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Serialization and deserialization and custom plugins

Kafka-ui supports multiple ways to serialize/deserialize data.

Int32, Int64, UInt32, UInt64

Big-endian 4/8 bytes representation of signed/unsigned integers.

Base64

Base64 (RFC4648) binary data representation. Can be useful in case if the actual data is not important, but exactly the same (byte-wise) key/value should be send.

String

Treats binary data as a string in specified encoding. Default encoding is UTF-8.

Class name: com.provectus.kafka.ui.serdes.builtin.StringSerde

Sample configuration (if you want to overwrite default configuration):

kafka:
  clusters:
    - name: Cluster1
      # Other Cluster configuration omitted ... 
      serde:
          # registering String serde with custom config
        - name: AsciiString
          className: com.provectus.kafka.ui.serdes.builtin.StringSerde
          properties:
            encoding: "ASCII"
        
          # overriding build-it String serde config   
        - name: String 
          properties:
            encoding: "UTF-16"

Protobuf

Class name: com.provectus.kafka.ui.serdes.builtin.ProtobufFileSerde

Sample configuration:

kafka:
  clusters:
    - name: Cluster1
      # Other Cluster configuration omitted ... 
      serde:
        - name: ProtobufFile
          properties:
            # path to the protobuf schema files directory
            protobufFilesDir: "path/to/protofiles"
            # default protobuf type that is used for KEY serialization/deserialization
            # optional
            protobufMessageNameForKey: my.Type1
            # mapping of topic names to protobuf types, that will be used for KEYS  serialization/deserialization
            # optional
            protobufMessageNameForKeyByTopic:
              topic1: my.KeyType1
              topic2: my.KeyType2
            # default protobuf type that is used for VALUE serialization/deserialization
            # optional, if not set - first type in file will be used as default
            protobufMessageName: my.Type1
            # mapping of topic names to protobuf types, that will be used for VALUES  serialization/deserialization
            # optional
            protobufMessageNameByTopic:
              topic1: my.Type1
              "topic.2": my.Type2

Docker-compose sample for Protobuf serialization is here.

Legacy configuration for protobuf is here.

SchemaRegistry

SchemaRegistry serde is automatically configured if schema registry properties set on cluster level. But you can add new SchemaRegistry-typed serdes that will connect to another schema-registry instance.

Class name: com.provectus.kafka.ui.serdes.builtin.sr.SchemaRegistrySerde

Sample configuration:

kafka:
  clusters:
    - name: Cluster1
      # this url will be used by "SchemaRegistry" by default
      schemaRegistry: http://main-schema-registry:8081
      serde:
        - name: AnotherSchemaRegistry
          className: com.provectus.kafka.ui.serdes.builtin.sr.SchemaRegistrySerde
          properties:
            url:  http://another-schema-registry:8081
            # auth properties, optional
            username: nameForAuth
            password: P@ssW0RdForAuth
        
          # and also add another SchemaRegistry serde
        - name: ThirdSchemaRegistry
          className: com.provectus.kafka.ui.serdes.builtin.sr.SchemaRegistrySerde
          properties:
            url:  http://another-yet-schema-registry:8081

Setting serdes for specific topics

You can specify preferable serde for topics key/value. This serde will be chosen by default in UI on topic's view/produce pages. To do so, set topicValuesPattern/topicValuesPattern properties for the selected serde. Kafka-ui will choose a first serde that matches specified pattern.

Sample configuration:

kafka:
  clusters:
    - name: Cluster1
      serde:
        - name: String
          topicKeysPattern: click-events|imp-events
        
        - name: Int64
          topicKeysPattern: ".*-events"
        
        - name: SchemaRegistry
          topicValuesPattern: click-events|imp-events

Default serdes

You can specify which serde will be chosen in UI by default if no other serdes selected via topicKeysPattern/topicValuesPattern settings.

Sample configuration:

kafka:
  clusters:
    - name: Cluster1
      defaultKeySerde: Int32
      defaultValueSerde: String
      serde:
        - name: Int32
          topicKeysPattern: click-events|imp-events

Fallback

If selected serde couldn't be applied (exception was thrown), then fallback (String serde with UTF-8 encoding) serde will be applied. Such messages will be specially highlighted in UI.

Custom pluggable serde registration

You can implement your own serde and register it in kafka-ui application. To do so:

  1. Add kafka-ui-serde-api dependency (should be downloadable via maven central)
  2. Implement com.provectus.kafka.ui.serde.api.Serde interface. See javadoc for implementation requirements.
  3. Pack your serde into uber jar, or provide directory with no-dependency jar and it's dependencies jars

Example pluggable serdes : https://github.com/provectus/kafkaui-smile-serde https://github.com/provectus/kafkaui-glue-sr-serde

Sample configuration:

kafka:
  clusters:
    - name: Cluster1
      serde:
        - name: MyCustomSerde
          className: my.lovely.org.KafkaUiSerde
          filePath: /var/lib/kui-serde/my-kui-serde.jar
          
        - name: MyCustomSerde2
          className: my.lovely.org.KafkaUiSerde2
          filePath: /var/lib/kui-serde2
          properties:
            prop1: v1