Colleague: “No, you cannot do functional programming in Python!”

Me: “Hold my pretzel.”

multiinsertL = (lambda list, new, old:
                [] if not list
                else [new, old, *multiinsertL(list[1:], new, old)] if list[0] == old
                else [list[0], *multiinsertL(list[1:], new, old)])

Gitlab 9.5 container registry with amazon S3

After some struggles with some missing documentation I finally did it.

Step 1

Create a bucket and an IAM-User with the recommended policy from

#Step 2
Use this conf in /etc/gitlab/gitlab.rb: (Don’t forget the region)

registry['storage'] = {
  's3' => {
    'accesskey' => 'ACCESS_KEY',
    'secretkey' => 'SECRET_ACCESS_KEY',
    'bucket' => 'S3_BUCKET_NAME',
    'region' => 'S3_REGION' # e.g. 'eu-central-1'

Step 3

(This is the step that drove me almost mad)
Create a folder named “test” in the bucket

Step 4

Start your CI and enjoy your success!

Add a /ping route to your services

You have to rely on something to check if our services are up and running. Wether it’s a monitoring tool, a loadbalancer checking for healthy endpoints, …

I recommend using a a route named /ping and use good old http request for checking.

This way – imho – you have a stronger guarantee that your service is up and running.

PS: Don’t forget to disable logging for this route 😉


Limit access to your staging environment in rails

There exists some confusing information on how to implement password protection for your staging environment. I found the following config suitable: Use your production env for staging and configure the required password with an env-variable.

Add to your config/deploy/production.rb:

    config.middleware.insert_after(::Rack::Runtime, "::Rack::Auth::Basic", "Staging") do |u, p|
        [u, p] == ['staging', ENV['STAGING_PASSWORD']]

Microservice Development Environment on OSX

If you are a Mac user who likes the feeling of deleting stuff and have drunken the docker inc. kool-aid (i.e. implementing microservice architecures on top of the “docker-toolbox”) this just might mean a breath of fresh air for you as well:

  1. uninstall vagrant
  2. trash your “favourite” hypervisor (vmware, virtualbox, etc) with it
  3. learn about the existence of the lean xhyve built on top of Apple’s own hypervisor framework (only on OSX 10.10+)
  4. dlite and docker-compose your docker development containers
  5. docker-compose up  yourself towards getting some programming done again


Post by dlite creator Nathan LaFreniere – Simplifying Docker on OS X