gistfile1.java

package com.chronon.apm.utils;

import com.chronon.apm.Log;
import com.google.common.collect.Iterables;

import java.net.*;
import java.util.Collections;
import java.util.List;

public class Hostname
{

    public static String getHostname()
    {
        try
        {
            return InetAddress.getLocalHost().getHostName();
        } catch (UnknownHostException e)
        {
            String ipAddress = ipAddress();
            if (ipAddress != null)
            {
                Log.logger.info("Couldnt obtain hostname. Using ip address instead");
                return ipAddress;
            }
        }

        Log.logger.info("Couldnt obtain hostname. Using localhost");
        return "localhost";
    }

    private static String ipAddress()
    {
        try
        {
            for (NetworkInterface networkInterface : Collections.list(NetworkInterface.getNetworkInterfaces()))
            {
                if ((networkInterface.getName().startsWith("eth")) || (networkInterface.getName().startsWith("en")))
                {
                    List<InterfaceAddress> addresses = networkInterface.getInterfaceAddresses();
                    if (!addresses.isEmpty())
                    {

                        //prefer ip4 address
                        String ipv4Address = getIpv4Address(addresses);
                        if (ipv4Address != null)
                            return ipv4Address;

                        //other just return the first one in the list
                        return Iterables.getFirst(addresses, null).getAddress().getHostAddress();
                    }
                }
            }
        } catch (SocketException e)
        {

        }
        return null;
    }


    private static String getIpv4Address(List<InterfaceAddress> addresses)
    {
        for (InterfaceAddress address : addresses)
        {
            InetAddress inetAddress = address.getAddress();
            if (inetAddress instanceof Inet4Address)
            {
                return inetAddress.getHostAddress();
            }
        }
        return null;
    }
}