Class: Runnable

Inherits:
Object
  • Object
show all
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 < Runnable
  command_style :extended
end

ls = LS.new
ls.alh
ls.run

Constant Summary collapse

HERTZ =

Constant to calculate cpu usage.

100
@@processes =

List of runnable instances running on the system order by pid.

Hash.new

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(option_hash = {}) ⇒ Runnable

Create a new instance of a runnable command.

Parameters:

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

    Options.

Options Hash (option_hash):

  • :delete_log (Object) — default: true —

    Delete the log after execution.

  • :command_options (Object) — default: "" —

    Command options.

  • :log_path (Object) — default: "/var/log/runnable" —

    Path for the log files.



77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
 
# File 'lib/runnable.rb', line 77

def initialize( option_hash = {} )
  # keys :delete_log
  #      :command_options
  #      :log_path
  
  # If we have the command class in a namespace, we need to remove
  # the namespace name
  @command = self.class.to_s.split( "::" ).last.downcase
  
  # Set the default command option
  # Empty by default
  option_hash[:command_options] ||= ""
  @options = option_hash[:command_options]
  
  # Set the log path
  # Default path is "/var/log/runnable"
  option_hash[:log_path] ||= "/var/log/runnable/"
  @log_path = option_hash[:log_path]

  # Set the delete_log option
  # true by default
  if option_hash[:delete_log] == nil
    @delete_log = true
  else 
    @delete_log = option_hash[:delete_log]
  end

  # Store input options
  @input = String.new

  # Store output options
  @output = String.new

  # Standar Outputs
  @std_output = {
    :out => "",
    :err => ""
    }

  # @todo: checks that command is in the PATH
  # ...
  
  # we dont set the pid, because we dont know until run
  @pid = nil
  @excep_array = []
  

  # Metaprogramming part  
  # Create a new instance of the parser class
  @command_line_interface = Object.const_get( command_style.to_s.capitalize.to_sym ).new
  # End Metaprogramming part
 
  #End of initialize instance variables
 
  create_log_directory
end

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) 


356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
 
# File 'lib/runnable.rb', line 356

def method_missing( method, *params, &block )
  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.



40
41
42
 
# File 'lib/runnable.rb', line 40

def group
  @group
end

#input ⇒ Object

Input file



45
46
47
 
# File 'lib/runnable.rb', line 45

def input
  @input
end

#output ⇒ Object

Set the output file



48
49
50
 
# File 'lib/runnable.rb', line 48

def output
  @output
end

#owner ⇒ Object (readonly)

Process owner.



38
39
40
 
# File 'lib/runnable.rb', line 38

def owner
  @owner
end

#pid ⇒ Object (readonly)

Process id.



36
37
38
 
# File 'lib/runnable.rb', line 36

def pid
  @pid
end

#pwd ⇒ Object (readonly)

Directory where process was called from.



42
43
44
 
# File 'lib/runnable.rb', line 42

def pwd
  @pwd
end

Class Method Details

.command_style(style) ⇒ nil

Define the parameter style to be used.

Returns:

  • (nil) 


54
55
56
57
58
 
# File 'lib/runnable.rb', line 54

def self.command_style( style )
  define_method( :command_style ) do
    style
  end
end

.processes ⇒ Hash

List of runnable instances running on the system.

Returns:

  • (Hash) —

    Using process pids as keys and instances as values.



374
375
376
 
# File 'lib/runnable.rb', line 374

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.



326
327
328
329
330
331
332
333
334
335
336
337
 
# File 'lib/runnable.rb', line 326

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_style ⇒ Symbol

Parameter style used for the command.

Returns:

  • (Symbol) —

    Command style.



62
63
64
 
# File 'lib/runnable.rb', line 62

def command_style
  :gnu
end

#cpu ⇒ Number

Estimated CPU usage in %.

Returns:

  • (Number) —

    The estimated cpu usage.



288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
 
# File 'lib/runnable.rb', line 288

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

#exceptions ⇒ Hash

This method is abstract.
Note:

This method should be overwritten in child classes.

Returns a hash of regular expressions and exceptions associated to them. Command output is match against those regular expressions, if it does match an appropiate exception is included in the return value of execution.

Examples:

Usage:

class ls < Runnable
  def exceptions
    { /ls: (invalid option.*)/ => ArgumentError }
  end
end

Returns:

  • (Hash) —

    Using regular expressions as keys and exceptions that should be raised as values.



392
393
394
 
# File 'lib/runnable.rb', line 392

def exceptions
  {}
end

#failed(exceptions) ⇒ nil

This method is abstract.

Method called when command executions fail. This method is a hook so it should be overwritten in child classes.

Parameters:

  • exceptions (Array) —

    Array containing exceptions raised during the command execution.

Returns:

  • (nil) 


408
409
 
# File 'lib/runnable.rb', line 408

def failed( exceptions )
end

#finish ⇒ nil

This method is abstract.

Method called when command ends with no erros. This method is a hook so it should be overwritten in child classes.

Returns:

  • (nil) 


400
401
 
# File 'lib/runnable.rb', line 400

def finish
end

#join ⇒ nil

Wait for command thread to finish it execution.

Returns:

  • (nil) 


258
259
260
 
# File 'lib/runnable.rb', line 258

def join
  @run_thread.join if @run_thread.alive?
end

#kill ⇒ nil

TODO:

Raise an exeption if process is not running.

Kill the comand.

Returns:

  • (nil) 


248
249
250
251
252
253
254
 
# File 'lib/runnable.rb', line 248

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.



282
283
284
 
# File 'lib/runnable.rb', line 282

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

#run ⇒ nil

Start the execution of the command.

Returns:

  • (nil) 


136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
 
# File 'lib/runnable.rb', line 136

def run
  # Create a new mutex
  @pid_mutex = Mutex.new

  # 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
  @excep_array = []

  # Set up the command line
  command = []          
  #command << @command
  command << @input.to_s
  command << @options.to_s
  command << @command_line_interface.parse
  command << @output.to_s
  #command = command.join( " " )
  command.flatten!
  
  command = command.select do |value| 
    !value.to_s.strip.empty?
  end
=begin
  # Debugging purpose
  puts "I: #{@input}"
  puts "OP: #{@options}"
  puts "CLI: #{@command_line_interface.parse}"
  puts "O: #{@output}"
  puts "C: #{command}"
=end
  #@pid = Process.spawn( command, { :out => out_wr, :err => err_wr } )
  @pid = Process.spawn( @command, *command, { :out => out_wr, :err => err_wr } )

  # Include instance in class variable
  @@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
  create_logs(:out => [out_wr, out_rd], :err => [err_wr, err_rd])
  
  # Create a new thread to avoid blocked processes
  @run_thread = Thread.new do
    # Wait to get the pid process even if it has finished
    Process.wait( @pid, Process::WUNTRACED )

    # Wait each I/O thread
    @output_threads.each { |thread| thread.join }
    # Delete log if its necesary
    delete_log

    # Get the exit code from command
    exit_status = $?.exitstatus
    
    # In case of error add an Exception to the @excep_array
    @excep_array << SystemCallError.new( exit_status ) if exit_status != 0
    
    # Call methods according to the exit code
    if @excep_array.empty?
      finish
    else
      failed( @excep_array )
    end
    
    # This instance is finished and we remove it
    @@processes.delete( @pid )
  end
  
  # 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
    # 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
  end
end

#running? ⇒ Bool

Check if prcess is running on the system.

Returns:

  • (Bool) —

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



264
265
266
 
# File 'lib/runnable.rb', line 264

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.



415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
 
# File 'lib/runnable.rb', line 415

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



276
277
278
 
# File 'lib/runnable.rb', line 276

def std_err
  @std_output[:err]
end

#std_out ⇒ String

Standar output of command

Returns:

  • (String) —

    Standar output



270
271
272
 
# File 'lib/runnable.rb', line 270

def std_out
  @std_output[:out]
end

#stop ⇒ nil

TODO:

Raise an exception if process is not running.

Stop the command.

Returns:

  • (nil) 


237
238
239
240
241
242
243
 
# File 'lib/runnable.rb', line 237

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