Random   •   Archives   •   RSS   •   About   •   Contact > Tag: Code

Ubuntu 22.04 Letsencrypt Docker Hints

letsencrypt certbot is now installable via snap (the deb apt repository is no longer maintained).

alternatively you can use certbot via docker if you plan to use the certonly mode.

I did run into some issues & I will document my workarounds here:


for domain …
Continue Reading

Vertically Scaling GitLab Server For As Cheap As Possible

Today's essay acts as a power-up love story for the underdog.

A living document & quickstart for:

  • bootstrappers
  • small business under 99 employees
  • solo ops or devs
  • entrepreneurs
  • hackers
  • tinkerers

You also deserve a quick start to a GitLab Server power house!

Regardless of my intended audience, this strategy should scale …

Continue Reading

GNUnet GNS Nameserver Operator Notes, Quickstart, & Cheatsheet

We GROW with Truth, Freedom, Love.

"You have an ally".

We scroll through the official GNUnet handbook, everything is covered in details, sections have examples. Seems verbose at first glance but also familiar .

Freedom of speech is under attack.

I AM not scared, we understand the technology we have and …

Continue Reading

Copying files between cloud object stores like S3 GCP and Spaces using Boto3

tl;dr if you just want something like aws s3 cp cli, try gsutil rsync.

At work one key item of team's sprint is properly utilizing and securing Google Cloud Platform (GCP).

For one of my projects, I'm learning GCP's Object Store called Google Cloud Storage (GCS).

I have prior …

Continue Reading

I tried to install GitLab on TrueNAS and failed

Ok, so a month ago I changed employment and the new company uses GitLab exclusively for centralized code version control system.

This is my first time using GitLab and my first projects was integrating a dou/cloudmapper with a GitLab runner on a schedule.

After a couple weeks I've learned …

Continue Reading

Unity Collab not working on Fedora because of an invalid CA certificate path

This issue blocked me for about two days and prevented me from collaborating with another engineer at gumyum co-operative video game studio.

An image showing that Unity Collab is not linked

The other engineer's environment was Windows and he was able to interact with collab and our shared project owned by our shared org. My environment was Fedora 30 …

Continue Reading

How to fallback to an older FreeNAS version on update failure

try to log in as root locally, I needed to press ctrl-alt-f7 to get to a log in prompt.

Once logged in as root, I used the beadm command.

For example, beadm list and beadm activate <old-version>.

Finally reboot.

I followed this process and then got my FreeNAS server to …

Continue Reading

Installing Unity on Linux

Russell, why are you installing Unity? I thought you were an open source developer and homegrown video game engine builder?!

gumyum logo

The TL;DR we are starting a video game co-operative called gumyum. The basic idea is to build a large video game company owned completely by members. There will be …

Continue Reading

Pre-signed GET and POST for Digital Ocean Spaces

A pre-signed request grants a semi-trusted user temporary access to a private resource.

Let's unpack that statement ...

Pre-signed means, we bless a specific action on a specific private resource for a short duration of time.

Semi-trusted means, we have authenticated the user, but we don't trust them to have full …

Continue Reading

AWS nvme to block mapping

Recently at work I transitioned our fleet from Ubuntu 14.04 LTS to Ubuntu 18.04 LTS. During the process I noticed an issue with our newer generation AWS EC2 "nitro" based instance types (specifically c5.2xlarge).

AWS was presenting my root block device as /dev/nvme1n1 and my data …

Continue Reading

Yuletide Trains and Homegrown Video Games

pixel art style seasonal wrapped gift

Each holiday season I find myself drawn to a side passion of mine.

While some build model trains and others create Christmas light shows with synchronized music you'll find me on my sofa where I build, explore, and tinker on my own video game engine.

Maybe the sound of wrapping …

Continue Reading

Running DynamoDB Local service container on CircleCI 2.0

tl;dr use a custom entrypoint in your CircleCI 2.0 config to limit Java memory to 1G.

The new CircleCI 2.0 docker configuration supports a "primary image" (listed first) which runs all the "steps" as well as zero or many "service images" (listed subsequently). The "service images", although …

Continue Reading

Pyramid SQLAlchemy bootstrap console script with transaction.manager

So I've struggled for a while with the best way to properly setup a console script for my SQLAlchemy Pyramid apps.

I use the Pyramid Cookiecutter Alchemy to setup my projects and as such, I do not have a global and thus importable DBSession object. Instead my database session is …

Continue Reading

Quickstart to DKIM Sign Email with Python

For a long time I have put off DKIM signing email sent from my web services because I couldn't wrap my head around all the indirection Postfix requires to make it work.

Honestly, I put it off for over 5 years...

Today a thought sprung into my head:

"Could I …
Continue Reading

webwords: a minimal viable web app with docker in as many languages as possible

The companion webwords git repo lives here.

This project shows how to code the same minimal web app called webwords in as many different programming languages as possible. It also provides guides for building and running webwords as a docker image.

Continue Reading

Selenium grid on Kubernetes

This post continues from where we left off on the Minikube guide. If you do not already have a Kubernetes cluster, you should read that first.

Selenium Grid allows you to build a cluster of Selenium nodes. Today we will create a Selenium cluster with 1 hub and 4 nodes …

Continue Reading

Nginx throw HTTP 503 maintenance JSON for all requests

I found this technique after stumbling on Aaron Parecki's blog. You can read his post here:

Lets pretend you have an API and you need to turn on maintenance for a major change. All your …

Continue Reading

Capability driven Presentation

A web page does not need to look the same on every browser or device. We cannot control the capabilities of a user's browser or device. As web designers, we have the duty to give the viewer the best experience possible. A user will come with what they have and …

Continue Reading

Build RPM or DEB packages for Node.js using Jenkins and FPM

This blog post assumes you already have:

  • a Jenkins master and none or many build servers
  • FPM installed on the build servers
  • Node.js installed on the build servers

I add jenkins-build.sh in the root of the Node.js code repo:

# example usage: JOB_NAME=example-api BUILD_NUMBER=101 bash jenkins-build …
Continue Reading

Register Super Powers with Pyramid add_request_method

The Pyramid web application framework uses a request object to hold state regarding an inbound HTTP connection. A view must accept a request object as the first argument which makes it always available to our views and templates.

This behavior rocks, but Pyramid makes it even better by allowing us …

Continue Reading

Sharing a Pyramid cookie with Flask or Tornado

Do you have a Pyramid application which authenticates users and uses a signed cookie as a session? Do you want to build a microservice using another framework and allow it to use the same cookie and session? Me too!

First we will review a bit of Pyramid code which describes …

Continue Reading

My first Systemd Service Script and Override

At work we mostly run Centos and I have some NodeJS services to deploy. I feel most familiar with Ubuntu / Upstart so this post serves as my notes on systemd.

In this contrived example, we define a service for our taco-api application. The taco-api source code lives in /opt/taco-api …

Continue Reading

Set static hostname for RHEL Centos 7 on AWS

This took me about 2 hours to figure out, hopefully it saves you time.






preserve_hostname: true
Continue Reading

If I swallow lots of air will I be lighter?

After dinner tonight, Carter, my four year old asked me, "If I swallow lots of air will I be lighter?". I thought about the question for a moment and then told him it depends on what surrounds you.

If you are surrounded by:
  • air and you swallow lots of air …
Continue Reading

Output all instance identifiers of an AWS VPC to JSON

At work today I needed an easy way to collect private IP addresses of every instance in one of our production VPCs.

I ended up adding a tool to https://botoform.com to perform this task.

bf --profile <aws_profile> dump <vpc_name_tag> instances --output-format json

For example:

bf --profile customer3 dump …
Continue Reading

Migrating from WordPress to Pelican

Five hints to save time during your migration from WordPress.

Continue Reading

Boto3 get main route table

Library work around.

Continue Reading

List all installed package names in Python

You only need a two lines of code to access package names and versions.

Continue Reading

Filtering AWS resources with Boto3

References to take you from filtering novice to expert.

Continue Reading

Working with botocore's ~/.aws/config

Don't reinvent the wheel, use Botocores Config facilities for work with AWS.

Continue Reading

A Python script which searches for available interpreters

Continue Reading

Setting region programmatically in Boto3

Continue Reading

Custom Rundeck HipChat notification templates

Today I built a GUI and workflow around Ansible using Rundeck. Tonight I started diving into sending HipChat notifications and after a bit of research, I managed to create a custom notification template for each Rundeck project.

Modify your project's configuration file, on Ubuntu it was in /var/rundeck/projects …

Continue Reading

Build release pipelines on S3 with s3p

This weekend I finished my first sprint on s3p which is a Python library and CLI application that manages release pipelines on AWS S3. I put a lot of effort into the readme.rst file, so look there for usage and examples.

The main purpose of s3p is to use …

Continue Reading

Dealing with pagination in Python

So I'm working with an API (AWS ElastiCache) that offers mandatory pagination of results. I need to get all results, so I took some time to work out this logic.

def combine_results(function, key, marker=0, **kwargs):
    """deal with manditory pagination of AWS result descriptions"""
    results = []
    while marker != None:
        result …
Continue Reading

Turn python dict into a key=value string and back again

I'm currently refactoring a script that tags AWS resources and I came up with this one liner to generate pretty output. It basically turns {'tag1':'value1','tag2':'value2'} into tag1=value1, tag2=value2. Here is the code:

', '.join(['='.join(key_value) for key_value in {'a':'1','b':'2'}.items() ])

Oh, and …

Continue Reading

You can hack on FreeNAS 9

This post analyses the FreeNAS 9 code base and discusses the various places users may feel confident to hack on.

FreeNAS uses the following software stack:

A Python Web Application Framework which complies with WSGI
A very fast web server which may act as a reverse proxy server …
Continue Reading

Nginx with SSL and mixed content errors with upstream WSGI servers

Mixed content errors occur because Nginx (the front-end server) communicates to the upstream WSGI server using http. WSGI does not know (or care) about the SSL session between Nginx and the user. The WSGI server will naively generate URIs and serve assets as http.

To fix mixed content errors, we …

Continue Reading

IRC Bot (Foxbot) runs canned remote executions using Salt Stack

I extended my IRC Bot Foxbot today to allow it to run canned remote executions on behalf of users in an IRC channel. This is only a prototype or proof-of-concept. Be very careful not to allow users to inject their own commands. Foxbot must be running on the Salt Master …

Continue Reading

Filter Salt Stack Return Data Output

Sometimes you only want to see what has changed, and that is OK.

Create a file like this:



from json import loads
from json import dumps

import fileinput

stdin_lines = [line for line in fileinput.input()]

ret = loads(''.join(stdin_lines))

for minion_id, data in ret.items …
Continue Reading

Replace the Nagios Scheduler and NRPE with Salt Stack

Note: I will update this post as I progress.

So the idea is to use Salt Stack's remote execution to communicate with all nodes and run the Nagios checks and collect the return output instead of using the NRPE client/service protocol. This reduces the number of agents running on …

Continue Reading

Automatic Backups

My tools for creating automatic backups for various systems

Continue Reading


tar-back is a backup utility to tar and gzip target filesystems.
It supports a custom retention, filter exclusions, and backup directory.

I use tar-back in combination with cron to perform regular backups of all localhost filesystems into /archive/fs. I then have a central long term storage server that collects …

Continue Reading


mysql-backis a backup utility script to dump (backup) and gzip every MySQL database on a host.

I use mysql-back in combination with cron to perform regular database dumps of MySQL servers to the /archive/db partition on localhost. I then have a central long term storage server that collects …

Continue Reading

Test Game Engine with Python and SFML

Over this holiday season, Christmas and New Years, I took the time to mess with some Game Development. I wrote a demo game engine using Python and SFML. I plan to use this post to track my progress.

Video Evolution Playlist


Continue Reading

virt-back's Domfetcher class returns doms from libvirt API

Continue Reading

How to overload default function arguments in python using lambda

Python Lambda functions are very powerful but I often forget how they work or the fun things they do. This post will document how to use a lambda to provide different default arguments to a function.

We will use the human function found in ago.py as an example - because …

Continue Reading

ago.py human readable timedelta 0.0.4 release

We have released ago.py 0.0.4

Special thanks to David Beitey for supplying ideas and python code for this update!

All changes are backward compatible.

Change log:

  • added support for future dates
  • added optional past_tense …
Continue Reading

Tips for getting pull requests approved

Pull rejection sucks!

You have just coded, implemented, and submitted a pull …

Continue Reading

Explaining cache with python

What is cache? I define cache as "a saved answer to a question". Caching can speed up an application if a computationally complex question is asked frequently. Instead of the computing the answer over and over, we can use the previously cached answer. This post will present one method of …

Continue Reading

miniuri parser and ago human timedelta

I just packaged and published a couple of python modules to pypi:

To install them, run:


pip install --upgrade ago miniuri

If you want to view their source code, look here:

I hope you enjoy them.

Continue Reading

Prevent a certain program from running too long in bash

Update - I opensourced this script here: bash kira

I came up this this script to kill certain programs after they run for too long. This works like similar to a timeout. Warning this script is pretty harsh and kills the program.


for …
Continue Reading

Zenoss or Nagios monitoring of HTTPS using client certificate authentication

I recently needed to monitor an HTTPS API for response time and availability. At first I planned to just use the Nagios check_http command.

After gathering more requirements I learned that the API was protected by client certificate authentication. After some research I quickly found that no solution existed to …

Continue Reading

Block cipher lab

Consider the following block cipher. Suppose that each block cipher T simply reverses the order of the eight input bits (so that, for example 11110000 becomes 00001111).
Further suppose that the 64-bit scrambler does not modify any bits. With n = 3 iterations and the original 64-bit input equal to 10100000 …
Continue Reading

Monoalphabetic Cipher and Inverse Written in Python

introduction and background

A monoalphabetic cipher uses fixed substitution over the entire message.

You can build a monoalphabetic cipher using a Python dictionary, like so:

monoalpha_cipher = {
    'a': 'm',
    'b': 'n',
    'c': 'b',
    'd': 'v',
    'e': 'c',
    'f': 'x',
    'g': 'z …
Continue Reading

Why does a Hash provide better message integrity then an Internet checksum?

Why does a Hash provide better message integrity then an Internet checksum?

Hash function and checksum function both return a value which cannot be reversed.

An Internet checksum (TCP checksum or IP checksum) is designed to detect common errors quickly and efficiently. An Internet checksum does not attempt to prevent …
Continue Reading

How to Incorporate Custom Configuration in a Pyramid Application

Note: This post shows an old way to modify the request object. I discuss a new way in my Pyramid add_request_method post.

Imagine that you have just built a wiki, blog, or cms web application that will be deployed multiple times by different people. You would like to provide the …

Continue Reading

CSS frameworks not rendering properly on all browsers

Read on for the one line fix.

Continue Reading

LinkPeek.com web address thumbnail api alpha release

Convert any webpage to an image.

Continue Reading

Python Image Grabber pig.py

Download all the images from a URI with this simple tool!

Continue Reading

virt-back: restoring from backups

In a perfect world we should create backups but never need them. Although this statement holds truth, creating guest backups provides many more benefits.

The most common reasons system administrators restore from a virt-back guest backup:

  • recovering from data corruption
  • recovering deleted files
  • recovering from a virus infection
  • recovering from …
Continue Reading

The Great Gist Heist

Please listen to my story before jumping to conclusions.

Continue Reading

a hack to gain 80 percent efficiency when creating github projects

Continue Reading

Add a Breadcrumb Subscriber to a Pyramid project using 4 simple steps

Continue Reading

Google Bot Attempts to Crawl Shortest Urls First

Continue Reading

Porting the ChaosTheory Wordpress theme to Pylowiki

Continue Reading

virt-back: a python libvirt backup utility for kvm xen virtualbox

backup your virtual maching guests.

Continue Reading

Response to L-Theanine: a 4000 Year Old Mind-Hack

Solve problems and write code in your sleep.

Continue Reading

A homegrown python bread crumb module

I have placed bread.py, a python breadcrumb module, into the public domain.

The bread object accepts a url string and grants access to the url crumbs (parts) or url links (list of hrefs to each crumb).

Tutorial: Add a Breadcrumb Subscriber to a Pyramid project using 4 simple steps …

Continue Reading
© Russell Ballestrini.