/*
* 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.util;
import java.util.Arrays;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import java.util.Timer;
import java.util.TimerTask;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.TimeUnit;
import com.google.common.base.Strings;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.amazonaws.ClientConfiguration;
import com.amazonaws.auth.BasicAWSCredentials;
import com.amazonaws.auth.InstanceProfileCredentialsProvider;
import com.amazonaws.services.autoscaling.AmazonAutoScaling;
import com.amazonaws.services.autoscaling.AmazonAutoScalingClient;
import com.amazonaws.services.autoscaling.model.AutoScalingGroup;
import com.amazonaws.services.autoscaling.model.DescribeAutoScalingGroupsRequest;
import com.amazonaws.services.autoscaling.model.DescribeAutoScalingGroupsResult;
import com.amazonaws.services.autoscaling.model.SuspendedProcess;
import com.google.common.cache.CacheBuilder;
import com.google.common.cache.CacheLoader;
import com.google.common.cache.LoadingCache;
import com.netflix.appinfo.InstanceInfo;
import com.netflix.discovery.DiscoveryManager;
import com.netflix.discovery.shared.Application;
import com.netflix.discovery.shared.Applications;
import com.netflix.eureka.EurekaServerConfig;
import com.netflix.eureka.EurekaServerConfigurationManager;
import com.netflix.eureka.PeerAwareInstanceRegistry;
import com.netflix.servo.annotations.DataSourceType;
import com.netflix.servo.monitor.Monitors;
import com.netflix.servo.monitor.Stopwatch;
/**
* A utility class for querying and updating information about amazon
* autoscaling groups using the AWS APIs.
*
* @author Karthik Ranganathan
*
*/
public class AwsAsgUtil {
private final Logger logger = LoggerFactory.getLogger(AwsAsgUtil.class);
private static final String PROP_ADD_TO_LOAD_BALANCER = "AddToLoadBalancer";
private static final EurekaServerConfig eurekaConfig = EurekaServerConfigurationManager
.getInstance().getConfiguration();
private static final AmazonAutoScaling client = getAmazonAutoScalingClient();
// Cache for the AWS ASG information
private final LoadingCache<String, Boolean> asgCache = CacheBuilder
.newBuilder().initialCapacity(500)
.expireAfterAccess(5, TimeUnit.MINUTES)
.build(new CacheLoader<String, Boolean>() {
@Override
public Boolean load(String key) throws Exception {
return isASGEnabledinAWS(key);
}
});
private final Timer timer = new Timer("Eureka-ASGCacheRefresh", true);
private final com.netflix.servo.monitor.Timer loadASGInfoTimer = Monitors
.newTimer("Eureka-loadASGInfo");
private static final AwsAsgUtil awsAsgUtil = new AwsAsgUtil();
private AwsAsgUtil() {
String region = DiscoveryManager.getInstance().getEurekaClientConfig()
.getRegion();
client.setEndpoint("autoscaling." + region + ".amazonaws.com");
timer.schedule(getASGUpdateTask(),
eurekaConfig.getASGUpdateIntervalMs(),
eurekaConfig.getASGUpdateIntervalMs());
try {
Monitors.registerObject(this);
} catch (Throwable e) {
logger.warn("Cannot register the JMX monitor :", e);
}
}
public static AwsAsgUtil getInstance() {
return awsAsgUtil;
}
/**
* Return the status of the ASG whether is enabled or disabled for service.
* The value is picked up from the cache except the very first time.
*
* @param asgName
* - The name of the ASG
* @return - true if enabled, false otherwise
*/
public boolean isASGEnabled(String asgName) {
try {
return asgCache.get(asgName);
} catch (ExecutionException e) {
logger.error("Error getting cache value for asg : " + asgName, e);
}
return true;
}
/**
* Sets the status of the ASG.
*
* @param asgName
* - The name of the ASG
* @param enabled
* - true to enable, false to disable
*/
public void setStatus(String asgName, boolean enabled) {
asgCache.put(asgName, enabled);
}
/**
* Check if the ASG is disabled. The amazon flag "AddToLoadBalancer" is
* queried to figure out if it is or not.
*
* @param asgName
* - The name of the ASG for which the status needs to be queried
* @return - true if the ASG is disabled, false otherwise
*/
private boolean isAddToLoadBalancerSuspended(String asgName) {
AutoScalingGroup asg = retrieveAutoScalingGroup(asgName);
if (asg == null) {
logger.warn(
"The ASG information for {} could not be found. So returning false.",
asgName);
return false;
}
return isAddToLoadBalancerSuspended(asg);
}
/**
* Checks if the load balancer addition is disabled or not.
*
* @param asg
* - The ASG object for which the status needs to be checked
* @return - true, if the load balancer addition is suspended, false
* otherwise.
*/
private boolean isAddToLoadBalancerSuspended(AutoScalingGroup asg) {
List<SuspendedProcess> suspendedProcesses = asg.getSuspendedProcesses();
for (SuspendedProcess process : suspendedProcesses) {
if (PROP_ADD_TO_LOAD_BALANCER.equals(process.getProcessName())) {
return true;
}
}
return false;
}
/**
* Queries AWS to get the autoscaling information given the asgName.
*
* @param asgName
* - The name of the ASG.
* @return - The auto scaling group information.
*/
private AutoScalingGroup retrieveAutoScalingGroup(String asgName) {
if (Strings.isNullOrEmpty(asgName)) {
logger.warn("null asgName specified, not attempting to retrieve AutoScalingGroup from AWS");
return null;
}
// You can pass one name or a list of names in the request
DescribeAutoScalingGroupsRequest request = new DescribeAutoScalingGroupsRequest()
.withAutoScalingGroupNames(asgName);
DescribeAutoScalingGroupsResult result = client
.describeAutoScalingGroups(request);
List<AutoScalingGroup> asgs = result.getAutoScalingGroups();
if (asgs.isEmpty()) {
return null;
} else {
return asgs.get(0);
}
}
/**
* Queries AWS to see if the load balancer flag is suspended.
*
* @param key
* - The name of the ASG for which the flag needs to be checked.
* @return - true, if the load balancer flag is not suspended, false
* otherwise.
*/
private Boolean isASGEnabledinAWS(Object key) {
String myKey = (String) key;
try {
Stopwatch t = this.loadASGInfoTimer.start();
boolean returnValue = !isAddToLoadBalancerSuspended(myKey);
t.stop();
return returnValue;
} catch (Throwable e) {
logger.error("Could not get ASG information from AWS: ", e);
}
return Boolean.TRUE;
}
/**
* Gets the number of elements in the ASG cache.
*
* @return the long value representing the number of elements in the ASG
* cache.
*/
@com.netflix.servo.annotations.Monitor(name = "numOfElementsinASGCache",
description = "Number of elements in the ASG Cache", type = DataSourceType.GAUGE)
public long getNumberofElementsinASGCache() {
return asgCache.size();
}
/**
* Gets the number of ASG queries done in the period.
*
* @return the long value representing the number of ASG queries done in the
* period.
*/
@com.netflix.servo.annotations.Monitor(name = "numOfASGQueries",
description = "Number of queries made to AWS to retrieve ASG information", type = DataSourceType.COUNTER)
public long getNumberofASGQueries() {
return asgCache.stats().loadCount();
}
/**
* Gets the number of ASG queries that failed because of some reason.
*
* @return the long value representing the number of ASG queries that failed
* because of some reason.
*/
@com.netflix.servo.annotations.Monitor(name = "numOfASGQueryFailures",
description = "Number of queries made to AWS to retrieve ASG information and that failed",
type = DataSourceType.COUNTER)
public long getNumberofASGQueryFailures() {
return asgCache.stats().loadExceptionCount();
}
/**
* Gets the task that updates the ASG information periodically.
*
* @return TimerTask that updates the ASG information periodically.
*/
private TimerTask getASGUpdateTask() {
return new TimerTask() {
@Override
public void run() {
try {
// First get the active ASG names
Set<String> asgNames = getASGNames();
logger.debug("Trying to refresh the keys for {}",
Arrays.toString(asgNames.toArray()));
for (String key : asgNames) {
try {
asgCache.refresh(key);
} catch (Throwable e) {
logger.error("Error updating the ASG cache for "
+ key, e);
}
}
} catch (Throwable e) {
logger.error("Error updating the ASG cache", e);
}
}
};
}
/**
* Get the names of all the ASG to which query AWS for.
*
* <p>
* The names are obtained from the {@link com.netflix.eureka.InstanceRegistry} which is then
* used for querying the AWS.
* </p>
*
* @return the set of ASG names.
*/
private Set<String> getASGNames() {
Set<String> asgNames = new HashSet<String>();
Applications apps = PeerAwareInstanceRegistry.getInstance()
.getApplications(false);
for (Application app : apps.getRegisteredApplications()) {
for (InstanceInfo instanceInfo : app.getInstances()) {
String asgName = instanceInfo.getASGName();
if (asgName != null) {
asgNames.add(asgName);
}
}
}
return asgNames;
}
private static AmazonAutoScaling getAmazonAutoScalingClient() {
String aWSAccessId = eurekaConfig.getAWSAccessId();
String aWSSecretKey = eurekaConfig.getAWSSecretKey();
ClientConfiguration clientConfiguration = new ClientConfiguration()
.withConnectionTimeout(eurekaConfig.getASGQueryTimeoutMs());
if (null != aWSAccessId && !"".equals(aWSAccessId)
&& null != aWSSecretKey && !"".equals(aWSSecretKey)) {
return new AmazonAutoScalingClient(
new BasicAWSCredentials(aWSAccessId, aWSSecretKey),
clientConfiguration);
} else {
return new AmazonAutoScalingClient(
new InstanceProfileCredentialsProvider(),
clientConfiguration);
}
}
}