Fix Solr health indicator

This commit changes the solr health indicator to request the status of
all available cores, rather than invoking a generic ping on the admin
handler.

Recent versions of Solr now have a ping handler per core and the general
admin handler is gone, leading to incorrect health status. For backward
compatible reason the `solrStatus` attribute is kept to `OK` if all cores
are running properly (that's actually `0` behind the scenes).

Closes gh-8463

spring-boot-actuator/src/main/java/org/springframework/boot/actuate/health/SolrHealthIndicator.java

 /*
- * Copyright 2012-2016 the original author or authors.
+ * Copyright 2012-2017 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.
@@ -17,11 +17,15 @@
 package org.springframework.boot.actuate.health;
 
 import org.apache.solr.client.solrj.SolrClient;
+import org.apache.solr.client.solrj.request.CoreAdminRequest;
+import org.apache.solr.client.solrj.response.CoreAdminResponse;
+import org.apache.solr.common.params.CoreAdminParams;
 
 /**
  * {@link HealthIndicator} for Apache Solr.
  *
  * @author Andy Wilkinson
+ * @author Stephane Nicoll
  * @since 1.1.0
  */
 public class SolrHealthIndicator extends AbstractHealthIndicator {
@@ -34,8 +38,16 @@ public class SolrHealthIndicator extends AbstractHealthIndicator {
 
 	@Override
 	protected void doHealthCheck(Health.Builder builder) throws Exception {
-		Object status = this.solrClient.ping().getResponse().get("status");
-		builder.up().withDetail("solrStatus", status);
+		CoreAdminRequest request = new CoreAdminRequest();
+		request.setAction(CoreAdminParams.CoreAdminAction.STATUS);
+		CoreAdminResponse response = request.process(this.solrClient);
+		int status = response.getStatus();
+		if (status == 0) {
+			builder.up().withDetail("solrStatus", "OK");
+		}
+		else {
+			builder.down().withDetail("solrStatus", status);
+		}
 	}
 
 }

spring-boot-actuator/src/test/java/org/springframework/boot/actuate/health/SolrHealthIndicatorTests.java

 /*
- * Copyright 2012-2016 the original author or authors.
+ * Copyright 2012-2017 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.
@@ -19,7 +19,7 @@ package org.springframework.boot.actuate.health;
 import java.io.IOException;
 
 import org.apache.solr.client.solrj.SolrClient;
-import org.apache.solr.client.solrj.response.SolrPingResponse;
+import org.apache.solr.client.solrj.request.CoreAdminRequest;
 import org.apache.solr.common.util.NamedList;
 import org.junit.After;
 import org.junit.Test;
@@ -32,6 +32,8 @@ import org.springframework.context.annotation.AnnotationConfigApplicationContext
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.mockito.BDDMockito.given;
+import static org.mockito.Matchers.any;
+import static org.mockito.Matchers.isNull;
 import static org.mockito.Mockito.mock;
 
 /**
@@ -65,21 +67,30 @@ public class SolrHealthIndicatorTests {
 	@Test
 	public void solrIsUp() throws Exception {
 		SolrClient solrClient = mock(SolrClient.class);
-		SolrPingResponse pingResponse = new SolrPingResponse();
-		NamedList<Object> response = new NamedList<Object>();
-		response.add("status", "OK");
-		pingResponse.setResponse(response);
-		given(solrClient.ping()).willReturn(pingResponse);
+		given(solrClient.request(any(CoreAdminRequest.class), (String) isNull()))
+			.willReturn(mockResponse(0));
 		SolrHealthIndicator healthIndicator = new SolrHealthIndicator(solrClient);
 		Health health = healthIndicator.health();
 		assertThat(health.getStatus()).isEqualTo(Status.UP);
 		assertThat(health.getDetails().get("solrStatus")).isEqualTo("OK");
 	}
 
+	@Test
+	public void solrIsUpAndRequestFailed() throws Exception {
+		SolrClient solrClient = mock(SolrClient.class);
+		given(solrClient.request(any(CoreAdminRequest.class), (String) isNull()))
+			.willReturn(mockResponse(400));
+		SolrHealthIndicator healthIndicator = new SolrHealthIndicator(solrClient);
+		Health health = healthIndicator.health();
+		assertThat(health.getStatus()).isEqualTo(Status.DOWN);
+		assertThat(health.getDetails().get("solrStatus")).isEqualTo(400);
+	}
+
 	@Test
 	public void solrIsDown() throws Exception {
 		SolrClient solrClient = mock(SolrClient.class);
-		given(solrClient.ping()).willThrow(new IOException("Connection failed"));
+		given(solrClient.request(any(CoreAdminRequest.class), (String) isNull()))
+			.willThrow(new IOException("Connection failed"));
 		SolrHealthIndicator healthIndicator = new SolrHealthIndicator(solrClient);
 		Health health = healthIndicator.health();
 		assertThat(health.getStatus()).isEqualTo(Status.DOWN);
@@ -87,4 +98,12 @@ public class SolrHealthIndicatorTests {
 				.contains("Connection failed"));
 	}
 
+	private NamedList<Object> mockResponse(int status) {
+		NamedList<Object> response = new NamedList<Object>();
+		NamedList<Object> headers = new NamedList<Object>();
+		headers.add("status", status);
+		response.add("responseHeader", headers);
+		return response;
+	}
+
 }