calculate keepalive timeout dynamically with formula

modules/hivemq-edge-module-opcua/src/main/java/com/hivemq/edge/adapters/opcua/listeners/OpcUaSubscriptionLifecycleHandler.java

@@ -54,20 +54,19 @@
 
 public class OpcUaSubscriptionLifecycleHandler implements OpcUaSubscription.SubscriptionListener {
 
-    private static final Logger log = LoggerFactory.getLogger(OpcUaSubscriptionLifecycleHandler.class);
-    private static final long KEEP_ALIVE_TIMEOUT_MS = 30_000; // 30 seconds
+    private static final @NotNull Logger log = LoggerFactory.getLogger(OpcUaSubscriptionLifecycleHandler.class);
     private static final int MAX_MONITORED_ITEM_COUNT = 5;
 
     private final @NotNull ProtocolAdapterMetricsService protocolAdapterMetricsService;
     private final @NotNull ProtocolAdapterTagStreamingService tagStreamingService;
     private final @NotNull EventService eventService;
     private final @NotNull String adapterId;
-    final Map<OpcuaTag, Boolean> tagToFirstSeen = new ConcurrentHashMap<>();
+    private final @NotNull Map<OpcuaTag, Boolean> tagToFirstSeen;
     private final @NotNull Map<NodeId, OpcuaTag> nodeIdToTag;
     private final @NotNull List<OpcuaTag> tags;
     private final @NotNull OpcUaClient client;
     private final @NotNull DataPointFactory dataPointFactory;
-    final @NotNull OpcUaSpecificAdapterConfig config;
+    private final @NotNull OpcUaSpecificAdapterConfig config;
 
     // Track last keep-alive timestamp for health monitoring
     private volatile long lastKeepAliveTimestamp;
@@ -89,8 +88,9 @@ public OpcUaSubscriptionLifecycleHandler(
         this.client = client;
         this.dataPointFactory = dataPointFactory;
         this.tags = tags;
+        this.tagToFirstSeen = new ConcurrentHashMap<>();
         this.lastKeepAliveTimestamp = System.currentTimeMillis();
-        nodeIdToTag = tags.stream()
+        this.nodeIdToTag = tags.stream()
                 .collect(Collectors.toMap(tag -> NodeId.parse(tag.getDefinition().getNode()), Function.identity()));
     }
 
@@ -226,20 +226,33 @@ public void onKeepAliveReceived(final @NotNull OpcUaSubscription subscription) {
         lastKeepAliveTimestamp = System.currentTimeMillis();
         protocolAdapterMetricsService.increment(Constants.METRIC_SUBSCRIPTION_KEEPALIVE_COUNT);
 
-        subscription.getSubscriptionId().ifPresent(subscriptionId -> {
-            log.debug("Keep-alive received for subscription {} of adapter '{}'", subscriptionId, adapterId);
-        });
+        subscription.getSubscriptionId().ifPresent(subscriptionId ->
+                log.debug("Keep-alive received for subscription {} of adapter '{}'", subscriptionId, adapterId));
     }
 
     /**
      * Checks if keep-alive messages are being received within the expected timeout.
+     * The timeout is computed dynamically from ConnectionOptions.
      * Can be used for health monitoring to detect subscription issues.
      *
-     * @return true if last keep-alive was received within KEEP_ALIVE_TIMEOUT_MS, false otherwise
+     * @return true if last keep-alive was received within the computed timeout, false otherwise
      */
     public boolean isKeepAliveHealthy() {
         final long timeSinceLastKeepAlive = System.currentTimeMillis() - lastKeepAliveTimestamp;
-        return timeSinceLastKeepAlive < KEEP_ALIVE_TIMEOUT_MS;
+        return timeSinceLastKeepAlive < getKeepAliveTimeoutMs();
+    }
+
+    /**
+     * Computes the keep-alive timeout based on ConnectionOptions.
+     * The timeout allows for the configured number of missed keep-alives plus one
+     * before considering the connection unhealthy, plus a safety margin.
+     * Formula: keepAliveIntervalMs × (keepAliveFailuresAllowed + 1) + SAFETY_MARGIN_MS
+     *
+     * @return the computed keep-alive timeout in milliseconds
+     */
+    public long getKeepAliveTimeoutMs() {
+        final var connOpts = config.getConnectionOptions();
+        return connOpts.keepAliveIntervalMs() * (connOpts.keepAliveFailuresAllowed() + 1) + 5_000L;
     }
 
     @Override
@@ -259,9 +272,7 @@ public void onTransferFailed(
                             replacementSubscription.setSubscriptionListener(this);
                             syncTagsAndMonitoredItems(replacementSubscription, tags, config);
                         },
-                        () -> {
-                            log.error("Subscription Transfer failed, unable to create new subscription '{}'", adapterId);
-                        }
+                        () -> log.error("Subscription Transfer failed, unable to create new subscription '{}'", adapterId)
                 );
     }