fix: handle empty MQ messages (#135)

With this commit, the Connector will create tombstone (null value)
Kafka records to represent empty MQ messages.

Contributes to: #134

Signed-off-by: Dale Lane <dale.lane@uk.ibm.com>

Author: dalelane

.github/ISSUE_TEMPLATE/BUG-REPORT.yml

@@ -57,8 +57,8 @@ body:
       label: Version
       description: What version of our software are you running?
       options:
-        - 1.3.4 (Default)
-        - older (<1.3.4)
+        - 1.3.5 (Default)
+        - older (<1.3.5)
     validations:
       required: true
   - type: textarea

pom.xml

@@ -21,7 +21,7 @@
     <groupId>com.ibm.eventstreams.connect</groupId>
     <artifactId>kafka-connect-mq-source</artifactId>
     <packaging>jar</packaging>
-    <version>1.3.4</version>
+    <version>1.3.5</version>
     <name>kafka-connect-mq-source</name>
     <organization>
         <name>IBM Corporation</name>

src/integration/java/com/ibm/eventstreams/connect/mqsource/MQSourceTaskIT.java

@@ -426,4 +426,52 @@ public void verifyDestinationAsKey() throws Exception {
 
         connectTask.commitRecord(kafkaMessage);
     }
+
+
+    @Test
+    public void verifyEmptyMessage() throws Exception {
+        connectTask = new MQSourceTask();
+
+        final Map<String, String> connectorConfigProps = createDefaultConnectorProperties();
+        connectorConfigProps.put("mq.message.body.jms", "true");
+        connectorConfigProps.put("mq.record.builder",
+                "com.ibm.eventstreams.connect.mqsource.builders.DefaultRecordBuilder");
+
+        connectTask.start(connectorConfigProps);
+
+        Message emptyMessage = getJmsContext().createMessage();
+        putAllMessagesToQueue(MQ_QUEUE, Arrays.asList(emptyMessage));
+
+        final List<SourceRecord> kafkaMessages = connectTask.poll();
+        assertEquals(1, kafkaMessages.size());
+
+        final SourceRecord kafkaMessage = kafkaMessages.get(0);
+        assertNull(kafkaMessage.value());
+
+        connectTask.commitRecord(kafkaMessage);
+    }
+
+
+    @Test
+    public void verifyEmptyTextMessage() throws Exception {
+        connectTask = new MQSourceTask();
+
+        final Map<String, String> connectorConfigProps = createDefaultConnectorProperties();
+        connectorConfigProps.put("mq.message.body.jms", "true");
+        connectorConfigProps.put("mq.record.builder",
+                "com.ibm.eventstreams.connect.mqsource.builders.DefaultRecordBuilder");
+
+        connectTask.start(connectorConfigProps);
+
+        TextMessage emptyMessage = getJmsContext().createTextMessage();
+        putAllMessagesToQueue(MQ_QUEUE, Arrays.asList(emptyMessage));
+
+        final List<SourceRecord> kafkaMessages = connectTask.poll();
+        assertEquals(1, kafkaMessages.size());
+
+        final SourceRecord kafkaMessage = kafkaMessages.get(0);
+        assertNull(kafkaMessage.value());
+
+        connectTask.commitRecord(kafkaMessage);
+    }
 }

src/main/java/com/ibm/eventstreams/connect/mqsource/MQSourceConnector.java

@@ -141,7 +141,7 @@ public class MQSourceConnector extends SourceConnector {
     public static final String CONFIG_DOCUMENTATION_TOPIC = "The name of the target Kafka topic.";
     public static final String CONFIG_DISPLAY_TOPIC = "Target Kafka topic";
 
-    public static String version = "1.3.4";
+    public static String version = "1.3.5";
 
     private Map<String, String> configProps;
 

src/main/java/com/ibm/eventstreams/connect/mqsource/builders/DefaultRecordBuilder.java

@@ -70,6 +70,9 @@ public DefaultRecordBuilder() {
             } else if (message instanceof TextMessage) {
                 log.debug("Text message with no schema");
                 value = message.getBody(String.class);
+            } else if (message.getBody(Object.class) == null) {
+                log.debug("Empty message");
+                value = null;
             } else {
                 log.error("Unsupported JMS message type {}", message.getClass());
                 throw new ConnectException("Unsupported JMS message type");