com.yahoo.net.HostName Maven / Gradle / Ivy
// Copyright Vespa.ai. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.net;
import java.util.Optional;
/**
* This class has utilities for getting the hostname of the system running the JVM.
* Detection of the hostname is now done before starting any Vespa
* programs and provided in the environment variable VESPA_HOSTNAME;
* if that variable isn't set a default of "localhost" is always returned.
*
* @author arnej
*/
public class HostName {
private static String preferredHostName = null;
/**
* Return a public and fully qualified hostname for localhost that
* resolves to an IP address on a network interface.
*
* @return the preferred name of localhost
*/
public static synchronized String getLocalhost() {
if (preferredHostName == null) {
preferredHostName = getPreferredHostName();
}
return preferredHostName;
}
static private String getPreferredHostName() {
Optional vespaHostEnv = Optional.ofNullable(System.getenv("VESPA_HOSTNAME"));
if (vespaHostEnv.isPresent() && ! vespaHostEnv.get().trim().isEmpty()) {
return vespaHostEnv.get().trim();
}
return "localhost";
}
public static void setHostNameForTestingOnly(String hostName) {
preferredHostName = hostName;
}
}