：Use Kafka to write data to the Lindorm streaming engine

Step 1: Prepare data

1. Use the Kafka API to write data that you want to process to the Kafka topic. You can use one of the following methods to write data:

   • Use an open source Apache Kafka client to write data to the Lindorm streaming engine

   • Use an open source Apache Kafka script tool to write data to the Lindorm streaming engine

   In this topic, an open source Kafka script tool is used to write data as an example.

   # Create a topic.
   ./kafka-topics.sh --bootstrap-server <Lindorm Stream Kafka Endpoint> --topic log_topic --create
   
   # Write data to the topic.
   ./kafka-console-producer.sh --bootstrap-server <Lindorm Stream Kafka Endpoint> --topic log_topic
   {"loglevel": "INFO", "thread":"thread-1", "class": "com.alibaba.stream.test", "detail":"thread-1 info detail", "timestamp": "1675840911549"}
   {"loglevel": "ERROR", "thread":"thread-2", "class": "com.alibaba.stream.test", "detail":"thread-2 error detail", "timestamp": "1675840911549"}
   {"loglevel": "WARN", "thread":"thread-3", "class": "com.alibaba.stream.test", "detail":"thread-3 warn detail", "timestamp": "1675840911549"}
   {"loglevel": "ERROR", "thread":"thread-4", "class": "com.alibaba.stream.test", "detail":"thread-4 error detail", "timestamp": "1675840911549"}

   For more information about how to view the Lindorm Stream Kafka endpoint, see View endpoints.

2. Create a result table in LindormTable to store the processing result.

   1. Use Lindorm-cli to connect to LindormTable. For more information, see Use Lindorm-cli to connect to and use LindormTable.

   2. Create a result table named log.

      CREATE TABLE IF NOT EXISTS log (
        loglevel VARCHAR,
        thread VARCHAR,
        class VARCHAR,
        detail VARCHAR,
        timestamp BIGINT,
      primary key (loglevel, thread) );

Step 2: Install the Lindorm streaming engine client

1. Run the following command on the ECS instance to download the package of the Lindorm streaming engine client:

   wget https://hbaseuepublic.oss-cn-beijing.aliyuncs.com/lindorm-sqlline-2.0.2.tar.gz

2. Run the following command to decompress the package:

   tar zxvf lindorm-sqlline-2.0.2.tar.gz

3. Go to the lindorm-sqlline-2.0.2/bin path, and then run the following command to connect to the Lindorm streaming engine:

   ./lindorm-sqlline -url <Lindorm Stream SQL Endpoint>

   For more information about how to view the Lindorm Stream SQL endpoint, see View endpoints.

Step 3: Submit a compute task in the Lindorm streaming engine

In the example described in this step, the following operations are performed:

1. Create a Flink job named log_to_lindorm and create two tables named originalData and lindorm_log_table. The originalData table is the source table associated with the Kafka topic. The lindorm_log_table is the sink table that stores the result logs.

2. Create a stream job to filter out the logs whose loglevel is ERROR and write the logs to the result table.

Sample code:

CREATE FJOB log_to_lindorm(
    --Create the Kafka source table.
    CREATE TABLE originalData(
        `loglevel` VARCHAR,
        `thread` VARCHAR,
        `class` VARCHAR,
        `detail` VARCHAR,
        `timestamp` BIGINT
    )WITH(
        'connector'='kafka',
        'topic'='log_topic',
        'scan.startup.mode'='earliest-offset',
        'properties.bootstrap.servers'='Lindorm Stream Kafka Endpoint',
        'format'='json'
    );
    -- Create the Lindorm wide table.
    CREATE TABLE lindorm_log_table(
        `loglevel` VARCHAR,
        `thread` VARCHAR,
        `class` VARCHAR,
        `detail` VARCHAR,
        `timestamp` BIGINT,
        PRIMARY KEY (`loglevel`, `thread`) NOT ENFORCED
    )WITH(
        'connector'='lindorm',
        'seedServer'='LindormTable Endpoint for HBase APIs',
        'userName'='root',
        'password'='test',
        'tableName'='log',
        'namespace'='default'
    );
    --Filter out the ERROR logs from the data in the Kafka topic and write the logs to the result wide table.
    INSERT INTO lindorm_log_table SELECT * FROM originalData WHERE loglevel = 'ERROR';
);

Step 4: Query the processing result

You can use one of the following methods to query the processing result:

• Use Lindorm-cli to connect to LindormTable and run the following command to query the processing result:

  SELECT * FROM log LIMIT 5;

  The following result is returned:

  +----------+----------+-------------------------+-----------------------+---------------+
  | loglevel |  thread  |          class          |        detail         |   timestamp   |
  +----------+----------+-------------------------+-----------------------+---------------+
  | ERROR    | thread-2 | com.alibaba.stream.test | thread-2 error detail | 1675840911549 |
  | ERROR    | thread-4 | com.alibaba.stream.test | thread-4 error detail | 1675840911549 |
  +----------+----------+-------------------------+-----------------------+---------------+                                     

• Use the cluster management system of LindormTable to query the processing result. For more information, see Data query.