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.bifromq.baserpc.client.interceptor;
  
  import static org.apache.bifromq.baserpc.MetadataKeys.CUSTOM_METADATA_META_KEY;
  import static org.apache.bifromq.baserpc.MetadataKeys.TENANT_ID_META_KEY;
  
  import org.apache.bifromq.baserpc.RPCContext;
  import org.apache.bifromq.baserpc.client.loadbalancer.Constants;
  import org.apache.bifromq.baserpc.proto.PipelineMetadata;
  import io.grpc.CallOptions;
  import io.grpc.Channel;
  import io.grpc.ClientCall;
  import io.grpc.ClientInterceptor;
  import io.grpc.ForwardingClientCall;
  import io.grpc.Metadata;
  import io.grpc.MethodDescriptor;
  import lombok.extern.slf4j.Slf4j;
  
  @Slf4j
  public class TenantAwareClientInterceptor implements ClientInterceptor {
      private final String serviceUniqueName;
  
      public TenantAwareClientInterceptor() {
          this(null);
      }
  
      // used in in-process mode
      public TenantAwareClientInterceptor(String serviceUniqueName) {
          this.serviceUniqueName = serviceUniqueName;
      }
  
      @Override
      public <ReqT, RespT> ClientCall<ReqT, RespT> interceptCall(MethodDescriptor<ReqT, RespT> method,
                                                                 CallOptions callOptions, Channel next) {
          return new ForwardingClientCall.SimpleForwardingClientCall<>(next.newCall(method, callOptions)) {
              @Override
              public void start(Listener<RespT> responseListener, Metadata headers) {
                  headers.put(TENANT_ID_META_KEY, RPCContext.TENANT_ID_CTX_KEY.get());
                  if (RPCContext.DESIRED_SERVER_ID_CTX_KEY.get() != null) {
                      headers.put(Constants.DESIRED_SERVER_META_KEY, RPCContext.DESIRED_SERVER_ID_CTX_KEY.get());
                  }
                  if (RPCContext.CUSTOM_METADATA_CTX_KEY.get() != null) {
                      headers.put(CUSTOM_METADATA_META_KEY, PipelineMetadata.newBuilder()
                          .putAllEntry(RPCContext.CUSTOM_METADATA_CTX_KEY.get()).build().toByteArray());
                  }
                  super.start(responseListener, headers);
              }
          };
      }
  }
  