/*
* 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.brooklyn.core.location.geo;
import java.util.Collections;
import java.util.List;
import java.util.concurrent.Callable;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import org.apache.brooklyn.util.core.ResourceUtils;
import org.apache.brooklyn.util.exceptions.Exceptions;
import org.apache.brooklyn.util.text.StringPredicates;
import org.apache.brooklyn.util.time.Duration;
import org.apache.brooklyn.util.time.Durations;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Predicates;
import com.google.common.base.Splitter;
import com.google.common.collect.Iterables;
import com.google.common.collect.Lists;
public class LocalhostExternalIpLoader {
public static final Logger LOG = LoggerFactory.getLogger(LocalhostExternalIpLoader.class);
/**
* Mutex to guard access to retrievingLocalExternalIp.
*/
private static final Object mutex = new Object();
/**
* When null there is no ongoing attempt to load the external IP address. Either no attempt has been made or the
* last attempt has been completed.
* When set there is an ongoing attempt to load the external IP address. New attempts to lookup the external IP
* address should wait on this latch instead of making another attempt to load the IP address.
*/
private static CountDownLatch retrievingLocalExternalIp;
/**
* Cached external IP address of localhost. Null if either no attempt has been made to resolve the address or the
* last attempt failed.
*/
private static volatile String localExternalIp;
private static class IpLoader implements Callable<String> {
private static final Pattern ipPattern = Pattern.compile(
"\\b((25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9]?[0-9])\\.){3}(25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9]?[0-9])\\b");
final String url;
protected IpLoader(String url) {
this.url = url;
}
@Override
public String call() {
String response = ResourceUtils.create(LocalhostExternalIpLoader.class)
.getResourceAsString(url).trim();
return postProcessResponse(response);
}
String postProcessResponse(String response) {
Matcher matcher = ipPattern.matcher(response);
boolean matched = matcher.find();
if (!matched) {
LOG.error("No IP address matched in output from {}: {}", url, response);
return null;
} else {
return matcher.group();
}
}
}
@VisibleForTesting
static List<String> getIpAddressWebsites() {
String file = new ResourceUtils(LocalhostExternalIpLoader.class)
.getResourceAsString("classpath://org/apache/brooklyn/location/geo/external-ip-address-resolvers.txt");
Iterable<String> lines = Splitter.on('\n')
.omitEmptyStrings()
.trimResults()
.split(file);
List<String> urls = Lists.newArrayList(Iterables.filter(lines, Predicates.not(StringPredicates.startsWith("#"))));
Collections.shuffle(urls);
return urls;
}
@VisibleForTesting
static String getIpAddressFrom(String url) {
return new IpLoader(url).call();
}
/** As {@link #getLocalhostIpWithin(Duration)} but returning 127.0.0.1 if not accessible */
public static String getLocalhostIpQuicklyOrDefault() {
String result = doLoad(Duration.seconds(2));
if (result==null) return "127.0.0.1";
return result;
}
/** As {@link #getLocalhostIpWithin(Duration)} but without the time limit cut-off, failing if the load gives an error. */
public static String getLocalhostIpWaiting() {
return getLocalhostIpWithin(null);
}
/**
* Attempts to load the public IP address of localhost, failing if the load
* does not complete within the given duration.
* @return The public IP address of localhost
*/
public static String getLocalhostIpWithin(Duration timeout) {
String result = doLoad(timeout);
if (result == null) {
throw new IllegalStateException("Unable to retrieve external IP for localhost; network may be down or slow or remote service otherwise not responding");
}
return result;
}
/**
* Requests URLs returned by {@link #getIpAddressWebsites()} until one returns an IP address or all URLs have been tried.
* The address is assumed to be the external IP address of localhost.
* @param blockFor The maximum duration to wait for the IP address to be resolved.
* An indefinite way if null.
* @return A string in IPv4 format, or null if no such address could be ascertained.
*/
private static String doLoad(Duration blockFor) {
// Check for a cached external IP address
final String resolvedIp = localExternalIp;
if (resolvedIp != null) {
return resolvedIp;
}
// Check for an ongoing attempt to load an external IP address
final boolean startAttemptToLoadIp;
final CountDownLatch attemptToRetrieveLocalExternalIp;
synchronized (mutex) {
if (retrievingLocalExternalIp == null) {
retrievingLocalExternalIp = new CountDownLatch(1);
startAttemptToLoadIp = true;
}
else {
startAttemptToLoadIp = false;
}
attemptToRetrieveLocalExternalIp = retrievingLocalExternalIp;
}
// Attempt to load the external IP address in private thread, otherwise blocks for 30s+ on dodgy network!
// (we can skip it if someone else is doing it, we have synch lock so we'll get notified)
if (startAttemptToLoadIp) {
final List<String> candidateUrls = getIpAddressWebsites();
if (candidateUrls.isEmpty()) {
LOG.debug("No candidate URLs to use to determine external IP of localhost");
return null;
}
new Thread() {
public void run() {
for (String url : candidateUrls) {
try {
LOG.debug("Looking up external IP of this host from {} in private thread {}", url, Thread.currentThread());
final String loadedIp = new IpLoader(url).call();
localExternalIp = loadedIp;
LOG.debug("Finished looking up external IP of this host from {} in private thread, result {}", url, loadedIp);
break;
} catch (Throwable t) {
LOG.debug("Unable to look up external IP of this host from {}, probably offline {})", url, t);
}
}
attemptToRetrieveLocalExternalIp.countDown();
synchronized (mutex) {
retrievingLocalExternalIp = null;
}
}
}.start();
}
try {
if (blockFor!=null) {
Durations.await(attemptToRetrieveLocalExternalIp, blockFor);
} else {
attemptToRetrieveLocalExternalIp.await();
}
} catch (InterruptedException e) {
throw Exceptions.propagate(e);
}
return localExternalIp;
}
}