Asti deviousasti

Overview

Internet connection and DNS routing are broken from WSL2 instances, when some VPNs are active.

The root cause seems to be that WSL2 and the VPN use the same IP address block, and the VPN routing clobbers WSL2's network routing.

This problem is tracked in multiple microsoft/WSL issues including, but not limited to:

Some of the books I'll be recommending are based on .NET. Do not be discouraged. We shouldn't strive to stick to a specific technology stack. Your ambitions and goals will evolve over time and that might lead you a completely new space. Moreover, there are lessons to be learned from an environment that's different from what you're used to.

Software Development

"C# in depth" by Jon Skeet (Book)
"F# for C# developers" by Tao Liu (Book)
F# to C# interop tips by Scott Wlaschin (Gist)
Effective F#, tips and tricks (Gist)

Architecture

Use Onion architecture
- Dependencies go inwards. That is, the Core domain doesn't know about outside layers
Use pipeline model to implement workflows/use-cases/stories
- Business logic makes decisions
- IO does storage with minimal logic
- Keep Business logic and IO separate
Keep IO at edges

There doesn't seem to be a good resource online describing the issues with protocol buffers and deterministic serialization (or lack thereof). This is a collection of links on the subject.

Protocol Buffers v3.0.0. release notes:

The deterministic serialization is, however, NOT canonical across languages; it is also unstable across different builds with schema changes due to unknown fields.

Maps documentation:

Wire format ordering and map iteration ordering of map values is undefined, so you cannot rely on your map items being in a particular order.

Railway Oriented Programming and F# Result

Full source: https://gist.github.com/mrange/aa9e0898492b6d384dd839bc4a2f96a1

Option<_> is great for ROP (Railway Oriented Programming) but we get no info on what went wrong (the failure value is None which carries no info).

With the introduction F# 4.1 we got Result<_, _> a "smarter" Option<_> as it allows us to pass a failure value.

However, when one inspects the signature of Result.bind one sees a potential issue for ROP:

Map of 2014 Parliamentary Constituencies in India

This is a d3 map using topojson files derived from shapefiles from the datameet/maps repo.

Many thanks to authors of these awesome code samples.

How to setup your own CA with OpenSSL

For educational reasons I've decided to create my own CA. Here is what I learned.

First things first

Lets get some context first.

	(*
	Simulation of the Lorentz attractor, using Fable.
	If you want to see this code in action, just copy this code into the Fable REPL:
	https://fable.io/repl/
	*)

	module App

	open Elmish
	open Elmish.React

	public static TypeReference ResolveGenericParameter(this TypeReference type, TypeReference parent)
	{
	var genericParent = parent as GenericInstanceType;
	if (genericParent == null)
	return type;

	if (type.IsGenericParameter)
	return genericParent.GenericArguments[(type as GenericParameter).Position];

	if (type.IsArray)

	// ===================
	// Monadic parsing in F#
	// by Murat Girgin
	// Translated from "Monadic parsing in Haskell" paper by Graham Hutton & Erik Meijer
	// Source: http://www.cs.nott.ac.uk/~gmh/pearl.pdf
	// ===================

	#nowarn "40"

	// ---------------------------------------------------------------------------------