }

2.TopologyManager删除服务

void removeService(ServiceReference sref) {        synchronized (exportedServices) {            if (exportedServices.containsKey(sref)) {                Map<RemoteServiceAdmin, Collection<ExportRegistration>> rsas = exportedServices.get(sref);                for (Map.Entry<RemoteServiceAdmin, Collection<ExportRegistration>> entry : rsas.entrySet()) {                    if (entry.getValue() != null) {                        for (ExportRegistration exReg : entry.getValue()) {                            if (exReg != null)                                exReg.close();                        }                    }                }                exportedServices.remove(sref);            }        }    }

3.org.apache.cxf.dosgi.dsw.service.ExportRegistrationImpl调用RemoteServiceAdminCore删除服务注册

 public synchronized void close() {        if (closed)            return;        closed = true;        rsaCore.removeExportRegistration(this);                parent.instanceClosed();    }

三、Zookeeper节点删除

• Bundle 状态变化引起

             1.1.LocalDiscovery implements BundleListener 当bundle状态变化,都会得到通知，

public void bundleChanged(BundleEvent be) {        switch (be.getType()) {        case BundleEvent.STARTED:            findDeclaredRemoteServices(be.getBundle());            break;        case BundleEvent.STOPPED:            removeServicesDeclaredInBundle(be.getBundle());            break;        }    }

private void removeServicesDeclaredInBundle(Bundle bundle) {        for (Iterator<Entry<EndpointDescription, Bundle>> i = endpointDescriptions.entrySet().iterator(); i.hasNext(); ) {            Entry<EndpointDescription, Bundle> entry = i.next();            if (bundle.equals(entry.getValue())) {                removedEndpointDescription(entry.getKey());                i.remove();            }        }    }

private void removedEndpointDescription(EndpointDescription ed) {        triggerCallbacks(ed, false);    }

private void triggerCallbacks(EndpointDescription ed, boolean added) {        for (Map.Entry<EndpointListener, Collection<String>> entry : listenerToFilters.entrySet()) {            for (String match : entry.getValue()) {                triggerCallbacks(entry.getKey(), match, ed, added);            }        }    }

private void triggerCallbacks(EndpointListener listener, String toMatch,            EndpointDescription ed, boolean added) {        if (!filterMatches(toMatch, ed)) {            return;        }                if (added) {            listener.endpointAdded(ed, toMatch);        } else {            listener.endpointRemoved(ed, toMatch);        }    }

2.org.apache.cxf.dosgi.discovery.zookeeper.EndpointListenerImpl收到通知删除endpoint节点

 public void endpointRemoved(EndpointDescription endpoint, String matchedFilter) {        LOG.info("endpointDescription removed: " + endpoint);        if (closed)            return;        synchronized (endpoints) {            if (!endpoints.contains(endpoint)) {                return;            }            try {                removeEndpoint(endpoint);                endpoints.remove(endpoint);            } catch (Exception ex) {                LOG.log(Level.SEVERE, "Exception while processing the removal of a ServicePublication.", ex);            }        }    }

private void removeEndpoint(EndpointDescription endpoint) throws UnknownHostException,        URISyntaxException, InterruptedException, KeeperException {        Collection<String> interfaces = endpoint.getInterfaces();        String endpointKey = getKey(endpoint.getId());        ZooKeeper zk = getZooKeeper();        for (String name : interfaces) {            String path = Util.getZooKeeperPath(name);            String fullPath = path + '/' + endpointKey;            LOG.fine("Removing ZooKeeper node: " + fullPath);            zk.delete(fullPath, -1);        }    } 

•  Service 变化引起

       1.RemoteServiceAdminList中
            

stRemoteServiceAdmin = new ServiceTracker(bctx, RemoteServiceAdmin.class.getName(), null) {            @Override            public Object addingService(ServiceReference reference) {                LOG.info("Adding RemoteServiceAdmin to list of admins ");                RemoteServiceAdmin rsa = (RemoteServiceAdmin)bctx.getService(reference);                synchronized (rsal) {                    rsal.add(rsa);                }                LOG.info("enlisted RemoteEventAdmins: " + this.size());                triggerExportImportForRemoteSericeAdmin(rsa);                return super.addingService(reference);            }            @Override            public void removedService(ServiceReference reference, Object service) {                LOG.info("TopologyManager: Removing RemoteServiceAdmin from list of admins ");                synchronized (rsal) {                    rsal.remove(service);                }                // TODO: remove service exports from management structure and notify discovery stuff...                removeRemoteServiceAdmin((RemoteServiceAdmin)service);                LOG.info("TopologyManager: enlisted RemoteEventAdmins: " + rsal.size());                super.removedService(reference, service);            }        };

 protected void removeRemoteServiceAdmin(RemoteServiceAdmin service) {        topManager.removeRemoteServiceAdmin(service);    }

2.调用TopologyManager删除RemoteServiceAdmin

protected void removeRemoteServiceAdmin(RemoteServiceAdmin rsa) {        synchronized (exportedServices) {            for (Map.Entry<ServiceReference, HashMap<RemoteServiceAdmin, Collection<ExportRegistration>>> exports : exportedServices                .entrySet()) {                if (exports.getValue().containsKey(rsa)) {                    // service was handled by this RemoteServiceAdmin                    Collection<ExportRegistration> endpoints = exports.getValue().get(rsa);                    // TODO for each notify discovery......                    try {                        ServiceReference[] refs = Utils.getEndpointListeners(bctx);                        for (ServiceReference sref : refs) {                            notifyListenersOfRemovalIfAppropriate(sref, endpoints);                        }                    } catch (InvalidSyntaxException e) {                        e.printStackTrace();                    }                    // remove all management information for the RemoteServiceAdmin                    exports.getValue().remove(rsa);                }            }        }    }

protected void notifyListenersOfRemovalIfAppropriate(ServiceReference sref,                                                         Collection<ExportRegistration> exportRegistrations) {        EndpointListener epl = (EndpointListener)bctx.getService(sref);        LOG.info("TopologyManager: notifyListenerOfREMOVALIfAppropriate() ");        List<Filter> filters;        try {            filters = Utils.normalizeScope(sref, bctx);            for (ExportRegistration exReg : exportRegistrations) {                // FIXME!!!!!!!!!!!!! There needs to be a better way ?!?!?!                Map props = exReg.getExportReference().getExportedEndpoint().getProperties();                Dictionary d = new Hashtable(props);                for (Filter filter : filters) {                    LOG.info("Matching: " + filter + "  against " + d);                }                for (Filter filter : filters) {                    if (filter.match(d)) {                        LOG.info("Listener matched one of the Endpoints !!!! --> calling removed() ...");                        epl.endpointRemoved(exReg.getExportReference().getExportedEndpoint(), filter                            .toString());                    }                }            }        } catch (InvalidSyntaxException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }    }                    

3.org.apache.cxf.dosgi.discovery.zookeeper.EndpointListenerImpl    

public void endpointRemoved(EndpointDescription endpoint, String matchedFilter) {        LOG.info("endpointDescription removed: " + endpoint);        if (closed)            return;        synchronized (endpoints) {            if (!endpoints.contains(endpoint)) {                return;            }            try {                removeEndpoint(endpoint);                endpoints.remove(endpoint);            } catch (Exception ex) {                LOG.log(Level.SEVERE, "Exception while processing the removal of a ServicePublication.", ex);            }        }    }

• 直接调用Stop
  调用ZooKeeperDiscovery的stop方法，也会EndpointListenerImpl的close方法，进而调用endpointRemoved方法。这里不详细描述了。
  

总结：

服务的暴露:

在TopologyManager初始化时，会做服务暴露初始化，

另外在Service变化时，注册ServiceLisentener来获取服务的变化通知，通过调用RemoteServiceAdmin来启动http server和注册Web Service;通过EndpointListenerImpl来获取EndPoint的变化通知，注册到zookeeper上。

删除在bundle ,service changed时触发。

附：zookeeper上的日志信息

连接：

2011-10-17 17:34:41,539 - INFO  [NIOServerCxn.Factory:0.0.0.0/0.0.0.0:2181:NIOSe
rverCnxn$Factory@251] - Accepted socket connection from /127.0.0.1:62107
2011-10-17 17:34:41,555 - INFO  [NIOServerCxn.Factory:0.0.0.0/0.0.0.0:2181:NIOSe
rverCnxn@777] - Client attempting to establish new session at /127.0.0.1:62107
2011-10-17 17:34:41,602 - INFO  [SyncThread:0:NIOServerCnxn@1580] - Established
session 0x133113b5f2e0000 with negotiated timeout 4000 for client /127.0.0.1:62107

中断：

2011-10-17 17:35:45,704 - WARN  [NIOServerCxn.Factory:0.0.0.0/0.0.0.0:2181:NIOSe
rverCnxn@639] - Exception causing close of session 0x133113b5f2e0000 due to java
.io.IOException: 远程主机强迫关闭了一个现有的连接。
2011-10-17 17:35:45,704 - INFO  [NIOServerCxn.Factory:0.0.0.0/0.0.0.0:2181:NIOSe
rverCnxn@1435] - Closed socket connection for client /127.0.0.1:62107 which had
sessionid 0x133113b5f2e0000
2011-10-17 17:35:50,011 - INFO  [SessionTracker:ZooKeeperServer@314] - Expiring
session 0x133113b5f2e0000, timeout of 4000ms exceeded
2011-10-17 17:35:50,011 - INFO  [ProcessThread:-1:PrepRequestProcessor@387] - Pr
ocessed session termination for sessionid: 0x133113b5f2e0000