Class: Erlnixify::Node

Inherits:
Object
  • Object
show all
Defined in:
lib/erlnixify/node.rb

Overview

The process class owns the Running erlang process. It knows how to query it if its active, and kill it if something goes long. This class is the guts of erlnixify

Instance Method Summary collapse

Constructor Details

#initialize(settings) ⇒ Node

Returns a new instance of Node.



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# File 'lib/erlnixify/node.rb', line 17

def initialize(settings)
  @settings = settings
  @command = @settings[:command] % settings.settings
  @check_command = self.interpolate_cmd(@settings[:check])
  @halt_command = self.interpolate_cmd(SHUTDOWN_COMMAND)
  @brutal_halt_command = self.interpolate_cmd(BRUTAL_SHUTDOWN_COMMAND)
  @checkregex = Regexp.new @settings[:checkregex]

  @log = Logger.new(STDOUT)
  @log.level = Logger::DEBUG

end

Instance Method Details

#check ⇒ Object 



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# File 'lib/erlnixify/node.rb', line 98

def check
  begin
    Timeout.timeout(@settings[:checktimeout]) do
      self.raw_check
    end
  rescue Timeout::Error
    self.halt_nicely
    raise NodeError, "Check command timeout occurred"
  end
end

#external_kill ⇒ Object 



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# File 'lib/erlnixify/node.rb', line 175

def external_kill
  if self.is_running?
    @log.debug "Killing pid: #{@pid}"
    Process.kill("KILL", @pid) if @pid
  end
end

#halt_brutally ⇒ Object 



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# File 'lib/erlnixify/node.rb', line 166

def halt_brutally
  if self.is_running?
    @log.debug "Executing halt brutally: #{@brutal_halt_command}"
    `#{@brutal_halt_command}`
    sleep @settings[:checkinterval]
    self.external_kill
  end
end

#halt_nicely ⇒ Object 



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# File 'lib/erlnixify/node.rb', line 157

def halt_nicely
  if self.is_running?
    @log.debug "Executing halt nicely: #{@halt_command}"
    `#{@halt_command}`
    sleep @settings[:checkinterval]
    self.halt_brutally
  end
end

#interpolate_cmd(cmd) ⇒ Object 



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# File 'lib/erlnixify/node.rb', line 182

def interpolate_cmd(cmd)
  local_settings = @settings.settings.clone
  local_settings[:cmd] = cmd % local_settings
  COMMAND_WRAPPER % local_settings
end

#is_running? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/erlnixify/node.rb', line 133

def is_running?
  @log.debug "Checking if Pid (#{@pid}) is running"
  if @pid
    begin
      Process.getpgid(@pid)
      true
    rescue Errno::ESRCH
      false
    end
  else
    false
  end
end

#monitor ⇒ Object 



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# File 'lib/erlnixify/node.rb', line 84

def monitor
  @log.debug "starting monitor of Pid #{@pid}"
  loop do
    if is_running?
      self.check
      sleep @settings[:checkinterval]
    else
      raise NodeError, "Node not running"
    end
    break if @stop
    @log.debug "Node responded correctly, continuing check"
  end
end

#raw_check ⇒ Object 



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# File 'lib/erlnixify/node.rb', line 120

def raw_check
  @log.debug "#{@check_command} =~ #{@checkregex}"
  result = `#{@check_command}`
  @log.debug "result #{result}"
  if not (result =~ @checkregex)
    @log.info "invalid state"
    self.halt_nicely
    raise NodeError, "Node check failed"
  else
    @log.info "running"
  end
end

#raw_start_daemon ⇒ Object 



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# File 'lib/erlnixify/node.rb', line 65

def raw_start_daemon
  @log.debug "starting daemon"
  env = {}
  env["HOME"] = @settings[:home] if @settings[:home]

  begin
    @log.debug "spawning command '#{@command}' with #{env}"
    @pid = Process.spawn(env, @command)
    Process.detach @pid
  rescue Errno::ENOENT
    @log.debug "Invalid command provided, raising error"
    raise NodeError, "Command does not exist"
  end

  @log.debug "waiting for #{@settings[:startuptimeout]} seconds for startup"
  sleep @settings[:startuptimeout]
  self.status
end

#start ⇒ Object 



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# File 'lib/erlnixify/node.rb', line 30

def start
  self.start_daemon

  Signal.trap("TERM") do
    # This is going to propagate to the running erlang
    # node. Unfortunately, there is no way to stop that that I
    # have found yet. Hopefully, in the near future we can resolve
    # that.
    raise NodeError, "SIGTERM recieved, shutting down"
  end

  Signal.trap("INT") do
    # This is going to propagate to the running erlang
    # node. Unfortunately, there is no way to stop that that I
    # have found yet. Hopefully, in the near future we can resolve
    # that.
    raise NodeError, "SIGINT recieved, shutting down"
  end

  at_exit { self.external_kill }

  @log.debug "waiting for #{@settings[:startuptimeout]} seconds for startup"
  sleep @settings[:startuptimeout]
  self.monitor
end

#start_daemon ⇒ Object

Raises:



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# File 'lib/erlnixify/node.rb', line 56

def start_daemon
  begin
    self.status
  rescue NodeError => msg
    return self.raw_start_daemon
  end
  raise NodeError, "Already started"
end

#status ⇒ Object 



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# File 'lib/erlnixify/node.rb', line 109

def status
  begin
    Timeout.timeout(@settings[:checktimeout]) do
        self.raw_check
    end
  rescue Timeout::Error
    self.halt_nicely
    raise NodeError, "Check command timeout occurred"
  end
end

#stop ⇒ Object 



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# File 'lib/erlnixify/node.rb', line 147

def stop
  @log.debug "Executing halt nicely: #{@halt_command}"
  `#{@halt_command}`
  if not $?
    sleep @settings[:checkinterval]
  else
    raise NodeError, "Got status #{$?}"
  end
end