package com.alibaba.dcm;
import com.alibaba.dcm.internal.InetAddressCacheUtil;
import java.io.InputStream;
import java.util.Arrays;
import java.util.List;
import java.util.Map;
import java.util.Properties;
import java.util.regex.Pattern;
import javax.annotation.Nullable;
/**
* Setting dns (in fact dns cache).
* <p/>
* Throw {@link DnsCacheManipulatorException} if operation fail for all methods.
*
* @author Jerry Lee (oldratlee at gmail dot com)
* @see DnsCacheEntry
* @see DnsCacheManipulatorException
*/
public class DnsCacheManipulator {
private static final long NEVER_EXPIRATION = Long.MAX_VALUE;
/**
* Set a <b>never expired</b> dns cache entry
*
* @param host host
* @param ips ips
* @throws DnsCacheManipulatorException Operation fail
* @see DnsCacheManipulator#setDnsCache(long, java.lang.String, java.lang.String...)
*/
public static void setDnsCache(String host, String... ips) {
try {
InetAddressCacheUtil.setInetAddressCache(host, ips, NEVER_EXPIRATION);
} catch (Exception e) {
final String message = String.format("Fail to setDnsCache for host %s ip %s, cause: %s",
host, Arrays.toString(ips), e.toString());
throw new DnsCacheManipulatorException(message, e);
}
}
/**
* Set a dns cache entry.
*
* @param expireMillis expire time in milliseconds.
* @param host host
* @param ips ips
* @throws DnsCacheManipulatorException Operation fail
*/
public static void setDnsCache(long expireMillis, String host, String... ips) {
try {
InetAddressCacheUtil.setInetAddressCache(host, ips, System.currentTimeMillis() + expireMillis);
} catch (Exception e) {
final String message = String.format("Fail to setDnsCache for host %s ip %s expireMillis %s, cause: %s",
host, Arrays.toString(ips), expireMillis, e.toString());
throw new DnsCacheManipulatorException(message, e);
}
}
private static Pattern COMMA_SEPARATOR = Pattern.compile("\\s*,\\s*");
/**
* Set dns cache entries by properties
*
* @param properties input properties. eg. {@code www.example.com=42.42.42.42}, or {@code www.example.com=42.42.42.42,43.43.43.43}
* @throws DnsCacheManipulatorException Operation fail
*/
public static void setDnsCache(Properties properties) {
for (Map.Entry<Object, Object> entry : properties.entrySet()) {
final String host = (String) entry.getKey();
String ipList = (String) entry.getValue();
ipList = ipList.trim();
if (ipList.isEmpty()) continue;
final String[] ips = COMMA_SEPARATOR.split(ipList);
setDnsCache(host, ips);
}
}
/**
* Load dns config from properties file {@code dns-cache.properties} on classpath, then set to dns cache.
* <p/>
* {@code dns-cache.properties} can be reset/customized by {@code JVM -D option} {@code dcm.config.filename}
*
* @throws DnsCacheManipulatorException Operation fail
* @see DnsCacheManipulator#setDnsCache(java.util.Properties)
* @see DnsCacheManipulator#loadDnsCacheConfig(java.lang.String)
*/
public static void loadDnsCacheConfig() {
final String DCM_CONFIG_FILE_NAME_KEY = "dcm.config.filename";
final String dcmConfigFileName = System.getProperty(DCM_CONFIG_FILE_NAME_KEY, "dns-cache.properties");
loadDnsCacheConfig(dcmConfigFileName);
}
/**
* Load dns config from the specified properties file on classpath, then set dns cache.
*
* @param propertiesFileName specified properties file name on classpath.
* @throws DnsCacheManipulatorException Operation fail
* @see DnsCacheManipulator#setDnsCache(java.util.Properties)
*/
public static void loadDnsCacheConfig(String propertiesFileName) {
InputStream inputStream = Thread.currentThread().getContextClassLoader().getResourceAsStream(propertiesFileName);
if (inputStream == null) {
inputStream = DnsCacheManipulator.class.getClassLoader().getResourceAsStream(propertiesFileName);
}
if (inputStream == null) {
throw new DnsCacheManipulatorException("Fail to find " + propertiesFileName + " on classpath!");
}
try {
Properties properties = new Properties();
properties.load(inputStream);
inputStream.close();
setDnsCache(properties);
} catch (Exception e) {
final String message = String.format("Fail to loadDnsCacheConfig from %s, cause: %s",
propertiesFileName, e.toString());
throw new DnsCacheManipulatorException(message, e);
}
}
/**
* Get dns cache.
*
* @return dns cache. return {@code null} if no entry for host or dns cache is expired.
* @throws DnsCacheManipulatorException Operation fail
*/
@Nullable
public static DnsCacheEntry getDnsCache(String host) {
try {
return InetAddressCacheUtil.getInetAddressCache(host);
} catch (Exception e) {
throw new DnsCacheManipulatorException("Fail to getDnsCache, cause: " + e.toString(), e);
}
}
/**
* Get all dns cache entries.
*
* @return dns cache entries
* @throws DnsCacheManipulatorException Operation fail
* @deprecated use {@link #listDnsCache} instead.
*/
@Deprecated
public static List<DnsCacheEntry> getAllDnsCache() {
return listDnsCache();
}
/**
* Get all dns cache entries.
*
* @return dns cache entries
* @throws DnsCacheManipulatorException Operation fail
* @see #getWholeDnsCache()
* @since 1.2.0
*/
public static List<DnsCacheEntry> listDnsCache() {
try {
return InetAddressCacheUtil.listInetAddressCache().getCache();
} catch (Exception e) {
throw new DnsCacheManipulatorException("Fail to listDnsCache, cause: " + e.toString(), e);
}
}
/**
* Get whole dns cache info.
*
* @return dns cache entries
* @throws DnsCacheManipulatorException Operation fail
* @since 1.2.0
*/
public static DnsCache getWholeDnsCache() {
try {
return InetAddressCacheUtil.listInetAddressCache();
} catch (Exception e) {
throw new DnsCacheManipulatorException("Fail to getWholeDnsCache, cause: " + e.toString(), e);
}
}
/**
* Remove dns cache entry, cause lookup dns server for host after.
*
* @param host host
* @throws DnsCacheManipulatorException Operation fail
* @see DnsCacheManipulator#clearDnsCache
*/
public static void removeDnsCache(String host) {
try {
InetAddressCacheUtil.removeInetAddressCache(host);
} catch (Exception e) {
final String message = String.format("Fail to removeDnsCache for host %s, cause: %s", host, e.toString());
throw new DnsCacheManipulatorException(message, e);
}
}
/**
* Clear all dns cache entries, cause lookup dns server for all host after.
*
* @throws DnsCacheManipulatorException Operation fail
*/
public static void clearDnsCache() {
try {
InetAddressCacheUtil.clearInetAddressCache();
} catch (Exception e) {
throw new DnsCacheManipulatorException("Fail to clearDnsCache, cause: " + e.toString(), e);
}
}
/**
* Get JVM DNS cache policy.
*
* @return cache seconds.
* <p/>
* <ul>
* <li> {@code -1} means never expired.(In effect, all negative value)</li>
* <li> {@code 0} never cached.</li>
* </ul>
* @throws DnsCacheManipulatorException Operation fail
* @since 1.3.0
*/
public static int getDnsCachePolicy() {
try {
return InetAddressCacheUtil.getDnsCachePolicy();
} catch (Exception e) {
throw new DnsCacheManipulatorException("Fail to getDnsCachePolicy, cause: " + e.toString(), e);
}
}
/**
* Set JVM DNS cache policy
* <p/>
* NOTE: if Security Manage is turn on, JVM DNS cache policy set will not take effective. You can check by method {@link #getDnsCachePolicy()}.
*
* @param cacheSeconds set default dns cache time. Special input case:
* <ul>
* <li> {@code -1} means never expired.(In effect, all negative value)</li>
* <li> {@code 0} never cached.</li>
* </ul>
* @throws DnsCacheManipulatorException Operation fail
* @since 1.3.0
*/
public static void setDnsCachePolicy(int cacheSeconds) {
try {
InetAddressCacheUtil.setDnsCachePolicy(cacheSeconds);
} catch (Exception e) {
throw new DnsCacheManipulatorException("Fail to setDnsCachePolicy, cause: " + e.toString(), e);
}
}
/**
* JVM DNS negative cache policy
*
* @return negative cache seconds.
* <p/>
* <ul>
* <li> {@code -1} means never expired.(In effect, all negative value)</li>
* <li> {@code 0} never cached.</li>
* </ul>
* @throws DnsCacheManipulatorException Operation fail
* @since 1.3.0
*/
public static int getDnsNegativeCachePolicy() {
try {
return InetAddressCacheUtil.getDnsNegativeCachePolicy();
} catch (Exception e) {
throw new DnsCacheManipulatorException("Fail to getDnsNegativeCachePolicy, cause: " + e.toString(), e);
}
}
/**
* Set JVM DNS negative cache policy
*
* @param negativeCacheSeconds set default dns cache time. Special input case:
* <ul>
* <li> {@code -1} means never expired.(In effect, all negative value)</li>
* <li> {@code 0} never cached.</li>
* </ul>
* @throws DnsCacheManipulatorException Operation fail
* @since 1.3.0
*/
public static void setDnsNegativeCachePolicy(int negativeCacheSeconds) {
try {
InetAddressCacheUtil.setDnsNegativeCachePolicy(negativeCacheSeconds);
} catch (Exception e) {
throw new DnsCacheManipulatorException("Fail to setDnsNegativeCachePolicy, cause: " + e.toString(), e);
}
}
private DnsCacheManipulator() {
}
}