Java tutorial
/* * 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.HashMap; import java.util.HashSet; import java.util.List; import java.util.Map; import java.util.Set; import java.util.Timer; import java.util.TimerTask; import java.util.concurrent.Callable; import java.util.concurrent.ExecutorService; import java.util.concurrent.LinkedBlockingQueue; import java.util.concurrent.ThreadFactory; import java.util.concurrent.ThreadPoolExecutor; import java.util.concurrent.TimeUnit; import com.amazonaws.services.securitytoken.AWSSecurityTokenService; import com.amazonaws.services.securitytoken.AWSSecurityTokenServiceClient; import com.amazonaws.services.securitytoken.model.AssumeRoleResult; import com.amazonaws.services.securitytoken.model.Credentials; import com.google.common.base.Strings; import com.google.common.util.concurrent.ListenableFuture; import com.google.common.util.concurrent.ListeningExecutorService; import com.google.common.util.concurrent.MoreExecutors; import com.netflix.appinfo.AmazonInfo; import com.netflix.appinfo.AmazonInfo.MetaDataKey; import com.netflix.appinfo.ApplicationInfoManager; import com.netflix.eureka.PeerAwareInstanceRegistryImpl; import com.netflix.appinfo.DataCenterInfo; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import com.amazonaws.ClientConfiguration; import com.amazonaws.auth.BasicAWSCredentials; import com.amazonaws.auth.BasicSessionCredentials; 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.amazonaws.services.securitytoken.model.AssumeRoleRequest; 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.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 static 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(); private static final String accountId = getAccountId(); private Map<String, Credentials> stsCredentials = new HashMap<String, Credentials>(); private final ExecutorService cacheReloadExecutor = new ThreadPoolExecutor(1, 10, 60, TimeUnit.SECONDS, new LinkedBlockingQueue<Runnable>(), new ThreadFactory() { @Override public Thread newThread(Runnable r) { Thread thread = new Thread(r, "Eureka-AWS-isASGEnabled"); thread.setDaemon(true); return thread; } }); private ListeningExecutorService listeningCacheReloadExecutor = MoreExecutors .listeningDecorator(cacheReloadExecutor); // Cache for the AWS ASG information private final LoadingCache<CacheKey, Boolean> asgCache = CacheBuilder.newBuilder().initialCapacity(500) .expireAfterAccess(eurekaConfig.getASGCacheExpiryTimeoutMs(), TimeUnit.MILLISECONDS) .build(new CacheLoader<CacheKey, Boolean>() { @Override public Boolean load(CacheKey key) throws Exception { return isASGEnabledinAWS(key.asgAccountId, key.asgName); } @Override public ListenableFuture<Boolean> reload(final CacheKey key, Boolean oldValue) throws Exception { return listeningCacheReloadExecutor.submit(new Callable<Boolean>() { @Override public Boolean call() throws Exception { return load(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 instanceInfo the instanceInfo for the lookup * @return true if enabled, false otherwise */ public boolean isASGEnabled(InstanceInfo instanceInfo) { CacheKey cacheKey = new CacheKey(getAccountId(instanceInfo, accountId), instanceInfo.getASGName()); Boolean result = asgCache.getIfPresent(cacheKey); if (result != null) { return result; } else { logger.info("Cache value for asg {} does not exist yet, async refreshing.", cacheKey.asgName); // Only do an async refresh if it does not yet exist. Do this to refrain from calling aws api too much asgCache.refresh(cacheKey); 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) { String asgAccountId = getASGAccount(asgName); asgCache.put(new CacheKey(asgAccountId, 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 asgAccountId, String asgName) { AutoScalingGroup asg; if (asgAccountId == null || asgAccountId.equals(accountId)) { asg = retrieveAutoScalingGroup(asgName); } else { asg = retrieveAutoScalingGroupCrossAccount(asgAccountId, 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); } } private Credentials initializeStsSession(String asgAccount) { AWSSecurityTokenService sts = new AWSSecurityTokenServiceClient(new InstanceProfileCredentialsProvider()); String region = DiscoveryManager.getInstance().getEurekaClientConfig().getRegion(); if (!region.equals("us-east-1")) { sts.setEndpoint("sts." + region + ".amazonaws.com"); } String roleName = EurekaServerConfigurationManager.getInstance().getConfiguration() .getListAutoScalingGroupsRoleName(); String roleArn = "arn:aws:iam::" + asgAccount + ":role/" + roleName; AssumeRoleResult assumeRoleResult = sts.assumeRole( new AssumeRoleRequest().withRoleArn(roleArn).withRoleSessionName("sts-session-" + asgAccount)); return assumeRoleResult.getCredentials(); } private AutoScalingGroup retrieveAutoScalingGroupCrossAccount(String asgAccount, String asgName) { logger.debug("Getting cross account ASG for asgName: " + asgName + ", asgAccount: " + asgAccount); Credentials credentials = stsCredentials.get(asgAccount); if (credentials == null || credentials.getExpiration().getTime() < System.currentTimeMillis() + 1000) { stsCredentials.put(asgAccount, initializeStsSession(asgAccount)); credentials = stsCredentials.get(asgAccount); } ClientConfiguration clientConfiguration = new ClientConfiguration() .withConnectionTimeout(eurekaConfig.getASGQueryTimeoutMs()); AmazonAutoScaling autoScalingClient = new AmazonAutoScalingClient( new BasicSessionCredentials(credentials.getAccessKeyId(), credentials.getSecretAccessKey(), credentials.getSessionToken()), clientConfiguration); String region = DiscoveryManager.getInstance().getEurekaClientConfig().getRegion(); if (!region.equals("us-east-1")) { autoScalingClient.setEndpoint("autoscaling." + region + ".amazonaws.com"); } DescribeAutoScalingGroupsRequest request = new DescribeAutoScalingGroupsRequest() .withAutoScalingGroupNames(asgName); DescribeAutoScalingGroupsResult result = autoScalingClient.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 asgAccountid the accountId this asg resides in, if applicable (null will use the default accountId) * @param asgName the name of the asg * @return true, if the load balancer flag is not suspended, false otherwise. */ private Boolean isASGEnabledinAWS(String asgAccountid, String asgName) { try { Stopwatch t = this.loadASGInfoTimer.start(); boolean returnValue = !isAddToLoadBalancerSuspended(asgAccountid, asgName); 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<CacheKey> cacheKeys = getCacheKeys(); logger.debug("Trying to refresh the keys for {}", Arrays.toString(cacheKeys.toArray())); for (CacheKey key : cacheKeys) { 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 cacheKeys 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 cacheKeys (asgName + accountId). */ private Set<CacheKey> getCacheKeys() { Set<CacheKey> cacheKeys = new HashSet<CacheKey>(); Applications apps = PeerAwareInstanceRegistryImpl.getInstance().getApplications(false); for (Application app : apps.getRegisteredApplications()) { for (InstanceInfo instanceInfo : app.getInstances()) { String localAccountId = getAccountId(instanceInfo, accountId); String asgName = instanceInfo.getASGName(); if (asgName != null) { CacheKey key = new CacheKey(localAccountId, asgName); cacheKeys.add(key); } } } return cacheKeys; } /** * Get the AWS account id where an ASG is created. * Warning: This is expensive as it loops through all instances currently registered. * * @param asgName The name of the ASG * @return the account id */ private String getASGAccount(String asgName) { Applications apps = PeerAwareInstanceRegistryImpl.getInstance().getApplications(false); for (Application app : apps.getRegisteredApplications()) { for (InstanceInfo instanceInfo : app.getInstances()) { String thisAsgName = instanceInfo.getASGName(); if (thisAsgName != null && thisAsgName.equals(asgName)) { String localAccountId = getAccountId(instanceInfo, null); if (localAccountId != null) { return localAccountId; } } } } logger.info("Couldn't get the ASG account for {}, using the default accountId instead", asgName); return accountId; } private String getAccountId(InstanceInfo instanceInfo, String fallbackId) { String localAccountId = null; DataCenterInfo dataCenterInfo = instanceInfo.getDataCenterInfo(); if (dataCenterInfo instanceof AmazonInfo) { localAccountId = ((AmazonInfo) dataCenterInfo).get(MetaDataKey.accountId); } return localAccountId == null ? fallbackId : localAccountId; } 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); } } private static String getAccountId() { InstanceInfo myInfo = ApplicationInfoManager.getInstance().getInfo(); return ((AmazonInfo) myInfo.getDataCenterInfo()).get(MetaDataKey.accountId); } private static class CacheKey { final String asgAccountId; final String asgName; CacheKey(String asgAccountId, String asgName) { this.asgAccountId = asgAccountId; this.asgName = asgName; } @Override public String toString() { return "CacheKey{" + "asgName='" + asgName + '\'' + ", asgAccountId='" + asgAccountId + '\'' + '}'; } @Override public boolean equals(Object o) { if (this == o) return true; if (!(o instanceof CacheKey)) return false; CacheKey cacheKey = (CacheKey) o; if (asgAccountId != null ? !asgAccountId.equals(cacheKey.asgAccountId) : cacheKey.asgAccountId != null) return false; if (asgName != null ? !asgName.equals(cacheKey.asgName) : cacheKey.asgName != null) return false; return true; } @Override public int hashCode() { int result = asgName != null ? asgName.hashCode() : 0; result = 31 * result + (asgAccountId != null ? asgAccountId.hashCode() : 0); return result; } } }