Kafka Connect configuration is easy - you just write some JSON! But what if you’ve got credentials that you need to pass? Embedding those in a config file is not always such a smart idea. Fortunately with KIP-297 which was released in Apache Kafka 2.0 there is support for external secrets. It’s extendable to use your own ConfigProvider, and ships with its own for just putting credentials in a file - which I’ll show here. You can read more here.

Kafka Connect exposes a REST interface through which all config and monitoring operations can be done. You can create connectors, delete them, restart them, check their status, and so on. But, I found a situation recently in which I needed to delete a connector and couldn’t do so with the REST API. Here’s another way to do it, by amending the configuration Kafka topic that Kafka Connect in distributed mode uses to persist configuration information for connectors. Note that this is not a recommended way of working with Kafka Connect—the REST API is there for a good reason :)

There is an open issue for support of EXPLODE/UNNEST functionality in KSQL, and if you need it then do up-vote the issue. Here I detail a hacky, but effective, workaround for exploding arrays into multiple messages—so long as you know the upper-bound on your array.

Kafka Connect is a API within Apache Kafka and its modular nature makes it powerful and flexible. Converters are part of the API but not always fully understood. I’ve written previously about Kafka Connect converters, and this post is just a hands-on example to show even further what they are—and are not—about.

When you run Kafka Connect in distributed mode it uses a Kafka topic to store the offset information for each connector. Because it’s just a Kafka topic, you can read that information using any consumer.

See also : https://docs.confluent.io/current/ksql/docs/installation/server-config/security.html#configuring-ksql-for-secured-sr-long

Confluent Cloud now includes a secured Schema Registry, which you can use from external applications, including KSQL.

To configure KSQL for it you need to set:

I’ve hit these errors when creating a connector with Debezium against MySQL a couple of times now, and seen them asked about on StackOverflow too. In essence it means that you’ve not configured MySQL correctly for Debezium to be able to connect to it.

Before you can drop a stream or table that’s populated by a query in KSQL, you have to terminate any queries upon which the object is dependent. Here’s a bit of jq & xargs magic to terminate all queries that are currently running

This post is the companion to an earlier one that I wrote about conference abstracts. In the same way that the last one was inspired by reviewing a ton of abstracts and noticing a recurring pattern in my suggestions, so this one comes from reviewing a bunch of slide decks for a forthcoming conference. They all look like good talks, but in several cases these great talks are fighting to get out from underneath the deadening weight of slides.

Herewith follows my highly-opinionated, fairly-subjective, and extremely-terse advice and general suggestions for slide decks. You can also find relating ramblings in this recent post too. My friend and colleague Vik Gamov also wrote a good post on this same topic, and linked to a good video that I’d recommend you watch.

This shows how to use httpie with the Confluent REST Proxy.

A script I’d batch-run on my Markdown files had inserted a UTF-8 non-breaking-space between Markdown heading indicator and the text, which meant that # My title actually got rendered as that, instead of an H3 title.

Looking at the file contents, I could see it wasn’t just a space between the # and the text, but a non-breaking space.

KSQL is generally case-sensitive. Very sensitive, at times ;-)

Full reference is here

The Schema Registry support a REST API for finding out information about the schemas within it. Here’s a quick cheatsheat with REST calls that I often use.