Refactored service monitor to perform on-demand checks when service status is unknown

Core/src/org/sleuthkit/autopsy/core/ServicesMonitor.java

@@ -38,7 +38,6 @@ import org.sleuthkit.autopsy.coreutils.MessageNotifyUtil;
 import org.sleuthkit.autopsy.events.AutopsyEventPublisher;
 import org.sleuthkit.autopsy.events.MessageServiceConnectionInfo;
 import org.sleuthkit.autopsy.keywordsearchservice.KeywordSearchService;
-import org.sleuthkit.datamodel.CaseDbConnectionInfo;
 
 /**
  * This class periodically checks availability of collaboration resources -
@@ -61,7 +60,8 @@ public class ServicesMonitor {
             .collect(Collectors.toSet());
 
     /**
-     * The service monitor maintains a mapping of each service to it's last status update.
+     * The service monitor maintains a mapping of each service to it's last
+     * status update.
      */
     private final ConcurrentHashMap<String, String> statusByService;
 
@@ -77,13 +77,12 @@ public class ServicesMonitor {
          * New value is set to updated ServiceStatus, old value is null.
          */
         REMOTE_CASE_DATABASE,
-        
         /**
-         * Property change event fired when remote keyword search service status changes.
+         * Property change event fired when remote keyword search service status
-         * New value is set to updated ServiceStatus, old value is null.
+         * changes. New value is set to updated ServiceStatus, old value is
+         * null.
          */
         REMOTE_KEYWORD_SEARCH,
-        
         /**
          * Property change event fired when messaging service status changes.
          * New value is set to updated ServiceStatus, old value is null.
@@ -100,11 +99,14 @@ public class ServicesMonitor {
          * Service is currently up.
          */
         UP,
-        
         /**
          * Service is currently down.
          */
-        DOWN
+        DOWN,
+        /**
+         * Service status is unknown.
+         */
+        UNKNOWN,
     };
 
     public synchronized static ServicesMonitor getInstance() {
@@ -118,10 +120,8 @@ public class ServicesMonitor {
 
         this.eventPublisher = new AutopsyEventPublisher();
         this.statusByService = new ConcurrentHashMap<>();
-        
-        // Services are assumed to be "UP" by default. See CrashDetectionTask class for more info.
         for (String serviceName : serviceNames) {
-            this.statusByService.put(serviceName, ServiceStatus.UP.toString());
+            this.statusByService.put(serviceName, ServiceStatus.UNKNOWN.toString());
         }
 
         /**
@@ -161,12 +161,56 @@ public class ServicesMonitor {
         if (status == null) {
             // no such service
             throw new UnknownServiceException("Requested service name " + service + " is unknown");
+
+        } else if (status.equals(ServiceStatus.UNKNOWN.toString())) {
+            // status for the service is not known. This is likely because we haven't 
+            // checked it's status yet. Perform an on-demand check of the service status.
+            status = checkServiceStatusStatus(service);
         }
         return status;
     }
 
     /**
-     * Publish an event signifying change in service status. Event is published locally.
+     * Performs on-demand check of service availability.
+     *
+     * @param service Name of the service.
+     * @return String Status for the service.
+     */
+    private String checkServiceStatusStatus(String service) {
+
+        if (service.equals(ServiceName.REMOTE_CASE_DATABASE.toString())) {
+            if (canConnectToRemoteDb()) {
+                setServiceStatus(ServiceName.REMOTE_CASE_DATABASE.toString(), ServiceStatus.UP.toString());
+                return ServiceStatus.UP.toString();
+            } else {
+                setServiceStatus(ServiceName.REMOTE_CASE_DATABASE.toString(), ServiceStatus.DOWN.toString());
+                return ServiceStatus.DOWN.toString();
+            }
+        } else if (service.equals(ServiceName.REMOTE_KEYWORD_SEARCH.toString())){
+            KeywordSearchService kwsService = Lookup.getDefault().lookup(KeywordSearchService.class);
+            // TODO - do I need to check for kwsService == null?
+            if (kwsService.canConnectToRemoteSolrServer()) {
+                setServiceStatus(ServiceName.REMOTE_KEYWORD_SEARCH.toString(), ServiceStatus.UP.toString());
+                return ServiceStatus.UP.toString();
+            } else {
+                setServiceStatus(ServiceName.REMOTE_KEYWORD_SEARCH.toString(), ServiceStatus.DOWN.toString());
+                return ServiceStatus.DOWN.toString();
+            }
+        } else if (service.equals(ServiceName.MESSAGING.toString())) {
+            if (canConnectToMessagingService()) {
+                setServiceStatus(ServiceName.MESSAGING.toString(), ServiceStatus.UP.toString());
+                return ServiceStatus.UP.toString();
+            } else {
+                setServiceStatus(ServiceName.MESSAGING.toString(), ServiceStatus.DOWN.toString());
+                return ServiceStatus.DOWN.toString();
+            }            
+        }
+        return ServiceStatus.UNKNOWN.toString();
+    }
+
+    /**
+     * Publish an event signifying change in service status. Event is published
+     * locally.
      *
      * @param service Name of the service.
      * @param status Updated status for the event.
@@ -246,20 +290,41 @@ public class ServicesMonitor {
         eventPublisher.removeSubscriber(serviceNames, subscriber);
     }
 
+    /**
+     * Verifies connection to remote database.
+     *
+     * @return True if connection can be established, false otherwise.
+     */
+    private boolean canConnectToRemoteDb() {
+        return UserPreferences.getDatabaseConnectionInfo().canConnect();
+    }
+
+    /**
+     * Verifies connection to messaging service.
+     *
+     * @return True if connection can be established, false otherwise.
+     */
+    private boolean canConnectToMessagingService() {
+        MessageServiceConnectionInfo msgInfo = UserPreferences.getMessageServiceConnectionInfo();
+        try {
+            ActiveMQConnectionFactory connectionFactory = new ActiveMQConnectionFactory(msgInfo.getUserName(), msgInfo.getPassword(), msgInfo.getURI());
+            Connection connection = connectionFactory.createConnection();
+            connection.start();
+            connection.close();
+            return true;
+        } catch (URISyntaxException | JMSException ex) {
+            return false;
+        }
+    }
+
     /**
      * A Runnable task that periodically checks the availability of
-     * collaboration resources (PostgreSQL server, Solr server, Active MQ
+     * collaboration resources (remote database, remote keyword search service,
      * message broker) and reports status to the user in case of a gap in
      * service.
      */
     private final class CrashDetectionTask implements Runnable {
 
-        // Services are assumed to be "UP" by default. Change default value in ServicesMonitor() 
-        // constructor if this assumption changes.
-        private boolean dbServerIsRunning = true;
-        private boolean solrServerIsRunning = true;
-        private boolean messageServerIsRunning = true;
-        
         private final Object lock = new Object();
 
         /**
@@ -268,17 +333,15 @@ public class ServicesMonitor {
         @Override
         public void run() {
             synchronized (lock) {
-                CaseDbConnectionInfo dbInfo = UserPreferences.getDatabaseConnectionInfo();
+                try {
-                if (dbInfo.canConnect()) {
+                    if (canConnectToRemoteDb()) {
-                    if (!dbServerIsRunning) {
+                        if (!getServiceStatus(ServiceName.REMOTE_CASE_DATABASE.toString()).equals(ServiceStatus.UP.toString())) {
-                        dbServerIsRunning = true;
                             logger.log(Level.INFO, "Connection to PostgreSQL server restored"); //NON-NLS
                             MessageNotifyUtil.Notify.info(NbBundle.getMessage(ServicesMonitor.class, "ServicesMonitor.restoredService.notify.title"), NbBundle.getMessage(ServicesMonitor.class, "ServicesMonitor.restoredDbService.notify.msg"));
                             setServiceStatus(ServiceName.REMOTE_CASE_DATABASE.toString(), ServiceStatus.UP.toString());
                         }
                     } else {
-                    if (dbServerIsRunning) {
+                        if (!getServiceStatus(ServiceName.REMOTE_CASE_DATABASE.toString()).equals(ServiceStatus.DOWN.toString())) {
-                        dbServerIsRunning = false;
                             logger.log(Level.SEVERE, "Failed to connect to PostgreSQL server"); //NON-NLS
                             MessageNotifyUtil.Notify.error(NbBundle.getMessage(ServicesMonitor.class, "ServicesMonitor.failedService.notify.title"), NbBundle.getMessage(ServicesMonitor.class, "ServicesMonitor.failedDbService.notify.msg"));
                             setServiceStatus(ServiceName.REMOTE_CASE_DATABASE.toString(), ServiceStatus.DOWN.toString());
@@ -288,41 +351,36 @@ public class ServicesMonitor {
                     KeywordSearchService kwsService = Lookup.getDefault().lookup(KeywordSearchService.class);
                     // TODO - do I need to check for kwsService == null?
                     if (kwsService.canConnectToRemoteSolrServer()) {
-                    if (!solrServerIsRunning) {
+                        if (!getServiceStatus(ServiceName.REMOTE_KEYWORD_SEARCH.toString()).equals(ServiceStatus.UP.toString())) {
-                        solrServerIsRunning = true;
                             logger.log(Level.INFO, "Connection to Solr server restored"); //NON-NLS
                             MessageNotifyUtil.Notify.info(NbBundle.getMessage(ServicesMonitor.class, "ServicesMonitor.restoredService.notify.title"), NbBundle.getMessage(ServicesMonitor.class, "ServicesMonitor.restoredSolrService.notify.msg"));
                             setServiceStatus(ServiceName.REMOTE_KEYWORD_SEARCH.toString(), ServiceStatus.UP.toString());
                         }
                     } else {
-                    if (solrServerIsRunning) {
+                        if (!getServiceStatus(ServiceName.REMOTE_KEYWORD_SEARCH.toString()).equals(ServiceStatus.DOWN.toString())) {
-                        solrServerIsRunning = false;
                             logger.log(Level.SEVERE, "Failed to connect to Solr server"); //NON-NLS
                             MessageNotifyUtil.Notify.error(NbBundle.getMessage(ServicesMonitor.class, "ServicesMonitor.failedService.notify.title"), NbBundle.getMessage(ServicesMonitor.class, "ServicesMonitor.failedSolrService.notify.msg"));
                             setServiceStatus(ServiceName.REMOTE_KEYWORD_SEARCH.toString(), ServiceStatus.DOWN.toString());
                         }
                     }
 
-                MessageServiceConnectionInfo msgInfo = UserPreferences.getMessageServiceConnectionInfo();
+                    if (canConnectToMessagingService()) {
-                try {
+                        if (!getServiceStatus(ServiceName.MESSAGING.toString()).equals(ServiceStatus.UP.toString())) {
-                    ActiveMQConnectionFactory connectionFactory = new ActiveMQConnectionFactory(msgInfo.getUserName(), msgInfo.getPassword(), msgInfo.getURI());
-                    Connection connection = connectionFactory.createConnection();
-                    connection.start();
-                    connection.close();
-                    if (!messageServerIsRunning) {
-                        messageServerIsRunning = true;
                             logger.log(Level.INFO, "Connection to ActiveMQ server restored"); //NON-NLS
                             MessageNotifyUtil.Notify.info(NbBundle.getMessage(ServicesMonitor.class, "ServicesMonitor.restoredService.notify.title"), NbBundle.getMessage(ServicesMonitor.class, "ServicesMonitor.restoredMessageService.notify.msg"));
                             setServiceStatus(ServiceName.MESSAGING.toString(), ServiceStatus.UP.toString());
                         }
-                } catch (URISyntaxException | JMSException ex) {
+                    } else {
-                    if (messageServerIsRunning) {
+                        if (!getServiceStatus(ServiceName.MESSAGING.toString()).equals(ServiceStatus.DOWN.toString())) {
-                        messageServerIsRunning = false;
+                            logger.log(Level.SEVERE, "Failed to connect to ActiveMQ server"); //NON-NLS
-                        logger.log(Level.SEVERE, "Failed to connect to ActiveMQ server", ex); //NON-NLS
                             MessageNotifyUtil.Notify.error(NbBundle.getMessage(ServicesMonitor.class, "ServicesMonitor.failedService.notify.title"), NbBundle.getMessage(ServicesMonitor.class, "ServicesMonitor.failedMessageService.notify.msg"));
                             setServiceStatus(ServiceName.MESSAGING.toString(), ServiceStatus.DOWN.toString());
                         }
                     }
+
+                } catch (UnknownServiceException ex) {
+                    logger.log(Level.SEVERE, "Exception while checking current service status", ex); //NON-NLS
+                }
             }
         }
     }