Mark McDonnell Integralist

Common Table Expressions

A Common Table Expression (CTE) in MySQL is a temporary result set that you can reference within a SELECT, INSERT, UPDATE, or DELETE statement.

Think of it as a temporary view that exists only for the duration of that single query. It allows you to write cleaner, more readable SQL by breaking down complex queries into smaller, modular building blocks.

CTEs were introduced in MySQL 8.0, so you will need that version or higher to use them.

The Basic Syntax

livenessProbe: tells Kubernetes whether the container is still alive. If it fails repeatedly, Kubernetes restarts the container.
readinessProbe: tells Kubernetes whether the container is ready to receive traffic. If it fails, the pod stays running but is removed from Service load balancing.
startupProbe: tells Kubernetes whether the app has finished starting up. While it is still failing, Kubernetes suppresses liveness/readiness handling for slow-starting apps.

Typical behavior:

Use livenessProbe to detect deadlocks/hung processes.
Use readinessProbe to gate traffic until dependencies/init work are done.
Use startupProbe when startup is slow and you don’t want liveness to kill the app too early.

Simple mental model:

Discoverable Test Config in Go: Use Flags

Summary of rednafi.com/go/test-config-with-flags.

The article compares three ways to toggle tests in Go (snapshot, integration, real-vs-mock) and argues for custom flags.

1. Build tags — discouraged

//go:build snapshot

Go "Shebang": Running Go Files as Scripts

Summary of lorentz.app: go-shebang by Lorentz Kinde (2025-12).

The trick

Prepend this line to a .go file, chmod +x, then run it directly:

//usr/local/go/bin/go run "$0" "$@"; exit

Documentation Principles & Best Practices

The primary goal of documentation is to reduce friction for the reader. While the best starting point is simply ensuring a README.md exists, adhering to the following pillars will significantly improve the quality and longevity of your technical writing.

Prioritize Brevity and Professionalism

Be Concise: Value the reader’s time. Use AI as a tool to trim wordy explanations and get straight to the point.
Maintain an Even Tone: Avoid letting personal frustrations or over-enthusiasm color the technical content. Aim for a "neutral-expert" voice that remains consistent from start to finish.

Eliminate Assumptions

Define Your Terms: Never assume a concept is "common knowledge."
External Context: Use hyperlinks to Wikipedia or official documentation for industry terms, protocols, or third-party tools to ensure readers of all levels can follow along.

Prometheus Metric Types: A Quick Reference

This guide explains the four core Prometheus metric types, including common "patterns" that might seem counter-intuitive at first glance.

1. Counter

Definition: A cumulative metric that represents a single monotonically increasing counter. Its value can only increase or be reset to zero on restart.

Best for: "How many times has X happened?"
Examples: Total HTTP requests, total errors, bytes received.

https://www.w3schools.com/tags/ref_urlencode.ASP

" %22
, %2C
: %3A
= %3D
\ %5C
[ %5B
] %5D

In a multi-language repository—for example, one that includes both Go and Ruby—you can run into conflicts around the vendor/ directory. Ruby commonly uses a vendor/ directory to store dependencies, but Go’s toolchain assumes that a vendor/ directory follows its own vendoring format (including the modules.txt file that defines vendored modules).

If Ruby’s vendor/ directory is present, the Go toolchain may attempt to interpret it as a Go vendoring directory, leading to unexpected errors.

To prevent this, configure Go to use module mode explicitly and ignore the vendor/ directory (which, in this case, is only relevant to Ruby):

Add -mod=mod to commands such as go build and go test.
Set a global flag with export GOFLAGS=-mod=mod for commands like go tool that do not expose a -mod flag directly.

	// This code demonstrates how you can embed a type,
	// and have it satisfy an interface (`ProblemDetailer`)
	// but only for the embedded type.
	// This works because the interface uses an unexported method,
	// that is part of the embedded type's package.
	// https://go.dev/play/p/7lbikIyPHi1
	//
	// IMPORTANT: If the `isProblem` inteface method was exported (i.e `IsProblem`),
	// then our `Fake` struct would pass the `.(errorsx.ProblemDetailer)` type assertion
	// e.g. https://go.dev/play/p/pPD3OgtiyHx

	// First complete match wins.
	// Because exact children are tried before `` which is tried before `*`.
	// The most-specific rule wins without an explicit priority sort.
	package redirect

	import (
	"fmt"
	"strings"
	)