Merge pull request #1108 from PropertyOfTuckerSystems/pts/aws-asg-int…

…erface

Add an interface for AwsAsgUtil

eureka-core/src/main/java/com/netflix/eureka/DefaultEurekaServerConfig.java

@@ -16,8 +16,6 @@
 
 package com.netflix.eureka;
 
-import javax.annotation.Nullable;
-import javax.inject.Singleton;
 import java.io.IOException;
 import java.util.Arrays;
 import java.util.Collections;
@@ -26,13 +24,17 @@
 import java.util.Map;
 import java.util.Set;
 
+import javax.annotation.Nullable;
+import javax.inject.Singleton;
+
 import com.netflix.config.ConfigurationManager;
 import com.netflix.config.DynamicBooleanProperty;
 import com.netflix.config.DynamicIntProperty;
 import com.netflix.config.DynamicPropertyFactory;
 import com.netflix.config.DynamicStringProperty;
 import com.netflix.config.DynamicStringSetProperty;
 import com.netflix.eureka.aws.AwsBindingStrategy;
+
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -314,6 +316,11 @@ public long getEvictionIntervalTimerInMs() {
                 namespace + "evictionIntervalTimerInMs", (60 * 1000)).get();
     }
 
+    @Override
+    public boolean shouldUseAwsAsgApi() {
+        return configInstance.getBooleanProperty(namespace + "shouldUseAwsAsgApi", true).get();
+    }
+
     @Override
     public int getASGQueryTimeoutMs() {
         return configInstance.getIntProperty(namespace + "asgQueryTimeoutMs",

eureka-core/src/main/java/com/netflix/eureka/EurekaServerConfig.java

@@ -16,12 +16,13 @@
 
 package com.netflix.eureka;
 
-import com.netflix.eureka.aws.AwsBindingStrategy;
-
-import javax.annotation.Nullable;
 import java.util.Map;
 import java.util.Set;
 
+import javax.annotation.Nullable;
+
+import com.netflix.eureka.aws.AwsBindingStrategy;
+
 /**
  * Configuration information required by the eureka server to operate.
  *
@@ -264,6 +265,13 @@ public interface EurekaServerConfig {
      */
     long getEvictionIntervalTimerInMs();
 
+    /**
+     * Whether to use AWS API to query ASG statuses.
+     *
+     * @return true if AWS API is used, false otherwise.
+     */
+    boolean shouldUseAwsAsgApi();
+
     /**
      * Get the timeout value for querying the <em>AWS</em> for <em>ASG</em>
      * information.
@@ -418,7 +426,7 @@ public interface EurekaServerConfig {
      * @return maximum number of threads to be used for replication.
      */
     int getMaxThreadsForPeerReplication();
-    
+
     /**
      * Get the minimum number of available peer replication instances
      * for this instance to be considered healthy. The design of eureka allows
@@ -428,7 +436,7 @@ public interface EurekaServerConfig {
      * The default value of -1 is interpreted as a marker to not compare
      * the number of replicas. This would be done to either disable this check
      * or to run eureka in a single node configuration.
-     * 
+     *
      * @return minimum number of available peer replication instances
      *         for this instance to be considered healthy.
      */

eureka-core/src/main/java/com/netflix/eureka/aws/AsgClient.java

@@ -0,0 +1,9 @@
+package com.netflix.eureka.aws;
+
+import com.netflix.appinfo.InstanceInfo;
+
+public interface AsgClient {
+    boolean isASGEnabled(InstanceInfo instanceInfo);
+
+    void setStatus(String asgName, boolean enabled);
+}

eureka-core/src/main/java/com/netflix/eureka/aws/AwsAsgUtil.java

@@ -31,22 +31,8 @@
 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.discovery.EurekaClientConfig;
-import com.netflix.eureka.registry.InstanceRegistry;
-import com.netflix.appinfo.DataCenterInfo;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
+import javax.inject.Inject;
+import javax.inject.Singleton;
 
 import com.amazonaws.ClientConfiguration;
 import com.amazonaws.auth.BasicAWSCredentials;
@@ -58,20 +44,34 @@
 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.AWSSecurityTokenService;
+import com.amazonaws.services.securitytoken.AWSSecurityTokenServiceClient;
 import com.amazonaws.services.securitytoken.model.AssumeRoleRequest;
+import com.amazonaws.services.securitytoken.model.AssumeRoleResult;
+import com.amazonaws.services.securitytoken.model.Credentials;
+import com.google.common.base.Strings;
 import com.google.common.cache.CacheBuilder;
 import com.google.common.cache.CacheLoader;
 import com.google.common.cache.LoadingCache;
+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.appinfo.DataCenterInfo;
 import com.netflix.appinfo.InstanceInfo;
+import com.netflix.discovery.EurekaClientConfig;
 import com.netflix.discovery.shared.Application;
 import com.netflix.discovery.shared.Applications;
 import com.netflix.eureka.EurekaServerConfig;
+import com.netflix.eureka.registry.InstanceRegistry;
 import com.netflix.servo.annotations.DataSourceType;
 import com.netflix.servo.monitor.Monitors;
 import com.netflix.servo.monitor.Stopwatch;
 
-import javax.inject.Inject;
-import javax.inject.Singleton;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
  * A utility class for querying and updating information about amazon
@@ -81,7 +81,7 @@
  *
  */
 @Singleton
-public class AwsAsgUtil {
+public class AwsAsgUtil implements AsgClient {
     private static final Logger logger = LoggerFactory.getLogger(AwsAsgUtil.class);
 
     private static final String PROP_ADD_TO_LOAD_BALANCER = "AddToLoadBalancer";
@@ -165,6 +165,18 @@ public boolean isASGEnabled(InstanceInfo instanceInfo) {
         if (result != null) {
             return result;
         } else {
+            if (!serverConfig.shouldUseAwsAsgApi()) {
+                // Disabled, cached values (if any) are still being returned if the caller makes
+                // a decision to call the disabled client during some sort of transitioning
+                // period, but no new values will be fetched while disabled.
+
+                logger.info(("'{}' is not cached at the moment and won't be fetched because querying AWS ASGs "
+                        + "has been disabled via the config, returning the fallback value."),
+                            cacheKey);
+
+                return true;
+            }
+
             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);
@@ -371,6 +383,11 @@ private TimerTask getASGUpdateTask() {
             @Override
             public void run() {
                 try {
+                    if (!serverConfig.shouldUseAwsAsgApi()) {
+                        // Disabled via the config, no-op.
+                        return;
+                    }
+
                     // First get the active ASG names
                     Set<CacheKey> cacheKeys = getCacheKeys();
                     if (logger.isDebugEnabled()) {

eureka-core/src/main/java/com/netflix/eureka/registry/rule/AsgEnabledRule.java

@@ -2,8 +2,9 @@
 
 import com.netflix.appinfo.InstanceInfo;
 import com.netflix.appinfo.InstanceInfo.InstanceStatus;
-import com.netflix.eureka.aws.AwsAsgUtil;
+import com.netflix.eureka.aws.AsgClient;
 import com.netflix.eureka.lease.Lease;
+
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -16,17 +17,17 @@
 public class AsgEnabledRule implements InstanceStatusOverrideRule {
     private static final Logger logger = LoggerFactory.getLogger(AsgEnabledRule.class);
 
-    private final AwsAsgUtil awsAsgUtil;
+    private final AsgClient asgClient;
 
-    public AsgEnabledRule(AwsAsgUtil awsAsgUtil) {
-        this.awsAsgUtil = awsAsgUtil;
+    public AsgEnabledRule(AsgClient asgClient) {
+        this.asgClient = asgClient;
     }
 
     @Override
     public StatusOverrideResult apply(InstanceInfo instanceInfo, Lease<InstanceInfo> existingLease, boolean isReplication) {
         // If the ASGName is present- check for its status
         if (instanceInfo.getASGName() != null) {
-            boolean isASGDisabled = !awsAsgUtil.isASGEnabled(instanceInfo);
+            boolean isASGDisabled = !asgClient.isASGEnabled(instanceInfo);
             logger.debug("The ASG name is specified {} and the value is {}", instanceInfo.getASGName(), isASGDisabled);
             if (isASGDisabled) {
                 return StatusOverrideResult.matchingStatus(InstanceStatus.OUT_OF_SERVICE);