Class: DynamicDns::Daemon

Inherits:
Object
  • Object
show all
Defined in:
lib/dynamic_dns/daemon.rb

Constant Summary collapse

@@GET_IP_URI =

create URI to fetch IP address with

URI('https://ipinfo.io/ip')

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(domain, subdomain, interval) ⇒ Daemon

Returns a new instance of Daemon.



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# File 'lib/dynamic_dns/daemon.rb', line 12

def initialize(domain, subdomain, interval)
  log 'created instance'
  # initialize ip address
  @ip = 'NO_IP_SET'
  # initialize the daemon IP interval if necessary
  interval.is_a? Integer or interval = 60
  @INTERVAL = interval
  # set up the dns updater instance
  @UPDATER = DynamicDns::DnsUpdater.new domain, subdomain
end

Instance Attribute Details

#INTERVAL ⇒ Object (readonly)

Returns the value of attribute INTERVAL.



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# File 'lib/dynamic_dns/daemon.rb', line 25

def INTERVAL
  @INTERVAL
end

#ip ⇒ Object (readonly)

accessor methods



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# File 'lib/dynamic_dns/daemon.rb', line 24

def ip
  @ip
end

Instance Method Details

#fetch_ip ⇒ Object

helper to fetch the IP address returns a string represents the ip address



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# File 'lib/dynamic_dns/daemon.rb', line 29

def fetch_ip
  log 'fetching ip'
  request = Net::HTTP::Get.new @@GET_IP_URI
  response = Net::HTTP.start(@@GET_IP_URI.host, @@GET_IP_URI.port, :use_ssl => true) { |http| http.request request }
  response.body.strip!
end

#log(msg) ⇒ Object 



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# File 'lib/dynamic_dns/daemon.rb', line 79

def log(msg)
  puts "[dynamic-dns:daemon] #{msg}"
end

#on_new_ip(new_ip) ⇒ Object 



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# File 'lib/dynamic_dns/daemon.rb', line 69

def on_new_ip(new_ip)
  log "ip has changed from #@ip to #{new_ip}"
  #persist new ip to instance
  @ip = new_ip
  #notify aws
  log "update DNS with new IP #@ip"
  # interval corresponds to ttl in seconds
  @UPDATER.update_record_ip @ip, @INTERVAL
end

#start ⇒ Object 



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# File 'lib/dynamic_dns/daemon.rb', line 36

def start
  log "starting daemon, will check for new ip every #@INTERVAL seconds"
  # set up the thread to loop
  thread = Thread.new do
    log 'set up thread'
    loop do
      log 'start thread loop iteration'
      # get the ip address
      # if it has changed, update DNS
      new_ip = fetch_ip 
      if new_ip != @ip
        on_new_ip(new_ip)
      else
        log "ip has not changed from #@ip"
      end
      # sleep the number of seconds in the interval
      sleep @INTERVAL
    end
  end  

  # ensure thread exits on an exception
  thread.abort_on_exception = true

  # trap SIGINT to exit threads
  trap 'SIGINT' do
    log "received SIGINT, killing thread"
    thread.kill
  end

  # keep main thread attached while background thread runs
  thread.join
end