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 static org.apache.bookkeeper.clients.utils.ClientConstants.TOKEN;
  
  import io.grpc.CallCredentials;
  import io.grpc.Metadata;
  import io.grpc.stub.AbstractStub;
  import java.util.Optional;
  import java.util.concurrent.CompletableFuture;
  import java.util.concurrent.Executor;
  
  /**
   * Grpc related utils.
   */
  public final class GrpcUtils {
  
      private GrpcUtils() {
      }
  
      /**
       * Configure a grpc stub with optional credential token.
       *
       * @param stub  grpc stub
       * @param token credential token
       * @param <T>
       * @return a configured grpc stub.
       */
      public static <T extends AbstractStub<T>> T configureGrpcStub(T stub, Optional<String> token) {
          return token.map(t -> {
              Metadata metadata = new Metadata();
              Metadata.Key<String> tokenKey = Metadata.Key.of(TOKEN, Metadata.ASCII_STRING_MARSHALLER);
              metadata.put(tokenKey, t);
              CallCredentials callCredentials = new CallCredentials() {
                  @Override
                  public void applyRequestMetadata(RequestInfo requestInfo,
                                                   Executor appExecutor,
                                                   MetadataApplier applier) {
                      applier.apply(metadata);
                  }
  
                  @Override
                  public void thisUsesUnstableApi() {
                      // no-op;
                  }
              };
              return stub.withCallCredentials(callCredentials);
          }).orElse(stub);
      }
  
      /**
       * Process rpc exception.
       *
       * @param rpcCause rpc cause.
       * @param future   future to complete exceptionally
       */
      public static <T> void processRpcException(Throwable rpcCause, CompletableFuture<T> future) {
          future.completeExceptionally(rpcCause);
      }
  
  }
  