Sep 30, 2020

Setting key value when piping from jq to kafkacat

One of my favourite hacks for getting data into Kafka is using kafkacat and stdin, often from jq. You can see this in action with Wi-Fi data, IoT data, and data from a REST endpoint. This is fine for getting values into a Kafka message - but Kafka messages are key/value, and being able to specify a key is can often be important.

Here’s a way to do that, using a separator and some jq magic. Note that at the moment kafkacat only supports single byte separator characters, so you need to choose carefully. If you pick a separator that also appears in your data, it’s possibly going to have unintended consequences.

Dec 3, 2018

Kafka Connect CLI tricks

I do lots of work with Kafka Connect, almost entirely in Distributed mode—even just with 1 node -> makes scaling out much easier when/if needed. Because I’m using Distributed mode, I use the Kafka Connect REST API to configure and manage it. Whilst others might use GUI REST tools like Postman etc, I tend to just use the commandline. Here are some useful snippets that I use all the time.

Jun 20, 2018

Syntax highlighting code for presentation slides

So you’ve got a code sample you want to share in a presentation, but whilst it looks beautiful in your text-editor with syntax highlighting, it’s fugly in Keynote? You could screenshot it and paste the image into your slide, but you just know that you’ll want to change that code, and end up re-snapshotting it…what a PITA. Better to have a nicely syntax-highlighted code snippet that you can paste as formatted text into Keynote and amend from there as needed.

Aug 8, 2017

Simple export/import of Data Sources in Grafana

Grafana API Reference Export all Grafana data sources to data_sources folder mkdir -p data_sources && curl -s "http://localhost:3000/api/datasources" -u admin:admin|jq -c -M '.[]'|split -l 1 - data_sources/ This exports each data source to a separate JSON file in the data_sources folder. Load data sources back in from folder This submits every file that exists in the data_sources folder to Grafana as a new data source definition. for i in data_sources/*; do \ curl -X "POST" "http://localhost:3000/api/datasources" \ -H "Content-Type: application/json" \ --user admin:admin \ --data-binary @$i done