DMF health check (#577)

* DMF support PING message for health checks.

Signed-off-by: kaizimmerm <kai.zimmermann@bosch-si.com>

* Device simulator supports PING.

Signed-off-by: kaizimmerm <kai.zimmermann@bosch-si.com>

* Code cleanup.

Signed-off-by: kaizimmerm <kai.zimmermann@bosch-si.com>

* Revert accidental checkin.

Signed-off-by: kaizimmerm <kai.zimmermann@bosch-si.com>

* Fix tests.

Signed-off-by: kaizimmerm <kai.zimmermann@bosch-si.com>

* Simplify API.

Signed-off-by: kaizimmerm <kai.zimmermann@bosch-si.com>

* Remove simulator dead letter.

Signed-off-by: kaizimmerm <kai.zimmermann@bosch-si.com>

* Remove dead code. 

Signed-off-by: kaizimmerm <kai.zimmermann@bosch-si.com>

* Reduce code.

Signed-off-by: kaizimmerm <kai.zimmermann@bosch-si.com>

* Add message for one more error case.

Signed-off-by: kaizimmerm <kai.zimmermann@bosch-si.com>

examples/hawkbit-device-simulator/src/main/java/org/eclipse/hawkbit/simulator/DeviceSimulator.java

@@ -14,6 +14,9 @@ import java.util.concurrent.ScheduledExecutorService;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
 import org.springframework.context.annotation.Bean;
+import org.springframework.scheduling.TaskScheduler;
+import org.springframework.scheduling.annotation.EnableScheduling;
+import org.springframework.scheduling.concurrent.ConcurrentTaskScheduler;
 
 import com.google.common.eventbus.AsyncEventBus;
 import com.google.common.eventbus.EventBus;
@@ -25,6 +28,7 @@ import com.vaadin.spring.annotation.EnableVaadin;
  */
 @SpringBootApplication
 @EnableVaadin
+@EnableScheduling
 public class DeviceSimulator {
 
     public DeviceSimulator() {
@@ -35,7 +39,7 @@ public class DeviceSimulator {
      * @return an asynchronous event bus to publish and retrieve events.
      */
     @Bean
-    public EventBus eventBus() {
+    EventBus eventBus() {
         return new AsyncEventBus(Executors.newFixedThreadPool(4));
     }
 
@@ -43,10 +47,15 @@ public class DeviceSimulator {
      * @return central ScheduledExecutorService
      */
     @Bean
-    public ScheduledExecutorService threadPool() {
+    ScheduledExecutorService threadPool() {
         return Executors.newScheduledThreadPool(8);
     }
 
+    @Bean
+    TaskScheduler taskScheduler() {
+        return new ConcurrentTaskScheduler(threadPool());
+    }
+
     /**
      * Start the Spring Boot Application.
      *

examples/hawkbit-device-simulator/src/main/java/org/eclipse/hawkbit/simulator/DeviceSimulatorRepository.java

@@ -9,10 +9,11 @@
 package org.eclipse.hawkbit.simulator;
 
 import java.util.Collection;
+import java.util.HashSet;
 import java.util.Map;
+import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
 
-import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Service;
 
 /**
@@ -27,8 +28,7 @@ public class DeviceSimulatorRepository {
 
     private final Map<DeviceKey, AbstractSimulatedDevice> devices = new ConcurrentHashMap<>();
 
-    @Autowired
+    private final Set<String> tenants = new HashSet<>();
-    private SimulatedDeviceFactory deviceFactory;
 
     /**
      * Adds a simulated device to the repository.
@@ -39,6 +39,7 @@ public class DeviceSimulatorRepository {
      */
     public AbstractSimulatedDevice add(final AbstractSimulatedDevice simulatedDevice) {
         devices.put(new DeviceKey(simulatedDevice.getTenant().toLowerCase(), simulatedDevice.getId()), simulatedDevice);
+        tenants.add(simulatedDevice.getTenant().toLowerCase());
         return simulatedDevice;
     }
 
@@ -78,12 +79,17 @@ public class DeviceSimulatorRepository {
         return devices.remove(new DeviceKey(tenant.toLowerCase(), id));
     }
 
+    public Set<String> getTenants() {
+        return tenants;
+    }
+
     /**
      * Clears all stored devices.
      */
     public void clear() {
-        devices.values().forEach(device -> device.clean());
+        devices.values().forEach(AbstractSimulatedDevice::clean);
         devices.clear();
+        tenants.clear();
     }
 
     private static final class DeviceKey {

examples/hawkbit-device-simulator/src/main/java/org/eclipse/hawkbit/simulator/amqp/AmqpConfiguration.java

@@ -122,8 +122,7 @@ public class AmqpConfiguration {
      */
     @Bean
     public Queue receiverConnectorQueueFromHawkBit() {
-        final Map<String, Object> arguments = getDeadLetterExchangeArgs();
+        final Map<String, Object> arguments = getTTLMaxArgs();
-        arguments.putAll(getTTLMaxArgs());
 
         return QueueBuilder.nonDurable(amqpProperties.getReceiverConnectorQueueFromSp()).autoDelete()
                 .withArguments(arguments).build();
@@ -151,36 +150,6 @@ public class AmqpConfiguration {
         return BindingBuilder.bind(receiverConnectorQueueFromHawkBit()).to(exchangeQueueToConnector());
     }
 
-    /**
-     * Create dead letter queue.
-     *
-     * @return the queue
-     */
-    @Bean
-    public Queue deadLetterQueue() {
-        return QueueBuilder.nonDurable(amqpProperties.getDeadLetterQueue()).withArguments(getTTLMaxArgs()).build();
-    }
-
-    /**
-     * Create the dead letter fanout exchange.
-     *
-     * @return the fanout exchange
-     */
-    @Bean
-    public FanoutExchange exchangeDeadLetter() {
-        return new FanoutExchange(amqpProperties.getDeadLetterExchange(), false, true);
-    }
-
-    /**
-     * Create the Binding deadLetterQueue to exchangeDeadLetter.
-     *
-     * @return the binding
-     */
-    @Bean
-    public Binding bindDeadLetterQueueToLwm2mExchange() {
-        return BindingBuilder.bind(deadLetterQueue()).to(exchangeDeadLetter());
-    }
-
     /**
      * Returns the Listener factory.
      *
@@ -198,12 +167,6 @@ public class AmqpConfiguration {
         return containerFactory;
     }
 
-    private Map<String, Object> getDeadLetterExchangeArgs() {
-        final Map<String, Object> args = Maps.newHashMapWithExpectedSize(1);
-        args.put("x-dead-letter-exchange", amqpProperties.getDeadLetterExchange());
-        return args;
-    }
-
     private static Map<String, Object> getTTLMaxArgs() {
         final Map<String, Object> args = Maps.newHashMapWithExpectedSize(2);
         args.put("x-message-ttl", Duration.ofDays(1).toMillis());

examples/hawkbit-device-simulator/src/main/java/org/eclipse/hawkbit/simulator/amqp/AmqpProperties.java

@@ -30,6 +30,11 @@ public class AmqpProperties {
      */
     private boolean enabled;
 
+    /**
+     * Set to true for the simulator run DMF health check.
+     */
+    private boolean checkDmfHealth = false;
+
     /**
      * Queue for receiving DMF messages from update server.
      */
@@ -40,22 +45,20 @@ public class AmqpProperties {
      */
     private String senderForSpExchange = "simulator.replyTo";
 
-    /**
-     * Simulator dead letter queue.
-     */
-    private String deadLetterQueue = "simulator_deadletter";
-
-    /**
-     * Simulator dead letter exchange.
-     */
-    private String deadLetterExchange = "simulator.deadletter";
-
     /**
      * Message time to live (ttl) for the deadletter queue. Default ttl is 1
      * hour.
      */
     private int deadLetterTtl = 60_000;
 
+    public boolean isCheckDmfHealth() {
+        return checkDmfHealth;
+    }
+
+    public void setCheckDmfHealth(final boolean checkDmfHealth) {
+        this.checkDmfHealth = checkDmfHealth;
+    }
+
     public String getReceiverConnectorQueueFromSp() {
         return receiverConnectorQueueFromSp;
     }
@@ -64,22 +67,6 @@ public class AmqpProperties {
         this.receiverConnectorQueueFromSp = receiverConnectorQueueFromSp;
     }
 
-    public String getDeadLetterExchange() {
-        return deadLetterExchange;
-    }
-
-    public void setDeadLetterExchange(final String deadLetterExchange) {
-        this.deadLetterExchange = deadLetterExchange;
-    }
-
-    public String getDeadLetterQueue() {
-        return deadLetterQueue;
-    }
-
-    public void setDeadLetterQueue(final String deadLetterQueue) {
-        this.deadLetterQueue = deadLetterQueue;
-    }
-
     public String getSenderForSpExchange() {
         return senderForSpExchange;
     }

examples/hawkbit-device-simulator/src/main/java/org/eclipse/hawkbit/simulator/amqp/SenderService.java

@@ -58,8 +58,12 @@ public abstract class SenderService extends MessageService {
             return;
         }
         message.getMessageProperties().getHeaders().remove(AbstractJavaTypeMapper.DEFAULT_CLASSID_FIELD_NAME);
+
         final String correlationId = UUID.randomUUID().toString();
-        message.getMessageProperties().setCorrelationId(correlationId.getBytes(StandardCharsets.UTF_8));
+
+        if (isCorrelationIdEmpty(message)) {
+            message.getMessageProperties().setCorrelationId(correlationId.getBytes(StandardCharsets.UTF_8));
+        }
 
         if (LOGGER.isTraceEnabled()) {
             LOGGER.trace("Sending message {} to exchange {} with correlationId {}", message, address, correlationId);
@@ -70,6 +74,11 @@ public abstract class SenderService extends MessageService {
         rabbitTemplate.send(address, null, message, new CorrelationData(correlationId));
     }
 
+    private static boolean isCorrelationIdEmpty(final Message message) {
+        return message.getMessageProperties().getCorrelationId() == null
+                || message.getMessageProperties().getCorrelationId().length <= 0;
+    }
+
     /**
      * Convert object and message properties to message.
      *

examples/hawkbit-device-simulator/src/main/java/org/eclipse/hawkbit/simulator/amqp/SpReceiverService.java

@@ -8,8 +8,11 @@
  */
 package org.eclipse.hawkbit.simulator.amqp;
 
+import java.nio.charset.StandardCharsets;
 import java.util.Arrays;
 import java.util.Map;
+import java.util.Set;
+import java.util.UUID;
 
 import org.eclipse.hawkbit.dmf.amqp.api.EventTopic;
 import org.eclipse.hawkbit.dmf.amqp.api.MessageHeaderKey;
@@ -17,6 +20,7 @@ import org.eclipse.hawkbit.dmf.amqp.api.MessageType;
 import org.eclipse.hawkbit.dmf.json.model.DmfDownloadAndUpdateRequest;
 import org.eclipse.hawkbit.simulator.DeviceSimulatorRepository;
 import org.eclipse.hawkbit.simulator.DeviceSimulatorUpdater;
+import org.eclipse.jetty.util.ConcurrentHashSet;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.amqp.core.Message;
@@ -26,6 +30,7 @@ import org.springframework.amqp.rabbit.core.RabbitTemplate;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
 import org.springframework.messaging.handler.annotation.Header;
+import org.springframework.scheduling.annotation.Scheduled;
 import org.springframework.stereotype.Component;
 
 /**
@@ -43,6 +48,8 @@ public class SpReceiverService extends ReceiverService {
 
     private final DeviceSimulatorRepository repository;
 
+    private final Set<String> openPings = new ConcurrentHashSet<>();
+
     /**
      * Constructor.
      * 
@@ -82,28 +89,60 @@ public class SpReceiverService extends ReceiverService {
      */
     @RabbitListener(queues = "${hawkbit.device.simulator.amqp.receiverConnectorQueueFromSp}", containerFactory = "listenerContainerFactory")
     public void recieveMessageSp(final Message message, @Header(MessageHeaderKey.TYPE) final String type,
-            @Header(MessageHeaderKey.THING_ID) final String thingId,
+            @Header(name = MessageHeaderKey.THING_ID, required = false) final String thingId,
             @Header(MessageHeaderKey.TENANT) final String tenant) {
-        checkContentTypeJson(message);
-        delegateMessage(message, type, thingId, tenant);
-    }
-
-    private void delegateMessage(final Message message, final String type, final String thingId, final String tenant) {
         final MessageType messageType = MessageType.valueOf(type);
 
         if (MessageType.EVENT.equals(messageType)) {
+            checkContentTypeJson(message);
             handleEventMessage(message, thingId);
             return;
         }
 
         if (MessageType.THING_DELETED.equals(messageType)) {
+            checkContentTypeJson(message);
             repository.remove(tenant, thingId);
             return;
         }
 
+        if (MessageType.PING_RESPONSE.equals(messageType)) {
+            final String correlationId = new String(message.getMessageProperties().getCorrelationId(),
+                    StandardCharsets.UTF_8);
+            if (!openPings.remove(correlationId)) {
+                LOGGER.error("Unknown PING_RESPONSE received for correlationId: {}.", correlationId);
+            }
+
+            if (LOGGER.isDebugEnabled()) {
+                LOGGER.debug("Got ping response from tenant {} with correlationId {} with timestamp {}", tenant,
+                        correlationId, new String(message.getBody(), StandardCharsets.UTF_8));
+            }
+
+            return;
+        }
+
         LOGGER.info("No valid message type property.");
     }
 
+    @Scheduled(fixedDelay = 5_000, initialDelay = 5_000)
+    void checkDmfHealth() {
+        if (!amqpProperties.isCheckDmfHealth()) {
+            return;
+        }
+
+        if (openPings.size() > 5) {
+            LOGGER.error("Currently {} open pings! DMF does not seem to be reachable.", openPings.size());
+        } else {
+            LOGGER.debug("Currently {} open pings", openPings.size());
+        }
+
+        repository.getTenants().forEach(tenant -> {
+            final String correlationId = UUID.randomUUID().toString();
+            spSenderService.ping(tenant, correlationId);
+            openPings.add(correlationId);
+            LOGGER.debug("Ping tenant {} with correlationId {}", tenant, correlationId);
+        });
+    }
+
     private void handleEventMessage(final Message message, final String thingId) {
         final Object eventHeader = message.getMessageProperties().getHeaders().get(MessageHeaderKey.TOPIC);
         if (eventHeader == null) {

examples/hawkbit-device-simulator/src/main/java/org/eclipse/hawkbit/simulator/amqp/SpSenderService.java

@@ -57,6 +57,17 @@ public class SpSenderService extends SenderService {
         this.simulationProperties = simulationProperties;
     }
 
+    public void ping(final String tenant, final String correlationId) {
+        final MessageProperties messageProperties = new MessageProperties();
+        messageProperties.getHeaders().put(MessageHeaderKey.TENANT, tenant);
+        messageProperties.getHeaders().put(MessageHeaderKey.TYPE, MessageType.PING.toString());
+        messageProperties.setCorrelationId(correlationId.getBytes());
+        messageProperties.setReplyTo(amqpProperties.getSenderForSpExchange());
+        messageProperties.setContentType(MessageProperties.CONTENT_TYPE_TEXT_PLAIN);
+
+        sendMessage(spExchange, new Message(null, messageProperties));
+    }
+
     /**
      * Finish the update process. This will send a action status to SP.
      *
@@ -96,7 +107,8 @@ public class SpSenderService extends SenderService {
      *            the ID of the action for the error message
      */
     public void sendErrorMessage(final String tenant, final List<String> updateResultMessages, final Long actionId) {
-        final Message message = createActionStatusMessage(tenant, DmfActionStatus.ERROR, updateResultMessages, actionId);
+        final Message message = createActionStatusMessage(tenant, DmfActionStatus.ERROR, updateResultMessages,
+                actionId);
         sendMessage(spExchange, message);
     }
 
@@ -240,7 +252,8 @@ public class SpSenderService extends SenderService {
             final List<String> updateResultMessages) {
         final MessageProperties messageProperties = new MessageProperties();
         final Map<String, Object> headers = messageProperties.getHeaders();
-        final DmfActionUpdateStatus actionUpdateStatus = new DmfActionUpdateStatus(cacheValue.getActionId(), actionStatus);
+        final DmfActionUpdateStatus actionUpdateStatus = new DmfActionUpdateStatus(cacheValue.getActionId(),
+                actionStatus);
         headers.put(MessageHeaderKey.TYPE, MessageType.EVENT.name());
         headers.put(MessageHeaderKey.TENANT, cacheValue.getTenant());
         headers.put(MessageHeaderKey.TOPIC, EventTopic.UPDATE_ACTION_STATUS.name());

hawkbit-dmf/hawkbit-dmf-amqp/src/main/java/org/eclipse/hawkbit/amqp/AmqpConfiguration.java

@@ -264,8 +264,8 @@ public class AmqpConfiguration {
      */
     @Bean
     @ConditionalOnMissingBean
-    public AmqpSenderService amqpSenderServiceBean() {
+    public AmqpMessageSenderService amqpSenderServiceBean() {
-        return new DefaultAmqpSenderService(rabbitTemplate());
+        return new DefaultAmqpMessageSenderService(rabbitTemplate());
     }
 
     @Bean
@@ -325,7 +325,7 @@ public class AmqpConfiguration {
     @Bean
     @ConditionalOnMissingBean(AmqpMessageDispatcherService.class)
     public AmqpMessageDispatcherService amqpMessageDispatcherService(final RabbitTemplate rabbitTemplate,
-            final AmqpSenderService amqpSenderService, final ArtifactUrlHandler artifactUrlHandler,
+            final AmqpMessageSenderService amqpSenderService, final ArtifactUrlHandler artifactUrlHandler,
             final SystemSecurityContext systemSecurityContext, final SystemManagement systemManagement,
             final TargetManagement targetManagement) {
         return new AmqpMessageDispatcherService(rabbitTemplate, amqpSenderService, artifactUrlHandler,

hawkbit-dmf/hawkbit-dmf-amqp/src/main/java/org/eclipse/hawkbit/amqp/AmqpMessageDispatcherService.java

@@ -39,6 +39,7 @@ import org.eclipse.hawkbit.util.IpUtil;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.amqp.core.Message;
+import org.springframework.amqp.core.MessageBuilder;
 import org.springframework.amqp.core.MessageProperties;
 import org.springframework.amqp.rabbit.core.RabbitTemplate;
 import org.springframework.cloud.bus.ServiceMatcher;
@@ -47,7 +48,7 @@ import org.springframework.context.event.EventListener;
 
 /**
  * {@link AmqpMessageDispatcherService} create all outgoing AMQP messages and
- * delegate the messages to a {@link AmqpSenderService}.
+ * delegate the messages to a {@link AmqpMessageSenderService}.
  *
  * Additionally the dispatcher listener/subscribe for some target events e.g.
  * assignment.
@@ -58,7 +59,7 @@ public class AmqpMessageDispatcherService extends BaseAmqpService {
     private static final Logger LOG = LoggerFactory.getLogger(AmqpMessageDispatcherService.class);
 
     private final ArtifactUrlHandler artifactUrlHandler;
-    private final AmqpSenderService amqpSenderService;
+    private final AmqpMessageSenderService amqpSenderService;
     private final SystemSecurityContext systemSecurityContext;
     private final SystemManagement systemManagement;
     private final TargetManagement targetManagement;
@@ -83,10 +84,10 @@ public class AmqpMessageDispatcherService extends BaseAmqpService {
      *            to check in cluster case if the message is from the same
      *            cluster node
      */
-    public AmqpMessageDispatcherService(final RabbitTemplate rabbitTemplate, final AmqpSenderService amqpSenderService,
+    public AmqpMessageDispatcherService(final RabbitTemplate rabbitTemplate,
-            final ArtifactUrlHandler artifactUrlHandler, final SystemSecurityContext systemSecurityContext,
+            final AmqpMessageSenderService amqpSenderService, final ArtifactUrlHandler artifactUrlHandler,
-            final SystemManagement systemManagement, final TargetManagement targetManagement,
+            final SystemSecurityContext systemSecurityContext, final SystemManagement systemManagement,
-            final ServiceMatcher serviceMatcher) {
+            final TargetManagement targetManagement, final ServiceMatcher serviceMatcher) {
         super(rabbitTemplate);
         this.artifactUrlHandler = artifactUrlHandler;
         this.amqpSenderService = amqpSenderService;
@@ -143,6 +144,16 @@ public class AmqpMessageDispatcherService extends BaseAmqpService {
         amqpSenderService.sendMessage(message, targetAdress);
     }
 
+    void sendPingReponseToDmfReceiver(final Message ping, final String tenant) {
+        final Message message = MessageBuilder.withBody(String.valueOf(System.currentTimeMillis()).getBytes())
+                .setContentType(MessageProperties.CONTENT_TYPE_TEXT_PLAIN)
+                .setCorrelationId(ping.getMessageProperties().getCorrelationId())
+                .setHeader(MessageHeaderKey.TYPE, MessageType.PING_RESPONSE).setHeader(MessageHeaderKey.TENANT, tenant)
+                .build();
+
+        amqpSenderService.sendMessage(message, ping.getMessageProperties().getReplyTo());
+    }
+
     /**
      * Method to send a message to a RabbitMQ Exchange after the assignment of
      * the Distribution set to a Target has been canceled.

hawkbit-dmf/hawkbit-dmf-amqp/src/main/java/org/eclipse/hawkbit/amqp/AmqpMessageHandlerService.java

@@ -115,20 +115,25 @@ public class AmqpMessageHandlerService extends BaseAmqpService {
      * @return the rpc message back to supplier.
      */
     public Message onMessage(final Message message, final String type, final String tenant, final String virtualHost) {
-        checkContentTypeJson(message);
+
         final SecurityContext oldContext = SecurityContextHolder.getContext();
         try {
             final MessageType messageType = MessageType.valueOf(type);
             switch (messageType) {
             case THING_CREATED:
+                checkContentTypeJson(message);
                 setTenantSecurityContext(tenant);
                 registerTarget(message, virtualHost);
                 break;
             case EVENT:
+                checkContentTypeJson(message);
                 setTenantSecurityContext(tenant);
-                final String topicValue = getStringHeaderKey(message, MessageHeaderKey.TOPIC, "EventTopic is null");
+                handleIncomingEvent(message);
-                final EventTopic eventTopic = EventTopic.valueOf(topicValue);
+                break;
-                handleIncomingEvent(message, eventTopic);
+            case PING:
+                if (isCorrelationIdNotEmpty(message)) {
+                    amqpMessageDispatcherService.sendPingReponseToDmfReceiver(message, tenant);
+                }
                 break;
             default:
                 logAndThrowMessageError(message, "No handle method was found for the given message type.");
@@ -206,8 +211,8 @@ public class AmqpMessageHandlerService extends BaseAmqpService {
      * @param topic
      *            the topic of the event.
      */
-    private void handleIncomingEvent(final Message message, final EventTopic topic) {
+    private void handleIncomingEvent(final Message message) {
-        switch (topic) {
+        switch (EventTopic.valueOf(getStringHeaderKey(message, MessageHeaderKey.TOPIC, "EventTopic is null"))) {
         case UPDATE_ACTION_STATUS:
             updateActionStatus(message);
             break;

hawkbit-dmf/hawkbit-dmf-amqp/src/main/java/org/eclipse/hawkbit/amqp/AmqpMessageSenderService.java

@@ -12,13 +12,14 @@ import java.net.URI;
 
 import javax.validation.constraints.NotNull;
 
+import org.eclipse.hawkbit.util.IpUtil;
 import org.springframework.amqp.core.Message;
 
 /**
  * Interface to send a amqp message.
  */
 @FunctionalInterface
-public interface AmqpSenderService {
+public interface AmqpMessageSenderService {
 
     /**
      * Send the given message to the given uri. The uri contains the (virtual)
@@ -29,18 +30,24 @@ public interface AmqpSenderService {
      * @param replyTo
      *            the reply to uri
      */
-    void sendMessage(@NotNull Message message, @NotNull URI replyTo);
+    default void sendMessage(@NotNull final Message message, @NotNull final URI replyTo) {
+        if (!IpUtil.isAmqpUri(replyTo)) {
+            return;
+        }
 
-    /**
+        sendMessage(message, replyTo.getPath().substring(1));
-     * Extract the exchange from the uri. Default implementation removes the
-     * first /.
-     * 
-     * @param amqpUri
-     *            the amqp uri
-     * @return the exchange.
-     */
-    default String extractExchange(final URI amqpUri) {
-        return amqpUri.getPath().substring(1);
     }
 
+    /**
+     * Send the given message to the given host and exchange.
+     * 
+     * @param message
+     *            the amqp message
+     * @param exchange
+     *            to send to
+     * @param virtualHost
+     *            to send to
+     */
+    void sendMessage(@NotNull final Message message, @NotNull final String exchange);
+
 }

hawkbit-dmf/hawkbit-dmf-amqp/src/main/java/org/eclipse/hawkbit/amqp/DefaultAmqpMessageSenderService.java

@@ -8,11 +8,9 @@
  */
 package org.eclipse.hawkbit.amqp;
 
-import java.net.URI;
 import java.nio.charset.StandardCharsets;
 import java.util.UUID;
 
-import org.eclipse.hawkbit.util.IpUtil;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.amqp.core.Message;
@@ -24,30 +22,27 @@ import org.springframework.amqp.rabbit.support.CorrelationData;
  * message to the configured spring rabbitmq connections. The exchange is
  * extracted from the uri.
  */
-public class DefaultAmqpSenderService implements AmqpSenderService {
+public class DefaultAmqpMessageSenderService extends BaseAmqpService implements AmqpMessageSenderService {
-    private static final Logger LOGGER = LoggerFactory.getLogger(DefaultAmqpSenderService.class);
+    private static final Logger LOGGER = LoggerFactory.getLogger(DefaultAmqpMessageSenderService.class);
-
-    private final RabbitTemplate internalAmqpTemplate;
 
     /**
      * Constructor.
      * 
-     * @param internalAmqpTemplate
+     * @param rabbitTemplate
-     *            the amqp template
+     *            the AMQP template
      */
-    public DefaultAmqpSenderService(final RabbitTemplate internalAmqpTemplate) {
+    public DefaultAmqpMessageSenderService(final RabbitTemplate rabbitTemplate) {
-        this.internalAmqpTemplate = internalAmqpTemplate;
+        super(rabbitTemplate);
     }
 
     @Override
-    public void sendMessage(final Message message, final URI replyTo) {
+    public void sendMessage(final Message message, final String exchange) {
-        if (!IpUtil.isAmqpUri(replyTo)) {
-            return;
-        }
 
         final String correlationId = UUID.randomUUID().toString();
-        final String exchange = extractExchange(replyTo);
+
-        message.getMessageProperties().setCorrelationId(correlationId.getBytes(StandardCharsets.UTF_8));
+        if (isCorrelationIdEmpty(message)) {
+            message.getMessageProperties().setCorrelationId(correlationId.getBytes(StandardCharsets.UTF_8));
+        }
 
         if (LOGGER.isTraceEnabled()) {
             LOGGER.trace("Sending message {} to exchange {} with correlationId {}", message, exchange, correlationId);
@@ -55,7 +50,12 @@ public class DefaultAmqpSenderService implements AmqpSenderService {
             LOGGER.debug("Sending message to exchange {} with correlationId {}", exchange, correlationId);
         }
 
-        internalAmqpTemplate.send(exchange, null, message, new CorrelationData(correlationId));
+        getRabbitTemplate().send(exchange, null, message, new CorrelationData(correlationId));
+    }
+
+    protected static boolean isCorrelationIdEmpty(final Message message) {
+        return message.getMessageProperties().getCorrelationId() == null
+                || message.getMessageProperties().getCorrelationId().length <= 0;
     }
 
 }

hawkbit-dmf/hawkbit-dmf-amqp/src/test/java/org/eclipse/hawkbit/amqp/AmqpMessageDispatcherServiceTest.java

@@ -81,7 +81,7 @@ public class AmqpMessageDispatcherServiceTest extends AbstractIntegrationTest {
 
     private RabbitTemplate rabbitTemplate;
 
-    private DefaultAmqpSenderService senderService;
+    private DefaultAmqpMessageSenderService senderService;
 
     private Target testTarget;
 
@@ -94,7 +94,7 @@ public class AmqpMessageDispatcherServiceTest extends AbstractIntegrationTest {
         this.rabbitTemplate = Mockito.mock(RabbitTemplate.class);
         when(rabbitTemplate.getMessageConverter()).thenReturn(new Jackson2JsonMessageConverter());
 
-        senderService = Mockito.mock(DefaultAmqpSenderService.class);
+        senderService = Mockito.mock(DefaultAmqpMessageSenderService.class);
 
         final ArtifactUrlHandler artifactUrlHandlerMock = Mockito.mock(ArtifactUrlHandler.class);
         when(artifactUrlHandlerMock.getUrls(anyObject(), anyObject()))

hawkbit-dmf/hawkbit-dmf-amqp/src/test/java/org/eclipse/hawkbit/integration/AmqpMessageHandlerServiceIntegrationTest.java

@@ -59,6 +59,17 @@ public class AmqpMessageHandlerServiceIntegrationTest extends AmqpServiceIntegra
     @Autowired
     private AmqpProperties amqpProperties;
 
+    @Test
+    @Description("Tests DMF PING request and expected reponse.")
+    public void pingDmfInterface() {
+        final Message pingMessage = createPingMessage(CORRELATION_ID, TENANT_EXIST);
+        getDmfClient().send(pingMessage);
+
+        assertPingReplyMessage(CORRELATION_ID);
+
+        Mockito.verifyZeroInteractions(getDeadletterListener());
+    }
+
     @Test
     @Description("Tests register target")
     @ExpectEvents({ @Expect(type = TargetCreatedEvent.class, count = 2),
@@ -450,7 +461,7 @@ public class AmqpMessageHandlerServiceIntegrationTest extends AmqpServiceIntegra
         final String controllerId = TARGET_PREFIX + "receiveDownLoadAndInstallMessageAfterAssignment";
 
         // setup
-        controllerManagement.findOrRegisterTargetIfItDoesNotexist(controllerId, TEST_URI);
+        createAndSendTarget(controllerId, TENANT_EXIST);
         final DistributionSet distributionSet = testdataFactory.createDistributionSet(UUID.randomUUID().toString());
         assignDistributionSet(distributionSet.getId(), controllerId);
 
@@ -476,7 +487,7 @@ public class AmqpMessageHandlerServiceIntegrationTest extends AmqpServiceIntegra
         final String controllerId = TARGET_PREFIX + "receiveCancelUpdateMessageAfterAssignmentWasCanceled";
 
         // Setup
-        controllerManagement.findOrRegisterTargetIfItDoesNotexist(controllerId, TEST_URI);
+        createAndSendTarget(controllerId, TENANT_EXIST);
         final DistributionSet distributionSet = testdataFactory.createDistributionSet(UUID.randomUUID().toString());
         final DistributionSetAssignmentResult distributionSetAssignmentResult = assignDistributionSet(
                 distributionSet.getId(), controllerId);

hawkbit-dmf/hawkbit-dmf-amqp/src/test/java/org/eclipse/hawkbit/integration/AmqpServiceIntegrationTest.java

@@ -10,6 +10,7 @@ package org.eclipse.hawkbit.integration;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
+import java.nio.charset.StandardCharsets;
 import java.util.Map;
 import java.util.Optional;
 import java.util.Set;
@@ -138,6 +139,22 @@ public abstract class AmqpServiceIntegrationTest extends AbstractAmqpIntegration
         assertThat(headers.get(MessageHeaderKey.TYPE)).isEqualTo(MessageType.THING_DELETED.toString());
     }
 
+    protected void assertPingReplyMessage(final String correlationId) {
+
+        verifyReplyToListener();
+        final Message replyMessage = replyToListener.getPingResponseMessages().get(correlationId);
+
+        final Map<String, Object> headers = replyMessage.getMessageProperties().getHeaders();
+
+        assertThat(headers.get(MessageHeaderKey.TENANT)).isEqualTo(TENANT_EXIST);
+        assertThat(correlationId)
+                .isEqualTo(new String(replyMessage.getMessageProperties().getCorrelationId(), StandardCharsets.UTF_8));
+        assertThat(headers.get(MessageHeaderKey.TYPE)).isEqualTo(MessageType.PING_RESPONSE.toString());
+        assertThat(Long.valueOf(new String(replyMessage.getBody(), StandardCharsets.UTF_8)))
+                .isLessThanOrEqualTo(System.currentTimeMillis());
+
+    }
+
     protected void assertDownloadAndInstallMessage(final Set<SoftwareModule> dsModules, final String controllerId) {
         final Message replyMessage = assertReplyMessageHeader(EventTopic.DOWNLOAD_AND_INSTALL, controllerId);
         assertAllTargetsCount(1);
@@ -158,6 +175,12 @@ public abstract class AmqpServiceIntegrationTest extends AbstractAmqpIntegration
         getDmfClient().send(message);
     }
 
+    protected Message createAndSendPingMessage(final String correlationId, final String tenant) {
+        final Message message = createPingMessage(correlationId, tenant);
+        getDmfClient().send(message);
+        return message;
+    }
+
     protected void verifyReplyToListener() {
         createConditionFactory().until(() -> {
             Mockito.verify(replyToListener, Mockito.atLeast(1)).handleMessage(Mockito.any());
@@ -244,6 +267,15 @@ public abstract class AmqpServiceIntegrationTest extends AbstractAmqpIntegration
         return createMessage(null, messageProperties);
     }
 
+    protected Message createPingMessage(final String correlationId, final String tenant) {
+        final MessageProperties messageProperties = createMessagePropertiesWithTenant(tenant);
+        messageProperties.getHeaders().put(MessageHeaderKey.TYPE, MessageType.PING.toString());
+        messageProperties.setCorrelationId(correlationId.getBytes());
+        messageProperties.setReplyTo(DmfTestConfiguration.REPLY_TO_EXCHANGE);
+
+        return createMessage(null, messageProperties);
+    }
+
     protected MessageProperties createMessagePropertiesWithTenant(final String tenant) {
         final MessageProperties messageProperties = new MessageProperties();
         messageProperties.getHeaders().put(MessageHeaderKey.TENANT, tenant);

hawkbit-dmf/hawkbit-dmf-amqp/src/test/java/org/eclipse/hawkbit/integration/listener/ReplyToListener.java

@@ -10,6 +10,8 @@ package org.eclipse.hawkbit.integration.listener;
 
 import static org.junit.Assert.fail;
 
+import java.nio.charset.StandardCharsets;
+import java.util.EnumMap;
 import java.util.HashMap;
 import java.util.Map;
 
@@ -25,8 +27,9 @@ public class ReplyToListener implements TestRabbitListener {
     public static final String LISTENER_ID = "replyto";
     public static final String REPLY_TO_QUEUE = "reply_queue";
 
-    private final Map<EventTopic, Message> eventTopicMessages = new HashMap<>();
+    private final Map<EventTopic, Message> eventTopicMessages = new EnumMap<>(EventTopic.class);
     private final Map<String, Message> deleteMessages = new HashMap<>();
+    private final Map<String, Message> pingResponseMessages = new HashMap<>();
 
     @Override
     @RabbitListener(id = LISTENER_ID, queues = REPLY_TO_QUEUE)
@@ -49,6 +52,13 @@ public class ReplyToListener implements TestRabbitListener {
             return;
         }
 
+        if (messageType == MessageType.PING_RESPONSE) {
+            final String correlationId = new String(message.getMessageProperties().getCorrelationId(),
+                    StandardCharsets.UTF_8);
+            pingResponseMessages.put(correlationId, message);
+            return;
+        }
+
         // if message type is not EVENT or THING_DELETED something unexpected
         // happened
         fail("Unexpected message type");
@@ -63,4 +73,8 @@ public class ReplyToListener implements TestRabbitListener {
         return deleteMessages;
     }
 
+    public Map<String, Message> getPingResponseMessages() {
+        return pingResponseMessages;
+    }
+
 }

hawkbit-dmf/hawkbit-dmf-api/src/main/java/org/eclipse/hawkbit/dmf/amqp/api/MessageType.java

@@ -15,7 +15,7 @@ package org.eclipse.hawkbit.dmf.amqp.api;
 public enum MessageType {
 
     /**
-     * The event type.
+     * The event type related to interaction with a thing.
      */
     EVENT,
 
@@ -29,4 +29,14 @@ public enum MessageType {
      */
     THING_DELETED,
 
+    /**
+     * DMF receiver health check type.
+     */
+    PING,
+
+    /**
+     * DMF receiver health check reponse type.
+     */
+    PING_RESPONSE;
+
 }

hawkbit-dmf/hawkbit-dmf-rabbitmq-test/src/main/java/org/eclipse/hawkbit/rabbitmq/test/AbstractAmqpIntegrationTest.java

@@ -8,12 +8,10 @@
  */
 package org.eclipse.hawkbit.rabbitmq.test;
 
-import java.net.URI;
 import java.util.concurrent.TimeUnit;
 
 import org.eclipse.hawkbit.repository.jpa.RepositoryApplicationConfiguration;
 import org.eclipse.hawkbit.repository.test.util.AbstractIntegrationTest;
-import org.eclipse.hawkbit.util.IpUtil;
 import org.junit.Before;
 import org.junit.Rule;
 import org.springframework.amqp.core.Message;
@@ -37,8 +35,6 @@ import com.jayway.awaitility.core.ConditionFactory;
 @DirtiesContext(classMode = ClassMode.AFTER_CLASS)
 public abstract class AbstractAmqpIntegrationTest extends AbstractIntegrationTest {
 
-    protected static final URI TEST_URI = IpUtil.createAmqpUri("testHost", "testExcange");
-
     @Rule
     @Autowired
     public BrokerRunning brokerRunning;