Adds UrlHealthIndicator based on WebClient

spring-cloud-commons/src/main/java/org/springframework/cloud/commons/util/UrlHealthIndicator.java

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+/*
+ * Copyright 2013-2020 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.commons.util;
+
+import java.util.Map;
+
+import reactor.core.publisher.Mono;
+
+import org.springframework.boot.actuate.health.AbstractReactiveHealthIndicator;
+import org.springframework.boot.actuate.health.Health;
+import org.springframework.boot.actuate.health.ReactiveHealthIndicator;
+import org.springframework.web.reactive.function.client.WebClient;
+
+/**
+ * {@link ReactiveHealthIndicator} that checks the configured {@link WebClient} for the
+ * Spring Boot Health status format.
+ * @author Spencer Gibb
+ * @author Fabrizio Di Napoli
+ */
+public class UrlHealthIndicator extends AbstractReactiveHealthIndicator {
+
+	private final WebClient webClient;
+
+	public UrlHealthIndicator(WebClient webClient) {
+		this.webClient = webClient;
+	}
+
+	public UrlHealthIndicator(WebClient.Builder builder, String baseUrl) {
+		this.webClient = builder.baseUrl(baseUrl).build();
+	}
+
+	@Override
+	protected Mono<Health> doHealthCheck(Health.Builder builder) {
+		if (this.webClient == null) {
+			return Mono.just(builder.up().build());
+		}
+
+		return webClient.get().retrieve().bodyToMono(Map.class).map(map -> {
+			Object status = map.get("status");
+			if (status instanceof String) {
+				return builder.status(status.toString()).build();
+			}
+			else {
+				return builder.unknown()
+						.withDetail("warning", "no status field in response").build();
+			}
+		});
+	}
+
+}