module Vagrant::Util::IsPortOpen

Contains the method {#is_port_open?} to check if a port is open (listening) or closed (not in use). This method isn't completely fool-proof, but it works enough of the time to be useful.

Public Instance Methods

is_port_open?(host, port) click to toggle source

Checks if a port is open (listening) on a given host and port.

@param [String] host Hostname or IP address. @param [Integer] port Port to check. @return [Boolean] `true` if the port is open (listening), `false`

otherwise.
# File lib/vagrant/util/is_port_open.rb, line 16
def is_port_open?(host, port)
  # We wrap this in a timeout because once in awhile the TCPSocket
  # _will_ hang, but this signals that the port is closed.
  Timeout.timeout(1) do
    # Attempt to make a connection
    s = TCPSocket.new(host, port)

    # A connection was made! Properly clean up the socket, not caring
    # at all if any exception is raised, because we already know the
    # result.
    s.close rescue nil

    # The port is open if we reached this point, since we were able
    # to connect.
    return true
  end
rescue Timeout::Error, Errno::ECONNREFUSED, Errno::EHOSTUNREACH, Errno::ENETUNREACH
  # Any of the above exceptions signal that the port is closed.
  return false
end