Running the Sample Project

The following describes how to access DMS Kafka queues to produce and consume messages in Java.

Procedure

Log in to the ECS.

You can run the sample project on an ECS with an IP address in the 192 network segment.
Install JDK or Java runtime environment (JRE). Add the following settings of environment variables JAVA_HOME and PATH to the ~/.bash_profile:
```
export JAVA_HOME=/opt/java/jdk1.8.0_151
export PATH=$JAVA_HOME/bin:$PATH
```
Run the source .bash_profile command for the modification to take effect.

Use Oracle JDK instead of ECS's default JDK (for example, OpenJDK), because ECS's default JDK may not be suitable for the sample project. To obtain Oracle JDK, download Java Development Kit 1.8.111 or a later version from https://www.oracle.com/technetwork/java/javase/downloads/index.html.
Run the following command to download the code package of the sample project DmsKafkaDemo.zip.
```
$ wget https://dms-demo.obs.cn-north-1.myhuaweicloud.com/DmsKafkaDemo.zip
```
Run the following command to decompress DmsKafkaDemo.zip.
```
$ unzip DmsKafkaDemo.zip
```
Run the following command to navigate to the DmsKafkaDemo/dist directory, which contains pre-compiled binary files and executable scripts.
```
$ cd DmsKafkaDemo/dist
```

Edit the config/dms_kafka_client_jaas.conf file and configure access_key, secret_key, and project_id.

$ vim config/dms_kafka_client_jaas.conf

The values in bold are examples. Replace them with actual values.

KafkaClient {
  com.huawei.middleware.kafka.sasl.client.KafkaLoginModule required
  access_key="********************"
  secret_key="**********"
  project_id="bd67aaead60940d688b872c31bdc653b"
  target_project_id="bd67aaead60940d688b872c31bdc6539";
};

To access the queues authorized by other tenants, set target_project_id to the project ID of the authorizing tenant.

Edit the config/producer.properties file and configure topic and bootstrap.servers.

$ vim config/producer.properties

The values in bold are examples. Replace them with actual values.

topic=k-bd67aaead60940d688b872c31bdc653b-4df89da6-ede4-4072-93e0-28dc6e866299 
bootstrap.servers=dms-kafka.cn-north-1.myhuaweicloud.com:37000
ssl.truststore.password=************
acks=all
retries=1
batch.size=16384
buffer.memory=33554432
key.serializer=org.apache.kafka.common.serialization.StringSerializer
value.serializer=org.apache.kafka.common.serialization.StringSerializer
security.protocol=SASL_SSL
sasl.mechanism=DMS

The parameter topic can be set to a queue name or a Kafka topic name. For more information, see Table 2.

Edit the config/consumer.properties file and configure topic, bootstrap.servers, and group.id.

$ vim config/consumer.properties

The values in bold are examples. Replace them with actual values.

topic=k-bd67aaead60940d688b872c31bdc653b-4df89da6-ede4-4072-93e0-28dc6e866299
bootstrap.servers=dms-kafka.cn-north-1.myhuaweicloud.com:37000
group.id=g-7ec0caac-01fb-4f91-a4f2-0a9dd48f8af7
ssl.truststore.password=************
security.protocol=SASL_SSL
sasl.mechanism=DMS
key.deserializer=org.apache.kafka.common.serialization.StringDeserializer
value.deserializer=org.apache.kafka.common.serialization.StringDeserializer
auto.offset.reset=earliest
enable.auto.commit=false

The parameter topic can be set to a queue name or a Kafka topic name. For more information, see Table 2.

Run the sample project to produce messages:
```
$ bash produce.sh
```
After the command is run, 10 messages are automatically sent to the Kafka queue.
Run the sample project to consume messages:
```
$ bash consume.sh
```