klappradla

Debugging in JRuby

Step-by-step debugging and stack navigation for JRuby code.

Problem: the common tools byebug and pry-byebug are MRI-only.

Prerequisites

Force JRuby to run in fully interpreted mode:
(otherwise next would behave like step)

klappradla

# Convert .flac to .mp3 (lossless)
for f in *.flac; do ffmpeg -i "$f" -aq 1 "${f%flac}mp3"; done

# Convert .flac to .mp3, compress to ~ 120k
for f in *.flac; do ffmpeg -i "$f" -aq 5 "${f%flac}mp3"; done

# Convert .flac to mp3, compress to ~ 128k
for f in *.flac; do ffmpeg -i "$f" -b:a 128k "${f%flac}mp3"; done

# Convert .flac to mp3, compress to variable 190k

klappradla

Downgrade tmux installed via homebrew to v 29.a.

Uninstall current version and install from the old formula:

brew uninstall tmux
brew install https://raw.githubusercontent.com/Homebrew/homebrew-core/c8cff106b17b90472cc6e251b9e5c2daf4fd8d46/Formula/tmux.rb

Pin the version to prevent it from accidental upgrades:

klappradla

files:
  "/opt/elasticbeanstalk/hooks/appdeploy/post/01_do_stuff.sh" :
    mode: "000755"
    owner: ec2-user
    group: ec2-user
    content: |
      #! /usr/bin/env bash
      # Using similar syntax as the appdeploy pre hooks that is managed by AWS
      set -xe

klappradla

#!/bin/sh

set -o errexit
set -o nounset

# Create directory
mkdir example && cd example

# Initialize Git repository
git init && git commit --allow-empty -m "init commit"

klappradla

Create Postgres / Postgis Server EC2 Box

Launch Ubuntu instance

1. Click on Launch Instance` button
2. Choose Ubuntu Server 14.04 LTS (HVM), SSD Volume Type
3. Configure Security Group
   In step 6 Configure Security Group add the rule:
   Type: PostgreSQL
   Protocol: TCP
   PortRange: 5432 (default postgres port)

klappradla

begin
  require "bundler/inline"
rescue LoadError => e
  $stderr.puts "Bundler version 1.10 or later is required. Please update your Bundler"
  raise e
end

gemfile(true) do
  source "https://rubygems.org"

klappradla

Procs vs. Lambdas

Seem the same:

[1] pry(main)> pr = proc { p "Hi" }
=> #<Proc:0x007fdc7a1398f0@(pry):8>
[2] pry(main)> lam = -> { p "Hi" }
=> #<Proc:0x007fdc79c53110@(pry):9 (lambda)>
[3] pry(main)> pr.class

klappradla

cd `brew --prefix`
git fetch origin
git reset --hard origin/master

klappradla

# Stop and remove all docker containers
docker stop $(docker ps -a -q)
docker rm $(docker ps -a -q)

# Run an interative console (like byebug or pry)
docker-compose run --service-ports appname