tomholford

Plan: Switch to Rolling Deploys with docker-rollout

Context

Deployments currently use docker compose up -d --pull always --force-recreate, which stops and recreates all containers simultaneously, causing 10-30 seconds of downtime per deploy. docker-rollout eliminates this by scaling up new containers alongside old ones, health-checking, then removing old containers — zero-downtime.

The original investigation (gist from ~4 months ago) identified removing container_name as a blocker. That's now resolved — PR #628 confirmed all application services have no container_name and no host ports:.

First deploy does NOT require manually stopping stacks. docker-rollout works with running containers — it scales up alongside them, waits for health, then removes old ones. No manual intervention needed.

tomholford

Installing pg gem on macOS

If you're trying to install the postgresql gem pg and it is failing with the following error message:

Installing pg 1.2.3 with native extensions
Gem::Ext::BuildError: ERROR: Failed to build gem native extension.

    current directory: ~/.rbenv/versions/3.0.0/lib/ruby/gems/3.0.0/gems/pg-1.2.3/ext
~/.rbenv/versions/3.0.0/bin/ruby -I ~/.rbenv/versions/3.0.0/lib/ruby/3.0.0 -r ./siteconf20210125-97201-pycpo.rb extconf.rb

tomholford

extends

An elegant way to nest Rails layouts.

Example Usage

# devise.html.erb
<%= extends :application do %>
 

tomholford

curl https://thispersondoesnotexist.com/image -o ~/$(date +%s).jpg

tomholford

1. Add the following to app/helpers/application_helper.rb:

  def external_link_to(name = nil, options = nil, html_options = nil, &block)
    opts = { target: '_blank', rel: 'nofollow noopener' }
    if block_given?
      options ||= {}
      options = options.merge(opts)
    else
      html_options ||= {}
 html_options = html_options.merge(opts)

tomholford

f = proc do |p|
  Hash.new.merge(
   ->{ p.odd? }.call => 'odd',
   ->{ p.even? }.call => 'even'
  ).fetch(true)
end
=> #<Proc:0x00007ff91188af38@(irb):1>

> f[1]
=> "odd"