I had the pleasure of presenting at DataEngBytes recently, and am delighted to share with you the 🗒️ slides, 👾 code, and 🎥 recording of my ✨brand new talk✨:

🤖Building a Telegram bot with Apache Kafka, Go, and ksqlDB

The server sends Transfer-Encoding: chunked data, and you want to work with the data as you get it, instead of waiting for the server to finish, the EOF to fire, and then process the data?

At the beginning of all this my aim was to learn something new (Go), and use it to write a version of a utility that I’d previously hacked together in Python that checks your Apache Kafka broker configuration for possible problems with the infamous advertised.listeners setting. Check out a blog that I wrote which explains all about Apache Kafka and listener configuration.

So far I’ve been running all my code either in the Go Tour sandbox, using Go Playground, or from a single file in VS Code. My explorations in the previous article ended up with a a source file that was starting to get a little bit unwieldily, so let’s take a look at how that can be improved.

Within my most recent code, I have the main function and the doProduce function, which is fine when collapsed down:

When I set out to learn Go one of the aims I had in mind was to write a version of this little Python utility which accompanies a blog I wrote recently about understanding and diagnosing problems with Kafka advertised listeners. Having successfully got Producer, Consumer, and AdminClient API examples working, it is now time to turn to that task.

Having ticked off the basics with an Apache Kafka producer and consumer in Go, let’s now check out the AdminClient. This is useful for checking out metadata about the cluster, creating topics, and stuff like that.

Last time I looked at creating my first Apache Kafka consumer in Go, which used the now-deprecated channel-based consumer. Whilst idiomatic for Go, it has some issues which mean that the function-based consumer is recommended for use instead. So let’s go and use it!

Instead of reading from the Events() channel of the consumer, we read events using the Poll() function with a timeout. The way we handle events (a switch based on their type) is the same:

Having written my first Kafka producer in Go, and even added error handling to it, the next step was to write a consumer. It follows closely the pattern of Producer code I finished up with previously, using the channel-based approach for the Consumer:

I looked last time at the very bare basics of writing a Kafka producer using Go. It worked, but only with everything lined up and pointing the right way. There was no error handling of any sorts. Let’s see about fixing this now.

With the first leg of my journey with Go done (starting from a very rudimentary base), the next step for me was to bring it into my current area of interest and work - Apache Kafka.

👉 A Tour of Go : sync.Mutex

In the previous exercise I felt my absence of a formal CompSci background with the introduction of Binary Sorted Trees, and now I am concious of it again with learning about mutex. I’d heard of them before, mostly when Oracle performance folk were talking about wait types - TIL it stands for mutual exclusion!

A Tour of Go : Goroutines was OK but as with some previous material I headed over to Go by example for clearer explanations.

👉 A Tour of Go : Exercise: Images

This is based on the Picture generator from the Slices exercise.

👉 A Tour of Go : Readers

I’m not intending to pick holes in the Tour…but it’s not helping itself ;-)

For an introductory text, it makes a ton of assumptions about the user. Here it introduces Readers, and the explanation is good—but the example code looks like this:

👉 A Tour of Go : Exercise: Errors

Like Interfaces, the Tour didn’t really do it for me on Errors either. Too absract, and not enough explanation of the code examples for my liking. It also doesn’t cover the errors package which other tutorial do. I’m not clear if that’s because the errors package isn’t used much, or the Tour focusses only on teaching the raw basics.

👉 A Tour of Go : Interfaces

This page really threw me, for several reasons:

👉 A Tour of Go : Function Closures

So far the Tour has been 🤔 and 🧐 and even 🤨 but function closures had me 🤯 …

Each of the words on the page made sense but strung together in a sentence didn’t really make any sense to me.

👉 A Tour of Go : Exercise - Maps

This is probably bread-and-butter for any seasoned programmer, but I enjoyed the simple process and satisfaction of breaking the problem down into steps to solve using what the tutorial had just covered. Sketching out the logic in pseudo-code first, I figured that I wanted to do this:

👉 A Tour of Go : Slices

Slices made sense, until I got to Slice length and capacity. Two bits puzzled me in this code: