twill-yarn/src/test/java/org/apache/twill/yarn/EnvironmentEchoServer.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.twill.yarn;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.PrintWriter;

/**
 * Test server that returns back the value of the env key sent in.  Used to check env for
 * runnables is correctly set.
 */
public class EnvironmentEchoServer extends SocketServer {

  @Override
  public void handleRequest(BufferedReader reader, PrintWriter writer) throws IOException {
    String envKey = reader.readLine();
    writer.println(System.getenv(envKey));
  }
}