alluxio-master-2.x/core/common/src/main/java/alluxio/grpc/ClientVersionClientInjector.java
/*
 * The Alluxio Open Foundation licenses this work under the Apache License, version 2.0
 * (the "License"). You may not use this work except in compliance with the License, which is
 * available at www.apache.org/licenses/LICENSE-2.0
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied, as more fully set forth in the License.
 *
 * See the NOTICE file distributed with this work for information regarding copyright ownership.
 */

package alluxio.grpc;

import alluxio.RuntimeConstants;

import io.grpc.CallOptions;
import io.grpc.Channel;
import io.grpc.ClientCall;
import io.grpc.ClientInterceptor;
import io.grpc.ForwardingClientCall;
import io.grpc.ForwardingClientCallListener;
import io.grpc.Metadata;
import io.grpc.MethodDescriptor;

/**
 * Client side interceptor that is used to set the request header for the client version.
 */
public class ClientVersionClientInjector implements ClientInterceptor {
  public static final Metadata.Key<String> S_CLIENT_VERSION_KEY =
      Metadata.Key.of("alluxio-version", Metadata.ASCII_STRING_MARSHALLER);

  @Override
  public <ReqT, RespT> ClientCall<ReqT, RespT> interceptCall(MethodDescriptor<ReqT, RespT> method,
      CallOptions callOptions, Channel next) {
    return new ForwardingClientCall.SimpleForwardingClientCall<ReqT, RespT>(
        next.newCall(method, callOptions)) {
      @Override
      public void start(Listener<RespT> responseListener, Metadata headers) {
        // Put version to headers.
        headers.put(S_CLIENT_VERSION_KEY, RuntimeConstants.VERSION_AND_REVISION_SHORT);
        super.start(new ForwardingClientCallListener.SimpleForwardingClientCallListener<RespT>(
            responseListener) {
          @Override
          public void onHeaders(Metadata headers) {
            super.onHeaders(headers);
          }
        }, headers);
      }
    };
  }
}
