Class: CemAcpt::LocalPortAllocator

Inherits:
Object
  • Object
show all
Defined in:
lib/cem_acpt/shared_objects.rb

Overview

Handles local port allocation for things like local SSH tunnels. This class is thread-safe as the port range is a Concurrent::Array, which blocks when modified. When this class is initialized, it's total assignable ports are set to all ports in the ephemeral port range. When a port is allocated, it's removed from the port range.

Constant Summary collapse

EPHEMERAL_PORT_RANGE = 
(49_152..65_535).to_a.freeze

Instance Method Summary collapse

Constructor Details

#initialize ⇒ LocalPortAllocator

Returns a new instance of LocalPortAllocator.



370
371
372
 
# File 'lib/cem_acpt/shared_objects.rb', line 370

def initialize
  @port_range = Concurrent::Array.new(EPHEMERAL_PORT_RANGE.dup).shuffle!
end

Instance Method Details

#allocate(number_of_ports = 1) ⇒ Integer+

Returns an open port(s) in the ephemeral port range on the local machine. If 'number_of_ports' is specified and greater than one, returns an array of ports. If 'number_of_ports' is not specified or is one, returns a single port.

Parameters:

  • number_of_ports (Integer) (defaults to: 1) —

    the number of ports to allocate

Returns:

  • (Integer, Array<Integer>) —

    the port(s) allocated

Raises:

  • (ArgumentError) —

    if number_of_ports is not an Integer or is less than one

  • (LocalPortAllocationError) —

    if there are no ports available



381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
 
# File 'lib/cem_acpt/shared_objects.rb', line 381

def allocate(number_of_ports = 1)
  unless number_of_ports.is_a?(Integer) && number_of_ports.positive?
    raise ArgumentError, 'number_of_ports must be a positive integer'
  end
  raise LocalPortAllocationError, 'No ports available' if @port_range.empty?

  ports = []
  while ports.length < number_of_ports
    port = @port_range.pop
    next unless local_port_open?(port)

    ports << port
  end
  return ports[0] if ports.length == 1

  ports
end