Class: Aptible::CLI::Helpers::Tunnel

Inherits:
Object
  • Object
show all
Defined in:
lib/aptible/cli/helpers/tunnel.rb

Instance Method Summary collapse

Constructor Details

#initialize(env, ssh_cmd) ⇒ Tunnel

Returns a new instance of Tunnel.



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# File 'lib/aptible/cli/helpers/tunnel.rb', line 8

def initialize(env, ssh_cmd)
  @env = env
  @ssh_cmd = ssh_cmd
end

Instance Method Details

#port ⇒ Object 



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# File 'lib/aptible/cli/helpers/tunnel.rb', line 75

def port
  fail 'You must call #start before calling #port!' if @local_port.nil?
  @local_port
end

#start(desired_port = 0) ⇒ Object 



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# File 'lib/aptible/cli/helpers/tunnel.rb', line 13

def start(desired_port = 0)
  @local_port = desired_port
  @local_port = random_local_port if @local_port.zero?

  # First, grab a remote port
  out, err, status = Open3.capture3(@env, *@ssh_cmd)
  fail "Failed to request remote port: #{err}" unless status.success?
  remote_port = out.chomp

  # Then, spin up a SSH session using that port and port forwarding.
  # Pass ExitOnForwardFailure to ensure nothing else can be listening
  # on this port (thanks to Diego Argueta for reporting this issue).
  tunnel_env = @env.merge(
    'TUNNEL_PORT' => remote_port, # Request a specific port
    'TUNNEL_SIGNAL_OPEN' => '1'   # Request signal when tunnel is up
  )

  # TODO: Dynamically compose SendEnv from tunnel_env
  tunnel_cmd = @ssh_cmd + [
    '-L', "#{@local_port}:localhost:#{remote_port}",
    '-o', 'SendEnv=TUNNEL_PORT',
    '-o', 'SendEnv=TUNNEL_SIGNAL_OPEN',
    '-o', 'ExitOnForwardFailure=yes'
  ]

  out_read, out_write = IO.pipe
  err_read, err_write = IO.pipe
  @pid = Process.spawn(tunnel_env, *tunnel_cmd, in: :close,
                                                out: out_write,
                                                err: err_write)

  # Wait for the tunnel to come up before returning. The other end
  # will send a message on stdout to indicate that the tunnel is ready.
  [out_write, err_write].map(&:close)
  begin
    out_read.readline
  rescue EOFError
    stop
    e = 'Tunnel did not come up, is something else listening on port ' \
        "#{@local_port}?\n#{err_read.read}"
    raise e
  ensure
    [out_read, err_read].map(&:close)
  end
end

#stop ⇒ Object 



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# File 'lib/aptible/cli/helpers/tunnel.rb', line 59

def stop
  fail 'You must call #start before calling #stop' if @pid.nil?
  begin
    Process.kill('HUP', @pid)
  rescue Errno::ESRCH
    nil # Dear Rubocop: I know what I'm doing.
  end
  wait
end

#wait ⇒ Object 



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# File 'lib/aptible/cli/helpers/tunnel.rb', line 69

def wait
  Process.wait @pid
rescue Errno::ECHILD
  nil
end