I yesterday ported the tear-down part of MicroFW from Python back to Bash. (It was just unhappy in Python.) In doing so, I tested it by uploading it to my server, running it and seeing what happens. This is obviously unsatisfactory, but since the script runs a bunch of iptables calls and the like, how am I supposed to test it? This integrates pretty deeply into the system, no way of mocking that, right?

Well, yes way: You just need to shamelessly abuse the function keyword…

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I wrote about a nice threading pattern using Queues for synchronization a while ago. In the meantime, I’ve stumbled across Trio and I loved their concept of nurseries, which is basically a wrapper around the threads-and-queues concept that also makes sure that threads are properly joined and do not run out of control.

So today I ran across a case where I’d have to query large chunks of data from two systems in parallel, that I would then have to compare and merge into a third data set. Thus I needed a way to start two threads, return stuff from them to the main thread, and join them back together. A nursery came to mind, because it does just that. So that’s what I used, and here’s the code for it!

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I want to try something new today: Write about philosophical topics, because those have been catching my interest for a while. I’ll start looking into the story of the game Obduction which has caught on to me, so I think it’s worth exploring. If you haven’t played the game yet, lots’a spoilers ahead, so probably go play it first.

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Have you ever wanted to set up a Samba4-based Read-Only DC in a remote location? Here’s how.

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I’m currently building some home automation stuff using NodeRED. One of the things I need to do is trigger home automation actions from Prometheus: I’m monitoring our Solar panels using it, and I want the shutters to go down whenever it’s sunny outside. I have a Prometheus alert rule that tells me when that is. But how can I trigger NodeRED from there?

As an extra challenge, I wanted to see if I can actually do this without writing a single line of code. I do need a couple more nodes this way, but it works and it’s not all that complicated. Here’s how it’s done.

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I’ve recently started building stuff with NodeRED, which I really enjoy. Since I’m using MQTT as the central message bus for my system, I find myself regularly in need of knowing the current state of my MQTT topics. There are a couple of tools around, for instance MQTT.fx, which are specifically built for this purpose; but I found that MQTT.fx likes to cause high CPU load when the topic scanner thingy is running. So I’m looking for an alternative, and I thought, why not build it in NodeRED? So that’s what I did.

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Here’s a systemd service template for running Dockerized services, for example the Prometheus Blackbox Exporter.

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