/*
* Copyright 2012 Netflix, Inc.
*
* 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.
*/
package com.netflix.eureka.resources;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Supplier;
import com.google.common.cache.CacheBuilder;
import com.google.common.cache.CacheLoader;
import com.google.common.cache.LoadingCache;
import com.google.common.cache.RemovalListener;
import com.google.common.cache.RemovalNotification;
import com.google.common.collect.Multimap;
import com.google.common.collect.Multimaps;
import com.netflix.appinfo.InstanceInfo;
import com.netflix.discovery.converters.JsonXStream;
import com.netflix.discovery.converters.XmlXStream;
import com.netflix.discovery.shared.Application;
import com.netflix.discovery.shared.Applications;
import com.netflix.eureka.CurrentRequestVersion;
import com.netflix.eureka.EurekaServerConfig;
import com.netflix.eureka.EurekaServerConfigurationManager;
import com.netflix.eureka.InstanceRegistry;
import com.netflix.eureka.PeerAwareInstanceRegistry;
import com.netflix.eureka.Version;
import com.netflix.servo.annotations.DataSourceType;
import com.netflix.servo.annotations.Monitor;
import com.netflix.servo.monitor.Monitors;
import com.netflix.servo.monitor.Stopwatch;
import com.netflix.servo.monitor.Timer;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import javax.annotation.Nullable;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.Arrays;
import java.util.Collection;
import java.util.Date;
import java.util.List;
import java.util.TimerTask;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicLong;
import java.util.zip.GZIPOutputStream;
/**
* The class that is responsible for caching registry information that will be
* queried by the clients.
*
* <p>
* The cache is maintained in compressed and non-compressed form for three
* categories of requests - all applications, delta changes and for individual
* applications. The compressed form is probably the most efficient in terms of
* network traffic especially when querying all applications.
*
* The cache also maintains separate pay load for <em>JSON</em> and <em>XML</em>
* formats and for multiple versions too.
* </p>
*
* @author Karthik Ranganathan, Greg Kim
*/
public class ResponseCache {
private static final Logger logger = LoggerFactory
.getLogger(ResponseCache.class);
private final EurekaServerConfig eurekaConfig = EurekaServerConfigurationManager
.getInstance().getConfiguration();
public static final String ALL_APPS = "ALL_APPS";
public static final String ALL_APPS_DELTA = "ALL_APPS_DELTA";
private final Timer serializeAllAppsTimer = Monitors
.newTimer("serialize-all");
private final Timer serializeDeltaAppsTimer = Monitors
.newTimer("serialize-all-delta");
private final Timer serializeAllAppsWithRemoteRegionTimer = Monitors
.newTimer("serialize-all_remote_region");
private final Timer serializeDeltaAppsWithRemoteRegionTimer = Monitors
.newTimer("serialize-all-delta_remote_region");
private final Timer serializeOneApptimer = Monitors
.newTimer("serialize-one");
private final Timer serializeViptimer = Monitors.newTimer("serialize-one-vip");
private final Timer compressPayloadTimer = Monitors
.newTimer("compress-payload");
private static final AtomicLong versionDelta = new AtomicLong(0);
private static final AtomicLong versionDeltaWithRegions = new AtomicLong(0);
private static final String EMPTY_PAYLOAD = "";
public enum KeyType {
JSON, XML
}
/**
* This map holds mapping of keys without regions to a list of keys with region (provided by clients)
* Since, during invalidation, triggered by a change in registry for local region, we do not know the regions
* requested by clients, we use this mapping to get all the keys with regions to be invalidated.
* If we do not do this, any cached user requests containing region keys will not be invalidated and will stick
* around till expiry. Github issue: https://github.com/Netflix/eureka/issues/118
*/
private final Multimap<Key, Key> regionSpecificKeys =
Multimaps.newListMultimap(new ConcurrentHashMap<Key, Collection<Key>>(), new Supplier<List<Key>>() {
@Override
public List<Key> get() {
return new CopyOnWriteArrayList<Key>();
}
});
private final ConcurrentMap<Key, Value> readOnlyCacheMap = new ConcurrentHashMap<Key, Value>();
private static final java.util.Timer timer = new java.util.Timer("Eureka -CacheFillTimer", true);
private final LoadingCache<Key, Value> readWriteCacheMap =
CacheBuilder.newBuilder().initialCapacity(1000)
.expireAfterWrite(eurekaConfig.getResponseCacheAutoExpirationInSeconds(), TimeUnit.SECONDS)
.removalListener(new RemovalListener<Key, Value>() {
@Override
public void onRemoval(RemovalNotification<Key, Value> notification) {
Key removedKey = notification.getKey();
if (removedKey.hasRegions()) {
Key cloneWithNoRegions = removedKey.cloneWithoutRegions();
regionSpecificKeys.remove(cloneWithNoRegions, removedKey);
}
}
})
.build(new CacheLoader<Key, Value>() {
@Override
public Value load(Key key) throws Exception {
if (key.hasRegions()) {
Key cloneWithNoRegions = key.cloneWithoutRegions();
regionSpecificKeys.put(cloneWithNoRegions, key);
}
Value value = generatePayload(key);
return value;
}
});
private static final ResponseCache s_instance = new ResponseCache();
private ResponseCache() {
long responseCacheUpdateIntervalMs = eurekaConfig.getResponseCacheUpdateIntervalMs();
timer.schedule(getCacheUpdateTask(),
new Date(((System.currentTimeMillis() / responseCacheUpdateIntervalMs) * responseCacheUpdateIntervalMs)
+ responseCacheUpdateIntervalMs),
responseCacheUpdateIntervalMs);
try {
Monitors.registerObject(this);
} catch (Throwable e) {
logger.warn(
"Cannot register the JMX monitor for the InstanceRegistry :",
e);
}
}
private TimerTask getCacheUpdateTask() {
return new TimerTask() {
@Override
public void run() {
logger.debug("Updating the client cache from response cache");
for (Key key : readOnlyCacheMap.keySet()) {
if (logger.isDebugEnabled()) {
Object[] args = {key.getEntityType(), key.getName(), key.getVersion(), key.getType()};
logger.debug("Updating the client cache from response cache for key : {} {} {} {}", args);
}
try {
CurrentRequestVersion.set(key.getVersion());
Value cacheValue = readWriteCacheMap.get(key);
Value currentCacheValue = readOnlyCacheMap.get(key);
if (cacheValue != currentCacheValue) {
readOnlyCacheMap.put(key, cacheValue);
}
} catch (Throwable th) {
logger.error("Error while updating the client cache from response cache", th);
}
}
}
};
}
public static ResponseCache getInstance() {
return s_instance;
}
/**
* Get the cached information about applications.
*
* <p>
* If the cached information is not available it is generated on the first
* request. After the first request, the information is then updated
* periodically by a background thread.
* </p>
*
* @param key
* the key for which the cached information needs to be obtained.
* @return payload which contains information about the applications.
*/
public String get(final Key key) {
return get(key, false);
}
@VisibleForTesting String get(final Key key, boolean ignoreReadOnlyCache) {
Value payload = getValue(key, ignoreReadOnlyCache);
if (payload == null || payload.getPayload() == EMPTY_PAYLOAD) {
return null;
} else {
return payload.getPayload();
}
}
/**
* Get the compressed information about the applications.
*
* @param key
* the key for which the compressed cached information needs to
* be obtained.
* @return compressed payload which contains information about the
* applications.
*/
public byte[] getGZIP(Key key) {
Value payload = getValue(key, false);
if (payload == null) {
return null;
}
return payload.getGzipped();
}
/**
* Invalidate the cache of a particular application.
*
* @param appName
* the application name of the application.
*/
public void invalidate(String appName, @Nullable String vipAddress, @Nullable String secureVipAddress) {
for (KeyType type : KeyType.values()) {
for (Version v : Version.values()) {
invalidate(new Key(Key.EntityType.Application, appName, type, v),
new Key(Key.EntityType.Application, ALL_APPS, type, v),
new Key(Key.EntityType.Application, ALL_APPS_DELTA, type, v));
if (null != vipAddress) {
invalidate(new Key(Key.EntityType.VIP, vipAddress, type, v));
}
if (null != secureVipAddress) {
invalidate(new Key(Key.EntityType.SVIP, secureVipAddress, type, v));
}
}
}
}
/**
* Invalidate the cache information given the list of keys.
*
* @param keys
* the list of keys for which the cache information needs to be
* invalidated.
*/
public void invalidate(Key... keys) {
for (Key key : keys) {
Object[] args = {key.getEntityType(), key.getName(), key.getVersion(), key.getType()};
logger.debug("Invalidating the response cache key : {} {} {} {}", args);
readWriteCacheMap.invalidate(key);
Collection<Key> keysWithRegions = regionSpecificKeys.get(key);
if (null != keysWithRegions && !keysWithRegions.isEmpty()) {
for (Key keysWithRegion : keysWithRegions) {
logger.debug("Invalidating the response cache key : {} {} {} {}", args);
readWriteCacheMap.invalidate(keysWithRegion);
}
}
}
}
/**
* Gets the version number of the cached data.
*
* @return teh version number of the cached data.
*/
public static AtomicLong getVersionDelta() {
return versionDelta;
}
/**
* Gets the version number of the cached data with remote regions.
*
* @return teh version number of the cached data with remote regions.
*/
public static AtomicLong getVersionDeltaWithRegions() {
return versionDeltaWithRegions;
}
/**
* Get the number of items in the response cache.
*
* @return int value representing the number of items in response cache.
*/
@Monitor(name = "responseCacheSize", type = DataSourceType.GAUGE)
public int getCurrentSize() {
return readWriteCacheMap.asMap().size();
}
/**
* Get the payload in both compressed and uncompressed form.
*/
@VisibleForTesting Value getValue(final Key key, boolean ignoreReadOnlyCache) {
Value payload = null;
try {
if (ignoreReadOnlyCache) {
payload = readWriteCacheMap.get(key);
} else {
final Value currentPayload = readOnlyCacheMap.get(key);
if (currentPayload != null) {
payload = currentPayload;
} else {
payload = readWriteCacheMap.get(key);
readOnlyCacheMap.put(key, payload);
}
}
} catch (Throwable t) {
logger.error("Cannot get value for key :" + key, t);
}
return payload;
}
/**
* Generate pay load with both JSON and XML formats for all applications.
*/
private static String getPayLoad(Key key, Applications apps) {
if (key.getType() == KeyType.JSON) {
return JsonXStream.getInstance().toXML(apps);
} else {
return XmlXStream.getInstance().toXML(apps);
}
}
/**
* Generate pay load with both JSON and XML formats for a given application.
*/
private static String getPayLoad(Key key, Application app) {
if (app == null) {
return EMPTY_PAYLOAD;
}
if (key.getType() == KeyType.JSON) {
return JsonXStream.getInstance().toXML(app);
} else {
return XmlXStream.getInstance().toXML(app);
}
}
/*
* Generate pay load for the given key.
*/
private Value generatePayload(Key key) {
Stopwatch tracer = null;
InstanceRegistry registry = PeerAwareInstanceRegistry.getInstance();
try {
String payload;
switch (key.getEntityType()) {
case Application:
boolean isRemoteRegionRequested = key.hasRegions();
if (ALL_APPS.equals(key.getName())) {
if (isRemoteRegionRequested) {
tracer = serializeAllAppsWithRemoteRegionTimer.start();
payload = getPayLoad(key, registry.getApplicationsFromMultipleRegions(key.getRegions()));
} else {
tracer = serializeAllAppsTimer.start();
payload = getPayLoad(key, registry.getApplications());
}
} else if (ALL_APPS_DELTA.equals(key.getName())) {
if (isRemoteRegionRequested) {
tracer = serializeDeltaAppsWithRemoteRegionTimer.start();
versionDeltaWithRegions.incrementAndGet();
payload = getPayLoad(key,
registry.getApplicationDeltasFromMultipleRegions(key.getRegions()));
} else {
tracer = serializeDeltaAppsTimer.start();
versionDelta.incrementAndGet();
payload = getPayLoad(key, registry.getApplicationDeltas());
}
} else {
tracer = serializeOneApptimer.start();
payload = getPayLoad(key, registry.getApplication(key.getName()));
}
break;
case VIP:
case SVIP:
tracer = serializeViptimer.start();
payload = getPayLoad(key, getApplicationsForVip(key, registry));
break;
default:
logger.error("Unidentified entity type: " + key.getEntityType() + " found in the cache key.");
payload = "";
break;
}
return new Value(payload);
} finally {
if (tracer != null) {
tracer.stop();
}
}
}
private static Applications getApplicationsForVip(Key key, InstanceRegistry registry) {
Object[] args = {key.getEntityType(), key.getName(), key.getVersion(), key.getType()};
logger.debug(
"Retrieving applications from registry for key : {} {} {} {}",
args);
Applications toReturn = new Applications();
Applications applications = registry.getApplications();
for (Application application : applications.getRegisteredApplications()) {
Application appToAdd = null;
for (InstanceInfo instanceInfo : application.getInstances()) {
String vipAddress;
if (Key.EntityType.VIP.equals(key.getEntityType())) {
vipAddress = instanceInfo.getVIPAddress();
} else if (Key.EntityType.SVIP.equals(key.getEntityType())) {
vipAddress = instanceInfo.getSecureVipAddress();
} else {
// should not happen, but just in case.
continue;
}
if (null != vipAddress) {
String[] vipAddresses = vipAddress.split(",");
Arrays.sort(vipAddresses);
if (Arrays.binarySearch(vipAddresses, key.getName()) >= 0) {
if (null == appToAdd) {
appToAdd = new Application(application.getName());
toReturn.addApplication(appToAdd);
}
appToAdd.addInstance(instanceInfo);
}
}
}
}
toReturn.setAppsHashCode(toReturn.getReconcileHashCode());
args = new Object[] {key.getEntityType(), key.getName(), key.getVersion(), key.getType(),
toReturn.getReconcileHashCode()};
logger.debug(
"Retrieved applications from registry for key : {} {} {} {}, reconcile hashcode: {}",
args);
return toReturn;
}
/**
* The key for the cached payload.
*/
public static class Key {
/**
* An enum to define the entity that is stored in this cache for this key.
*/
public enum EntityType { Application, VIP, SVIP }
private final String entityName;
private final String[] regions;
private final KeyType requestType;
private final Version requestVersion;
private final String hashKey;
private final EntityType entityType;
public Key(EntityType entityType, String entityName, KeyType type, Version v) {
this(entityType, entityName, null, type, v);
}
public Key(EntityType entityType, String entityName, @Nullable String[] regions, KeyType type, Version v) {
this.regions = regions;
this.entityType = entityType;
this.entityName = entityName;
requestType = type;
requestVersion = v;
hashKey = this.entityType + this.entityName + (null != this.regions ? Arrays.toString(this.regions) : "")
+ requestType.name() + requestVersion.name();
}
public String getName() {
return entityName;
}
public String getHashKey() {
return hashKey;
}
public KeyType getType() {
return requestType;
}
public Version getVersion() {
return requestVersion;
}
public EntityType getEntityType() {
return entityType;
}
public boolean hasRegions() {
return null != regions && regions.length != 0;
}
public String[] getRegions() {
return regions;
}
public Key cloneWithoutRegions() {
return new Key(entityType, entityName, requestType, requestVersion);
}
@Override
public int hashCode() {
String hashKey = getHashKey();
return hashKey.hashCode();
}
@Override
public boolean equals(Object other) {
if (other instanceof Key) {
return getHashKey().equals(((Key) other).getHashKey());
} else {
return false;
}
}
}
/**
* The class that stores payload in both compressed and uncompressed form.
*
*/
public class Value {
private final String payload;
private byte[] gzipped;
public Value(String payload) {
this.payload = payload;
if (payload != EMPTY_PAYLOAD) {
Stopwatch tracer = compressPayloadTimer.start();
try {
ByteArrayOutputStream bos = new ByteArrayOutputStream();
GZIPOutputStream out = new GZIPOutputStream(bos);
byte[] rawBytes = payload.getBytes();
out.write(rawBytes);
// Finish creation of gzip file
out.finish();
out.close();
bos.close();
gzipped = bos.toByteArray();
} catch (IOException e) {
gzipped = null;
} finally {
if (tracer != null) {
tracer.stop();
}
}
} else {
gzipped = null;
}
}
public String getPayload() {
return payload;
}
public byte[] getGzipped() {
return gzipped;
}
}
}