fix(impl): Remove useless errorStrategy configuration entry

Indeed the error strategies are activated in Kafka Streams and Kafka in general with `kafka.error.strategy` configuration.
So a dedicated configuration was defined that had no effect.

The proper fix is to deprecated that config entry, and switch the business logic so it uses `kafka.error.strategy` instead.

impl/src/main/java/io/quarkiverse/kafkastreamsprocessor/impl/decorator/processor/DlqDecorator.java

@@ -23,7 +23,6 @@
 import java.util.Set;
 
 import jakarta.annotation.Priority;
-import jakarta.decorator.Delegate;
 import jakarta.enterprise.context.Dependent;
 import jakarta.inject.Inject;
 
@@ -44,7 +43,6 @@
 import io.quarkiverse.kafkastreamsprocessor.impl.errors.ErrorHandlingStrategy;
 import io.quarkiverse.kafkastreamsprocessor.impl.metrics.KafkaStreamsProcessorMetrics;
 import io.quarkiverse.kafkastreamsprocessor.spi.SinkToTopicMappingBuilder;
-import io.quarkiverse.kafkastreamsprocessor.spi.properties.KStreamsProcessorConfig;
 import lombok.AccessLevel;
 import lombok.RequiredArgsConstructor;
 
@@ -54,7 +52,7 @@
  * Uses a dead-letter sink from the topology, rather than a raw producer, to benefit from the same KStreams guarantees
  * (at least once / exactly once).
  */
-//@Decorator
+// @Decorator
 @Priority(ProcessorDecoratorPriorities.DLQ)
 @Dependent
 public class DlqDecorator extends AbstractProcessorDecorator {
@@ -105,19 +103,16 @@ public class DlqDecorator extends AbstractProcessorDecorator {
      *        the enricher of metadata before sending message to the dead letter queue
      * @param metrics
      *        container of all metrics of the framework
-     * @param kStreamsProcessorConfig
-     *        It contains the configuration for the error strategy configuration property value (default
-     *        {@link ErrorHandlingStrategy#CONTINUE})
-     *        and the configuration Kafka topic to use for dead letter queue (optional)
+     * @param errorHandlingStrategy
+     *        tells whether DLQ is activated
      */
     @Inject
     public DlqDecorator(
             SinkToTopicMappingBuilder sinkToTopicMappingBuilder, DlqMetadataHandler dlqMetadataHandler,
             KafkaStreamsProcessorMetrics metrics,
-            KStreamsProcessorConfig kStreamsProcessorConfig) { // NOSONAR Optional with microprofile-config
+            ErrorHandlingStrategy errorHandlingStrategy) { // NOSONAR Optional with microprofile-config
         this(sinkToTopicMappingBuilder.sinkToTopicMapping().keySet(), dlqMetadataHandler, metrics,
-                ErrorHandlingStrategy.shouldSendToDlq(kStreamsProcessorConfig.errorStrategy(),
-                        kStreamsProcessorConfig.dlq().topic()));
+                errorHandlingStrategy.shouldSendToDlq());
     }
 
     /**

impl/src/main/java/io/quarkiverse/kafkastreamsprocessor/impl/errors/ErrorHandlingStrategy.java

@@ -19,11 +19,17 @@
  */
 package io.quarkiverse.kafkastreamsprocessor.impl.errors;
 
-import java.util.Optional;
+import jakarta.enterprise.context.ApplicationScoped;
+import jakarta.inject.Inject;
+
+import org.eclipse.microprofile.config.inject.ConfigProperty;
+
+import io.quarkiverse.kafkastreamsprocessor.spi.properties.KStreamsProcessorConfig;
 
 /**
  * Constants related to Kafka error handling
  */
+@ApplicationScoped
 public class ErrorHandlingStrategy {
     /**
      * Configuration property to check for the Kafka error handling strategy
@@ -45,28 +51,30 @@ public class ErrorHandlingStrategy {
      */
     public static final String FAIL = "fail";
 
+    private final String errorStrategy;
+
+    private final KStreamsProcessorConfig kStreamsProcessorConfig;
+
+    @Inject
+    public ErrorHandlingStrategy(@ConfigProperty(name = CONFIG_PROPERTY, defaultValue = CONTINUE) String errorStrategy,
+            KStreamsProcessorConfig config) {
+        this.errorStrategy = errorStrategy;
+        this.kStreamsProcessorConfig = config;
+    }
+
     /**
      * Tells whether microservice-specific DLQ is activated and has a dedicated topic
      *
-     * @param errorStrategy
-     *        the error strategy chosen by an application between <code>continue</code>, <code>dead-letter-queue</code>
-     *        and <code>fail</code>, configured with <code>kafka.error.strategy</code>
-     * @param dlqTopic
-     *        the optional topic that is mandatory if the chosen error strategy is <code>dead-letter-queue</code>
      * @return whether DLQ mechanism is activated by the configuration or not
      */
-    public static boolean shouldSendToDlq(String errorStrategy, Optional<String> dlqTopic) {
-        if (ErrorHandlingStrategy.DEAD_LETTER_QUEUE.equals(errorStrategy)) {
-            if (dlqTopic.isPresent()) {
+    public boolean shouldSendToDlq() {
+        if (DEAD_LETTER_QUEUE.equals(errorStrategy)) {
+            if (kStreamsProcessorConfig.dlq().topic().isPresent()) {
                 return true;
             } else {
                 throw new IllegalStateException("DLQ strategy enabled but dlq.topic configuration property is missing");
             }
         }
         return false;
     }
-
-    private ErrorHandlingStrategy() {
-        // Prevent instantiation of utility class
-    }
 }

impl/src/main/java/io/quarkiverse/kafkastreamsprocessor/impl/errors/LogAndSendToDlqExceptionHandlerDelegate.java

@@ -72,6 +72,8 @@ public class LogAndSendToDlqExceptionHandlerDelegate implements DeserializationE
      */
     private final KStreamsProcessorConfig kStreamsProcessorConfig;
 
+    private final ErrorHandlingStrategy errorHandlingStrategy;
+
     /** True if the dead letter queue strategy is selected and properly configured */
     boolean sendToDlq;
 
@@ -91,11 +93,13 @@ public class LogAndSendToDlqExceptionHandlerDelegate implements DeserializationE
     public LogAndSendToDlqExceptionHandlerDelegate(KafkaClientSupplier kafkaClientSupplier,
             KafkaStreamsProcessorMetrics metrics,
             DlqMetadataHandler dlqMetadataHandler,
-            KStreamsProcessorConfig kStreamsProcessorConfig) {
+            KStreamsProcessorConfig kStreamsProcessorConfig,
+            ErrorHandlingStrategy errorHandlingStrategy) {
         this.clientSupplier = kafkaClientSupplier;
         this.metrics = metrics;
         this.dlqMetadataHandler = dlqMetadataHandler;
         this.kStreamsProcessorConfig = kStreamsProcessorConfig;
+        this.errorHandlingStrategy = errorHandlingStrategy;
     }
 
     /**
@@ -147,8 +151,7 @@ private void sendToDlq(final ProcessorContext context, final ConsumerRecord<byte
     @Override
     public void configure(final Map<String, ?> configs) {
         // Resolve the DLQ strategy once to fail fast in case of misconfiguration
-        sendToDlq = ErrorHandlingStrategy.shouldSendToDlq(kStreamsProcessorConfig.errorStrategy(),
-                kStreamsProcessorConfig.dlq().topic());
+        sendToDlq = errorHandlingStrategy.shouldSendToDlq();
         if (sendToDlq) {
             Map<String, Object> dlqConfigMap = new HashMap<>(configs);
             dlqConfigMap.put(KafkaClientSupplierDecorator.DLQ_PRODUCER, true);

impl/src/test/java/io/quarkiverse/kafkastreamsprocessor/impl/errors/ErrorHandlingStrategyTest.java

@@ -19,33 +19,60 @@
  */
 package io.quarkiverse.kafkastreamsprocessor.impl.errors;
 
-import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.mockito.Mockito.when;
 
 import java.util.Optional;
 
+import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.junit.jupiter.MockitoExtension;
 
+import io.quarkiverse.kafkastreamsprocessor.spi.properties.DlqConfig;
+import io.quarkiverse.kafkastreamsprocessor.spi.properties.KStreamsProcessorConfig;
+import io.quarkus.test.Mock;
+
+@ExtendWith({ MockitoExtension.class })
 class ErrorHandlingStrategyTest {
+
+    @Mock
+    KStreamsProcessorConfig extensionConfiguration;
+
+    @Mock
+    DlqConfig dlqConfig;
+
+    @BeforeEach
+    void setUp() {
+        when(extensionConfiguration.dlq()).thenReturn(dlqConfig);
+    }
+
     @Test
     void shouldSendToDlqIfRequested() {
+        when(dlqConfig.topic()).thenReturn(Optional.of("aTopicName"));
+
         assertTrue(
-                ErrorHandlingStrategy.shouldSendToDlq(ErrorHandlingStrategy.DEAD_LETTER_QUEUE, Optional.of("aTopicName")));
+                new ErrorHandlingStrategy(ErrorHandlingStrategy.DEAD_LETTER_QUEUE, extensionConfiguration).shouldSendToDlq());
     }
 
     @Test
     void shouldThrowIfDlqRequestedButNoTopic() {
         Optional<String> noTopic = Optional.empty();
+        when(dlqConfig.topic()).thenReturn(noTopic);
+
         assertThrows(IllegalStateException.class,
-                () -> ErrorHandlingStrategy.shouldSendToDlq(ErrorHandlingStrategy.DEAD_LETTER_QUEUE, noTopic));
+                () -> new ErrorHandlingStrategy(ErrorHandlingStrategy.DEAD_LETTER_QUEUE, extensionConfiguration)
+                        .shouldSendToDlq());
     }
 
     @Test
     void shouldNotSendToDlqWithOtherStrategy() {
-        assertFalse(
-                ErrorHandlingStrategy.shouldSendToDlq(ErrorHandlingStrategy.FAIL, Optional.of("aTopicName")));
-        assertFalse(
-                ErrorHandlingStrategy.shouldSendToDlq(ErrorHandlingStrategy.CONTINUE, Optional.of("aTopicName")));
+        when(dlqConfig.topic()).thenReturn(Optional.of("aTopicName"));
+
+        assertTrue(
+            new ErrorHandlingStrategy(ErrorHandlingStrategy.FAIL, extensionConfiguration).shouldSendToDlq());
+        assertTrue(
+            new ErrorHandlingStrategy(ErrorHandlingStrategy.CONTINUE, extensionConfiguration).shouldSendToDlq());
     }
 }

impl/src/test/java/io/quarkiverse/kafkastreamsprocessor/impl/errors/LogAndSendToDlqExceptionHandlerDelegateTest.java

@@ -22,7 +22,6 @@
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.closeTo;
 import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.ArgumentMatchers.anyInt;
 import static org.mockito.ArgumentMatchers.anyString;
@@ -70,6 +69,9 @@ class LogAndSendToDlqExceptionHandlerDelegateTest {
     @Mock
     private DlqConfig dlqConfig;
 
+    @Mock
+    private ErrorHandlingStrategy errorHandlingStrategy;
+
     @Mock
     private ProcessorContext context;
 
@@ -109,14 +111,14 @@ void shouldNotBlockAndSendToDlqIfPossible() {
     when(record.partition()).thenReturn(PARTITION);
     when(record.headers()).thenReturn(headers);
     when(dlqConfig.topic()).thenReturn(Optional.of(DLQ_TOPIC));
-    when(kStreamsProcessorConfig.errorStrategy()).thenReturn(ErrorHandlingStrategy.DEAD_LETTER_QUEUE);
+    when(errorHandlingStrategy.shouldSendToDlq()).thenReturn(true);
     RecordHeaders headersWithMetadata = new RecordHeaders();
     when(metadataHandler.withMetadata(any(Headers.class), anyString(), anyInt(), any(Exception.class)))
         .thenReturn(headersWithMetadata);
     when(kafkaClientSupplier.getProducer(any())).thenReturn(dlqProducerMock);
 
     handler = new LogAndSendToDlqExceptionHandlerDelegate(kafkaClientSupplier, metrics, metadataHandler,
-      kStreamsProcessorConfig);
+      kStreamsProcessorConfig, errorHandlingStrategy);
     handler.configure(Collections.emptyMap());
 
     DeserializationHandlerResponse response = handler.handle(context, record, exception);
@@ -131,12 +133,12 @@ void shouldNotBlockAndSendToDlqIfPossible() {
 
     @Test
     void shouldOnlyContinueIfDefaultErrorStrategy() {
-        when(kStreamsProcessorConfig.errorStrategy()).thenReturn("continue");
+      when(errorHandlingStrategy.shouldSendToDlq()).thenReturn(false);
         when(dlqConfig.topic()).thenReturn(Optional.of(DLQ_TOPIC));
         when(kStreamsProcessorConfig.dlq()).thenReturn(dlqConfig);
         when(dlqConfig.topic()).thenReturn(Optional.of(DLQ_TOPIC));
         handler = new LogAndSendToDlqExceptionHandlerDelegate(kafkaClientSupplier, metrics, metadataHandler,
-          kStreamsProcessorConfig);
+          kStreamsProcessorConfig, errorHandlingStrategy);
         handler.configure(Collections.emptyMap());
 
         DeserializationHandlerResponse response = handler.handle(context, record, exception);
@@ -146,14 +148,4 @@ void shouldOnlyContinueIfDefaultErrorStrategy() {
         assertThat(metrics.processorErrorCounter().count(), closeTo(1d, 0.01d));
     }
 
-    @Test
-    void shouldFailFastIfDlqStrategyWithoutTopic() {
-        when(dlqConfig.topic()).thenReturn(Optional.empty());
-        when(kStreamsProcessorConfig.dlq()).thenReturn(dlqConfig);
-        when(kStreamsProcessorConfig.errorStrategy()).thenReturn(ErrorHandlingStrategy.DEAD_LETTER_QUEUE);
-        handler = new LogAndSendToDlqExceptionHandlerDelegate(kafkaClientSupplier, metrics, metadataHandler,
-          kStreamsProcessorConfig);
-
-        assertThrows(IllegalStateException.class, () -> handler.configure(Collections.emptyMap()));
-    }
 }

spi/src/main/java/io/quarkiverse/kafkastreamsprocessor/spi/properties/KStreamsProcessorConfig.java

@@ -47,8 +47,12 @@ public interface KStreamsProcessorConfig {
 
     /**
      * Kafka error handling strategy
+     *
+     * @deprecated Has actually no effect whatsoever, as it is rather the kafka config entry
+     * <code>kafka.error.strategy</code> that activates in KafkaStreams the DLQ mechanism.
      */
     @WithDefault("continue")
+    @Deprecated(forRemoval = true, since = "3.0.2")
     String errorStrategy();
 
     /**