+/*-
+ * ========================LICENSE_START=================================
+ * O-RAN-SC
+ * %%
+ * Copyright (C) 2021 Nordix Foundation
+ * %%
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ========================LICENSE_END===================================
+ */
+
+package org.oran.datafile.tasks;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+
+import lombok.ToString;
+
+import org.apache.kafka.clients.consumer.ConsumerConfig;
+import org.apache.kafka.common.serialization.StringDeserializer;
+import org.oran.datafile.configuration.AppConfig;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import reactor.core.publisher.Flux;
+import reactor.kafka.receiver.KafkaReceiver;
+import reactor.kafka.receiver.ReceiverOptions;
+
+/**
+ * The class streams incoming requests from a Kafka topic and sends them further
+ * to a multi cast sink, which several other streams can connect to.
+ */
+@SuppressWarnings("squid:S2629") // Invoke method(s) only conditionally
+public class KafkaTopicListener {
+
+ @ToString
+ public static class DataFromTopic {
+ public final String key;
+ public final String value;
+
+ public DataFromTopic(String key, String value) {
+ this.key = key;
+ this.value = value;
+ }
+ }
+
+ private static final Logger logger = LoggerFactory.getLogger(KafkaTopicListener.class);
+
+ private Flux<DataFromTopic> dataFromTopic;
+ private final AppConfig appConfig;
+
+ public KafkaTopicListener(AppConfig applConfig) {
+ this.appConfig = applConfig;
+ }
+
+ public Flux<DataFromTopic> getFlux() {
+ if (this.dataFromTopic == null) {
+ this.dataFromTopic = startReceiveFromTopic();
+ }
+ return this.dataFromTopic;
+ }
+
+ private Flux<DataFromTopic> startReceiveFromTopic() {
+ logger.debug("Listening to kafka topic: {}, client id: {}", appConfig.getInputTopic(),
+ appConfig.getKafkaClientId());
+ return KafkaReceiver.create(kafkaInputProperties()) //
+ .receive() //
+ .doOnNext(
+ input -> logger.debug("Received from kafka topic: {} :{}", appConfig.getInputTopic(), input.value())) //
+ .doOnError(t -> logger.error("KafkaTopicReceiver error: {}", t.getMessage())) //
+ .doFinally(sig -> logger.error("KafkaTopicReceiver stopped, reason: {}", sig)) //
+ .doFinally(sig -> this.dataFromTopic = null) //
+ .filter(t -> !t.value().isEmpty() || !t.key().isEmpty()) //
+ .map(input -> new DataFromTopic(input.key(), input.value())) //
+ .publish() //
+ .autoConnect();
+ }
+
+ private ReceiverOptions<String, String> kafkaInputProperties() {
+ Map<String, Object> consumerProps = new HashMap<>();
+ if (appConfig.getKafkaBootStrapServers().isEmpty()) {
+ logger.error("No kafka boostrap server is setup");
+ }
+ consumerProps.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, appConfig.getKafkaBootStrapServers());
+ consumerProps.put(ConsumerConfig.GROUP_ID_CONFIG, "osc-dmaap-adapter-" + appConfig.getInputTopic());
+ consumerProps.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
+ consumerProps.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
+ consumerProps.put(ConsumerConfig.ENABLE_AUTO_COMMIT_CONFIG, true);
+ consumerProps.put(ConsumerConfig.CLIENT_ID_CONFIG, appConfig.getKafkaClientId());
+ this.appConfig.addKafkaSecurityProps(consumerProps);
+
+ return ReceiverOptions.<String, String>create(consumerProps)
+ .subscription(Collections.singleton(appConfig.getInputTopic()));
+ }
+
+}