pom.xml

@@ -164,6 +164,12 @@
 			<version>2.0.1.Final</version>
 		</dependency>
 
+		<!-- Add actuator dependency -->
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-actuator</artifactId>
+		</dependency>
+
 		<!-- Add dump schema dependency -->
 		<dependency>
 			<groupId>eu.dnetlib.dhp</groupId>

src/main/java/eu/openaire/api/config/health/HealthCheck.java

@@ -0,0 +1,55 @@
+package eu.openaire.api.config.health;
+
+import eu.openaire.api.repositories.SolrRepository;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.apache.solr.client.solrj.SolrServerException;
+import org.apache.solr.common.SolrException;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.actuate.health.Health;
+import org.springframework.boot.actuate.health.HealthIndicator;
+import org.springframework.stereotype.Component;
+
+import java.io.IOException;
+
+@Component
+public class HealthCheck implements HealthIndicator {
+
+	@Autowired
+	private SolrRepository solrRepository;
+
+	private final Logger log = LogManager.getLogger(this.getClass());
+
+
+	@Override
+	public Health health() {
+
+		log.info("Health check triggered");
+
+		// Custom health check logic
+		boolean isHealthy = checkHealth();
+		if (isHealthy) {
+			String healthMsg = "Successfully pinged Solr cluster";
+			log.info(healthMsg);
+			return Health.up().withDetail("message", healthMsg).build();
+		} else {
+			String notHealthyMsg = "Could not ping Solr cluster; please check the logs for details";
+			log.error(notHealthyMsg);
+			return Health.down().withDetail("message", notHealthyMsg).build();
+		}
+	}
+
+	private boolean checkHealth() {
+
+		// Ping Solr cluster to check health
+		try {
+			if (solrRepository.ping().getStatus() != 0) {
+				return false;
+			}
+		} catch (SolrException | IOException | SolrServerException e) {
+			return false;
+		}
+
+		return true;
+	}
+}

src/main/java/eu/openaire/api/config/health/SolrStartupHealthCheck.java

@@ -0,0 +1,34 @@
+package eu.openaire.api.config.health;
+
+import eu.openaire.api.repositories.SolrRepository;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.apache.solr.client.solrj.SolrServerException;
+import org.apache.solr.common.SolrException;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.ApplicationArguments;
+import org.springframework.boot.ApplicationRunner;
+import org.springframework.stereotype.Component;
+
+import java.io.IOException;
+
+@Component
+public class SolrStartupHealthCheck implements ApplicationRunner {
+	private final Logger log = LogManager.getLogger(this.getClass());
+
+	@Autowired
+	private SolrRepository solrRepository;
+
+	@Override
+	public void run(ApplicationArguments args) throws RuntimeException {
+		try {
+			if (solrRepository.ping().getStatus() != 0) {
+				throw new RuntimeException("Could not ping Solr cluster at startup");
+			}
+		} catch (SolrException | IOException | SolrServerException e) {
+			throw new RuntimeException("Failed to connect to Solr cluster at startup", e);
+		}
+
+		log.info("Successfully pinged Solr cluster at startup");
+	}
+}

src/main/java/eu/openaire/api/repositories/SolrRepository.java

@@ -9,6 +9,7 @@ import org.apache.logging.log4j.Logger;
 import org.apache.solr.client.solrj.SolrQuery;
 import org.apache.solr.client.solrj.SolrServerException;
 import org.apache.solr.client.solrj.response.QueryResponse;
+import org.apache.solr.client.solrj.response.SolrPingResponse;
 import org.apache.solr.common.SolrDocument;
 import org.springframework.stereotype.Repository;
 
@@ -62,4 +63,8 @@ public class SolrRepository {
         return solrConnectionManager.getSolrClient().query(query);
 
     }
+
+    public SolrPingResponse ping() throws SolrServerException, IOException {
+        return solrConnectionManager.ping();
+    }
 }

src/main/java/eu/openaire/api/solr/SolrConnectionManager.java

@@ -8,6 +8,7 @@ import org.apache.logging.log4j.Logger;
 import org.apache.solr.client.solrj.SolrClient;
 import org.apache.solr.client.solrj.SolrServerException;
 import org.apache.solr.client.solrj.impl.CloudSolrClient;
+import org.apache.solr.client.solrj.response.SolrPingResponse;
 import org.springframework.context.annotation.Scope;
 import org.springframework.stereotype.Component;
 
@@ -41,13 +42,20 @@ public class SolrConnectionManager {
 
         // create SolrClient with ZooKeeper hosts
         // TODO: add socket (or connection) timeout?
-        solrClient = new CloudSolrClient.Builder(zkHosts, Optional.empty()).build();
+        solrClient = new CloudSolrClient.Builder(zkHosts, Optional.empty())
+                // time to wait when trying to establish a connection
+                .withConnectionTimeout(3000)
+                // time to wait for data to be read from the socket
+                .withSocketTimeout(30000)
+                .build();
 
         // set the appropriate Solr collection
         ((CloudSolrClient) solrClient).setDefaultCollection(solrProperties.getCollection());
 
-        log.info("Creating Solr client - Ping response: " + solrClient.ping().toString());
+    }
 
+    public SolrPingResponse ping() throws IOException, SolrServerException {
+        return solrClient.ping();
     }
 
     @PreDestroy
@@ -58,6 +66,5 @@ public class SolrConnectionManager {
         if (solrClient != null) {
             solrClient.close();
         }
-
     }
 }

src/main/resources/application.properties

@@ -12,3 +12,13 @@ logging.level.org.springframework.web=DEBUG
 #removes 'trace' field from error responses; alternatively remove 'spring-boot-devtools' dependency
 server.error.include-stacktrace=never 
 
+# Enable the health endpoint
+management.endpoint.health.enabled=true
+
+# Expose the health endpoint
+management.endpoints.web.exposure.include=health,info
+
+# Customize health endpoint settings
+management.endpoint.health.show-details=always
+management.endpoint.health.show-components=always
+