Krowser

Web UI to browse kafka, schema registry and kafka-connect.

Features

• View kafka's topics, partitions, messages, consumer groups and brokers.
• View Confluent schema registry's subjects and schemas.
• View kafka-connect's connectors and tasks.
• The grid view destructures the messages/schemas (even nested json) into separate columns, and each of the columns can be (client-side) filtered and sorted.
• A decoding framework that allows for decoding messages by either auto-detecting the format from a configured list of decoders (with the ability to specify a different list of decoders for different topics or groups of topics) or by selecting the decoding from a list in the UI.
• Write your own custom decoder by implementing an interface, see example.
• Or, use one of the built-in decoders:
  • Avro (using Confluent schema registry)
  • UTF-8
  • Raw bytes
• The decoding framework supports different decoded messages in the same topic, and different decodings for keys and values for the same message. The avro decoder supports different subject messages in a topic. As you filter for a specific event type it auto-hides all of the irrelevant columns belonging to the other messages.
• The raw view shows the data in json format, and allows easy copying to clipboard
• Server-side search for messages and the ability to search multiple topics at once
• Filter messages via time range (or offsets/newest/oldest)
• Auto-refresh toggle
• Light and dark themes

Images

Topics View (light theme)

Messages View (dark theme)

Usage

A docker image is available in dockerhub.

Run it via: docker run -it -p 9999:9999 tzachs/krowser

If you need to configure URLs (of kafka, schema registry), you can run, for example (if you need to run against local kafka and schema-registry): docker run -it -p 9999:9999 --env KROWSER__KAFKA__URLS=host.docker.internal:9092 --env KROWSER__CONFLUENT_SCHEMA_REGISTRY__URL=host.docker.internal:8081 tzachs/krowser

Alternatively, you can use a config.toml config file to specify configurations. It needs to be placed in the same folder as the krowser binary (or in the src/server folder if you're running from source).

All available configurations can be seen in the default config file.

Note that for specifying custom decoders for specific topics you have to use a config file, this is currently not supported via environment variables.

A docker-compose example is also available.

Local Development

• Node.js v12 and Rust 2021 edition need to be installed first
• To install dependencies for the frontend, run: npm i
• To build backend, run: npm run build:backend
• To build frontend, run: npm run build:frontend
• To start the server, run: npm start
• If you need local kafka and schema registry (and zookeeper), run npm run kafka-up, and wait a few minutes (and run npm run kafka-down to shut those down)
• If you need dummy messages to be inserted to kafka, run npm run insert-events
• To build the docker image, run: docker build -t krowser .