Adding ability to define resolution order of the local InstanceInfo's

"default" network address based on data available in AmazonInfo.

eureka-client-archaius2/src/main/java/com/netflix/discovery/Ec2EurekaArchaius2InstanceConfig.java

@@ -27,8 +27,13 @@
 @Singleton
 public class Ec2EurekaArchaius2InstanceConfig extends EurekaArchaius2InstanceConfig {
     private static final Logger LOG = LoggerFactory.getLogger(Ec2EurekaArchaius2InstanceConfig.class);
-
-    private volatile DataCenterInfo info;
+
+    private static final String[] DEFAULT_AWS_ADDRESS_RESOLUTION_ORDER = new String[] {
+            MetaDataKey.publicHostname.name(),
+            MetaDataKey.localIpv4.name()
+    };
+
+    private volatile AmazonInfo amazonInfo;
 
     @Inject
     public Ec2EurekaArchaius2InstanceConfig(Config config) {
@@ -39,7 +44,7 @@ public Ec2EurekaArchaius2InstanceConfig(Config config, String namespace) {
         super(config, namespace);
 
         try {
-            this.info = AmazonInfo.Builder.newBuilder().autoBuild(namespace);
+            this.amazonInfo = AmazonInfo.Builder.newBuilder().autoBuild(namespace);
             LOG.info("Datacenter is: " + Name.Amazon);
         } 
         catch (Exception e) {
@@ -48,7 +53,6 @@ public Ec2EurekaArchaius2InstanceConfig(Config config, String namespace) {
         }
 
         // Instance id being null means we could not get the amazon metadata
-        AmazonInfo amazonInfo = (AmazonInfo) info;
         if (amazonInfo.get(MetaDataKey.instanceId) == null) {
             if (config.getBoolean(namespace + ".validateInstanceId", true)) {
                 throw new RuntimeException(
@@ -79,12 +83,18 @@ public String getHostName(boolean refresh) {
         if (refresh) {
             refreshAmazonInfo();
         }
-        return ((AmazonInfo) info).get(MetaDataKey.publicHostname);
+        return amazonInfo.get(MetaDataKey.publicHostname);
     }
 
     @Override
     public DataCenterInfo getDataCenterInfo() {
-        return info;
+        return amazonInfo;
+    }
+
+    @Override
+    public String[] getDefaultAddressResolutionOrder() {
+        String[] order = super.getDefaultAddressResolutionOrder();
+        return (order.length == 0) ? DEFAULT_AWS_ADDRESS_RESOLUTION_ORDER : order;
     }
 
     /**
@@ -94,14 +104,12 @@ public DataCenterInfo getDataCenterInfo() {
     public synchronized void refreshAmazonInfo() {
         try {
             AmazonInfo newInfo = AmazonInfo.Builder.newBuilder().autoBuild(DEFAULT_NAMESPACE);
-            String newHostname = newInfo.get(MetaDataKey.publicHostname);
-            String existingHostname = ((AmazonInfo) info).get(MetaDataKey.publicHostname);
-            if (newHostname != null && !newHostname.equals(existingHostname)) {
-                // public dns has changed on us, re-sync it
-                LOG.warn("The public hostname changed from : {} => {}", existingHostname, newHostname);
-                this.info = newInfo;
+            if (!newInfo.equals(amazonInfo)) {
+                // the datacenter info has changed, re-sync it
+                LOG.warn("The AmazonInfo changed from : {} => {}", amazonInfo, newInfo);
+                this.amazonInfo = newInfo;
             }
-        } 
+        }
         catch (Exception e) {
             LOG.error("Cannot refresh the Amazon Info ", e);
         }

eureka-client-archaius2/src/main/java/com/netflix/discovery/EurekaArchaius2InstanceConfig.java

@@ -166,6 +166,12 @@ public String getSecureHealthCheckUrl() {
         return config.getString("secureHealthCheckUrl", null);
     }
 
+    @Override
+    public String[] getDefaultAddressResolutionOrder() {
+        String result = config.getString(namespace + "defaultAddressResolutionOrder", null);
+        return result == null ? new String[0] : result.split(",");
+    }
+
     @Override
     public String getNamespace() {
         return namespace;

eureka-client/src/main/java/com/netflix/appinfo/AmazonInfo.java

@@ -316,4 +316,29 @@ public String get(MetaDataKey key) {
     public String getId() {
         return get(MetaDataKey.instanceId);
     }
+
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (!(o instanceof AmazonInfo)) return false;
+
+        AmazonInfo that = (AmazonInfo) o;
+
+        if (metadata != null ? !metadata.equals(that.metadata) : that.metadata != null) return false;
+
+        return true;
+    }
+
+    @Override
+    public int hashCode() {
+        return metadata != null ? metadata.hashCode() : 0;
+    }
+
+    @Override
+    public String toString() {
+        return "AmazonInfo{" +
+                "metadata=" + metadata +
+                '}';
+    }
 }

eureka-client/src/main/java/com/netflix/appinfo/ApplicationInfoManager.java

@@ -146,17 +146,29 @@ public void unregisterStatusChangeListener(String listenerId) {
      * Refetches the hostname to check if it has changed. If it has, the entire
      * <code>DataCenterInfo</code> is refetched and passed on to the eureka
      * server on next heartbeat.
+     *
+     * see {@link InstanceInfo#getDefaultAddress()} for explanation on why the hostname is used as the default address
      */
     public void refreshDataCenterInfoIfRequired() {
-        String existingHostname = instanceInfo.getHostName();
-        String newHostname = config.getHostName(true);
-        if (newHostname != null && !newHostname.equals(existingHostname)) {
-            logger.warn("The public hostname changed from : "
-                    + existingHostname + " => " + newHostname);
-            InstanceInfo.Builder builder = new InstanceInfo.Builder(
-                    instanceInfo);
-            builder.setHostName(newHostname).setDataCenterInfo(
-                    config.getDataCenterInfo());
+        String existingAddress = instanceInfo.getDefaultAddress();
+        DataCenterInfo dataCenterInfo = instanceInfo.getDataCenterInfo();
+
+        String newAddress;
+        if (config instanceof CloudInstanceConfig) {
+            newAddress = ((CloudInstanceConfig) config).resolveDefaultAddress(dataCenterInfo);
+        } else {
+            newAddress = config.getHostName(true);
+        }
+        String newIp = config.getIpAddress();
+
+        if (newAddress != null && !newAddress.equals(existingAddress)) {
+            logger.warn("The address changed from : {} => {}", existingAddress, newAddress);
+
+            // :( in the legacy code here the builder is acting as a mutator.
+            // This is hard to fix as this same instanceInfo instance is referenced elsewhere.
+            // We will most likely re-write the client at sometime so not fixing for now.
+            InstanceInfo.Builder builder = new InstanceInfo.Builder(instanceInfo);
+            builder.setHostName(newAddress).setIPAddr(newIp).setDataCenterInfo(config.getDataCenterInfo());
             instanceInfo.setIsDirty();
         }
     }
@@ -169,8 +181,7 @@ public void refreshLeaseInfoIfRequired() {
         int currentLeaseDuration = config.getLeaseExpirationDurationInSeconds();
         int currentLeaseRenewal = config.getLeaseRenewalIntervalInSeconds();
         if (leaseInfo.getDurationInSecs() != currentLeaseDuration || leaseInfo.getRenewalIntervalInSecs() != currentLeaseRenewal) {
-            LeaseInfo newLeaseInfo = LeaseInfo.Builder
-                    .newBuilder()
+            LeaseInfo newLeaseInfo = LeaseInfo.Builder.newBuilder()
                     .setRenewalIntervalInSecs(currentLeaseRenewal)
                     .setDurationInSecs(currentLeaseDuration)
                     .build();

eureka-client/src/main/java/com/netflix/appinfo/CloudInstanceConfig.java

@@ -50,8 +50,13 @@ public class CloudInstanceConfig extends PropertiesInstanceConfig {
     private static final Logger logger = LoggerFactory.getLogger(CloudInstanceConfig.class);
     private static final DynamicPropertyFactory INSTANCE = DynamicPropertyFactory.getInstance();
 
+    private static final String[] DEFAULT_AWS_ADDRESS_RESOLUTION_ORDER = new String[] {
+            MetaDataKey.publicHostname.name(),
+            MetaDataKey.localIpv4.name()
+    };
+
     private DynamicBooleanProperty propValidateInstanceId;
-    private DataCenterInfo info;
+    private volatile AmazonInfo info;
 
     public CloudInstanceConfig() {
         initCloudInstanceConfig(namespace);
@@ -63,13 +68,12 @@ public CloudInstanceConfig(String namespace) {
     }
 
     private void initCloudInstanceConfig(String namespace) {
-        propValidateInstanceId = INSTANCE.getBooleanProperty(namespace
-                + "validateInstanceId", true);
+        propValidateInstanceId = INSTANCE.getBooleanProperty(namespace + "validateInstanceId", true);
         info = initDataCenterInfo();
     }
 
-    private DataCenterInfo initDataCenterInfo() {
-        DataCenterInfo info;
+    private AmazonInfo initDataCenterInfo() {
+        AmazonInfo info;
         try {
             info = AmazonInfo.Builder.newBuilder().autoBuild(namespace);
             logger.info("Datacenter is: " + Name.Amazon);
@@ -78,62 +82,94 @@ private DataCenterInfo initDataCenterInfo() {
             throw new RuntimeException(e);
         }
         // Instance id being null means we could not get the amazon metadata
-        AmazonInfo amazonInfo = (AmazonInfo) info;
-        if (amazonInfo.get(MetaDataKey.instanceId) == null) {
+        if (info.get(MetaDataKey.instanceId) == null) {
             if (propValidateInstanceId.get()) {
                 throw new RuntimeException(
                         "Your datacenter is defined as cloud but we are not able to get the amazon metadata to "
-                                + "register. \nSet the property " + namespace + "validateInstanceId to false to ignore the"
-                                + "metadata call");
+                                + "register. \nSet the property " + namespace + "validateInstanceId to false to "
+                                + "ignore the metadata call");
             } else {
                 // The property to not validate instance ids may be set for
                 // development and in that scenario, populate instance id
                 // and public hostname with the hostname of the machine
                 Map<String, String> metadataMap = new HashMap<String, String>();
                 metadataMap.put(MetaDataKey.instanceId.getName(), super.getIpAddress());
                 metadataMap.put(MetaDataKey.publicHostname.getName(), super.getHostName(false));
-                amazonInfo.setMetadata(metadataMap);
+                info.setMetadata(metadataMap);
             }
-        } else if ((amazonInfo.get(MetaDataKey.publicHostname) == null)
-                && (amazonInfo.get(MetaDataKey.localIpv4) != null)) {
+        } else if ((info.get(MetaDataKey.publicHostname) == null)
+                && (info.get(MetaDataKey.localIpv4) != null)) {
+            // :( legacy code and logic
             // This might be a case of VPC where the instance id is not null, but
             // public hostname might be null
-            amazonInfo.getMetadata().put(MetaDataKey.publicHostname.getName(),
-                    (amazonInfo.get(MetaDataKey.localIpv4)));
+            info.getMetadata().put(MetaDataKey.publicHostname.getName(), (info.get(MetaDataKey.localIpv4)));
         }
         return info;
     }
 
+    public String resolveDefaultAddress(DataCenterInfo dataCenterInfo) {
+        String result = getHostName(true);
+
+        if (dataCenterInfo instanceof AmazonInfo) {
+            AmazonInfo amazonInfo = (AmazonInfo) dataCenterInfo;
+            for (String name : getDefaultAddressResolutionOrder()) {
+                try {
+                    AmazonInfo.MetaDataKey key = AmazonInfo.MetaDataKey.valueOf(name);
+                    String address = amazonInfo.get(key);
+                    if (address != null && !address.isEmpty()) {
+                        result = address;
+                        break;
+                    }
+                } catch (Exception e) {
+                    logger.error("failed to resolve default address for key {}, skipping", name, e);
+                }
+            }
+        } else {
+            logger.warn("DataCenterInfo is not of type AmazonInfo. Defaulting to default resolution");
+        }
+
+        return result;
+    }
+
     @Override
     public String getHostName(boolean refresh) {
         if (refresh) {
             refreshAmazonInfo();
         }
-        return ((AmazonInfo) info).get(MetaDataKey.publicHostname);
+        return info.get(MetaDataKey.publicHostname);
+    }
+
+    @Override
+    public String getIpAddress() {
+        String ipAddr = info.get(MetaDataKey.localIpv4);
+        return ipAddr == null ? super.getIpAddress() : ipAddr;
     }
 
     @Override
     public DataCenterInfo getDataCenterInfo() {
         return info;
     }
 
+    @Override
+    public String[] getDefaultAddressResolutionOrder() {
+        String[] order = super.getDefaultAddressResolutionOrder();
+        return (order.length == 0) ? DEFAULT_AWS_ADDRESS_RESOLUTION_ORDER : order;
+    }
+
     /**
      * Refresh instance info - currently only used when in AWS cloud
      * as a public ip can change whenever an EIP is associated or dissociated.
      */
     public synchronized void refreshAmazonInfo() {
         try {
             AmazonInfo newInfo = AmazonInfo.Builder.newBuilder().autoBuild(namespace);
-            String newHostname = newInfo.get(MetaDataKey.publicHostname);
-            String existingHostname = ((AmazonInfo) info).get(MetaDataKey.publicHostname);
-            if (newHostname != null && !newHostname.equals(existingHostname)) {
-                // public dns has changed on us, re-sync it
-                logger.warn("The public hostname changed from : {} => {}", existingHostname, newHostname);
+            if (!newInfo.equals(info)) {
+                // the datacenter info has changed, re-sync it
+                logger.warn("The AmazonInfo changed from : {} => {}", info, newInfo);
                 this.info = newInfo;
             }
         } catch (Throwable t) {
             logger.error("Cannot refresh the Amazon Info ", t);
         }
     }
-
 }

eureka-client/src/main/java/com/netflix/appinfo/EurekaInstanceConfig.java

@@ -350,6 +350,21 @@ public interface EurekaInstanceConfig {
      */
     String getSecureHealthCheckUrl();
 
+    /**
+     * An instance's network addresses should be fully expressed in it's {@link DataCenterInfo}.
+     * For example for instances in AWS, this will include the publicHostname, publicIp,
+     * privateHostname and privateIp, when available. The {@link com.netflix.appinfo.InstanceInfo}
+     * will further express a "default address", which is a field that can be configured by the
+     * registering instance to advertise it's default address. This configuration allowed
+     * for the expression of an ordered list of fields that can be used to resolve the default
+     * address. The exact field values will depend on the implementation details of the corresponding
+     * implementing DataCenterInfo types.
+     *
+     * @return an ordered list of fields that should be used to preferentially
+     *         resolve this instance's default address, empty String[] for default.
+     */
+    String[] getDefaultAddressResolutionOrder();
+
     /**
      * Get the namespace used to find properties.
      * @return the namespace used to find properties.

eureka-client/src/main/java/com/netflix/appinfo/InstanceInfo.java

@@ -861,6 +861,22 @@ public String getHostName() {
         return hostName;
     }
 
+    /**
+     * Return the default network address to connect to this instance.
+     *
+     * The address can either be a hostname or an ip and there is no guarantee which will be returned.
+     * Assume the address can change dynamically over time.
+     * If a usecase need more specific hostnames or ips, please use data from {@link #getDataCenterInfo()}.
+     *
+     * For legacy reasons, the data backing this field is extracted from the hostname field
+     *
+     * @return either a hostname or an ipAddress
+     */
+    @JsonIgnore
+    public String getDefaultAddress() {
+        return hostName;
+    }
+
     @Deprecated
     public void setSID(String sid) {
         this.sid = sid;

eureka-client/src/main/java/com/netflix/appinfo/PropertiesInstanceConfig.java

@@ -304,6 +304,12 @@ public String getSecureHealthCheckUrl() {
                 null).get();
     }
 
+    @Override
+    public String[] getDefaultAddressResolutionOrder() {
+        String result = INSTANCE.getStringProperty(namespace + "defaultAddressResolutionOrder", null).get();
+        return result == null ? new String[0] : result.split(",");
+    }
+
     @Override
     public String getNamespace() {
         return this.namespace;

eureka-client/src/main/java/com/netflix/appinfo/providers/EurekaConfigBasedInstanceInfoProvider.java

@@ -5,6 +5,7 @@
 import java.util.Map;
 
 import com.google.inject.Provider;
+import com.netflix.appinfo.CloudInstanceConfig;
 import com.netflix.appinfo.DataCenterInfo;
 import com.netflix.appinfo.EurekaInstanceConfig;
 import com.netflix.appinfo.InstanceInfo;
@@ -60,13 +61,20 @@ public synchronized InstanceInfo get() {
                 }
             }
 
+            String defaultAddress;
+            if (config instanceof CloudInstanceConfig) {
+                defaultAddress = ((CloudInstanceConfig) config).resolveDefaultAddress(dataCenterInfo);
+            } else {
+                defaultAddress = config.getHostName(false);
+            }
+
             builder.setNamespace(config.getNamespace())
                     .setInstanceId(instanceId)
                     .setAppName(config.getAppname())
                     .setAppGroupName(config.getAppGroupName())
                     .setDataCenterInfo(config.getDataCenterInfo())
                     .setIPAddr(config.getIpAddress())
-                    .setHostName(config.getHostName(false))
+                    .setHostName(defaultAddress)
                     .setPort(config.getNonSecurePort())
                     .enablePort(PortType.UNSECURE, config.isNonSecurePortEnabled())
                     .setSecurePort(config.getSecurePort())