code: /*
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You under the Apache License, Version 2.0
   * (the "License"); you may not use this file except in compliance with
   * the License.  You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   *
   */
  
  package org.apache.skywalking.oap.server.receiver.configuration.discovery;
  
  import org.apache.skywalking.oap.server.configuration.api.ConfigurationModule;
  import org.apache.skywalking.oap.server.configuration.api.DynamicConfigurationService;
  import org.apache.skywalking.oap.server.core.server.GRPCHandlerRegister;
  import org.apache.skywalking.oap.server.library.module.ModuleDefine;
  import org.apache.skywalking.oap.server.library.module.ModuleProvider;
  import org.apache.skywalking.oap.server.library.module.ModuleStartException;
  import org.apache.skywalking.oap.server.library.module.ServiceNotProvidedException;
  import org.apache.skywalking.oap.server.receiver.sharing.server.SharingServerModule;
  import org.apache.skywalking.oap.server.receiver.configuration.discovery.handler.grpc.ConfigurationDiscoveryServiceHandler;
  
  public class ConfigurationDiscoveryProvider extends ModuleProvider {
  
      private AgentConfigurationsWatcher agentConfigurationsWatcher;
      private ConfigurationDiscoveryModuleConfig configurationDiscoveryModuleConfig;
  
      @Override
      public String name() {
          return "default";
      }
  
      @Override
      public Class<? extends ModuleDefine> module() {
          return ConfigurationDiscoveryModule.class;
      }
  
      @Override
      public ConfigCreator newConfigCreator() {
          return new ConfigCreator<ConfigurationDiscoveryModuleConfig>() {
              @Override
              public Class type() {
                  return ConfigurationDiscoveryModuleConfig.class;
              }
  
              @Override
              public void onInitialized(final ConfigurationDiscoveryModuleConfig initialized) {
                  configurationDiscoveryModuleConfig = initialized;
              }
          };
      }
  
      @Override
      public void prepare() throws ServiceNotProvidedException, ModuleStartException {
          agentConfigurationsWatcher = new AgentConfigurationsWatcher(this);
      }
  
      @Override
      public void start() throws ServiceNotProvidedException, ModuleStartException {
          DynamicConfigurationService dynamicConfigurationService = getManager().find(ConfigurationModule.NAME)
                                                                                .provider()
                                                                                .getService(
                                                                                    DynamicConfigurationService.class);
          dynamicConfigurationService.registerConfigChangeWatcher(agentConfigurationsWatcher);
  
          /*
           * Register ConfigurationDiscoveryServiceHandler to process gRPC requests for ConfigurationDiscovery.
           */
          GRPCHandlerRegister grpcHandlerRegister = getManager().find(SharingServerModule.NAME)
                                                                .provider()
                                                                .getService(GRPCHandlerRegister.class);
          grpcHandlerRegister.addHandler(new ConfigurationDiscoveryServiceHandler(
              agentConfigurationsWatcher,
              configurationDiscoveryModuleConfig.isDisableMessageDigest()
          ));
      }
  
      @Override
      public void notifyAfterCompleted() throws ServiceNotProvidedException, ModuleStartException {
      }
  
      @Override
      public String[] requiredModules() {
          return new String[] {
              ConfigurationModule.NAME,
              SharingServerModule.NAME
          };
      }
  }
  