Posts on Sean's Blog

Quick and Dirty Python Logging Configuration

Wed, 16 Oct 2024 12:00:00 -0800

This is my quick-and-dirty logging configuration that works for both scripts and containerized applications.

from logging import StreamHandler, getLogger
from os import getenv

stderr_handler = StreamHandler()
log = getLogger(__name__)
log.setLevel(getenv('LOG_LEVEL', 'INFO'))
log.addHandler(stderr_handler)

This will provide console output when developing locally and will be picked up by the Docker/containerd logging driver when running in docker compose, Kubernetes, etc.

Running EJBCA on EKS

Wed, 20 Mar 2024 12:00:00 -0800

⚠️ Bitnami has taken most of their public images and Helm charts offline. Likely, this method no longer works.

Bitnami provides a nice Helm chart for EJBCA, a FOSS public key infrastructure certificate authority application with a REST API. However, the Service and Ingress setup doesn’t work very well if you’re deploying to Amazon EKS.

Our EKS clusters use the AWS Load Balancer Controller to automatically create ALBs from Kubernetes Ingresses which are properly annotated. This allows us to attach certificates stored in AWS Certificate Manager, set TLS policies, and establish health checks right in our manifests. Fantastic stuff.

Grogue: A Roguelike Tutorial in Go (Part 4)

Tue, 12 Mar 2024 12:00:00 -0800

Happy New Year and welcome back to part 4 of my Rougelike tutorial in Go! (EDIT: It’s been 2024 for a while now, as I’ve been busy and wasn’t able to get this published when I initially intended.)

We now have a dungeon that we can move around, but we’re not really exploring it if we can see it all from start. We should implement a “field of view” for the player to allow only a limited range around them to be seen.

Grogue: A Roguelike Tutorial in Go (Part 3)

Fri, 27 Oct 2023 12:00:00 -0800

In Part 1, we created the dungeon as a large, empty room with walls around the edge. In this part, we’ll modify our dungeon generation code to start by filling the entire map with walls and then carving out rooms and connecting them with tunnels.

Start by creating a structure we’ll use to create our rooms. Add the following code to level.go:

type RectangularRoom struct {
 X1 int
 Y1 int
 X2 int
 Y2 int
}

// Create a new RectangularRoom structure.
func NewRectangularRoom(x int, y int, width int, height int) RectangularRoom {
 return RectangularRoom{
 X1: x,
 Y1: y,
 X2: x + width,
 Y2: y + height,
 }
}

The constructor takes the x and y coordinates of the top-level corner and computes the bottom right corner based on the width and height parameters.

Grogue: A Roguelike Tutorial in Go (Part 2)

Mon, 16 Oct 2023 12:00:00 -0800

Now that we’re drawing the map on the screen, we need to add a player and have them move around on the map. Before diving in and creating a Player structure, we should probably consider how we want to handle all of the creatures or entities that will be moving around the map.

Let’s create a structure that represents not just the player, but just about everything we may want to represent on the map: enemies, items, and whatever else we dream up.

Grogue: A Roguelike Tutorial in Go (Part 1)

Tue, 10 Oct 2023 12:00:00 -0800

Welcome to part one of this series which will help you create your a roguelike game written in Go! This is based largely on the Roguebasin libtcod tutorial, which has proven very helpful in getting fledgling roguelike-devs off the ground.

If you haven’t already completed the steps outlined in Part 0, please go back and do that now.

With our dependencies installed and validated, let’s grab a few neat tiles created by by Jere Sikstus. Download wall.png and floor.png and place them in a folder called assets/ inside our project root.

Grogue: A Roguelike Tutorial in Go (Part 0)

Mon, 09 Oct 2023 12:00:00 -0800

Are you interested in the [Go programming language])https://go.dev/) and creating a roguelike game? This tutorial will help you build the basics of a roguelike game in thirteen parts. Those parts will be:

Drawing on the Screen
Entities and the Map
Generating a Dungeon
Field of View
Enemies
Doing Damage (and Taking Some, Too)
Adding an Interface
Items and Inventory
Ranged Attacks
Saving and Loading
Deeper into the Dungeon
Increasing the Difficulty (of the Game)
Gearing Up

In this part 0, we’ll get the base of the project set up.

Learning Go

Fri, 12 May 2023 12:00:00 -0800

At work, we recently forked a project which includes a code written in Go and I needed to fix a bug in that code. I don’t know Go, but my colleagues were able to help me out and I was able to get the code working.

I’ve decided, though, that it’s time for me to learn Go, as many Kubernetes utilities are written in it and I’m basically doing K8s day-in and day-out at this point. I’m taking a course on it to get the basics, but have a neat idea for deepening my knowledge. More on that later.

Deploy Python Lambdas with Terraform

Mon, 28 Feb 2022 12:00:00 -0800

Deploying lambdas to AWS has always been painful when those Lambdas need more than just boto3 and when sticking to Infrastructure-as-Code. You can bring in the Serverless Framework, but it is complicated to bring into your CICD pipelines and has some issues with repeatability of deployments. So, what if you want to deploy a single Lambda?

In this post, I’ll discuss the method I use to deploy a Lambda, written in Python 3, to AWS using Terraform and GitLab CI.

Moving off Docker Hub

Tue, 10 Aug 2021 12:00:00 -0800

Docker Hub was the place to get container images. To a degree, it still is, but support for other public registries has increased and if your software’s installation instructions include a Docker Compose file, then having that file pre-populated with images from a third-party registry is trivial.

Docker announced last year that they’d be limiting the pull rate of container images on free accounts. Later, they announced that they would discontinue autobuilds for free accounts. For my FOSS projects, this was a problem. I used autobuilds to create Docker images when I made a release. Since my images can get marked as “unused” and I have to build them with a CI tool anyway, I decided to move to GitHub Container Registry and use GitHub Actions–which was already running my unit tests–to build and push the images.

Fixing Firefox's Font Rendering

Sat, 27 Jun 2020 12:00:00 -0800

I’ve recently switched back to Firefox as my primary web browser, but on my workstation running Fedora 32, I found that the font rendering was kind of gross and was very unpleasant to look at. Luckily, Reddit user sweetcollector pointed out not only the problem(that Firefox doesn’t use the font configuration provided by the desktop environment), but the solution:

Create /etc/fonts/local.conf and place in it the following content:

<?xml version='1.0'?>
<!DOCTYPE fontconfig SYSTEM 'fonts.dtd'>
<fontconfig>
 <match target="font">
 <edit name="antialias" mode="assign">
 <bool>true</bool>
 </edit>
 <edit name="autohint" mode="assign">
 <bool>false</bool>
 </edit>
 <edit name="hinting" mode="assign">
 <bool>true</bool>
 </edit>
 <edit name="hintstyle" mode="assign">
 <const>hintslight</const>
 </edit>
 <edit name="lcdfilter" mode="assign">
 <const>lcddefault</const>
 </edit>
 <edit name="rgba" mode="assign">
 <const>rgb</const>
 </edit>
 </match>
</fontconfig>

After restarting Firefox, it should start using the fonts your DE recommends and better fit into your OS theme.

Side-Project: GroupVault

Fri, 08 May 2020 12:00:00 -0800

I’ve restarted work on my side-project: GroupVault.

This project comes from my dissatisfaction with many (read: all I’ve found) of the open-source team-based password managers out there. They either look good but don’t support folders; have folders, but look terrible and have no real API; or some combination of the above.

My goal is fairly simple: create a web app that provides a secure mechanism for storing credentials in a folder-based hierarchy with role-based access control. These credentials should be able to be accessed by authorized users via a clean, modern web interface or via a REST API. It may take some work, but I think it will be worth it.

Ansible Roles

Sat, 25 Apr 2020 12:00:00 -0800

I find myself creating a lot of Ansible playbooks and roles for work and I’ve decided that I should start making the more generic ones publicly available.

So, please check out my Ansible Galaxy page where I’ll be releasing my roles.

For now, there’s a single role that sets up Docker CE on a system, including adding a new disk in for overlay2 storage.

Black and White Cards

Mon, 13 Apr 2020 12:00:00 -0800

The COVID-19 epidemic has got me working on a new side project: a way to play Cards Against Humanity online.

I’m writing a Django application to allow folks to play CAH together and hopefully bring a little more brightness into isolation.

Finding Files in Found Directories with Ansible

Wed, 27 Nov 2019 12:00:00 -0800

If you spend some time around shell scripts, you’ve likely come across one that looks something like this:

#!/bin/bash
LOG_DIR=/my/log/dir

cd ${LOG_DIR}

for h in `ls -d web*`
do
 cd ${LOG_DIR}/${h};
 for f in `ls access.log-20??????.gz`
 do
 # move these to cold storage
 ...
 done
done

For those whose BASH is a little rusty, this script goes into a log directory, finds all of the subdirectories that begin with ‘web’, then finds files matching a glob pattern inside of those and does something with them.

New Blog Coming

Thu, 28 Feb 2019 12:00:00 -0800

With the release of .dev domains and therefore my ability to get a nice, clean domain for myself, I’ve decided to redo my blog. I’ll be moving relevant content over here, so all of my old articles that are still even remotely relevant will find their way here.

Also, the new blog will hopefully be much easier to use on my end, so I’ll be putting more content up.

Deploying Docker Containers without Leaking Secrets

Wed, 16 Jan 2019 12:00:00 -0800

I maintain a Django application at the company at which I am employed. Initially, changes weren’t very frequent, so logging into the host and running a few commands when the application needed to be updated wasn’t a big deal. However, feature creep has set in and changes to the code base are not only more frequent, but are done by more people. Something had to be done.

Notes on DMing on Roll20

Thu, 04 Jan 2018 12:00:00 -0800

Making Tokens

I use RPTools’ TokenTool (now 2.0, having upgraded from version b27) to create (N)PC tokens from the character’s portrait. The tool is fairly simple:

Extract the zip file and double-click on ‘tokentool-1.0.b27.jar’
- After a moment, the tool’s window will launch.
Drag-and-drop the character’s portrait onto the black portion of the window.
Size and position the image.
- Click-and-drag the image to reposition.
- Use the arrow buttons on the right to size the image. Double-arrows are for large size changes single-arrows are for smaller changes.
Using the dropdown box, select the ring for the token
- Personally, I use circles for PCs and hexagons for NPCs, but this is entirely up to you.
Under the file menu, select Save Token and save the new token where you want it.
Upload to Roll20
???
Profit

Using Tokens in Game

Now that your tokens have been created, you need to use them. Drop them onto the Object/Token layer, click on it, then on the gear to edit it.

NuPass Released

Thu, 29 Jun 2017 12:00:00 -0800

NuPass, my user-readable password generator, is now released (currently 0.2.1) and is available on PyPI.

This means that I should get to updating NuPassWeb and its live version, nupass.pw. I’m totally open to pull requests, if you feel like helping out.

Updating the Firmware on Quanta LB4M Switches

Wed, 20 Jul 2016 12:00:00 -0800

There seems to be a lack of information (that isn’t misinformation) on how to upgrade the firmware on Quanta LB4M switches. Posts abound containing warnings about bricking your switch. Likely, these people attempted some XMODEM transfer that was not needed. All you need is a TFTP server, which can even be running on your local computer.

Grab a copy of the firmware from Jared’s site (or my mirror: 1.1.0.8 / 1.0.2.17). I used lb4m.1.1.0.8.bin as it’s the latest and seems to be the most featureful, although I’m still trying to locate a copy of the release notes for each version.

Getting FDMA Working on a CPN

Fri, 15 Feb 2013 12:00:00 -0800

I will show here the basic configuration of how to get FDMA working on a Lot 10 CPN. All CECOM documentation only shows how to get a JNN working but as CPNs don’t have a GPS to provide timing, we have to do things a little differently.

Cabling

TFOCA-2 runs from Port 1 on the LOS case to J1 on the STT. In our LOS case, we had to use the spare fiber pair to connect to the CTM-100/C.
Serial cable connects from NT2R Serial0/0/0 to the LOS case’s Channel 1 Red.
Serial patch from Port 1 NRZ to Channel 1 Black (all on the LOS case).
FDMA modem and CTM-100/C installed as labeled in the STT.
KIV-7M installed as labeled in the LOS case, COMSEC loaded, and strappings matching the HUB.

CTM-100/C Configurations

The following setup will allow your CTMs to pull timing through your FDMA modem.