How to write to Manage Cassandra Service using Flink Cassandra Connector?

Question

I am able to connect to AWS Managed Cassandra Service, using the below code snippet.

CassandraSink.addSink(cassandraEntityStream)
    .setClusterBuilder(
        new ClusterBuilder() {

            private static final long serialVersionUID = 2793938419775311824L;

            @Override
            public Cluster buildCluster(Cluster.Builder builder) {
                return builder
                    .addContactPoint("cassandra.ap-northeast-1.amazonaws.com")
                    .withPort(9142)
                    .withSSL()
                    .withCredentials(
                        "username",
                        "password")
                    .withLoadBalancingPolicy(
                        DCAwareRoundRobinPolicy
                            .builder()
                            .withLocalDc("ap-northeast-1")
                            .build())
                    //.withQueryOptions(option)
                    .build();
            }
        })
    .setMapperOptions(() -> new Mapper.Option[] {Mapper.Option.saveNullFields(true)})
    .build()
    .name("Write to Cassandra")
    .uid("cassandra_sink");

I was getting the below exception while writing Stream POJO to Cassandra.

com.datastax.driver.core.exceptions.InvalidQueryException: Consistency level LOCAL_ONE is not supported for this operation. Supported consistency levels are: LOCAL_QUORUM

I was able to solve this issue in another project(without using flink), by setting ConsistencyLevel = LOCAL_QUORUM, using the below snippet.

QueryOptions option = new QueryOptions();
option.setConsistencyLevel(ConsistencyLevel.LOCAL_QUORUM);

final Cluster cluster =
    Cluster.builder()
        .addContactPoint("cassandra.ap-northeast-1.amazonaws.com")
        .withPort(9142)
        .withSSL()
        .withQueryOptions(option) // NOTE
        .withAuthProvider(
            new PlainTextAuthProvider(
                "username",
                "password"))
        .withLoadBalancingPolicy(
            DCAwareRoundRobinPolicy.builder().withLocalDc("ap-northeast-1").build())
        .build();
final Session session = cluster.connect("test");

When I tried the same in flink, I am getting the below error:

Exception in thread "main" org.apache.flink.api.common.InvalidProgramException: com.datastax.driver.core.QueryOptions@130161f7 is not serializable. The object probably contains or references non serializable fields.

Is there anything, I am missing out? Kindly elaborate on how to connect/write to MCS using Flink Cassandra connector.

PS:

I have used the below command for creating keyspace.

    CREATE KEYSPACE "test"
    WITH
        REPLICATION = {'class': 'SingleRegionStrategy'}

I didn't use AmazonRootCA1.pem in my code.
I am not using cassandra_truststore.jks in my code or environment.
I had Installed Certificate temp_file.der certificate, which was created by following these steps.
I am using Flink 1.8.2, since that is the environment version available in Kinesis Data Analytics.

UPDATE 07-04-2020

I am able to fix the serialization issue by creating a Serializable wrapper for QueryOptions. Please find the code snippet below:

import com.datastax.driver.core.QueryOptions;
import java.io.Serializable;

public class QueryOptionsSerializable extends QueryOptions implements Serializable {

  private static final long serialVersionUID = 2793938419775311824L;
}

With this solution, I was able to set the consistency level to LOCAL_QUORUM in the code and run without any exceptions.

    // Setting consistency level
    QueryOptionsSerializable option = new QueryOptionsSerializable();
    option.setConsistencyLevel(ConsistencyLevel.LOCAL_QUORUM);


    CassandraSink.addSink(entityStream)
        .setClusterBuilder(
            new ClusterBuilder() {

              private static final long serialVersionUID = 2793938419775311824L;

              @Override
              public Cluster buildCluster(Cluster.Builder builder) {
                Cluster.Builder tempBuilder = builder.addContactPoint(host).withPort(port);

                if (isSSLEnabled) {
                  // enable SSL config if isSSLEnabled flag is ON.
                  tempBuilder.withSSL();
                }

                if (username != null && password != null) {
                  // if username & password is provided, use it for connection.
                  tempBuilder.withCredentials(username, password);
                }

                tempBuilder.withQueryOptions(option);

                return tempBuilder.build();
              }
            })
        .setMapperOptions(() -> new Mapper.Option[] {Mapper.Option.saveNullFields(true)})
        .setDefaultKeyspace(keyspace)
        .build()
        .name("Write to Cassandra")
        .uid("cassandra_sink");

But while writing to MCS, I am getting the same error:

com.datastax.driver.core.exceptions.InvalidQueryException: Consistency level LOCAL_ONE is not supported for this operation. Supported consistency levels are: LOCAL_QUORUM

Any help would be deeply appreciated!

Arjun Sunil Kumar Arjun Sunil Kumar · Accepted Answer · 2020-04-06T22:15:36

Finally figured out. It was about the setting consistency using @Table annotation.

Code snippet provided below:

@Table(name = "report", readConsistency = "LOCAL_QUORUM", writeConsistency = "LOCAL_QUORUM")
public class SampleEntity {

  @Column(name = "user_id")
  @PartitionKey(0)
  private String userId;


  @Column(name = "join_date")
  @PartitionKey(0)
  private String joinDate;

}

How to write to Manage Cassandra Service using Flink Cassandra Connector?

1 Answers