Improvements/kafka rule node (#2505)

* added metadata key-values as kafka headers

* added default charset to configuration

* fix typo

@@ -16,16 +16,21 @@
 package org.thingsboard.rule.engine.kafka;
 
 import lombok.extern.slf4j.Slf4j;
+import org.apache.commons.lang3.BooleanUtils;
 import org.apache.kafka.clients.producer.*;
+import org.apache.kafka.common.header.Headers;
+import org.apache.kafka.common.header.internals.RecordHeader;
+import org.apache.kafka.common.header.internals.RecordHeaders;
 import org.thingsboard.rule.engine.api.util.TbNodeUtils;
 import org.thingsboard.rule.engine.api.*;
 import org.thingsboard.server.common.data.plugin.ComponentType;
 import org.thingsboard.server.common.msg.TbMsg;
 import org.thingsboard.server.common.msg.TbMsgMetaData;
 
+import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
 import java.util.Properties;
 import java.util.concurrent.ExecutionException;
-import java.util.concurrent.atomic.AtomicInteger;
 
 @Slf4j
 @RuleNode(
@@ -46,8 +51,11 @@ public class TbKafkaNode implements TbNode {
     private static final String PARTITION = "partition";
     private static final String TOPIC = "topic";
     private static final String ERROR = "error";
+    public static final String TB_MSG_MD_PREFIX = "tb_msg_md_";
 
     private TbKafkaNodeConfiguration config;
+    private boolean addMetadataKeyValuesAsKafkaHeaders;
+    private Charset toBytesCharset;
 
     private Producer<?, String> producer;
 
@@ -66,8 +74,10 @@ public class TbKafkaNode implements TbNode {
         properties.put(ProducerConfig.BUFFER_MEMORY_CONFIG, config.getBufferMemory());
         if (config.getOtherProperties() != null) {
             config.getOtherProperties()
-                    .forEach((k,v) -> properties.put(k, v));
+                    .forEach(properties::put);
         }
+        addMetadataKeyValuesAsKafkaHeaders = BooleanUtils.toBooleanDefaultIfNull(config.isAddMetadataKeyValuesAsKafkaHeaders(), false);
+        toBytesCharset = config.getKafkaHeadersCharset() != null ? Charset.forName(config.getKafkaHeadersCharset()) : StandardCharsets.UTF_8;
         try {
             this.producer = new KafkaProducer<>(properties);
         } catch (Exception e) {
@@ -79,16 +89,16 @@ public class TbKafkaNode implements TbNode {
     public void onMsg(TbContext ctx, TbMsg msg) throws ExecutionException, InterruptedException, TbNodeException {
         String topic = TbNodeUtils.processPattern(config.getTopicPattern(), msg.getMetaData());
         try {
-            producer.send(new ProducerRecord<>(topic, msg.getData()),
-                    (metadata, e) -> {
-                        if (metadata != null) {
-                            TbMsg next = processResponse(ctx, msg, metadata);
-                            ctx.tellNext(next, TbRelationTypes.SUCCESS);
-                        } else {
-                            TbMsg next = processException(ctx, msg, e);
-                            ctx.tellFailure(next, e);
-                        }
-                    });
+            if (!addMetadataKeyValuesAsKafkaHeaders) {
+                producer.send(new ProducerRecord<>(topic, msg.getData()),
+                        (metadata, e) -> processRecord(ctx, msg, metadata, e));
+            } else {
+                Headers headers = new RecordHeaders();
+                msg.getMetaData().values().forEach((key, value) -> headers.add(new RecordHeader(TB_MSG_MD_PREFIX + key, value.getBytes(toBytesCharset))));
+                producer.send(new ProducerRecord<>(topic, null, null, null, msg.getData(), headers),
+                        (metadata, e) -> processRecord(ctx, msg, metadata, e));
+            }
+
         } catch (Exception e) {
             ctx.tellFailure(msg, e);
         }
@@ -105,6 +115,16 @@ public class TbKafkaNode implements TbNode {
         }
     }
 
+    private void processRecord(TbContext ctx, TbMsg msg, RecordMetadata metadata, Exception e) {
+        if (metadata != null) {
+            TbMsg next = processResponse(ctx, msg, metadata);
+            ctx.tellNext(next, TbRelationTypes.SUCCESS);
+        } else {
+            TbMsg next = processException(ctx, msg, e);
+            ctx.tellFailure(next, e);
+        }
+    }
+
     private TbMsg processResponse(TbContext ctx, TbMsg origMsg, RecordMetadata recordMetadata) {
         TbMsgMetaData metaData = origMsg.getMetaData().copy();
         metaData.putValue(OFFSET, String.valueOf(recordMetadata.offset()));

@@ -36,6 +36,9 @@ public class TbKafkaNodeConfiguration implements NodeConfiguration<TbKafkaNodeCo
     private String valueSerializer;
     private Map<String, String> otherProperties;
 
+    private boolean addMetadataKeyValuesAsKafkaHeaders;
+    private String kafkaHeadersCharset;
+
     @Override
     public TbKafkaNodeConfiguration defaultConfiguration() {
         TbKafkaNodeConfiguration configuration = new TbKafkaNodeConfiguration();
@@ -49,6 +52,8 @@ public class TbKafkaNodeConfiguration implements NodeConfiguration<TbKafkaNodeCo
         configuration.setKeySerializer(StringSerializer.class.getName());
         configuration.setValueSerializer(StringSerializer.class.getName());
         configuration.setOtherProperties(Collections.emptyMap());
+        configuration.setAddMetadataKeyValuesAsKafkaHeaders(false);
+        configuration.setKafkaHeadersCharset("UTF-8");
         return configuration;
     }
 }