Kafka

Kafka source connector

Key Features​

• batch

• stream

• exactly-once

• column projection

• parallelism

• support user-defined split

Description​

Source connector for Apache Kafka.

Source Options​

Name	Type	Required	Default	Description
topic	String	Yes	-	Topic name(s) to read data from when the table is used as source. It also supports topic list for source by separating topic by comma like 'topic-1,topic-2'.
table_list	Map	No	-	Topic list config You can configure only one table_list and one topic at the same time
bootstrap.servers	String	Yes	-	Comma separated list of Kafka brokers.
pattern	Boolean	No	false	If pattern is set to true,the regular expression for a pattern of topic names to read from. All topics in clients with names that match the specified regular expression will be subscribed by the consumer.
consumer.group	String	No	Nexus-Consumer-Group	Kafka consumer group id, used to distinguish different consumer groups.
commit_on_checkpoint	Boolean	No	true	If true the consumer's offset will be periodically committed in the background.
kafka.config	Map	No	-	In addition to the above necessary parameters that must be specified by the Kafka consumer client, users can also specify multiple consumer client non-mandatory parameters, covering all consumer parameters specified in the official Kafka document.
schema	Config	No	-	The structure of the data, including field names and field types.
format	String	No	json	Data format. The default format is json. Optional text format, canal_json, debezium_json, ogg_json and avro.If you use json or text format. The default field separator is ", ". If you customize the delimiter, add the "field_delimiter" option.If you use canal format, please refer to Canal Format for details.If you use debezium format, please refer to Debezium Format for details.
format_error_handle_way	String	No	fail	The processing method of data format error. The default value is fail, and the optional value is (fail, skip). When fail is selected, data format error will block and an exception will be thrown. When skip is selected, data format error will skip this line data.
field_delimiter	String	No	,	Customize the field delimiter for data format.
start_mode	StartMode[earliest],[group_offsets],[latest],[specific_offsets],[timestamp]	No	group_offsets	The initial consumption pattern of consumers.
start_mode.offsets	Config	No	-	The offset required for consumption mode to be specific_offsets.
start_mode.timestamp	Long	No	-	The time required for consumption mode to be "timestamp".
partition-discovery.interval-millis	Long	No	-1	The interval for dynamically discovering topics and partitions.
common-options		No	-	Source plugin common parameters, please refer to Source Common Options for details

Task Example​

Simple​

This example reads the data of kafka's topic_1, topic_2, topic_3 and prints it to the client.

# Defining the runtime environment
env {
  parallelism = 2
  job.mode = "BATCH"
}
source {
  Kafka {
    schema = {
      fields {
        name = "string"
        age = "int"
      }
    }
    format = text
    field_delimiter = "#"
    topic = "topic_1,topic_2,topic_3"
    bootstrap.servers = "localhost:9092"
    kafka.config = {
      client.id = client_1
      max.poll.records = 500
      auto.offset.reset = "earliest"
      enable.auto.commit = "false"
    }
  }  
}
sink {
  Console {}
}

Regex Topic​

source {
    Kafka {
          topic = ".*nexus*."
          pattern = "true" 
          bootstrap.servers = "localhost:9092"
          consumer.group = "nexus_group"
    }
}

AWS MSK SASL/SCRAM​

Replace the following ${username} and ${password} with the configuration values in AWS MSK.

source {
    Kafka {
        topic = "nexus"
        bootstrap.servers = "xx.amazonaws.com.cn:9096,xxx.amazonaws.com.cn:9096,xxxx.amazonaws.com.cn:9096"
        consumer.group = "nexus_group"
        kafka.config = {
            security.protocol=SASL_SSL
            sasl.mechanism=SCRAM-SHA-512
            sasl.jaas.config="org.apache.kafka.common.security.scram.ScramLoginModule required username=\"username\" password=\"password\";"
            #security.protocol=SASL_SSL
            #sasl.mechanism=AWS_MSK_IAM
            #sasl.jaas.config="software.amazon.msk.auth.iam.IAMLoginModule required;"
            #sasl.client.callback.handler.class="software.amazon.msk.auth.iam.IAMClientCallbackHandler"
        }
    }
}

AWS MSK IAM​

Please ensure the IAM policy have "kafka-cluster:Connect",. Like this:

"Effect": "Allow",
"Action": [
    "kafka-cluster:Connect",
    "kafka-cluster:AlterCluster",
    "kafka-cluster:DescribeCluster"
],

Source Config

source {
    Kafka {
        topic = "nexus"
        bootstrap.servers = "xx.amazonaws.com.cn:9098,xxx.amazonaws.com.cn:9098,xxxx.amazonaws.com.cn:9098"
        consumer.group = "nexus_group"
        kafka.config = {
            #security.protocol=SASL_SSL
            #sasl.mechanism=SCRAM-SHA-512
            #sasl.jaas.config="org.apache.kafka.common.security.scram.ScramLoginModule required username=\"username\" password=\"password\";"
            security.protocol=SASL_SSL
            sasl.mechanism=AWS_MSK_IAM
            sasl.jaas.config="software.amazon.msk.auth.iam.IAMLoginModule required;"
            sasl.client.callback.handler.class="software.amazon.msk.auth.iam.IAMClientCallbackHandler"
        }
    }
}

Kerberos Authentication Example​

Source Config

source {
    Kafka {
        topic = "nexus"
        bootstrap.servers = "127.0.0.1:9092"
        consumer.group = "nexus_group"
        kafka.config = {
            security.protocol=SASL_PLAINTEXT
            sasl.kerberos.service.name=kafka
            sasl.mechanism=GSSAPI
            java.security.krb5.conf="/etc/krb5.conf"
            sasl.jaas.config="com.sun.security.auth.module.Krb5LoginModule required \n        useKeyTab=true \n        storeKey=true  \n        keyTab=\"/path/to/xxx.keytab\" \n        principal=\"[e-mail]\";"
        }
    }
}

Multiple Kafka Source​

This is written to the same pg table according to different formats and topics of parsing kafka Perform upsert operations based on the id

env {
  execution.parallelism = 1
  job.mode = "BATCH"
}

source {
  Kafka {
    bootstrap.servers = "kafka_e2e:9092"
    table_list = [
      {
        topic = "^test-ogg-sou.*"
        pattern = "true"
        consumer.group = "ogg_multi_group"
        start_mode = earliest
        schema = {
          fields {
            id = "int"
            name = "string"
            description = "string"
            weight = "string"
          }
        },
        format = ogg_json
      },
      {
        topic = "test-cdc_mds"
        start_mode = earliest
        schema = {
          fields {
            id = "int"
            name = "string"
            description = "string"
            weight = "string"
          }
        },
        format = canal_json
      }
    ]
  }
}

sink {
  Jdbc {
    driver = org.postgresql.Driver
    url = "jdbc:postgresql://postgresql:5432/test?loggerLevel=OFF"
    user = test
    password = test
    generate_sink_sql = true
    database = test
    table = public.sink
    primary_keys = ["id"]
  }
}