Script to get logs or a console into k8s pods

k8s.rb

# gem install tty-prompt
# gem install tty-command

require 'tty-prompt'
require 'tty-command'
require 'thor'
require 'pry'

class MyCLI < Thor
  class_option :env, type: :string, default: ENV['K8S_ENV']
  class_option :app, type: :string, default: ENV['K8S_APP']
  class_option :run, type: :string, default: ENV['K8S_RUN']

  desc "console", "Get a console"
  def console()
    if !options.key("run") && options["run"].nil?
      puts "Unknown run type, need to know if its rails or elixir\n  Use --run=RUN\n  Or set env K8S_RUN=RUN"
      exit(-1)
    end

    [:console, options]
  end

  desc "logs", "Show logs"
  def logs()
    [:logs, options]
  end
end

command, _options = MyCLI.start(ARGV)
options = _options.dup # to unfreeze Thor returned object
options ||= {}

if !options.key("env") && options["env"].nil?
  prompt = TTY::Prompt.new
  options["env"] = prompt.select("ENV", %w(qa staging prod))
end

if !options.key("app") && options["app"].nil?
  puts "Unknown app\n  Use --app=APP\n  Or set env K8S_APP=APP"
  exit(-1)
end

puts "* Finding #{options["app"]} pods on #{options["env"]}..."

# Get a list of pods on given ENV matching given APP
cmd = TTY::Command.new(printer: :null)
kubectl = "kubectl --context #{options["env"]} get pods | grep #{options["app"]}"
result, _err = cmd.run(kubectl)

# Extract pod names from kubectl result
pods = result.split.each_slice(5).map { |a| a[0] }

prompt = TTY::Prompt.new
pod = prompt.select("Which pod", pods)

def get_pod_command(run)
  case run
  when "rails"
    "rails console"
  when "elixir"
    "./bin/rex remote_console"
  end
end

def get_command(command, env, pod, run)
  case command
  when :logs
    "kubectl --context #{env} logs -f #{pod}"
  when :console
    "kubectl --context #{env} exec -it #{pod} #{get_pod_command(run)}"
  end
end

run_cmd = get_command(command, options["env"], pod, options["run"])
puts "* Performing : #{run_cmd}"
exec(run_cmd)