Marco Kamner

Kubernetes resources have quite a lot of lists in them and replacing an item in such lists is quite easy using kustomize patches with op: replace.

Replacing a specific list item safely however is not as obvious as the order of items could change, leading to a technically valid but practically incorrect manifest.

There are loads of better ways to do this using Google Search Console / Bing Webmaster Tools / ahrefs and similar tools.

Arguably these might be a bit too much for a small side project or a curious quick check, so this is how I do it. The same syntax works for both Google and Bing.

Building custom domains for your SaaS is not always easy, especially when certificates get involved.

With Caddy it becomes very easy!

Colorize a pattern in the given input using a neat regex and colorization hack in grep ($ matching all lines but not being able to be highlighted).

color () {
  # Color highlight the pattern in the incoming stream, writing to stdout
  # This effectively matches our PATTERN andy any "$" (line end)
  # But only our PATTERN can be highlighted, line end characters aren't actually there to be highlighted
  local PATTERN=$1

  if [ -z "$1" ]; then
    echo "Usage: color <pattern>"
    echo "Description: Greps input with --color=always -E 'PATTERN|\$' "
    echo "Example: echo \"hello world\" | color \"world\""
    return 1

  fi
  grep --color=always "$PATTERN\|\$"
}

kubeswitch (lazy: switch) is the single pane of glass for all of your kubeconfig files. Caters to operators of large scale Kubernetes installations. Designed as a drop-in replacement for kubectx.

I’m using it for all my cluster-switching needs.

Install a pip package from a git repo, using a specified git reference:

DNS is something so fundamental to most of our systems functioning that it’s often overlooked in initial troubleshooting, it’s also incredibly hard to troubleshoot if it’s only intermittently failing.

Doing local development on a bunch of interconnected services I often want to start multiple long running server processes.

This is the basic script I use for that.

When working with multiple Kubernetes clusters and namespaces switching context can be a chore.

For this I enjoy using kubectx and kubens.

They can be installed using kubectl krew.

kubectl krew install ctx
kubectl krew install ns

I often find myself replacing an existing MVP based on static html with a Django app, or just needing to preserve some old URL scheme.

This is the code I use to do that:

from django.shortcuts import redirect

def redirect_view(request, redirectable, permanent=True):
  return redirect(redirectable)

Which can then be used like this:

from django.urls import path
from . import views

urlpatterns = [
    path("old-url/", views.redirect_view, {"redirectable": "new_view"}),
    path("some-thing/", views.redirect_view, {"redirectable": "some_thing_new", permanent=False}),
]

Many of my scripts work with temporary files, usually relative to the scripts directory¹, while at the same time using set -e to exit as soon as something fails.

In this scenario the script leaves behind these temporary files by default, which is not desirable.

We can however do a proper cleanup using the trap concept.

In many CI/CD workflows interfacing with Hashicorp Vault is required.

However, their CLI (or better called unified binary¹) is stupidly big with more than 400MB and they seem to have no interest in making it any smaller².

This is often a undesired size increase, especially when optimizing for pull and run time in CI/CD.

This note outlines a solution that brings us down from 400MB+ on disk for vault to about 300KB using curl and jq.

Coming from NGINX and others the concept of a maintenance mode that can be manually enabled is something I have used many times before.

With Caddy it is equally as easy, just using a less obvious syntax.