Add ConnectionDetail support to Zipkin auto-configuration

Update Zipkin auto-configuration so that `ZipkinConnectionDetails`
beans may be optionally used to provide connection details.

See gh-34657

Co-Authored-By: Mortitz Halbritter <mkammerer@vmware.com>
Co-Authored-By: Phillip Webb <pwebb@vmware.com>

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/tracing/zipkin/PropertiesZipkinConnectionDetails.java

@@ -0,0 +1,39 @@
+/*
+ * Copyright 2012-2023 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.boot.actuate.autoconfigure.tracing.zipkin;
+
+/**
+ * Adapts {@link ZipkinProperties} to {@link ZipkinConnectionDetails}.
+ *
+ * @author Moritz Halbritter
+ * @author Andy Wilkinson
+ * @author Phillip Webb
+ */
+class PropertiesZipkinConnectionDetails implements ZipkinConnectionDetails {
+
+	private final ZipkinProperties properties;
+
+	PropertiesZipkinConnectionDetails(ZipkinProperties properties) {
+		this.properties = properties;
+	}
+
+	@Override
+	public String getSpanEndpoint() {
+		return this.properties.getEndpoint();
+	}
+
+}

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/tracing/zipkin/ZipkinConfigurations.java

@@ -59,11 +59,14 @@ class ZipkinConfigurations {
 
 		@Bean
 		@ConditionalOnMissingBean(Sender.class)
-		URLConnectionSender urlConnectionSender(ZipkinProperties properties) {
+		URLConnectionSender urlConnectionSender(ZipkinProperties properties,
+				ObjectProvider<ZipkinConnectionDetails> connectionDetailsProvider) {
+			ZipkinConnectionDetails connectionDetails = connectionDetailsProvider
+				.getIfAvailable(() -> new PropertiesZipkinConnectionDetails(properties));
 			URLConnectionSender.Builder builder = URLConnectionSender.newBuilder();
 			builder.connectTimeout((int) properties.getConnectTimeout().toMillis());
 			builder.readTimeout((int) properties.getReadTimeout().toMillis());
-			builder.endpoint(properties.getEndpoint());
+			builder.endpoint(connectionDetails.getSpanEndpoint());
 			return builder.build();
 		}
 
@@ -77,12 +80,15 @@ class ZipkinConfigurations {
 		@Bean
 		@ConditionalOnMissingBean(Sender.class)
 		ZipkinRestTemplateSender restTemplateSender(ZipkinProperties properties,
-				ObjectProvider<ZipkinRestTemplateBuilderCustomizer> customizers) {
+				ObjectProvider<ZipkinRestTemplateBuilderCustomizer> customizers,
+				ObjectProvider<ZipkinConnectionDetails> connectionDetailsProvider) {
+			ZipkinConnectionDetails connectionDetails = connectionDetailsProvider
+				.getIfAvailable(() -> new PropertiesZipkinConnectionDetails(properties));
 			RestTemplateBuilder restTemplateBuilder = new RestTemplateBuilder()
 				.setConnectTimeout(properties.getConnectTimeout())
 				.setReadTimeout(properties.getReadTimeout());
 			restTemplateBuilder = applyCustomizers(restTemplateBuilder, customizers);
-			return new ZipkinRestTemplateSender(properties.getEndpoint(), restTemplateBuilder.build());
+			return new ZipkinRestTemplateSender(connectionDetails.getSpanEndpoint(), restTemplateBuilder.build());
 		}
 
 		private RestTemplateBuilder applyCustomizers(RestTemplateBuilder restTemplateBuilder,
@@ -106,10 +112,13 @@ class ZipkinConfigurations {
 		@Bean
 		@ConditionalOnMissingBean(Sender.class)
 		ZipkinWebClientSender webClientSender(ZipkinProperties properties,
-				ObjectProvider<ZipkinWebClientBuilderCustomizer> customizers) {
+				ObjectProvider<ZipkinWebClientBuilderCustomizer> customizers,
+				ObjectProvider<ZipkinConnectionDetails> connectionDetailsProvider) {
+			ZipkinConnectionDetails connectionDetails = connectionDetailsProvider
+				.getIfAvailable(() -> new PropertiesZipkinConnectionDetails(properties));
 			WebClient.Builder builder = WebClient.builder();
 			customizers.orderedStream().forEach((customizer) -> customizer.customize(builder));
-			return new ZipkinWebClientSender(properties.getEndpoint(), builder.build());
+			return new ZipkinWebClientSender(connectionDetails.getSpanEndpoint(), builder.build());
 		}
 
 	}

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/tracing/zipkin/ZipkinConnectionDetails.java

@@ -0,0 +1,35 @@
+/*
+ * Copyright 2012-2023 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.boot.actuate.autoconfigure.tracing.zipkin;
+
+import org.springframework.boot.autoconfigure.service.connection.ConnectionDetails;
+
+/**
+ * Details required to establish a connection to a Zipkin server.
+ *
+ * @author Moritz Halbritter
+ * @since 3.1.0
+ */
+public interface ZipkinConnectionDetails extends ConnectionDetails {
+
+	/**
+	 * The endpoint for the span reporting.
+	 * @return the endpoint
+	 */
+	String getSpanEndpoint();
+
+}