Stavros' Stuff

Angry rants of programming and other things.

Gweet: Messaging for your things

A message queue for the abhorrently named "Internet of Things"

As you may recall, I have hooked up various parts of my house to a computer so I can control them remotely. To do that, I have an HTTP server for which I open a port, and everything runs on this server, but what if I need to add another device? What if I need to have multiple devices listening for a command?

Having to open a port for each and every one of them, exposing them to the internet and configuring all this is a huge hassle, a security problem and very brittle. Wouldn’t it be much better if there were a centralized message queue where I could post messages and have an arbitrary number of devices read them?

It turns out, the excellent folks at

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Writing an nginx authentication module in Lua

Spoiler: The nginx Lua module is pretty great.

In the last two days, I’ve had to solve a rather interesting problem. I have an nginx instance proxying various servers, and I need to be able to add an authentication layer that will authenticate people with an external source (such as a web app) and allow them to pass through the proxy if they have an account on the authentication source (the web app, in this example).

Exploring the requirements

I considered various solutions for this, and I will list a few alternatives:

  • A simple Python/Flask module that would do the actual proxying and authentication.
  • An nginx module that would authenticate using subrequests (nginx can now do that).
  • Using nginx’s Lua module to write some authentication code.

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