Handle conditionals for client properties

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

@@ -1269,6 +1269,15 @@ spring:
 
 The above example will result in a merged health-check `@ConfigurationProperties` object with `initial-delay=1s` and `interval=30s`.
 
+The per-client configuration properties work for most of the properties, apart from the following global ones:
+
+- `spring.cloud.loadbalancer.enabled` - globally enables or disables load-balancing
+- `spring.cloud.loadbalancer.retry.enabled` - globally enables or disables load-balanced retries. If you enable it globally, you can still disable retries for specific clients using the `client`-prefixed properties, but not the other way round
+- `spring.cloud.loadbalancer.cache.enabled` - globally enables or disables LoadBalancer caching. If you enable it globally, you can still disable caching for specific clients by creating a <<custom-loadbalancer-configuration, custom configuration>> that does not include the `CachingServiceInstanceListSupplier` in the `ServiceInstanceListSupplier` delegates hierarchy, but not the other way round.
+- `spring.cloud.loadbalancer.stats.micrometer.enabled` - globally enables or disables LoadBalancer Micrometer metrics
+
+NOTE: For the properties where maps where already used, where you could specify a different value per-client without using the `clients` keyword (for example, `hints`, `health-check.path`), we have kept that behaviour in order to keep the library backwards compatible. It will be modified in the next major release.
+
 == Spring Cloud Circuit Breaker
 
 include::spring-cloud-circuitbreaker.adoc[leveloffset=+1]

spring-cloud-loadbalancer/src/main/java/org/springframework/cloud/loadbalancer/annotation/LoadBalancerClientConfiguration.java

@@ -30,19 +30,24 @@
 import org.springframework.cloud.client.ServiceInstance;
 import org.springframework.cloud.client.discovery.DiscoveryClient;
 import org.springframework.cloud.client.discovery.ReactiveDiscoveryClient;
+import org.springframework.cloud.loadbalancer.config.XForwardedConfigurationCondition;
 import org.springframework.cloud.loadbalancer.core.ReactorLoadBalancer;
 import org.springframework.cloud.loadbalancer.core.RetryAwareServiceInstanceListSupplier;
 import org.springframework.cloud.loadbalancer.core.RoundRobinLoadBalancer;
 import org.springframework.cloud.loadbalancer.core.ServiceInstanceListSupplier;
 import org.springframework.cloud.loadbalancer.core.XForwardedHeadersTransformer;
 import org.springframework.cloud.loadbalancer.support.LoadBalancerClientFactory;
+import org.springframework.cloud.loadbalancer.support.LoadBalancerEnvironmentPropertyUtils;
 import org.springframework.context.ConfigurableApplicationContext;
 import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Condition;
+import org.springframework.context.annotation.ConditionContext;
 import org.springframework.context.annotation.Conditional;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.Primary;
 import org.springframework.core.annotation.Order;
 import org.springframework.core.env.Environment;
+import org.springframework.core.type.AnnotatedTypeMetadata;
 import org.springframework.retry.support.RetryTemplate;
 import org.springframework.web.client.RestTemplate;
 import org.springframework.web.reactive.function.client.WebClient;
@@ -76,8 +81,7 @@ public static class ReactiveSupportConfiguration {
 		@Bean
 		@ConditionalOnBean(ReactiveDiscoveryClient.class)
 		@ConditionalOnMissingBean
-		@ConditionalOnProperty(value = "spring.cloud.loadbalancer.configurations", havingValue = "default",
-				matchIfMissing = true)
+		@Conditional(DefaultConfigurationCondition.class)
 		public ServiceInstanceListSupplier discoveryClientServiceInstanceListSupplier(
 				ConfigurableApplicationContext context) {
 			return ServiceInstanceListSupplier.builder().withDiscoveryClient().withCaching().build(context);
@@ -86,7 +90,7 @@ public ServiceInstanceListSupplier discoveryClientServiceInstanceListSupplier(
 		@Bean
 		@ConditionalOnBean(ReactiveDiscoveryClient.class)
 		@ConditionalOnMissingBean
-		@ConditionalOnProperty(value = "spring.cloud.loadbalancer.configurations", havingValue = "zone-preference")
+		@Conditional(ZonePreferenceConfigurationCondition.class)
 		public ServiceInstanceListSupplier zonePreferenceDiscoveryClientServiceInstanceListSupplier(
 				ConfigurableApplicationContext context) {
 			return ServiceInstanceListSupplier.builder().withDiscoveryClient().withZonePreference().withCaching()
@@ -96,15 +100,15 @@ public ServiceInstanceListSupplier zonePreferenceDiscoveryClientServiceInstanceL
 		@Bean
 		@ConditionalOnBean({ XForwardedHeadersTransformer.class, LoadBalancerClientFactory.class })
 		@ConditionalOnMissingBean
-		@ConditionalOnProperty(value = "spring.cloud.loadbalancer.xForwarded.enabledXforwarded", havingValue = "true")
+		@Conditional(XForwardedConfigurationCondition.class)
 		public XForwardedHeadersTransformer xForwarderHeadersTransformer(LoadBalancerClientFactory clientFactory) {
 			return new XForwardedHeadersTransformer(clientFactory);
 		}
 
 		@Bean
 		@ConditionalOnBean({ ReactiveDiscoveryClient.class, WebClient.Builder.class })
 		@ConditionalOnMissingBean
-		@ConditionalOnProperty(value = "spring.cloud.loadbalancer.configurations", havingValue = "health-check")
+		@Conditional(HealthCheckConfigurationCondition.class)
 		public ServiceInstanceListSupplier healthCheckDiscoveryClientServiceInstanceListSupplier(
 				ConfigurableApplicationContext context) {
 			return ServiceInstanceListSupplier.builder().withDiscoveryClient().withHealthChecks().build(context);
@@ -113,8 +117,7 @@ public ServiceInstanceListSupplier healthCheckDiscoveryClientServiceInstanceList
 		@Bean
 		@ConditionalOnBean(ReactiveDiscoveryClient.class)
 		@ConditionalOnMissingBean
-		@ConditionalOnProperty(value = "spring.cloud.loadbalancer.configurations",
-				havingValue = "request-based-sticky-session")
+		@Conditional(RequestBasedStickySessionConfigurationCondition.class)
 		public ServiceInstanceListSupplier requestBasedStickySessionDiscoveryClientServiceInstanceListSupplier(
 				ConfigurableApplicationContext context) {
 			return ServiceInstanceListSupplier.builder().withDiscoveryClient().withRequestBasedStickySession()
@@ -124,8 +127,7 @@ public ServiceInstanceListSupplier requestBasedStickySessionDiscoveryClientServi
 		@Bean
 		@ConditionalOnBean(ReactiveDiscoveryClient.class)
 		@ConditionalOnMissingBean
-		@ConditionalOnProperty(value = "spring.cloud.loadbalancer.configurations",
-				havingValue = "same-instance-preference")
+		@Conditional(SameInstancePreferenceConfigurationCondition.class)
 		public ServiceInstanceListSupplier sameInstancePreferenceServiceInstanceListSupplier(
 				ConfigurableApplicationContext context) {
 			return ServiceInstanceListSupplier.builder().withDiscoveryClient().withSameInstancePreference()
@@ -142,8 +144,7 @@ public static class BlockingSupportConfiguration {
 		@Bean
 		@ConditionalOnBean(DiscoveryClient.class)
 		@ConditionalOnMissingBean
-		@ConditionalOnProperty(value = "spring.cloud.loadbalancer.configurations", havingValue = "default",
-				matchIfMissing = true)
+		@Conditional(DefaultConfigurationCondition.class)
 		public ServiceInstanceListSupplier discoveryClientServiceInstanceListSupplier(
 				ConfigurableApplicationContext context) {
 			return ServiceInstanceListSupplier.builder().withBlockingDiscoveryClient().withCaching().build(context);
@@ -152,7 +153,7 @@ public ServiceInstanceListSupplier discoveryClientServiceInstanceListSupplier(
 		@Bean
 		@ConditionalOnBean(DiscoveryClient.class)
 		@ConditionalOnMissingBean
-		@ConditionalOnProperty(value = "spring.cloud.loadbalancer.configurations", havingValue = "zone-preference")
+		@Conditional(ZonePreferenceConfigurationCondition.class)
 		public ServiceInstanceListSupplier zonePreferenceDiscoveryClientServiceInstanceListSupplier(
 				ConfigurableApplicationContext context) {
 			return ServiceInstanceListSupplier.builder().withBlockingDiscoveryClient().withZonePreference()
@@ -162,7 +163,7 @@ public ServiceInstanceListSupplier zonePreferenceDiscoveryClientServiceInstanceL
 		@Bean
 		@ConditionalOnBean({ DiscoveryClient.class, RestTemplate.class })
 		@ConditionalOnMissingBean
-		@ConditionalOnProperty(value = "spring.cloud.loadbalancer.configurations", havingValue = "health-check")
+		@Conditional(HealthCheckConfigurationCondition.class)
 		public ServiceInstanceListSupplier healthCheckDiscoveryClientServiceInstanceListSupplier(
 				ConfigurableApplicationContext context) {
 			return ServiceInstanceListSupplier.builder().withBlockingDiscoveryClient().withBlockingHealthChecks()
@@ -172,8 +173,7 @@ public ServiceInstanceListSupplier healthCheckDiscoveryClientServiceInstanceList
 		@Bean
 		@ConditionalOnBean(DiscoveryClient.class)
 		@ConditionalOnMissingBean
-		@ConditionalOnProperty(value = "spring.cloud.loadbalancer.configurations",
-				havingValue = "request-based-sticky-session")
+		@Conditional(RequestBasedStickySessionConfigurationCondition.class)
 		public ServiceInstanceListSupplier requestBasedStickySessionDiscoveryClientServiceInstanceListSupplier(
 				ConfigurableApplicationContext context) {
 			return ServiceInstanceListSupplier.builder().withBlockingDiscoveryClient().withRequestBasedStickySession()
@@ -183,8 +183,7 @@ public ServiceInstanceListSupplier requestBasedStickySessionDiscoveryClientServi
 		@Bean
 		@ConditionalOnBean(DiscoveryClient.class)
 		@ConditionalOnMissingBean
-		@ConditionalOnProperty(value = "spring.cloud.loadbalancer.configurations",
-				havingValue = "same-instance-preference")
+		@Conditional(SameInstancePreferenceConfigurationCondition.class)
 		public ServiceInstanceListSupplier sameInstancePreferenceServiceInstanceListSupplier(
 				ConfigurableApplicationContext context) {
 			return ServiceInstanceListSupplier.builder().withBlockingDiscoveryClient().withSameInstancePreference()
@@ -241,8 +240,7 @@ static class LoadBalancerRetryEnabled {
 
 		}
 
-		@ConditionalOnProperty(value = "spring.cloud.loadbalancer.retry.avoid-previous-instance", havingValue = "true",
-				matchIfMissing = true)
+		@Conditional(AvoidPreviousInstanceEnabledCondition.class)
 		static class AvoidPreviousInstanceEnabled {
 
 		}
@@ -260,12 +258,71 @@ static class LoadBalancerRetryEnabled {
 
 		}
 
-		@ConditionalOnProperty(value = "spring.cloud.loadbalancer.retry.avoid-previous-instance", havingValue = "true",
-				matchIfMissing = true)
+		@Conditional(AvoidPreviousInstanceEnabledCondition.class)
 		static class AvoidPreviousInstanceEnabled {
 
 		}
 
 	}
 
+	static class AvoidPreviousInstanceEnabledCondition implements Condition {
+
+		@Override
+		public boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {
+			return LoadBalancerEnvironmentPropertyUtils.trueOrMissingForClientOrDefault(context.getEnvironment(),
+					"retry.avoid-previous-instance");
+		}
+
+	}
+
+	static class DefaultConfigurationCondition implements Condition {
+
+		@Override
+		public boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {
+			return LoadBalancerEnvironmentPropertyUtils.equalToOrMissingForClientOrDefault(context.getEnvironment(),
+					"configurations", "default");
+		}
+
+	}
+
+	static class ZonePreferenceConfigurationCondition implements Condition {
+
+		@Override
+		public boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {
+			return LoadBalancerEnvironmentPropertyUtils.equalToForClientOrDefault(context.getEnvironment(),
+					"configurations", "zone-preference");
+		}
+
+	}
+
+	static class HealthCheckConfigurationCondition implements Condition {
+
+		@Override
+		public boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {
+			return LoadBalancerEnvironmentPropertyUtils.equalToForClientOrDefault(context.getEnvironment(),
+					"configurations", "health-check");
+		}
+
+	}
+
+	static class RequestBasedStickySessionConfigurationCondition implements Condition {
+
+		@Override
+		public boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {
+			return LoadBalancerEnvironmentPropertyUtils.equalToForClientOrDefault(context.getEnvironment(),
+					"configurations", "request-based-sticky-session");
+		}
+
+	}
+
+	static class SameInstancePreferenceConfigurationCondition implements Condition {
+
+		@Override
+		public boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {
+			return LoadBalancerEnvironmentPropertyUtils.equalToForClientOrDefault(context.getEnvironment(),
+					"configurations", "same-instance-preference");
+		}
+
+	}
+
 }

spring-cloud-loadbalancer/src/main/java/org/springframework/cloud/loadbalancer/config/BlockingLoadBalancerClientAutoConfiguration.java

@@ -21,7 +21,6 @@
 import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
-import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.cloud.client.ServiceInstance;
 import org.springframework.cloud.client.loadbalancer.AsyncLoadBalancerAutoConfiguration;
@@ -36,8 +35,13 @@
 import org.springframework.cloud.loadbalancer.blocking.retry.BlockingLoadBalancedRetryFactory;
 import org.springframework.cloud.loadbalancer.core.LoadBalancerServiceInstanceCookieTransformer;
 import org.springframework.cloud.loadbalancer.support.LoadBalancerClientFactory;
+import org.springframework.cloud.loadbalancer.support.LoadBalancerEnvironmentPropertyUtils;
 import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Condition;
+import org.springframework.context.annotation.ConditionContext;
+import org.springframework.context.annotation.Conditional;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.core.type.AnnotatedTypeMetadata;
 import org.springframework.retry.support.RetryTemplate;
 import org.springframework.web.client.RestTemplate;
 
@@ -64,16 +68,15 @@ public LoadBalancerClient blockingLoadBalancerClient(LoadBalancerClientFactory l
 	}
 
 	@Bean
-	@ConditionalOnProperty(value = "spring.cloud.loadbalancer.sticky-session.add-service-instance-cookie",
-			havingValue = "true")
+	@Conditional(AddServiceInstanceCookieCondition.class)
 	@ConditionalOnMissingBean(LoadBalancerServiceInstanceCookieTransformer.class)
 	public LoadBalancerServiceInstanceCookieTransformer loadBalancerServiceInstanceCookieTransformer(
 			LoadBalancerProperties properties) {
 		return new LoadBalancerServiceInstanceCookieTransformer(properties.getStickySession());
 	}
 
 	@Bean
-	@ConditionalOnProperty(value = "spring.cloud.loadbalancer.xforwarded.enabledXforwarded", havingValue = "true")
+	@Conditional(XForwardedConfigurationCondition.class)
 	@ConditionalOnMissingBean(XForwardedHeadersTransformer.class)
 	@ConditionalOnBean(LoadBalancerClientFactory.class)
 	public XForwardedHeadersTransformer xForwarderHeadersTransformer(
@@ -95,4 +98,14 @@ LoadBalancedRetryFactory loadBalancedRetryFactory(
 
 	}
 
+	static class AddServiceInstanceCookieCondition implements Condition {
+
+		@Override
+		public boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {
+			return LoadBalancerEnvironmentPropertyUtils.trueForClientOrDefault(context.getEnvironment(),
+					"sticky-session.add-service-instance-cookie");
+		}
+
+	}
+
 }

spring-cloud-loadbalancer/src/main/java/org/springframework/cloud/loadbalancer/config/XForwardedConfigurationCondition.java

@@ -0,0 +1,38 @@
+/*
+ * Copyright 2012-2021 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.loadbalancer.config;
+
+import org.springframework.cloud.loadbalancer.support.LoadBalancerEnvironmentPropertyUtils;
+import org.springframework.context.annotation.Condition;
+import org.springframework.context.annotation.ConditionContext;
+import org.springframework.core.type.AnnotatedTypeMetadata;
+
+/**
+ * Condition matched when x-forwarded headers are enabled via properties.
+ *
+ * @author Olga Maciaszek-Sharma
+ * @since 3.1.0
+ */
+public class XForwardedConfigurationCondition implements Condition {
+
+	@Override
+	public boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {
+		return LoadBalancerEnvironmentPropertyUtils.trueForClientOrDefault(context.getEnvironment(),
+				"spring.cloud.loadbalancer.x-forwarded.enabled");
+	}
+
+}

spring-cloud-loadbalancer/src/main/java/org/springframework/cloud/loadbalancer/support/LoadBalancerClientFactory.java

@@ -69,7 +69,7 @@ public LoadBalancerClientFactory(LoadBalancerClientsProperties properties) {
 		this.properties = properties;
 	}
 
-	public String getName(Environment environment) {
+	public static String getName(Environment environment) {
 		return environment.getProperty(PROPERTY_NAME);
 	}