content: /*
   * 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.bookkeeper.clients.utils;
  
  import io.grpc.ManagedChannelBuilder;
  import io.grpc.inprocess.InProcessChannelBuilder;
  import lombok.extern.slf4j.Slf4j;
  import org.apache.bookkeeper.clients.config.StorageClientSettings;
  import org.apache.bookkeeper.common.net.ServiceURI;
  import org.apache.bookkeeper.common.resolver.NameResolverFactoryProvider;
  import org.apache.bookkeeper.common.resolver.ServiceNameResolverProvider;
  import org.apache.bookkeeper.common.util.ReflectionUtils;
  
  /**
   * Utils to create grpc channels.
   */
  @Slf4j
  public final class GrpcChannels {
  
      private static final String BACKEND_INPROCESS = "inprocess";
      private static final String BK_REG_NAME_RESOLVER_PROVIDER =
          "org.apache.bookkeeper.grpc.resolver.BKRegistrationNameResolverProvider";
  
      private GrpcChannels() {}
  
      /**
       * Create a channel builder from <tt>serviceUri</tt> with client <tt>settings</tt>.
       *
       * @param serviceUri service uri
       * @param settings client settings
       * @return managed channel builder
       */
      @SuppressWarnings("deprecation")
      // One experimental API (ManagedChannelBuilder.nameResolverFactory)
      // is deprecated in favor of another experimental API (NameResolverRegistry).
      // https://github.com/grpc/grpc-java/issues/1770
      // https://github.com/grpc/grpc-java/issues/7133#issuecomment-680981331
      // Skipping the migration for now, will have to deal with this later when GRPC team
      // finalizes their API.
      public static ManagedChannelBuilder createChannelBuilder(String serviceUri,
                                                               StorageClientSettings settings) {
          ServiceURI uri = ServiceURI.create(serviceUri);
  
          ManagedChannelBuilder builder;
          if (uri.getServiceInfos().length > 0 && uri.getServiceInfos()[0].equals(BACKEND_INPROCESS)) {
              // this is an inprocess service, so build an inprocess channel.
              String serviceName = uri.getServiceHosts()[0];
              builder = InProcessChannelBuilder.forName(serviceName).directExecutor();
          } else if (null == uri.getServiceName() || ServiceURI.SERVICE_BK.equals(uri.getServiceName())) {
              builder = ManagedChannelBuilder.forTarget(serviceUri)
                  .nameResolverFactory(new ServiceNameResolverProvider().toFactory());
          } else {
              NameResolverFactoryProvider provider;
              try {
                  provider = ReflectionUtils.newInstance(
                      BK_REG_NAME_RESOLVER_PROVIDER,
                      NameResolverFactoryProvider.class);
              } catch (RuntimeException re) {
                  log.error("It seems that you don't have `bk-grpc-name-resolver` in your class path."
                      + " Please make sure you include it as your application's dependency.");
                  throw re;
              }
              builder = ManagedChannelBuilder.forTarget(serviceUri)
                  .nameResolverFactory(provider.toFactory());
          }
          if (settings.usePlaintext()) {
              builder = builder.usePlaintext();
          }
          return builder;
      }
  
  }
  