Timid

The shy container

Timid is a UDP proxy server that puts Docker containers to sleep when no connections are active. The interest for this project emerged as I was attempting to host a Valheim server for some friends. I ran the server using the excellent docker container lloesche/valheim-server, I did however notice that the server seemed to use a lot of resources even when no one was connected to it (both CPU and memory). Now, my server doesn't have that many resources so I was a little hesitant of hosting the valheim server if it meant that it would slow down all my other services and increase the power draw. I considered just turning the server on and off manually myself, but that defeats the point of having a dedicated server. Also my friends would not be able to play without me, unless I specifically left the server running. I also considered building a small website or similar that would allow my friends to manually turn the server on and off, but this seemed kind of hacky.

On the server I also host minecraft servers using the excellent itzg/minecraft-server in combination with the just as excellent Infrared. Using Infrared I can configure it to automatically start and stop Docker containers when connections are made. This is great as it means that I can host many servers at the same time and only the ones that are actually being used will use any resources.

Wouldn't it be excellent to build a similar tool that can work for any type of server hosted in docker? That's how I was inspired to make Timid, which does basically the same except for UDP based servers. In addition to stopping and starting containers you can also pause/unpause containers, meaning that you can circumvent the long startup times of certain game servers at the cost of memory consumption. You could also pause the container for a customisable amount of time and then stop it if nobody connects to it.

Building Timid taught me a lot, it was the first project I made using Go that wasn't a web API. It also required me to learn a lot about Docker and controlling Docker containers using the Docker API. I mostly learned by reading the great introductory book Docker Deep Dive.