.travis.yml

language: c
script: ./build.sh
env:
  global:
    - "ARTIFACTS_AWS_REGION=us-east-1"
    - "ARTIFACTS_S3_BUCKET=travis-rubies"
    - secure: "..."
    - secure: "..."
  matrix:
    - "RUBY=ruby-head"
    - "RUBY=jruby-head"
    - "RUBY=jruby-head-d20"

build.sh

#!/bin/bash -ex
[[ $RUBY ]] || (echo 'please set $RUBY' && exit 1)

rvm get stable
rvm reload

echo -n > $rvm_path/user/md5
echo -n > $rvm_path/user/sha512

rvm remove $RUBY
rvm install $RUBY --movable --verify-downloads 1
rvm prepare $RUBY

gem install travis-artifacts
travis-artifacts upload --path $RUBY.* --target-path binary

config.ru

require 'sinatra/base'
require 'travis/client'

app = Sinatra.new do
  # Configuration
  enable :logging
  set :travis, uri: 'https://api.travis-ci.com/', access_token: '...'
  set :signatures, [
    "...", # ruby/ruby
    "..."  # jruby/jruby
  ]

  # Travis client
  helpers Travis::Client::Methods
  before { @session = Travis::Client::Session.new(settings.travis) }
  attr_reader :session

  # Check authenticity
  before do
    next if settings.signatures.include? env['HTTP_AUTHORIZATION']
    halt 403, "requests need to come from Travis CI"
  end

  post '/rebuild/:ruby' do
    repo('travis-pro/travis-rubies').last_build.jobs.each do |job|
      next unless job.config['env'].include? "RUBY=#{params[:ruby]}"
      logger.info "restarting #%s" % job.number
      restart job
    end

    "ok"
  end
end

run app

Gemfile

source 'https://rubygems.org'

gem 'sinatra'
gem 'travis'
gem 'puma'

Procfile

web: bundle exec rackup -s puma -p $PORT