Read configuration topic from beginning

theodolite-benchmarks/uc4-flink/src/main/java/theodolite/uc4/application/AggregationServiceFlinkJob.java

@@ -15,6 +15,7 @@ import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
 import org.apache.flink.streaming.api.windowing.assigners.TumblingEventTimeWindows;
 import org.apache.flink.streaming.api.windowing.time.Time;
 import org.apache.flink.streaming.connectors.kafka.FlinkKafkaConsumer;
+import org.apache.flink.streaming.connectors.kafka.FlinkKafkaConsumerBase;
 import org.apache.flink.streaming.connectors.kafka.FlinkKafkaProducer;
 import org.apache.kafka.common.serialization.Serdes;
 import org.slf4j.Logger;
@@ -103,9 +104,11 @@ public final class AggregationServiceFlinkJob {
     this.env.getConfig().registerTypeWithKryoSerializer(Set.of(1, 2, 3, 4).getClass(), // NOCS
         new ImmutableSetSerializer());
 
-    this.env.getConfig().getRegisteredTypesWithKryoSerializers()
-        .forEach((c, s) -> LOGGER.info("Class " + c.getName() + " registered with serializer "
-            + s.getSerializer().getClass().getName()));
+    this.env
+        .getConfig()
+        .getRegisteredTypesWithKryoSerializers()
+        .forEach((c, s) -> LOGGER.info("Class '{}' registered with serializer '{}'.", c.getName(),
+            s.getSerializer().getClass().getName()));
   }
 
   private void buildPipeline() {
@@ -134,12 +137,13 @@ public final class AggregationServiceFlinkJob {
     final FlinkKafkaConsumer<AggregatedActivePowerRecord> kafkaOutputSource =
         kafkaConnector.createConsumer(outputTopic, AggregatedActivePowerRecord.class);
 
-    final FlinkKafkaConsumer<Tuple2<Event, String>> kafkaConfigSource =
+    final FlinkKafkaConsumerBase<Tuple2<Event, String>> kafkaConfigSource =
         kafkaConnector.createConsumer(
             configurationTopic,
             EventSerde::serde,
             Serdes::String,
-            TupleType.of(TypeInformation.of(Event.class), Types.STRING));
+            TupleType.of(TypeInformation.of(Event.class), Types.STRING))
+            .setStartFromEarliest();
 
     // Sink to output topic with SensorId, AggregatedActivePowerRecord
     final FlinkKafkaProducer<Tuple2<String, AggregatedActivePowerRecord>> kafkaAggregationSink =