Configuration Reference

Basics

Reference documentation of all configuration and authentication options:

Default system topics

System or control topics are created by services for their internal use. Below is the list of built-in configurations to identify them.

• _schemas

• __consumer_offsets

• _kafka_lenses_

• lsql_*

• lsql-*

• __transaction_state

• __topology

• __topology__metrics

• _confluent*

• *-KSTREAM-*

• *-TableSource-*

• *-changelog

• __amazon_msk*

Wildcard (*) is used to match any name in the path to capture a list of topics not just one. When the wildcard is not specified, Lenses matches on the entry name provided.

Security

TLS

Kerberos

Persistent storage

Common

H2

Postgres

Schema registries

If the records schema is centralized, the connectivity to Schema Registry nodes is defined by a Lenses Connection.

There are two static config entries to enable/disable the deletion of schemas:

Deployments

Options for specific deployment targets:

• Global options

• Kubernetes

Global options

Common settings, independently of the underlying deployment target:

Kubernetes

Kubernetes connectivity is optional. Minimum supported K8 version 0.11.10. All settings are string.

SQL snapshot (Explore & Studio)

Optimization settings for SQL queries.

Lenses internal Kafka topics

Lenses requires these Kafka topics to be available, otherwise, it will try to create them. The topics can be created manually before Lenses is run, or allow Lenses the correct Kafka ACLs to create the topics:

To allow for fine-grained control over the replication factor of the three topics, the following settings are available:

Advanced

All time configuration options are in milliseconds.

Connectors topology

Control how Lenses identifies your connectors in the Topology view. Catalogue your connector types, set their icons, and control how Lenses extracts the topics used by your connectors.

Lenses comes preconfigured for some of the popular connectors as well as the Stream Reactor connectors. If you see that Lenses doesn’t automatically identify your connector type then use the lenses.connectors.info setting to register it with Lenses.

Add a new HOCON object {} for every new Connector in your lenses.connectors.info list :

  lenses.connectors.info = [
      {
        class.name = "The connector full classpath"
        name = "The name which will be presented in the UI"
        instance = "Details about the instance. Contains the connector configuration field which holds the information. If  a database is involved it would be  the DB connection details, if it is a file it would be the file path, etc"
        sink = true
        extractor.class = "The full classpath for the implementation knowing how to extract the Kafka topics involved. This is only required for a Source"
        icon = "file.png"
        description = "A description for the connector"
        author = "The connector author"
      }
  ]

This configuration allows the connector to work with the topology graph, and also have the RBAC rules applied to it.

Source example

To extract the topic information from the connector configuration, source connectors require an extra configuration. The extractor class should be: io.lenses.config.kafka.connect.SimpleTopicsExtractor. Using this extractor requires an extra property configuration. It specifies the field in the connector configuration which determines the topics data is sent to.

Here is an example for the file source:

  lenses.connectors.info = [
    {
      class.name = "org.apache.kafka.connect.file.FileStreamSource"
      name = "File"
      instance = "file"
      sink = false
      property = "topic"
      extractor.class = "io.lenses.config.kafka.connect.SimpleTopicsExtractor"
    }
  ]

Sink example

An example of a Splunk sink connector and a Debezium SQL server connector

  lenses.connectors.info = [
    {
      class.name = "com.splunk.kafka.connect.SplunkSinkConnector"
      name = "Splunk Sink",
      instance = "splunk.hec.uri"
      sink = true,
      extractor.class = "io.lenses.config.kafka.connect.SimpleTopicsExtractor"
      icon = "splunk.png",
      description = "Stores Kafka data in Splunk"
      docs = "https://github.com/splunk/kafka-connect-splunk",
      author = "Splunk"
    },
    {
      class.name = "io.debezium.connector.sqlserver.SqlServerConnector"
      name = "CDC MySQL"
      instance = "database.hostname"
      sink = false,
      property = "database.history.kafka.topic"
      extractor.class = "io.lenses.config.kafka.connect.SimpleTopicsExtractor"
      icon = "debezium.png"
      description = "CDC data from RDBMS into Kafka"
      docs = "//debezium.io/docs/connectors/mysql/",
      author = "Debezium"
    }
  ]

External Applications