Offtopic

Offtopic is a simple web application built with Ratpack for inspecting and consuming events from Apache Kafka

The primary goal of this tool is to give you real-time insight into a running Kafka cluster.

System Requirements

• Java 8

• Apache Zookeeper

• Apache Kafka

Features

• Watch: From the /topics page clicking the "watch" button will set up a WebSockets-based stream of events straight from Kafka to your browser

• Multipass: From the /topics page you can select multiple topics to watch at once (screenshot of multipass in action)

• Binary data support: Clicking on a message row in the "watch" view will drop down a base64-encoded version of the message data

Usage Notes

As of 0.3.0 Offtopic is available as a wholly self-contained executable .jar file which means running the command below will start Offtopic on localhost:5050:

✗ java -jar offtopic*-all.jar
log4j:WARN No appenders could be found for logger (io.netty.util.internal.logging.InternalLoggerFactory).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.

By default Offtopic looks for a Zookeeper on localhost:2181, if you wish to connect it to another Zookeeper ensemble, use the zookeeper Java property, e.g.:

✗ java -Dzookeepers=example.com:2181 -jar offtopic*-all.jar
log4j:WARN No appenders could be found for logger (io.netty.util.internal.logging.InternalLoggerFactory).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.

Topic Watch Wildcards

A somewhat "hidden" feature is the ability to use regular expression when watching topics. A normal topic watch URL might be localhost:5050/topics/foo/watch. If there are a number of topics which are all prefixed with foo you can watch them all at the same time with: localhost:5050/topics/foo*/watch.

The regular expressions that Groovy supports should all be supported in the URL space.