Kafdrop 3

Kafdrop 3 is a UI for monitoring Apache Kafka clusters. The tool displays information such as brokers, topics, partitions, and lets you view messages.

The project is a continuation of the original HomeAdvisor/Kafdrop, which has now been dragged kicking and screaming into the JDK 11 world. It's a lightweight application that runs on Spring Boot and requires very little configuration.

Requirements

• Java 11 or newer
• Kafka + ZooKeeper cluster

Optional, additional integration:

• Schema Registry

Getting Started

Maven build

After cloning the repository, building should just be a matter of running a standard Maven build:

$ mvn clean package

Running from JAR

java --add-exports=jdk.management.agent/jdk.internal.agent=ALL-UNNAMED \
    -jar target/kafdrop-<version>.jar --zookeeper.connect=<host>:<port>,<host>:<port>,...

Open a browser and navigate to http://localhost:9000. The port can be overridden by adding the following config:

--server.port=<port>

Optionally, configure a schema registry connection with:

--schemaregistry.connect=http://localhost:8081

Finally, a default message format (e.g. to deserialize Avro messages) can optionally be configured as follows:

--message.format=AVRO

Valid format values are DEFAULT and AVRO. This setting can also be configured at the topic level via dropdown when viewing messages.

Running with Docker

The following maven command will generate a Docker image:

mvn clean package assembly:single docker:build

Once the build finishes you can launch the image:

docker run -d -p 9000:9000 -e ZOOKEEPER_CONNECT=<host:port,host:port> obsidiandynamics/kafdrop

And access the UI at http://localhost:9000.

APIs

JSON endpoints

Starting with version 2.0.0, Kafdrop offers a set of Kafka APIs that mirror the existing HTML views. Any existing endpoint can be returned as JSON by simply setting the Accept: application/json header. There are also two endpoints that are JSON only:

• /topic: Returns array of all topic names.
• /topic/{topicName}/{consumerId}: Returns partition offset and lag details for a specific topic and consumer.

Swagger

To help document the Kafka APIs, Swagger has been included. The Swagger output is available by default at the following Kafdrop URL:

/v2/api-docs

This can be overridden with the following configuration:

springfox.documentation.swagger.v2.path=/new/swagger/path

Currently only the JSON endpoints are included in the Swagger output; the HTML views and Spring Boot debug endpoints are excluded.

You can disable Swagger output with the following configuration:

swagger.enabled=false

CORS Headers

Starting in version 2.0.0, Kafdrop sets CORS headers for all endpoints. You can control the CORS header values with the following configurations:

cors.allowOrigins (default is *)
cors.allowMethods (default is GET,POST,PUT,DELETE)
cors.maxAge (default is 3600)
cors.allowCredentials (default is true)
cors.allowHeaders (default is Origin,Accept,X-Requested-With,Content-Type,Access-Control-Request-Method,Access-Control-Request-Headers,Authorization)

You can also disable CORS entirely with the following configuration:

cors.enabled=false