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.

100

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 364

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 127

def group
  @group
end

#log_path ⇒ Object

Process log output



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# File 'lib/runnable.rb', line 137

def log_path
  @log_path
end

#options ⇒ Object

Process options



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# File 'lib/runnable.rb', line 135

def options
  @options
end

#output ⇒ Object

Process output



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# File 'lib/runnable.rb', line 132

def output
  @output
end

#owner ⇒ Object (readonly)

Process owner.



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

def owner
  @owner
end

#pid ⇒ Object (readonly)

Process id.



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

def pid
  @pid
end

#pwd ⇒ Object (readonly)

Directory where process was called from.



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# File 'lib/runnable.rb', line 129

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 383

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 334

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 149

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 143

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 297

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 279

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 254

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 244

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 291

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 158

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 261

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 391

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 273

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 267

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 233

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