[SDC] Add kafka native messaging

Change-Id: I5ab8f580947cbc264d94bec48a5e8b659dc44c08
Issue-ID: DMAAP-1787
Signed-off-by: david.mcweeney <david.mcweeney@est.tech>

1 files changed, 117 insertions, 0 deletions

diff --git a/catalog-be/src/main/java/org/openecomp/sdc/be/components/kafka/SdcKafkaConsumer.java b/catalog-be/src/main/java/org/openecomp/sdc/be/components/kafka/SdcKafkaConsumer.java
new file mode 100644
index 0000000000..8879bf000e
--- /dev/null
+++ b/catalog-be/src/main/java/org/openecomp/sdc/be/components/kafka/SdcKafkaConsumer.java
@@ -0,0 +1,117 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * SDC
+ * ================================================================================
+ * Copyright (C) 2022 Nordix Foundation. All rights reserved.
+ * ================================================================================
+ * 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.openecomp.sdc.be.components.kafka;
+
+import com.google.common.annotations.VisibleForTesting;
+import java.time.Duration;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Properties;
+import java.util.UUID;
+import org.apache.kafka.clients.CommonClientConfigs;
+import org.apache.kafka.clients.consumer.ConsumerConfig;
+import org.apache.kafka.clients.consumer.ConsumerRecord;
+import org.apache.kafka.clients.consumer.ConsumerRecords;
+import org.apache.kafka.clients.consumer.KafkaConsumer;
+import org.apache.kafka.common.KafkaException;
+import org.apache.kafka.common.config.SaslConfigs;
+import org.openecomp.sdc.be.config.DistributionEngineConfiguration;
+import org.openecomp.sdc.common.log.wrappers.Logger;
+
+/**
+ * Utility class that provides a KafkaConsumer to communicate with a kafka cluster
+ */
+public class SdcKafkaConsumer {
+
+    private static final Logger log = Logger.getLogger(SdcKafkaConsumer.class.getName());
+    private final DistributionEngineConfiguration deConfiguration;
+    private KafkaConsumer<String, String> kafkaConsumer;
+
+    /**
+     * Constructor setting up the KafkaConsumer from a predefined set of configurations
+     */
+    public SdcKafkaConsumer(DistributionEngineConfiguration deConfiguration){
+        log.info("Create SdcKafkaConsumer via constructor");
+        Properties properties = new Properties();
+        this.deConfiguration = deConfiguration;
+
+        properties.put(ConsumerConfig.CLIENT_ID_CONFIG, deConfiguration.getDistributionStatusTopic().getConsumerId()+ "-consumer-" + UUID.randomUUID());
+        properties.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, "org.apache.kafka.common.serialization.StringDeserializer");
+        properties.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG,  "org.apache.kafka.common.serialization.StringDeserializer");
+        properties.put(ConsumerConfig.GROUP_ID_CONFIG, deConfiguration.getDistributionStatusTopic().getConsumerGroup());
+        properties.put(CommonClientConfigs.BOOTSTRAP_SERVERS_CONFIG, deConfiguration.getKafkaBootStrapServers());
+        properties.put(CommonClientConfigs.SECURITY_PROTOCOL_CONFIG, "SASL_PLAINTEXT");
+        properties.put(ConsumerConfig.ALLOW_AUTO_CREATE_TOPICS_CONFIG, false);
+        properties.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, "latest");
+        properties.put(SaslConfigs.SASL_MECHANISM, "SCRAM-SHA-512");
+
+        properties.put(SaslConfigs.SASL_JAAS_CONFIG, getKafkaSaslJaasConfig());
+        kafkaConsumer = new KafkaConsumer<>(properties);
+    }
+
+    /**
+     *
+     * @param kafkaConsumer a kafkaConsumer to use within the class
+     * @param deConfiguration - Configuration to pass into the class
+     */
+    @VisibleForTesting
+    SdcKafkaConsumer(KafkaConsumer kafkaConsumer, DistributionEngineConfiguration deConfiguration){
+        this.deConfiguration = deConfiguration;
+        this.kafkaConsumer = kafkaConsumer;
+    }
+
+    /**
+     *
+     * @return the Sasl Jass Config
+     */
+    private String getKafkaSaslJaasConfig() {
+        String saslJaasConfFromEnv = System.getenv("SASL_JAAS_CONFIG");
+        if(saslJaasConfFromEnv != null) {
+            return saslJaasConfFromEnv;
+        } else {
+            throw new KafkaException("sasl.jaas.config not set for Kafka Consumer");
+        }
+    }
+
+    /**
+     *
+     * @param topic Topic in which to subscribe
+     */
+    public void subscribe(String topic) throws KafkaException {
+        if (!kafkaConsumer.subscription().contains(topic)) {
+            kafkaConsumer.subscribe(Collections.singleton(topic));
+        }
+    }
+
+    /**
+     *
+     * @return The list of messages for a specified topic, returned from the poll
+     */
+    public List<String> poll(String topicName) throws KafkaException {
+        log.info("SdcKafkaConsumer - polling for messages from Topic: {}", topicName);
+        List<String> msgs = new ArrayList<>();
+        ConsumerRecords<String, String> consumerRecordsForSpecificTopic = kafkaConsumer.poll(Duration.ofSeconds(deConfiguration.getDistributionStatusTopic().getPollingIntervalSec()));
+        for(ConsumerRecord<String, String> rec : consumerRecordsForSpecificTopic){
+            msgs.add(rec.value());
+        }
+        return msgs;
+    }
+}