ConfigurationException: Trigger class 'org.apache.cassandra.triggers.AuditTrigger' doesn't exist - cassandra

Question

I am creating trigger using here but it is not working at all and I am getting ConfigurationException: Trigger class 'org.apache.cassandra.triggers.AuditTrigger' doesn't exist.
Steps I followed to create trigger:
1: I have compiled my java file using
javac -cp /CassandraTriggerExample/lib/cassandra-all-3.6.jar
AuditTrigger.Java
2:Jar creation :
jar -cvf trigger-example.jar AuditTrigger.class
3: I checked content of my jar file:
"unzip -l trigger-example.jar"
4: Copied this jar file into:
cassandra_home/conf/triggers
5: Copied AuditTrigger.properties into:
cassandra_home/conf
6: Restarted cassandra server
7: ./nodetool -h localhost reloadtriggers
8: In system.log i can see the entry:
INFO [RMI TCP Connection(2)-127.0.0.1] 2018-07-22 22:15:25,827
CustomClassLoader.java:89 - Loading new jar
/Users/uname/cassandra/conf/triggers/trigger-example.jar
9: Now when i am creating my trigger using :
CREATE TRIGGER test1 ON test.test
USING 'org.apache.cassandra.triggers.AuditTrigger';
I am getting "ConfigurationException: Trigger class 'org.apache.cassandra.triggers.AuditTrigger' doesn't exist".

Answer 1

I think that the problem is that your jar isn't correctly packaged: if your class has name org.apache.cassandra.triggers.AuditTrigger, then it should be located under org/apache/cassandra/triggers/AuditTrigger.class inside jar file...
See this documentation for more details explanation how classes are found...

Answer 2

Did had a similar issue. Could be because you copied it but did not reload the trigger or created the trigger. Got it resolved by following the below checks and execution of command to re-load and create the trigger.
Check
Ensure that the class has name org.apache.cassandra.triggers.AuditTrigger and the same is located under org/apache/cassandra/triggers/AuditTrigger.class inside jar file.
CMD Command
Go to the bin folder of Cassandra installed folder to run the nodetool reloadtriggers command as below.
C:\Cassandra\apache-cassandra-3.11.6\bin>nodetool reloadtriggers
Execute the below statement at cqlsh prompt
CREATE TRIGGER test1 ON test.test USING 'org.apache.cassandra.triggers.AuditTrigger';
Your trigger should be now available!
In case if still the problem persists you can try to restart the server once to see if the same is available.
Find in the below code what I used to publish a message to Kafka consumer upon every insert to Cassandra DB as an example. You can modify the same for update. I used JDK 1.8.0_251, apache-cassandra-3.11.7, kafka_2.13-2.6.0 and Zookeeper-3.6.1.
/**
*
*/
package com.cass.kafka.insert.trigger;
import java.util.Collection;
import java.util.Collections;
import java.util.Iterator;
import java.util.Properties;
import java.util.concurrent.LinkedBlockingDeque;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
import org.apache.cassandra.config.ColumnDefinition;
import org.apache.cassandra.db.Mutation;
import org.apache.cassandra.db.partitions.Partition;
import org.apache.cassandra.db.rows.Cell;
import org.apache.cassandra.db.rows.Row;
import org.apache.cassandra.db.rows.Unfiltered;
import org.apache.cassandra.db.rows.UnfilteredRowIterator;
import org.apache.cassandra.triggers.ITrigger;
import org.apache.kafka.clients.producer.KafkaProducer;
import org.apache.kafka.clients.producer.Producer;
import org.apache.kafka.clients.producer.ProducerRecord;
/**
* #author Dinesh.Lomte
*
*/
public class InsertCassTriggerForKafkaPublish implements ITrigger {
private String topic;
private Producer<String, String> producer;
private ThreadPoolExecutor threadPoolExecutor;
/**
*
*/
public InsertCassTriggerForKafkaPublish() {
Thread.currentThread().setContextClassLoader(null);
topic = "test";
producer = new KafkaProducer<String, String>(getProps());
threadPoolExecutor = new ThreadPoolExecutor(4, 20, 30,
TimeUnit.SECONDS, new LinkedBlockingDeque<Runnable>());
}
/**
*
*/
#Override
public Collection<Mutation> augment(Partition partition) {
threadPoolExecutor.execute(() -> handleUpdate(partition));
return Collections.emptyList();
}
/**
*
* #param partition
*/
private void handleUpdate(Partition partition) {
if (!partition.partitionLevelDeletion().isLive()) {
return;
}
UnfilteredRowIterator it = partition.unfilteredIterator();
while (it.hasNext()) {
Unfiltered un = it.next();
Row row = (Row) un;
if (row.primaryKeyLivenessInfo().timestamp() != Long.MIN_VALUE) {
Iterator<Cell> cells = row.cells().iterator();
Iterator<ColumnDefinition> columns = row.columns().iterator();
while (cells.hasNext() && columns.hasNext()) {
ColumnDefinition columnDef = columns.next();
Cell cell = cells.next();
if ("payload_json".equals(columnDef.name.toString())) {
producer.send(new ProducerRecord<>(
topic, columnDef.type.getString(cell.value())));
break;
}
}
}
}
}
/**
*
* #return
*/
private Properties getProps() {
Properties properties = new Properties();
properties.put("bootstrap.servers", "localhost:9092");
properties.put("key.serializer", "org.apache.kafka.common.serialization.StringSerializer");
properties.put("value.serializer", "org.apache.kafka.common.serialization.StringSerializer");
return properties;
}
}