Heroku dyno networking workaround

gistfile1.txt

#!/usr/bin/env ruby

# 1. Add your environment variable keys below to check them
#    for connectivity.

CHECK = [
  'REDISGREEN_URL',
  # Any other services external to Heroku should have their URLs here
]

# 2. Save this file to bin/check-connection, then:
#   chmod +x bin/check-connection
#
# 3. To test without deploying, run:
#   env -i $(heroku config -s -a your-app) bin/check-connection
#
# 4. Lastly, add it to your Procfile:
#   web: bin/check-connection && bin/start
#
#----------------------------------------------
#----------------------------------------------

require 'uri'
require 'socket'
require 'timeout'

def check(host)
  if host.include?(',')
    return host.split(',').map { |h| check(h) }.inject { |a, b| a && b }
  end
  uri = URI(host)
  Timeout.timeout(1) do
    TCPSocket.new(uri.host, uri.port).close
  end
  true
# ECONNREFUSED, DNS failure, etc
rescue SocketError
  false
# connection timeout
rescue Timeout::Error
  false
# what was provided could not be parsed as uri
rescue URI::InvalidURIError
  true
end

should_exit = false
CHECK.each do |var|
  result = check(ENV[var])
  unless result
    $stderr.puts "!! #{var} failed connection check"
    should_exit = true
  end
end

exit 1 if should_exit