feat(lb): deterministic subsetting algorithm to limit the number of i…

…nstances
spring-cloud · Oct 31, 2023 · 9935bc5 · 9935bc5
1 parent 6ff2aa7
commit 9935bc5
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Showing 3 changed files with 31 additions and 10 deletions.
diff --git a/.../java/org/springframework/cloud/loadbalancer/core/ServiceInstanceListSupplierBuilder.java b/.../java/org/springframework/cloud/loadbalancer/core/ServiceInstanceListSupplierBuilder.java
@@ -35,6 +35,7 @@
 import org.springframework.cloud.loadbalancer.config.LoadBalancerZoneConfig;
 import org.springframework.cloud.loadbalancer.support.LoadBalancerClientFactory;
 import org.springframework.context.ConfigurableApplicationContext;
+import org.springframework.core.env.PropertyResolver;
 import org.springframework.http.HttpStatus;
 import org.springframework.util.Assert;
 import org.springframework.util.StringUtils;
@@ -301,6 +302,16 @@ public ServiceInstanceListSupplierBuilder withHints() {
 		return this;
 	}
 
+	public ServiceInstanceListSupplierBuilder withSubset() {
+		DelegateCreator creator = (context, delegate) -> {
+			PropertyResolver resolver = context.getBean(PropertyResolver.class);
+			LoadBalancerClientFactory factory = context.getBean(LoadBalancerClientFactory.class);
+			return new SubsetServiceInstanceListSupplier(delegate, resolver, factory);
+		};
+		creators.add(creator);
+		return this;
+	}
+
 	/**
 	 * Support {@link ServiceInstanceListSupplierBuilder} can be added to the expansion
 	 * implementation of {@link ServiceInstanceListSupplier} by this method.

diff --git a/...n/java/org/springframework/cloud/loadbalancer/core/SubsetServiceInstanceListSupplier.java b/...n/java/org/springframework/cloud/loadbalancer/core/SubsetServiceInstanceListSupplier.java
@@ -25,6 +25,7 @@
 
 import org.springframework.cloud.client.ServiceInstance;
 import org.springframework.cloud.client.loadbalancer.LoadBalancerProperties;
+import org.springframework.cloud.client.loadbalancer.reactive.ReactiveLoadBalancer;
 import org.springframework.core.env.PropertyResolver;
 
 /**
@@ -42,8 +43,9 @@ public class SubsetServiceInstanceListSupplier extends DelegatingServiceInstance
 	private final int size;
 
 	public SubsetServiceInstanceListSupplier(ServiceInstanceListSupplier delegate, PropertyResolver resolver,
-			LoadBalancerProperties properties) {
+			ReactiveLoadBalancer.Factory<ServiceInstance> factory) {
 		super(delegate);
+		LoadBalancerProperties properties = factory.getProperties(getServiceId());
 		this.instanceId = resolver.resolvePlaceholders(properties.getSubset().getInstanceId());
 		this.size = properties.getSubset().getSize();
 	}

diff --git a/...va/org/springframework/cloud/loadbalancer/core/SubsetServiceInstanceListSupplierTest.java b/...va/org/springframework/cloud/loadbalancer/core/SubsetServiceInstanceListSupplierTest.java
@@ -30,11 +30,13 @@
 import org.springframework.cloud.client.DefaultServiceInstance;
 import org.springframework.cloud.client.ServiceInstance;
 import org.springframework.cloud.client.loadbalancer.LoadBalancerProperties;
+import org.springframework.cloud.client.loadbalancer.reactive.ReactiveLoadBalancer;
 import org.springframework.mock.env.MockEnvironment;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;
+import static org.springframework.cloud.loadbalancer.core.LoadBalancerTestUtils.buildLoadBalancerClientFactory;
 
 /**
  * Tests for {@link SubsetServiceInstanceListSupplier}
@@ -60,9 +62,10 @@ public void destroy() {
 
 	@Test
 	void shouldReturnEmptyWhenDelegateReturnedEmpty() {
+		when(delegate.getServiceId()).thenReturn("test");
 		when(delegate.get()).thenReturn(Flux.just(Collections.emptyList()));
 		SubsetServiceInstanceListSupplier supplier = new SubsetServiceInstanceListSupplier(delegate, env,
-				subsetProperties("foobar", 100));
+				factory("foobar", 100));
 
 		List<ServiceInstance> serviceInstances = Objects.requireNonNull(supplier.get().blockFirst());
 		assertThat(serviceInstances).isEmpty();
@@ -74,9 +77,10 @@ void shouldReturnSublistWithGivenSubsetSize() {
 				.mapToObj(i -> new DefaultServiceInstance(Integer.toString(i), "test", "host" + i, 8080, false, null))
 				.collect(Collectors.toList());
 
+		when(delegate.getServiceId()).thenReturn("test");
 		when(delegate.get()).thenReturn(Flux.just(instances));
 		SubsetServiceInstanceListSupplier supplier = new SubsetServiceInstanceListSupplier(delegate, env,
-				subsetProperties("foobar", 5));
+				factory("foobar", 5));
 
 		List<ServiceInstance> serviceInstances = Objects.requireNonNull(supplier.get().blockFirst());
 		assertThat(serviceInstances).hasSize(5);
@@ -88,9 +92,10 @@ void shouldReturnRawWhenLessThanSubsetSize() {
 				.mapToObj(i -> new DefaultServiceInstance(Integer.toString(i), "test", "host" + i, 8080, false, null))
 				.collect(Collectors.toList());
 
+		when(delegate.getServiceId()).thenReturn("test");
 		when(delegate.get()).thenReturn(Flux.just(instances));
 		SubsetServiceInstanceListSupplier supplier = new SubsetServiceInstanceListSupplier(delegate, env,
-				subsetProperties("foobar", 1000));
+				factory("foobar", 1000));
 
 		List<ServiceInstance> serviceInstances = Objects.requireNonNull(supplier.get().blockFirst());
 		assertThat(serviceInstances).hasSize(101);
@@ -102,14 +107,15 @@ void shouldReturnSameSublistForSameInstanceId() {
 				.mapToObj(i -> new DefaultServiceInstance(Integer.toString(i), "test", "host" + i, 8080, false, null))
 				.collect(Collectors.toList());
 
+		when(delegate.getServiceId()).thenReturn("test");
 		when(delegate.get()).thenReturn(Flux.just(instances));
 
 		SubsetServiceInstanceListSupplier supplier1 = new SubsetServiceInstanceListSupplier(delegate, env,
-				subsetProperties("foobar", 5));
+				factory("foobar", 5));
 		List<ServiceInstance> serviceInstances1 = Objects.requireNonNull(supplier1.get().blockFirst());
 
 		SubsetServiceInstanceListSupplier supplier2 = new SubsetServiceInstanceListSupplier(delegate, env,
-				subsetProperties("foobar", 5));
+				factory("foobar", 5));
 		List<ServiceInstance> serviceInstances2 = Objects.requireNonNull(supplier2.get().blockFirst());
 
 		assertThat(serviceInstances1).isEqualTo(serviceInstances2);
@@ -121,26 +127,28 @@ void shouldReturnDifferentSublistForDifferentInstanceId() {
 				.mapToObj(i -> new DefaultServiceInstance(Integer.toString(i), "test", "host" + i, 8080, false, null))
 				.collect(Collectors.toList());
 
+		when(delegate.getServiceId()).thenReturn("test");
 		when(delegate.get()).thenReturn(Flux.just(instances));
 
 		SubsetServiceInstanceListSupplier supplier1 = new SubsetServiceInstanceListSupplier(delegate, env,
-				subsetProperties("foobar1", 5));
+				factory("foobar1", 5));
 		List<ServiceInstance> serviceInstances1 = Objects.requireNonNull(supplier1.get().blockFirst());
 
 		SubsetServiceInstanceListSupplier supplier2 = new SubsetServiceInstanceListSupplier(delegate, env,
-				subsetProperties("foobar2", 5));
+				factory("foobar2", 5));
 		List<ServiceInstance> serviceInstances2 = Objects.requireNonNull(supplier2.get().blockFirst());
 
 		assertThat(serviceInstances1).isNotEqualTo(serviceInstances2);
 	}
 
-	LoadBalancerProperties subsetProperties(String instanceId, int size) {
+	ReactiveLoadBalancer.Factory<ServiceInstance> factory(String instanceId, int size) {
 		LoadBalancerProperties properties = new LoadBalancerProperties();
 		LoadBalancerProperties.Subset subset = new LoadBalancerProperties.Subset();
 		subset.setInstanceId(instanceId);
 		subset.setSize(size);
 		properties.setSubset(subset);
-		return properties;
+
+		return buildLoadBalancerClientFactory("test", properties);
 	}
 
 }