test/src/main/java/org/apache/ratis/thirdparty/demo/GrpcClient.java

/**
 * 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.ratis.thirdparty.demo;

import org.apache.commons.lang3.StringUtils;
import org.apache.ratis.thirdparty.io.grpc.ManagedChannel;
import org.apache.ratis.thirdparty.io.grpc.ManagedChannelBuilder;
import org.apache.ratis.thirdparty.io.grpc.StatusRuntimeException;
import java.util.concurrent.TimeUnit;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * gRPC Demo client with shaded ratis thirdparty jar.
 */
public class GrpcClient {
  private static final Logger LOG = LoggerFactory.getLogger(
      GrpcClient.class.getName());

  private final ManagedChannel channel;
  private final GreeterGrpc.GreeterBlockingStub blockingStub;

  public GrpcClient(String host, int port) {
    this(ManagedChannelBuilder.forAddress(host, port)
        .usePlaintext()
        .build());
  }

  GrpcClient(ManagedChannel channel) {
    this.channel = channel;
    blockingStub = GreeterGrpc.newBlockingStub(channel);
  }

  public void shutdown() throws InterruptedException {
    channel.shutdown().awaitTermination(5, TimeUnit.SECONDS);
  }

  public String greet(String name) {
    HelloRequest request = HelloRequest.newBuilder().setName(name).build();
    HelloReply response;
    try {
      response = blockingStub.hello(request);
      LOG.trace("Greeting: " + response.getMessage());
      return response.getMessage();
    } catch (StatusRuntimeException e) {
      LOG.warn("RPC failed: {0}", e.getStatus());
      return StringUtils.EMPTY;
    }
  }

  public static void main(String[] args) throws Exception {
    GrpcClient client = new GrpcClient("localhost", 50001);
    try {
      String user = "testuser";
      if (args.length > 0) {
        user = args[0];
      }
      client.greet(user);
    } finally {
      client.shutdown();
    }
  }
}