# Camel-Kafka-connector Error Handling Example

## Introduction

This shows how to use dead letter queues for sink error handling with Camel Kafka Connector.
It tries to send a message to an invalid JMS message broker. Because the message broker does
not exist, the message will be routed to the dead letter queue (DLQ).

## What is needed

- Kafka

## Running Kafka

```
$KAFKA_HOME/bin/zookeeper-server-start.sh $KAFKA_HOME/config/zookeeper.properties
$KAFKA_HOME/bin/kafka-server-start.sh $KAFKA_HOME/config/server.properties
$KAFKA_HOME/bin/kafka-topics.sh --create --bootstrap-server localhost:9092 --replication-factor 1 --partitions 1 --topic mytopic
```

## Setting up the needed bits and running the example

You'll need to setup the plugin.path property in your kafka

Open the `$KAFKA_HOME/config/connect-standalone.properties`

and set the `plugin.path` property to your choosen location

In this example we'll use `/home/oscerd/connectors/`

```
> cd /home/otavio/connectors/
> wget https://repo1.maven.org/maven2/org/apache/camel/kafkaconnector/camel-sjms2-kafka-connector/0.10.1/camel-sjms2-kafka-connector-0.10.1-package.tar.gz
> untar.gz camel-sjms2-kafka-connector-0.10.1-package.tar.gz
```

Open the SJMS2 configuration file

```
name=CamelJmsSinkConnector
topics=mytopic
tasks.max=1
connector.class=org.apache.camel.kafkaconnector.sjms2.CamelSjms2SinkConnector
key.converter=org.apache.kafka.connect.storage.StringConverter
value.converter=org.apache.kafka.connect.storage.StringConverter

camel.sink.url=sjms2://queue:myqueue

camel.component.sjms2.connection-factory=#class:org.apache.activemq.ActiveMQConnectionFactory

# Note the invalid address below
camel.component.sjms2.connection-factory.brokerURL=tcp://invalid-host.some-domain.com

# This is the topic where they will be sent on errors
errors.deadletterqueue.topic.name=example-dlq
errors.deadletterqueue.topic.replication.factor=1
```

And add the correct address for the server.

Now you can run the example

```
$KAFKA_HOME/bin/connect-standalone.sh $KAFKA_HOME/config/connect-standalone.properties config/CamelSjms2Invalid.properties
```

To read the messages from the DLQ, first open a consumer attached to it:

```
$KAFKA_HOME/bin/kafka-console-consumer.sh --bootstrap-server localhost:9092 --topic example-dlq
```

On a different terminal run the kafka-producer and send a message to your Kafka Broker.

```
bin/kafka-console-producer.sh --broker-list localhost:9092 --topic mytopic
Invalid messsage
```

On the consumer, you should receive the message that was routed to the DLQ because it could
not be delivered to the JMS broker.

```
$KAFKA_HOME/bin/kafka-console-consumer.sh --bootstrap-server localhost:9092 --topic example-dlq
Invalid messsage
```