Class: Nerve::ServiceCheck::TcpServiceCheck

Inherits:
BaseServiceCheck show all
Includes:
Socket::Constants
Defined in:
lib/nerve/service_watcher/tcp.rb

Instance Method Summary collapse

Methods inherited from BaseServiceCheck

#catch_errors, #up?

Methods included from Logging

configure_logger_for, #log, logger_for

Methods included from Utils

#safe_run

Constructor Details

#initialize(opts = {}) ⇒ TcpServiceCheck

Returns a new instance of TcpServiceCheck.

Raises:

  • (ArgumentError) 


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# File 'lib/nerve/service_watcher/tcp.rb', line 9

def initialize(opts={})
  super

  raise ArgumentError, "missing required argument 'port' in tcp check" unless opts['port']

  @port = opts['port']
  @host = opts['host'] || '127.0.0.1'

  @address = Socket.sockaddr_in(@port, @host)
end

Instance Method Details

#check ⇒ Object 



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# File 'lib/nerve/service_watcher/tcp.rb', line 20

def check
  log.debug "nerve: running TCP health check #{@name}"

  # create a TCP socket
  socket = Socket.new(AF_INET, SOCK_STREAM, 0)

  begin
    # open a non-blocking connection
    socket.connect_nonblock(@address)
  rescue Errno::EINPROGRESS
    # opening a non-blocking socket will usually raise
    # this exception. it's just connect returning immediately,
    # so it's not really an exception, but ruby makes it into
    # one. if we got here, we are now free to wait until the timeout
    # expires for the socket to be writeable
    IO.select(nil, [socket], nil, @timeout)

    # we should be connected now; allow any other exception through
    begin
      socket.connect_nonblock(@address)
    rescue Errno::EISCONN
      return true
    end
  else
    # we managed to connect REALLY REALLY FAST
    log.debug "nerve: connected to non-blocking socket without an exception"
    return true
  ensure
    socket.close
  end
end