Class: ZTK::TCPSocketCheck

Inherits:
Base
  • Object
show all
Defined in:
lib/ztk/tcp_socket_check.rb

Overview

TCP Socket Checking Class

This class has two basic modes of operation:

  • Read Test

By default we will perform a read test against the host and port specified. In this mode we will attempt to connect to the host and port supplied and if we can read any amount of data, regardless of the content we view this as success.

  • Write Test

If data is supplied via the configuration, this will change the mode of operation to a write test. Certain services, such as HTTP don't send any data unless you send something first. In this mode we will attempt to connect to the host and port supplied, once connected we will write the supplied data to the socket and then attempt to read from the socket. If we can read any amount of data, reagardless of the conent we view this as success.

= Typical usage:

Given a host and port we want to check, we can do something like this:

sc = ZTK::TCPSocketCheck.new(:host => "www.github.com", :port => 22)

Then if we want to check if this host is responding on the specified port:

sc.ready? and puts("They are there!")

This works well for protocols that spew forth some data right away for use to read. However, with certain protocols, such as HTTP, we need to send some data first before we get a response.

Given we want to check a host and port that requires some giving before we can take:

sc = ZTK::TCPSocketCheck.new(:host => "www.google.com", :port => 80, :data => "GET")

Then if we want to check if this host is responding on the specified port:

sc.ready? and puts("They are there!")

The ready? methods timeout is bound to the configuration option timeout.

If we are waiting for a service to come online, we can do this:

sc.wait and puts("They are there!")

The wait methods timeout is bound to the configuration option wait.

Author:

Instance Method Summary (collapse)

Methods inherited from Base

build_config, #config, #direct_log, hash_config, log_and_raise, #log_and_raise

Constructor Details

- (TCPSocketCheck) initialize(configuration = {})

Returns a new instance of TCPSocketCheck

Parameters:

  • configuration (Hash) (defaults to: {}) —

    Configuration options hash.

  • config (Hash) —

    a customizable set of options



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# File 'lib/ztk/tcp_socket_check.rb', line 73

def initialize(configuration={})
  super({
    :timeout => 5,
    :wait => 60
  }, configuration)
end

Instance Method Details

- (Boolean) ready?

Check to see if socket on the host and port specified is ready. This method will timeout and return false after the amount of seconds specified in config.timeout has passed if the socket has not become ready.

Returns:

  • (Boolean) —

    Returns true or false depending on Whether the socket is ready or not.



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# File 'lib/ztk/tcp_socket_check.rb', line 86

def ready?
  config.host.nil? and log_and_raise(TCPSocketCheckError, "You must supply a host!")
  config.port.nil? and log_and_raise(TCPSocketCheckError, "You must supply a port!")

  socket = TCPSocket.new(config.host, config.port)

  if config.data.nil?
    config.ui.logger.debug { "read(#{config.host}:#{config.port})" }
    ((IO.select([socket], nil, nil, config.timeout) && socket.gets) ? true : false)
  else
    config.ui.logger.debug { "write(#{config.host}:#{config.port}, #{config.data.size} bytes)" }
    ((IO.select(nil, [socket], nil, config.timeout) && socket.write(config.data)) ? true : false)
  end

rescue Errno::ETIMEDOUT, Errno::ECONNREFUSED, Errno::ECONNRESET, Errno::EHOSTUNREACH, Errno::EHOSTDOWN, Errno::ENETUNREACH => e
  config.ui.logger.debug { "#{config.host}:#{config.port} - #{e.message}" }
  false
ensure
  (socket && socket.close)
end

- (Boolean) wait

Wait for the socket on the host and port specified to become ready. This method will timeout and return false after the amount of seconds specified in config.wait has passed if the socket has not become ready.

Returns:

  • (Boolean) —

    Returns true or false depending on Whether the socket became ready or not.



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# File 'lib/ztk/tcp_socket_check.rb', line 113

def wait
  config.ui.logger.debug { "Waiting for socket to become available; timeout after #{config.wait} seconds." }
  Timeout.timeout(config.wait) do
    until ready?
      config.ui.logger.debug { "Sleeping 1 second." }
      sleep(1)
    end
  end
  true
rescue Timeout::Error => e
  config.ui.logger.warn { "socket(#{config.host}:#{config.port}) timeout!" }
  false
end