ape.NetworkDisconnectCommand.java Source code

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Here is the source code for ape.NetworkDisconnectCommand.java

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/**
  * Copyright (c) 2012 Yahoo! Inc. All rights reserved.
  * Licensed 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. See accompanying LICENSE file.
*/

package ape;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.nio.CharBuffer;

import org.apache.commons.cli.Option;
import org.apache.commons.cli.OptionBuilder;
import org.apache.commons.cli.ParseException;

/**
 * This command will disconnect the host's network interface for a duration specified.
 * 
 * The ifdown command is invoked by this class.
 * 
 *
 */
public class NetworkDisconnectCommand extends ApeCommand {
    private Option option;

    /**
     * The constructor for this command simply creates its Option object (used by
     * the CLI parser)
     */
    public NetworkDisconnectCommand() {
        option = OptionBuilder.withArgName("time").hasArgs(1).withValueSeparator().withDescription(
                "Disconnect the network for a certain period of time specified in the argument, and then resumes")
                .withLongOpt("network-disconnect").create("d");
    }

    public String getName() {
        return option.getLongOpt();
    }

    public Option getOption() {
        return option;
    }

    public boolean runImpl(String[] args) throws ParseException, IOException {
        String argument = null;
        argument = args[0];

        double time = Double.parseDouble(argument);

        if (time <= 0) {
            System.out.println("ERROR: The duration of the disconnect must be positive, got " + time);
            Main.logger.info("ERROR: The duration of the disconnect must be positive, got " + time);
            return false;
        }

        if (!executecommand(time)) {
            System.out.println("ERROR: Simulating network failure unsuccessful.");
            Main.logger.info("ERROR: Simulating network failure unsuccessful.");
            return false;
        }

        return true;
    }

    /**
     * This method actually executes the command that would disconnect the network
     */
    private boolean executecommand(double time) throws IOException {
        String cmd = "ifdown eth0 && sleep " + time + " && /etc/init.d/network restart";
        ProcessBuilder pb = new ProcessBuilder("bash", "-c", cmd);
        pb.redirectErrorStream(true);
        Process p = null;

        try {
            p = pb.start();
        } catch (IOException e) {
            e.printStackTrace();
            return false;
        }

        try {
            if (p.waitFor() != 0) {
                System.out.println(
                        "ERROR: Non-zero return code (" + p.exitValue() + ") when executing: '" + cmd + "'");
                Main.logger
                        .info("ERROR: Non-zero return code (" + p.exitValue() + ") when executing: '" + cmd + "'");

                ProcessBuilder tmp2 = new ProcessBuilder("bash", "-c", "/etc/init.d/network restart");
                Process ptmp = tmp2.start();
                try {
                    if (ptmp.waitFor() == 0)
                        System.out.println("Connection resumed");
                    else {
                        System.out.println("Connection resume failed");
                        return false;
                    }
                } catch (InterruptedException e1) {
                    e1.printStackTrace();
                    System.err.println("Catches an exception when trying to recover the network");
                    return false;
                }

                return false;
            }
        } catch (InterruptedException e) {
            System.err.println("Executing Command catches an Interrupt, resume connection");
            ProcessBuilder tmp2 = new ProcessBuilder("bash", "-c", "/etc/init.d/network restart");
            Process ptmp = tmp2.start();
            try {
                if (ptmp.waitFor() == 0)
                    System.out.println("Connection Resumed");
                else {
                    System.out.println("Connection Resumed Failed");
                    return false;
                }
            } catch (InterruptedException e1) {
                e1.printStackTrace();
                System.err.println("Catches an exception when trying to recover the network");
                return false;

            }
            e.printStackTrace();
            return false;
        }

        return true;
    }

    /**
     * This method writes to the Stand output
     */
    private boolean writeSTDOut(Process p) {
        BufferedReader stdInput = new BufferedReader(new InputStreamReader(p.getInputStream()));
        int count;
        CharBuffer cbuf = CharBuffer.allocate(99999);
        try {
            count = stdInput.read(cbuf);
            if (count != -1)
                cbuf.array()[count] = '\0';
            else if (cbuf.array()[0] != '\0')
                count = cbuf.array().length;
            else
                count = 0;
            for (int i = 0; i < count; i++)
                System.out.print(cbuf.get(i));
        } catch (IOException e) {
            System.err.println(
                    "Writing Stdout in NetworkDisconnectCommand catches an exception, Turn on the VERBOSE flag to see the stack trace");
            e.printStackTrace();
            return false;
        }

        try {
            stdInput.close();
        } catch (IOException e) {
            System.err.println("Unable to close the IOStream");
            e.printStackTrace();
            return false;
        }
        return true;
    }
}