#2108

* add possibility to configure whether server address should be resolved by ditto in mqtt connection
* fix retry timeout strategy unable increase retry count and apply effective backoff

Signed-off-by: Vasil Vasilev <[email protected]>

Author: vvasilevbosch

connectivity/service/src/main/java/org/eclipse/ditto/connectivity/service/config/DefaultMqttConfig.java

@@ -42,6 +42,7 @@ final class DefaultMqttConfig implements MqttConfig {
     private final int maxQueueSize;
     private final int eventLoopThreads;
     private final boolean cleanSession;
+    private final boolean shouldResolveServerAddress;
     private final boolean reconnectForRedelivery;
     private final Duration reconnectForRedeliveryDelay;
     private final SessionExpiryInterval sessionExpiryInterval;
@@ -54,6 +55,7 @@ final class DefaultMqttConfig implements MqttConfig {
     private DefaultMqttConfig(final ScopedConfig config) {
         eventLoopThreads = config.getNonNegativeIntOrThrow(MqttConfigValue.EVENT_LOOP_THREADS);
         cleanSession = config.getBoolean(MqttConfigValue.CLEAN_SESSION.getConfigPath());
+        shouldResolveServerAddress = config.getBoolean(MqttConfigValue.SHOULD_RESOLVE_SERVER_ADDRESS.getConfigPath());
         reconnectForRedelivery = config.getBoolean(MqttConfigValue.RECONNECT_FOR_REDELIVERY.getConfigPath());
         reconnectForRedeliveryDelay =
                 config.getNonNegativeDurationOrThrow(MqttConfigValue.RECONNECT_FOR_REDELIVERY_DELAY);
@@ -108,6 +110,11 @@ public boolean isCleanSession() {
         return cleanSession;
     }
 
+    @Override
+    public boolean shouldResolveServerAddress() {
+        return shouldResolveServerAddress;
+    }
+
     @Override
     public boolean shouldReconnectForRedelivery() {
         return reconnectForRedelivery;

connectivity/service/src/main/java/org/eclipse/ditto/connectivity/service/config/MqttConfig.java

@@ -44,6 +44,8 @@ public interface MqttConfig {
      */
     boolean isCleanSession();
 
+    boolean shouldResolveServerAddress();
+
     /**
      * Indicates whether the client should reconnect to enforce a redelivery for a failed acknowledgement.
      *
@@ -136,6 +138,11 @@ enum MqttConfigValue implements KnownConfigValue {
          */
         CLEAN_SESSION("clean-session", false),
 
+        /**
+         * Indicates whether the provided connection uri should be resolved in-demand by ditto or on-demand.
+         */
+        SHOULD_RESOLVE_SERVER_ADDRESS("should-resolve-server-address", true),
+
         /**
          * Indicates whether the client should reconnect to enforce a redelivery for a failed acknowledgement.
          */

connectivity/service/src/main/java/org/eclipse/ditto/connectivity/service/messaging/mqtt/hivemq/MqttClientActor.java

@@ -74,9 +74,8 @@
 import com.hivemq.client.mqtt.lifecycle.MqttDisconnectSource;
 import com.typesafe.config.Config;
 
-import scala.concurrent.ExecutionContextExecutor;
-
 import io.reactivex.disposables.Disposable;
+import scala.concurrent.ExecutionContextExecutor;
 
 /**
  * Actor for handling connection to an MQTT broker for protocol versions 3 or 5.
@@ -89,6 +88,7 @@ public final class MqttClientActor extends BaseClientActor {
     private final GenericMqttClientFactory genericMqttClientFactory;
     @Nullable private GenericMqttClient genericMqttClient;
     private final AtomicBoolean automaticReconnect;
+    private final RetryTimeoutStrategy retryTimeoutStrategy;
     @Nullable private ActorRef publishingActorRef;
     private final List<ActorRef> mqttConsumerActorRefs;
     @Nullable private Disposable unsolicitedPublishesAutoAckSubscription;
@@ -105,6 +105,8 @@ private MqttClientActor(final Connection connection,
         final var connectivityConfig = connectivityConfig();
         final var connectionConfig = connectivityConfig.getConnectionConfig();
         mqttConfig = connectionConfig.getMqttConfig();
+        retryTimeoutStrategy = RetryTimeoutStrategy.newDuplicationRetryTimeoutStrategy(
+                mqttConfig.getReconnectBackOffConfig().getTimeoutConfig());
 
         mqttSpecificConfig = MqttSpecificConfig.fromConnection(connection, mqttConfig);
 
@@ -312,7 +314,6 @@ private static String getClientId(final ClientRole clientRole,
     private GenericMqttClientDisconnectedListener getClientDisconnectedListener() {
         return (context, clientRole) -> {
             final var mqttClientReconnector = context.getReconnector();
-            final var retryTimeoutStrategy = getRetryTimeoutStrategy();
 
             if (0 == mqttClientReconnector.getAttempts()) {
                 retryTimeoutStrategy.reset();
@@ -363,11 +364,6 @@ private GenericMqttClientDisconnectedListener getClientDisconnectedListener() {
         };
     }
 
-    private RetryTimeoutStrategy getRetryTimeoutStrategy() {
-        final var reconnectBackOffConfig = mqttConfig.getReconnectBackOffConfig();
-        return RetryTimeoutStrategy.newDuplicationRetryTimeoutStrategy(reconnectBackOffConfig.getTimeoutConfig());
-    }
-
     private static boolean isMqttClientInConnectingState(final MqttClientConfig mqttClientConfig) {
         return MqttClientState.CONNECTING == mqttClientConfig.getState();
     }

connectivity/service/src/main/java/org/eclipse/ditto/connectivity/service/messaging/mqtt/hivemq/client/HiveMqttClientFactory.java

@@ -115,7 +115,8 @@ private static MqttClientBuilder getGenericMqttClientBuilder(
         final var mqttConfig = hiveMqttClientProperties.getMqttConfig();
 
         return MqttClient.builder()
-                .serverAddress(getInetSocketAddress(getConnectionUri(hiveMqttClientProperties)))
+                .serverAddress(getInetSocketAddress(getConnectionUri(hiveMqttClientProperties),
+                        hiveMqttClientProperties.getMqttConfig().shouldResolveServerAddress()))
                 .executorConfig(getMqttClientExecutorConfig(mqttConfig.getEventLoopThreads()))
                 .sslConfig(getMqttClientSslConfig(hiveMqttClientProperties).orElse(null))
                 .addConnectedListener(getConnectedListener(
@@ -134,8 +135,9 @@ private static URI getConnectionUri(final HiveMqttClientProperties hiveMqttClien
         return sshTunnelState.getURI(hiveMqttClientProperties.getMqttConnection());
     }
 
-    private static InetSocketAddress getInetSocketAddress(final URI connectionUri) {
-        return new InetSocketAddress(connectionUri.getHost(), connectionUri.getPort());
+    private static InetSocketAddress getInetSocketAddress(final URI connectionUri, final boolean shouldResolveServerAddress) {
+        return shouldResolveServerAddress ? new InetSocketAddress(connectionUri.getHost(), connectionUri.getPort()) :
+                InetSocketAddress.createUnresolved(connectionUri.getHost(), connectionUri.getPort());
     }
 
     private static MqttClientExecutorConfig getMqttClientExecutorConfig(final int eventLoopThreadNumber) {

connectivity/service/src/main/resources/connectivity.conf

@@ -438,6 +438,12 @@ ditto {
         clean-session = false
         clean-session = ${?CONNECTIVITY_MQTT_CLEAN_SESSION}
 
+        # Indicates whether the provided connection uri should be resolved in-demand by ditto or on-demand.
+        #  When true, the address will be resolved before passing it to the used mqtt client.
+        #  When false, the address will be unresolved and will rely on the used mqtt client to resolve it when needed.
+        should-resolve-server-address = true
+        should-resolve-server-address = ${?CONNECTIVITY_MQTT_SHOULD_RESOLVE_SERVER_ADDRESS}
+
         # Indicates whether the client should reconnect to enforce a redelivery for a failed acknowledgement.
         reconnect-for-redelivery = false
         reconnect-for-redelivery = ${?CONNECTIVITY_MQTT_RECONNECT_FOR_REDELIVERY}

connectivity/service/src/test/java/org/eclipse/ditto/connectivity/service/messaging/mqtt/hivemq/client/HiveMqttClientFactoryTest.java

@@ -83,6 +83,7 @@ public void before() {
         Mockito.when(mqttConnection.getPassword()).thenReturn(Optional.of(PASSWORD));
 
         Mockito.when(mqttConfig.getEventLoopThreads()).thenReturn(EVENT_LOOP_THREAD_NUMBER);
+        Mockito.when(mqttConfig.shouldResolveServerAddress()).thenReturn(Boolean.TRUE);
 
         final var connectionConfig = Mockito.mock(ConnectionConfig.class);
         Mockito.when(connectionConfig.getMqttConfig()).thenReturn(mqttConfig);
@@ -396,4 +397,41 @@ public void getMqtt5ClientWithoutLastWillWithSslReturnsExpected() throws NoMqttC
                 });
     }
 
+    @Test
+    public void getMqttClientWithShouldResolveServerAddressFalseAddressShouldBeUnresolved()
+            throws NoMqttConnectionException {
+        Mockito.when(mqttConfig.shouldResolveServerAddress()).thenReturn(Boolean.FALSE);
+        final var hiveMqttClientProperties = HiveMqttClientProperties.builder()
+                .withMqttConnection(mqttConnection)
+                .withConnectivityConfig(connectivityConfig)
+                .withMqttSpecificConfig(MqttSpecificConfig.fromConnection(mqttConnection, mqttConfig))
+                .withSshTunnelStateSupplier(sshTunnelStateSupplier)
+                .withConnectionLogger(connectionLogger)
+                .withActorUuid(ACTOR_UUID)
+                .withClientConnectedListener(mqttClientConnectedListener)
+                .withClientDisconnectedListener(mqttClientDisconnectedListener)
+                .build();
+
+        final var mqtt3ClientUnderTest = HiveMqttClientFactory.getMqtt3Client(hiveMqttClientProperties,
+                MQTT_CLIENT_IDENTIFIER,
+                ClientRole.CONSUMER_PUBLISHER);
+
+        final var mqtt3ClientConfig = mqtt3ClientUnderTest.getConfig();
+        softly.assertThat(mqtt3ClientConfig.getTransportConfig())
+                .as("transport config")
+                .satisfies(transportConfig -> {
+                    softly.assertThat(transportConfig.getServerAddress().isUnresolved()).isTrue();
+                });
+
+        final var mqtt5ClientUnderTest = HiveMqttClientFactory.getMqtt3Client(hiveMqttClientProperties,
+                MQTT_CLIENT_IDENTIFIER,
+                ClientRole.CONSUMER_PUBLISHER);
+
+        final var mqtt5ClientConfig = mqtt5ClientUnderTest.getConfig();
+        softly.assertThat(mqtt5ClientConfig.getTransportConfig())
+                .as("transport config")
+                .satisfies(transportConfig -> {
+                    softly.assertThat(transportConfig.getServerAddress().isUnresolved()).isTrue();
+                });
+    }
 }