Use eureka.instance zone data consistently determining client zone

docs/src/main/asciidoc/spring-cloud-netflix.adoc

@@ -693,13 +693,27 @@ default is a `DomainExtractingServerList` and the purpose of this is
 to make physical metadata available to the load balancer without using
 AWS AMI metadata (which is what Netflix relies on). By default the
 server list will be constructed with "zone" information as provided in
-the instance metadata (so on the client set
+the instance metadata (so on the remote clients set
 `eureka.instance.metadataMap.zone`), and if that is missing it can use
 the domain name from the server hostname as a proxy for zone (if the
-flag `approximateZoneFromHostname` is set). Once the zone information is
-available it can be used in a `ServerListFilter` (by default it will
-be used to locate a server in the same zone as the client because the
-default is a `ZonePreferenceServerListFilter`).
+flag `approximateZoneFromHostname` is set). Once the zone information
+is available it can be used in a `ServerListFilter`. By default it
+will be used to locate a server in the same zone as the client because
+the default is a `ZonePreferenceServerListFilter`. The zone of the
+client is determined the same way as the remote instances by default,
+i.e. via `eureka.instance.metadataMap.zone`.
+
+NOTE: The orthodox "archaius" way to set the client zone is via a
+configuration property called "@zone", and Spring Cloud will use that
+in preference to all other settings if it is available (note that the
+key will have to be quoted in YAML configuration).
+
+NOTE: If there is no other source of zone data then a guess is made
+based on the client configuration (as opposed to the instance
+configuration). We take `eureka.client.availabilityZones`, which is a
+map from region name to a list of zones, and pull out the first zone
+for the instance's own region (i.e. the `eureka.client.region`, which
+defaults to "us-east-1" for comatibility with native Netflix).
 
 [[spring-cloud-ribbon-without-eureka]]
 === Example: How to Use Ribbon Without Eureka

spring-cloud-netflix-eureka-client/src/main/java/org/springframework/cloud/netflix/ribbon/eureka/EurekaRibbonClientConfiguration.java

@@ -36,12 +36,12 @@ import com.netflix.loadbalancer.ServerList;
 import com.netflix.niws.loadbalancer.DiscoveryEnabledNIWSServerList;
 import com.netflix.niws.loadbalancer.NIWSDiscoveryPing;
 
-import lombok.extern.apachecommons.CommonsLog;
-
 import static com.netflix.client.config.CommonClientConfigKey.DeploymentContextBasedVipAddresses;
 import static com.netflix.client.config.CommonClientConfigKey.EnableZoneAffinity;
 import static org.springframework.cloud.netflix.ribbon.RibbonProperyUtils.setRibbonProperty;
 
+import lombok.extern.apachecommons.CommonsLog;
+
 /**
  * Preprocessor that configures defaults for eureka-discovered ribbon clients. Such as:
  * <code>@zone</code>, NIWSServerListClassName, DeploymentContextBasedVipAddresses,
@@ -104,21 +104,26 @@ public class EurekaRibbonClientConfiguration {
 
 	@PostConstruct
 	public void preprocess() {
-		String zone = ConfigurationManager.getDeploymentContext().getValue(
-				ContextKey.zone);
+		String zone = ConfigurationManager.getDeploymentContext()
+				.getValue(ContextKey.zone);
 		if (this.clientConfig != null && StringUtils.isEmpty(zone)) {
-			if (approximateZoneFromHostname && eurekaConfig != null) {
-				String approxZone = ZoneUtils.extractApproximateZone(eurekaConfig
-						.getHostName(false));
+			if (this.approximateZoneFromHostname && this.eurekaConfig != null) {
+				String approxZone = ZoneUtils
+						.extractApproximateZone(this.eurekaConfig.getHostName(false));
 				log.debug("Setting Zone To " + approxZone);
 				ConfigurationManager.getDeploymentContext().setValue(ContextKey.zone,
 						approxZone);
 			}
 			else {
-				String[] zones = this.clientConfig.getAvailabilityZones(this.clientConfig
-						.getRegion());
-				String availabilityZone = zones != null && zones.length > 0 ? zones[0]
+				String availabilityZone = this.eurekaConfig == null ? null
+						: this.eurekaConfig.getMetadataMap().get("zone");
+				if (availabilityZone == null) {
+					String[] zones = this.clientConfig
+							.getAvailabilityZones(this.clientConfig.getRegion());
+					// Pick the first one from the regions we want to connect to
+					availabilityZone = zones != null && zones.length > 0 ? zones[0]
 							: null;
+				}
 				if (availabilityZone != null) {
 					// You can set this with archaius.deployment.* (maybe requires
 					// custom deployment context)?
@@ -127,7 +132,8 @@ public class EurekaRibbonClientConfiguration {
 				}
 			}
 		}
-		setRibbonProperty(this.serviceId, DeploymentContextBasedVipAddresses.key(), this.serviceId);
+		setRibbonProperty(this.serviceId, DeploymentContextBasedVipAddresses.key(),
+				this.serviceId);
 		setRibbonProperty(this.serviceId, EnableZoneAffinity.key(), "true");
 	}
 

spring-cloud-netflix-eureka-client/src/test/java/org/springframework/cloud/netflix/ribbon/eureka/EurekaRibbonClientConfigurationTests.java

@@ -36,8 +36,10 @@ import com.netflix.niws.loadbalancer.DiscoveryEnabledServer;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertTrue;
-
-import static org.springframework.cloud.netflix.ribbon.RibbonProperyUtils.*;
+import static org.springframework.cloud.netflix.ribbon.RibbonProperyUtils.VALUE_NOT_SET;
+import static org.springframework.cloud.netflix.ribbon.RibbonProperyUtils.getProperty;
+import static org.springframework.cloud.netflix.ribbon.RibbonProperyUtils.getRibbonKey;
+import static org.springframework.cloud.netflix.ribbon.RibbonProperyUtils.setRibbonProperty;
 
 /**
  * @author Dave Syer
@@ -83,9 +85,9 @@ public class EurekaRibbonClientConfigurationTests {
 		String serviceId = "myService";
 		String suffix = "mySuffix";
 		String value = "myValue";
-		DynamicStringProperty property = getProperty(getRibbonKey(
-				serviceId, suffix));
-		assertEquals("property doesn't have default value", VALUE_NOT_SET, property.get());
+		DynamicStringProperty property = getProperty(getRibbonKey(serviceId, suffix));
+		assertEquals("property doesn't have default value", VALUE_NOT_SET,
+				property.get());
 		setRibbonProperty(serviceId, suffix, value);
 		assertEquals("property has wrong value", value, property.get());
 		setRibbonProperty(serviceId, suffix, value);
@@ -93,13 +95,26 @@ public class EurekaRibbonClientConfigurationTests {
 	}
 
 	@Test
+	public void testExplicitZone() {
+		EurekaClientConfigBean client = new EurekaClientConfigBean();
+		EurekaInstanceConfigBean configBean = getEurekaInstanceConfigBean();
+		configBean.getMetadataMap().put("zone", "myZone");
+		EurekaRibbonClientConfiguration preprocessor = new EurekaRibbonClientConfiguration(
+				client, "myService", configBean, false);
+		preprocessor.preprocess();
+		assertEquals("myZone",
+				ConfigurationManager.getDeploymentContext().getValue(ContextKey.zone));
+	}
+
+	@Test
 	public void testDefaultZone() {
 		EurekaClientConfigBean client = new EurekaClientConfigBean();
 		EurekaInstanceConfigBean configBean = getEurekaInstanceConfigBean();
 		EurekaRibbonClientConfiguration preprocessor = new EurekaRibbonClientConfiguration(
 				client, "myService", configBean, false);
 		preprocessor.preprocess();
-		assertEquals("defaultZone", ConfigurationManager.getDeploymentContext().getValue(ContextKey.zone));
+		assertEquals("defaultZone",
+				ConfigurationManager.getDeploymentContext().getValue(ContextKey.zone));
 	}
 
 	@Test
@@ -110,7 +125,8 @@ public class EurekaRibbonClientConfigurationTests {
 		EurekaRibbonClientConfiguration preprocessor = new EurekaRibbonClientConfiguration(
 				client, "myService", configBean, true);
 		preprocessor.preprocess();
-		assertEquals("is.a.test.com", ConfigurationManager.getDeploymentContext().getValue(ContextKey.zone));
+		assertEquals("is.a.test.com",
+				ConfigurationManager.getDeploymentContext().getValue(ContextKey.zone));
 	}
 
 }