Gh 3718 add zoned loadbalancer instrumentation (#3720)

* Add instrumentation for zoned LoadBalancer.

* Add documentation.

* Fix after review.

* Fix after review.

docs/src/main/asciidoc/_configprops.adoc

@@ -19,6 +19,7 @@
 |management.metrics.binders.hystrix.enabled | true | Enables creation of OK Http Client factory beans.
 |ribbon.eureka.enabled | true | Enables the use of Eureka with Ribbon.
 |spring.cloud.circuitbreaker.hystrix.enabled | true | Enables auto-configuration of the Hystrix Spring Cloud CircuitBreaker API implementation.
+|spring.cloud.loadbalancer.eureka.approximate-zone-from-hostname | false | Used to determine whether we should try to get the `zone` value from host name.
 |spring.cloud.loadbalancer.ribbon.enabled | true | Causes `RibbonLoadBalancerClient` to be used by default.
 |zuul.ribbon-isolation-strategy |  | 
 |zuul.ribbon.eager-load.enabled | false | Enables eager loading of Ribbon clients on startup.

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

@@ -335,6 +335,18 @@ When a refresh occurs clients will be unregistered from the Eureka server and th
 where all instance of a given service are not available. One way to eliminate this from happening is to disable
 the ability to refresh Eureka clients.  To do this set `eureka.client.refresh.enable=false`.
 
+=== Using Eureka with Spring Cloud LoadBalancer
+
+We offer support for the Spring Cloud LoadBalancer `ZonePreferenceServiceInstanceListSupplier`.
+The `zone` value from the Eureka instance metadata (`eureka.instance.metadataMap.zone`) is used for setting the
+value of `spring-clod-loadbalancer-zone` property that is used to filter service instances by zone.
+
+If that is missing and if the `spring.cloud.loadbalancer.eureka.approximateZoneFromHostname` flag is set to `true`,
+it can use the domain name from the server hostname as a proxy for the zone.
+
+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 (that is, the `eureka.client.region`, which defaults to "us-east-1", for compatibility with native Netflix).
+
 [[spring-cloud-eureka-server]]
 == Service Discovery: Eureka Server
 

spring-cloud-netflix-eureka-client/pom.xml

@@ -51,6 +51,11 @@
 			<artifactId>spring-cloud-config-server</artifactId>
 			<optional>true</optional>
 		</dependency>
+		<dependency>
+			<groupId>org.springframework.cloud</groupId>
+			<artifactId>spring-cloud-loadbalancer</artifactId>
+			<optional>true</optional>
+		</dependency>
 		<dependency>
 			<groupId>com.netflix.eureka</groupId>
 			<artifactId>eureka-client</artifactId>

spring-cloud-netflix-eureka-client/src/main/java/org/springframework/cloud/netflix/eureka/loadbalancer/EurekaLoadBalancerClientConfiguration.java

@@ -0,0 +1,104 @@
+/*
+ * Copyright 2013-2019 the original author or authors.
+ *
+ * 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
+ *
+ *      https://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 org.springframework.cloud.netflix.eureka.loadbalancer;
+
+import javax.annotation.PostConstruct;
+
+import com.netflix.appinfo.EurekaInstanceConfig;
+import com.netflix.discovery.EurekaClientConfig;
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
+import org.springframework.cloud.client.loadbalancer.reactive.LoadBalancerProperties;
+import org.springframework.cloud.netflix.ribbon.eureka.ZoneUtils;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.util.StringUtils;
+
+/**
+ * A configuration for Spring Cloud LoadBalancer that retrieves client instance zone from
+ * Eureka and sets it as a property. Based on
+ * {@link EurekaLoadBalancerClientConfiguration}.
+ *
+ * @author Olga Maciaszek-Sharma
+ * @since 2.2.1
+ * @see EurekaLoadBalancerClientConfiguration
+ */
+@Configuration
+@ConditionalOnBean({ LoadBalancerProperties.class, EurekaLoadBalancerProperties.class })
+public class EurekaLoadBalancerClientConfiguration {
+
+	private static final String LOADBALANCER_ZONE = "spring.cloud.loadbalancer.zone";
+
+	private static final Log LOG = LogFactory
+			.getLog(EurekaLoadBalancerClientConfiguration.class);
+
+	private final EurekaClientConfig clientConfig;
+
+	private final EurekaInstanceConfig eurekaConfig;
+
+	private final LoadBalancerProperties loadBalancerProperties;
+
+	private final EurekaLoadBalancerProperties eurekaLoadBalancerProperties;
+
+	public EurekaLoadBalancerClientConfiguration(
+			@Autowired(required = false) EurekaClientConfig clientConfig,
+			@Autowired(required = false) EurekaInstanceConfig eurekaInstanceConfig,
+			LoadBalancerProperties loadBalancerProperties,
+			EurekaLoadBalancerProperties eurekaLoadBalancerProperties) {
+		this.clientConfig = clientConfig;
+		this.eurekaConfig = eurekaInstanceConfig;
+		this.loadBalancerProperties = loadBalancerProperties;
+		this.eurekaLoadBalancerProperties = eurekaLoadBalancerProperties;
+	}
+
+	@PostConstruct
+	public void postprocess() {
+		if (!StringUtils.isEmpty(loadBalancerProperties.getZone())) {
+			return;
+		}
+		String zone = getZoneFromEureka();
+		if (!StringUtils.isEmpty(zone)) {
+			if (LOG.isDebugEnabled()) {
+				LOG.debug("Setting the value of '" + LOADBALANCER_ZONE + "' to " + zone);
+			}
+			loadBalancerProperties.setZone(zone);
+		}
+	}
+
+	private String getZoneFromEureka() {
+		String zone;
+		boolean approximateZoneFromHostname = eurekaLoadBalancerProperties
+				.isApproximateZoneFromHostname();
+		if (approximateZoneFromHostname && eurekaConfig != null) {
+			return ZoneUtils.extractApproximateZone(this.eurekaConfig.getHostName(false));
+		}
+		else {
+			zone = eurekaConfig == null ? null
+					: eurekaConfig.getMetadataMap().get("zone");
+			if (StringUtils.isEmpty(zone)) {
+				String[] zones = clientConfig
+						.getAvailabilityZones(clientConfig.getRegion());
+				// Pick the first one from the regions we want to connect to
+				zone = zones != null && zones.length > 0 ? zones[0] : null;
+			}
+			return zone;
+		}
+	}
+
+}

spring-cloud-netflix-eureka-client/src/main/java/org/springframework/cloud/netflix/eureka/loadbalancer/EurekaLoadBalancerProperties.java

@@ -0,0 +1,44 @@
+/*
+ * Copyright 2012-2019 the original author or authors.
+ *
+ * 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
+ *
+ *      https://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 org.springframework.cloud.netflix.eureka.loadbalancer;
+
+import org.springframework.boot.context.properties.ConfigurationProperties;
+
+/**
+ * A {@link ConfigurationProperties} bean for the Eureka-specific instrumentation of
+ * Spring Cloud LoadBalancer.
+ *
+ * @author Olga Maciaszek-Sharma
+ * @since 2.2.1
+ */
+@ConfigurationProperties("spring.cloud.loadbalancer.eureka")
+public class EurekaLoadBalancerProperties {
+
+	/**
+	 * Used to determine whether we should try to get the `zone` value from host name.
+	 */
+	private boolean approximateZoneFromHostname = false;
+
+	public boolean isApproximateZoneFromHostname() {
+		return approximateZoneFromHostname;
+	}
+
+	public void setApproximateZoneFromHostname(boolean approximateZoneFromHostname) {
+		this.approximateZoneFromHostname = approximateZoneFromHostname;
+	}
+
+}

spring-cloud-netflix-eureka-client/src/main/java/org/springframework/cloud/netflix/eureka/loadbalancer/LoadBalancerEurekaAutoConfiguration.java

@@ -0,0 +1,55 @@
+/*
+ * Copyright 2013-2019 the original author or authors.
+ *
+ * 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
+ *
+ *      https://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 org.springframework.cloud.netflix.eureka.loadbalancer;
+
+import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
+import org.springframework.boot.context.properties.ConfigurationProperties;
+import org.springframework.boot.context.properties.EnableConfigurationProperties;
+import org.springframework.cloud.client.loadbalancer.reactive.LoadBalancerProperties;
+import org.springframework.cloud.loadbalancer.annotation.LoadBalancerClientConfigurationRegistrar;
+import org.springframework.cloud.loadbalancer.annotation.LoadBalancerClients;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+/**
+ * An Autoconfiguration that loads default config for Spring Cloud LoadBalancer clients.
+ *
+ * @author Olga Maciaszek-Sharma
+ * @since 2.2.1
+ * @see EurekaLoadBalancerClientConfiguration
+ */
+@Configuration(proxyBeanMethods = false)
+@EnableConfigurationProperties(EurekaLoadBalancerProperties.class)
+@ConditionalOnClass(LoadBalancerClientConfigurationRegistrar.class)
+@LoadBalancerClients(defaultConfiguration = EurekaLoadBalancerClientConfiguration.class)
+public class LoadBalancerEurekaAutoConfiguration {
+
+	@Bean
+	@ConditionalOnMissingBean
+	EurekaLoadBalancerProperties eurekaLoadBalancerProperties() {
+		return new EurekaLoadBalancerProperties();
+	}
+
+	@Bean
+	@ConditionalOnMissingBean
+	@ConfigurationProperties("spring.cloud.loadbalancer")
+	LoadBalancerProperties loadBalancerProperties() {
+		return new LoadBalancerProperties();
+	}
+
+}

spring-cloud-netflix-eureka-client/src/main/resources/META-INF/spring.factories

@@ -4,7 +4,8 @@ org.springframework.cloud.netflix.eureka.config.EurekaDiscoveryClientConfigServi
 org.springframework.cloud.netflix.eureka.EurekaClientAutoConfiguration,\
 org.springframework.cloud.netflix.ribbon.eureka.RibbonEurekaAutoConfiguration,\
 org.springframework.cloud.netflix.eureka.EurekaDiscoveryClientConfiguration,\
-org.springframework.cloud.netflix.eureka.reactive.EurekaReactiveDiscoveryClientConfiguration
+org.springframework.cloud.netflix.eureka.reactive.EurekaReactiveDiscoveryClientConfiguration,\
+org.springframework.cloud.netflix.eureka.loadbalancer.LoadBalancerEurekaAutoConfiguration
 
 org.springframework.cloud.bootstrap.BootstrapConfiguration=\
 org.springframework.cloud.netflix.eureka.config.EurekaDiscoveryClientConfigServiceBootstrapConfiguration

spring-cloud-netflix-eureka-client/src/test/java/org/springframework/cloud/netflix/eureka/loadbalancer/EurekaLoadBalancerClientConfigurationTests.java

@@ -0,0 +1,75 @@
+/*
+ * Copyright 2015-2019 the original author or authors.
+ *
+ * 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
+ *
+ *      https://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 org.springframework.cloud.netflix.eureka.loadbalancer;
+
+import org.junit.jupiter.api.Test;
+
+import org.springframework.cloud.client.loadbalancer.reactive.LoadBalancerProperties;
+import org.springframework.cloud.commons.util.InetUtils;
+import org.springframework.cloud.commons.util.InetUtilsProperties;
+import org.springframework.cloud.netflix.eureka.EurekaClientConfigBean;
+import org.springframework.cloud.netflix.eureka.EurekaInstanceConfigBean;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests for {@link EurekaLoadBalancerClientConfiguration}.
+ *
+ * @author Olga Maciaszek-Sharma
+ */
+class EurekaLoadBalancerClientConfigurationTests {
+
+	private EurekaClientConfigBean eurekaClientConfig = new EurekaClientConfigBean();
+
+	private EurekaInstanceConfigBean eurekaInstanceConfig = new EurekaInstanceConfigBean(
+			new InetUtils(new InetUtilsProperties()));
+
+	private LoadBalancerProperties loadBalancerProperties = new LoadBalancerProperties();
+
+	private EurekaLoadBalancerProperties eurekaLoadBalancerProperties = new EurekaLoadBalancerProperties();
+
+	private EurekaLoadBalancerClientConfiguration postprocessor = new EurekaLoadBalancerClientConfiguration(
+			eurekaClientConfig, eurekaInstanceConfig, loadBalancerProperties,
+			eurekaLoadBalancerProperties);
+
+	@Test
+	void shouldSetZoneFromInstanceMetadata() {
+		eurekaInstanceConfig.getMetadataMap().put("zone", "myZone");
+
+		postprocessor.postprocess();
+
+		assertThat(loadBalancerProperties.getZone()).isEqualTo("myZone");
+	}
+
+	@Test
+	public void shouldSetZoneToDefaultWhenNotSetInMetadata() {
+		postprocessor.postprocess();
+
+		assertThat(loadBalancerProperties.getZone()).isEqualTo("defaultZone");
+	}
+
+	@Test
+	public void shouldResolveApproximateZoneFromHost() {
+		eurekaInstanceConfig.setHostname("this.is.a.test.com");
+		eurekaLoadBalancerProperties.setApproximateZoneFromHostname(true);
+
+		postprocessor.postprocess();
+
+		assertThat(loadBalancerProperties.getZone()).isEqualTo("is.a.test.com");
+	}
+
+}