jroddev

Linux

Simple VPN Split Tunnel on Linux

The IP-based split-tunneling that I explore here allows control over which IP addresses go through a default VPN tunnel and which instead go through your regular network interface (or another VPN).

Linux

Kubernetes Rolling Volume Backups

Use rsync hard-links to perform rolling backups of Kubernetes Volumes

Quick Tricks

Bash script to check SSL certificate expiry

This script iterates through my list of targets, checks the certificate expiry and prints the details.

Android

Reading and Writing files in Android 10+ Scoped Storage

Use Kotlin and Jetpack Compose to read and write files with the new scoped storage system in Android 10 and above.

Android

Making HTTP requests with Coroutines in Android

Coroutines are a powerful feature in Kotlin to write asynchronous code that can look like synchronous code. Volley is a popular Android library for making HTTP requests. By combining the two we can drastically simplify code that depends on multiple API calls

Android

Basic XML Parsing in Android

A small code snippet showing how to read values from an xml file in Android

Rust

Rust AST

Examples of TokenStreams and DerivedInput objects in Rust using Syn crate.

Quick Tricks

Decode Webpages using FireFox Plugin

Create a FireFox extension that allows post processing a webpage. Use a mapping file to decode hidden values.

Rust

Writing Tests in Bevy

Here I build the classic phone game Snake,with tests using the Bevy Game Engine.

Testing

Unit Test Scope (Domain)

By understanding what a function is and is not responsible for we reduce duplication and make our code easier to understand and more resilient to change.

Testing

Smaller, Clearer Tests

Generating test values can better express intent of input values. The examples are written using Typescript, but the same technique can be used elsewhere.

Quick Tricks

Cmake, Conan, and GTest Example

A minimal example of a project that uses cmake, conan, and gtest. I make use of the very handy cmake-conan wrapper. This setup also works seamlessly in CLion

C++20

Concepts in Concept Member Functions

In this article I show a way to use Concepts in the member function parameters of other Concepts using function_traits.

C++

Dependency Injection with C++20 Concepts and the Service Provider Pattern

In this article I explore a system of using C++20 Concepts for Dependency Injection

C++

Jthread, Stop Tokens, and Latches

In this article I use jthread, stop tokens and latches to coordinate a worker pool

Quick Tricks

How to create a broken UTF-8 CSV

Create a broken utf8 CSV for use in your unit tests

Quick Tricks

List GitHub Repositories with Search Term

GitHub provides search functionality, but it returns every mention in code. I just needed the list of repositories. Using the GitHub API we are able to fetch these results.

Terraform

AWS Lambdas with Terraform

This project was used to quickly create some server-less functions with AWS Lambda and make them accessible via HTTP requests.

Quick Tricks

Rotating Password Generation Command

Use Linux Watch to continually generate passwords for you

Quick Tricks

Batch convert video files with grep, xargs, sed and ffmpeg

Explore a combination of tools including pipe, grep, find, xargs, and sed to do some video conversion

Linux

Docker is using all my inodes

We recently had an issue where one of our servers was getting out of disk space errors when trying to pull new Docker images. This caught us by surprise as none of our disk usage alerts had fired. Once we got on the box to investigate we realised that it

Quick Tricks

Multiple Git accounts with different SSH keys

It's quite simple to setup multiple Git (in this case GitHub) accounts on the same machine, each using different SSH keys. The scenario that I use this for is to have both a personal account and a work account. Host github-personal HostName github.com IdentityFile ~/.ssh/personal_github_

Kubernetes

K8s Grafana Doesn't Persist Data

I recently setup monitoring on my home MicroK8s [https://microk8s.io/] cluster (Prometheus, Grafana, InfluxDB) and found out the hard way that by default the Grafana deployment does not have any kind of Persistence (emptyDir volume [https://kubernetes.io/docs/concepts/storage/volumes/]). If the pod gets restarted all of

Kubernetes

K8 Host Storage Backups with Rsync and CronJob

I host a single node Kubernetes cluster (MicroK8s) at home running various applications. I use simple hostpath volumes for storage and need a way to create backups of this data. The solution I chose is to combine K8 CronJobs with Rsync. The basic steps are: * Create a backups namespace * Create

Quick Tricks

Application Data Sync with WebDAV

Use WebDAV in your application to sync files (sqlite in my case) between devices. Storage backed by NextCloud, AWS S3, Google Drive, Dropbox and more