Module: Runnable

Defined in:
lib/runnable.rb

Overview

Convert a executable command in a Ruby-like class you are able to start, define params and send signals (like kill, or stop)

Examples:

Usage:

class LS 
  include Runnable

  executes :ls
  command_style :extended
end

ls = LS.new
ls.alh
ls.run

Defined Under Namespace

Modules: ClassMethods

Accessors for the module class variables collapse

HERTZ =

Constant to calculate cpu usage.

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Accessors for the module class variables collapse

Accessors for the module class variables collapse

Class Method Summary collapse

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(method, *params, &block) ⇒ nil

Convert undefined methods (ruby-like syntax) into parameters to be parsed at the execution time. This only convert methods with zero or one parameters. A hash can be passed and each key will define a new method and method name will be ignored.

Examples:

Valid calls:

find.depth                                         #=> find -depth
find.iname( '"*.rb"')                              #=> find -iname "*.rb"
find.foo( { :iname => '"*.rb"', :type => '"f"' } ) #=> find -iname "*.rb" - type "f"

Invalid calls:

sleep.5 #=> Incorrect. "5" is not a valid call to a ruby method so method_missing will not be invoked and will
raise a tINTEGER exception

Parameters:

  • method (Symbol) —

    Method called that is missing

  • params (Array) —

    Params in the call

  • block (Block) —

    Block code in method

Returns:

  • (nil) 


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# File 'lib/runnable.rb', line 360

def method_missing( method, *params, &block )
  @command_line_interface ||= Object.const_get( command_style.to_s.capitalize.to_sym ).new

  if params.length > 1
    super( method, params, block )
  else
    if params[0].class == Hash
      # If only one param is passed and its a Hash
      # we need to expand the hash and call each key as a method with value as params
      # @see parse_hash for more information
    parse_hash( params[0] )
    else
      @command_line_interface.add_param( method.to_s, params != nil ? params.join(",") : nil )
    end
  end
end

Instance Attribute Details

#group ⇒ Object (readonly)

Process group.



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# File 'lib/runnable.rb', line 123

def group
  @group
end

#log_path ⇒ Object

Process log output



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# File 'lib/runnable.rb', line 133

def log_path
  @log_path
end

#options ⇒ Object

Process options



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# File 'lib/runnable.rb', line 131

def options
  @options
end

#output ⇒ Object

Process output



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# File 'lib/runnable.rb', line 128

def output
  @output
end

#owner ⇒ Object (readonly)

Process owner.



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# File 'lib/runnable.rb', line 121

def owner
  @owner
end

#pid ⇒ Object (readonly)

Process id.



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# File 'lib/runnable.rb', line 119

def pid
  @pid
end

#pwd ⇒ Object (readonly)

Directory where process was called from.



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# File 'lib/runnable.rb', line 125

def pwd
  @pwd
end

Class Method Details

.included(klass) ⇒ Object 



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# File 'lib/runnable.rb', line 38

def self.included(klass)
  klass.extend ClassMethods
end

.processes ⇒ Hash

List of runnable instances running on the system.

Returns:

  • (Hash) —

    Using process pids as keys and instances as values.



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# File 'lib/runnable.rb', line 379

def self.processes
  @@processes
end

Instance Method Details

#bandwidth(iface, sample_lapse = 0.1) ⇒ Number

Estimated bandwidth in kb/s.

Parameters:

  • iface (String) —

    Interface to be scaned.

  • sample_time (Number) —

    Time passed between samples in seconds. The longest lapse the more accurate stimation.

Returns:

  • (Number) —

    The estimated bandwidth used.



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# File 'lib/runnable.rb', line 330

def bandwidth( iface, sample_lapse = 0.1 )
  file = "/proc/#{@pid}/net/dev"
  File.open( file ).read =~ /#{iface}:\s+(\d+)\s+/
  init = $1.to_i
  
  sleep sample_lapse

  File.open( file ).read =~ /#{iface}:\s+(\d+)\s+/
  finish = $1.to_i

  (finish - init)*(1/sample_lapse)/1024
end

#command ⇒ String

Default command to be executed

Returns:

  • (String) —

    Command to be executed



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# File 'lib/runnable.rb', line 145

def command
  self.class.to_s.split( "::" ).last.downcase
end

#command_style ⇒ Symbol

Parameter style used for the command.

Returns:

  • (Symbol) —

    Command style.



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# File 'lib/runnable.rb', line 139

def command_style
  :gnu
end

#cpu ⇒ Number

Estimated CPU usage in %.

Returns:

  • (Number) —

    The estimated cpu usage.



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# File 'lib/runnable.rb', line 293

def cpu
  # Open the proc stat file
  begin
    stat = File.open( "/proc/#{@pid}/stat" ).read.split
    
    # Get time variables
    # utime = User Time
    # stime = System Time
    # start_time = Time passed from process starting
    utime = stat[13].to_f
    stime = stat[14].to_f
    start_time = stat[21].to_f
    
    # uptime = Time passed from system starting
    uptime = File.open( "/proc/uptime" ).read.split[0].to_f
    
    # Total time that the process has been executed
    total_time = utime + stime # in jiffies

    # Seconds passed between start the process and now
    seconds = uptime - ( start_time / HERTZ ) 
    # Percentage of used CPU ( ESTIMATED )
    (total_time / seconds.to_f)
  rescue IOError
    # Fails to open file
    0
  rescue ZeroDivisionError
    # Seconds is Zero!
    0
  end
end

#input=(opt) ⇒ Object

Sets the command input to be passed to the command execution

Parameters:

  • opt (String) —

    Command input



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# File 'lib/runnable.rb', line 275

def input=( opt )
  @command_input = opt
end

#join ⇒ nil

Wait for command thread to finish it execution.

Returns:

  • (nil) 


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# File 'lib/runnable.rb', line 250

def join
  @run_thread.join if @run_thread.alive?
  @output unless @output.empty?
end

#kill ⇒ nil

TODO:

Raise an exeption if process is not running.

Kill the comand.

Returns:

  • (nil) 


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# File 'lib/runnable.rb', line 240

def kill
  send_signal( :kill )

  # In order to maintain consistency of @@processes
  # we must assure that @run_thread finish correctly
  join
end

#mem ⇒ Number

Calculate the estimated memory usage in Kb.

Returns:

  • (Number) —

    Estimated mem usage in Kb.



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# File 'lib/runnable.rb', line 287

def mem
  File.open( "/proc/#{@pid}/status" ).read.split( "\n" )[11].split( " " )[1].to_i
end

#run(name = nil, opts = nil, log_path = nil) ⇒ nil

Start the execution of the command.

Returns:

  • (nil) 


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# File 'lib/runnable.rb', line 154

def run(name = nil, opts = nil, log_path = nil)
  return false if @pid
  # Create a new mutex
  @pid_mutex = Mutex.new
  
  # Log path should be an instance variable to avoid a mess
  @log_path = log_path || @log_path

  # Create pipes to redirect Standar I/O
  out_rd, out_wr = IO.pipe
  # Redirect Error I/O
  err_rd, err_wr = IO.pipe

  # Reset exceptions array to not store exceptions for
  # past executions
  command_argument = opts ? opts.split(" ") : compose_command

  @pid = Process.spawn( command.to_s, *command_argument, { :out => out_wr, :err => err_wr } )

  # Include instance in class variable
  self.class.processes[@pid] = self

  # Prepare the process info file to be read
  file_status = File.open( "/proc/#{@pid}/status" ).read.split( "\n" )
  # Owner: Read the owner of the process from /proc/@pid/status
  @owner = file_status[6].split( " " )[1]
  # Group: Read the Group owner from /proc/@pid/status
  @group = file_status[7].split( " " )[1]

  # Set @output_thread with new threads
  # wich execute the input/ouput loop
  stream_info = {
    :out => [out_wr, out_rd],
    :err => [err_wr, err_rd]
  }

  if name
    cmd_info = self.class.commands[name]
    stream_processors = {
      :outputs => cmd_info[:outputs],
      :exceptions => cmd_info[:exceptions]
    }
  end

  output_threads = process_streams( stream_info, stream_processors )

  # Create a new thread to avoid blocked processes
  @run_thread = threaded_process(@pid, output_threads)

  # Satuts Variables
  # PWD: Current Working Directory get by /proc/@pid/cwd
  # @rescue If a fast process is runned there isn't time to get
  # the correct PWD. If the readlink fails, we retry, if the process still alive
  # until the process finish.

  begin
    @pwd ||= File.readlink( "/proc/#{@pid}/cwd" )
  rescue Errno::ENOENT
    # If cwd is not available rerun @run_thread
    if @run_thread.alive?
      #If it is alive, we retry to get cwd
      @run_thread.run
      retry
    else
      #If process has terminated, we set pwd to current working directory of ruby
      @pwd = Dir.getwd
    end
  rescue #Errno::EACCESS
    @pwd = Dir.getwd
  end
end

#running? ⇒ Bool

Check if prcess is running on the system.

Returns:

  • (Bool) —

    True if process is running, false if it is not.



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# File 'lib/runnable.rb', line 257

def running?
  Dir.exists?( "/proc/#{@pid}") 
end

#send_signal(signal) ⇒ Object

TODO:

raise ESRCH if pid is not in system or EPERM if pid is not from user.

Send the desired signal to the command.

Parameters:

  • Signal (Symbol) —

    to be send to the command.



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# File 'lib/runnable.rb', line 387

def send_signal( signal )      
  if signal == :stop
    signal = :SIGINT
  elsif signal == :kill
    signal = :SIGKILL
  end
  
  `ps -ef`.each_line do |line|
    line = line.split
    pid = line[1]
    ppid = line[2]
   
    if ppid.to_i == @pid
      Process.kill( signal, pid.to_i )
    end
  end
  
  begin
    Process.kill( signal, @pid )
  rescue Errno::ESRCH
    # As we kill child processes, main process may have exit already
  end
end

#std_err ⇒ String

Standar error output of the command

Returns:

  • (String) —

    Standar error output



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# File 'lib/runnable.rb', line 269

def std_err
  @std_err ||= ""
end

#std_out ⇒ String

Standar output of command

Returns:

  • (String) —

    Standar output



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# File 'lib/runnable.rb', line 263

def std_out
  @std_out ||= ""
end

#stop ⇒ nil

TODO:

Raise an exception if process is not running.

Stop the command.

Returns:

  • (nil) 


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# File 'lib/runnable.rb', line 229

def stop
  send_signal( :stop )

  # In order to maintain consistency of @@processes
  # we must assure that @run_thread finish correctly
  @run_thread.run if @run_thread.alive?
end