Class: Amberletters::Process

Inherits:
Object
  • Object
show all
Extended by:
Forwardable
Defined in:
lib/amberletters.rb

Constant Summary collapse

END_MARKER = 
'__Amberletters_PROCESS_ENDED__'
DEFAULT_LOG_LEVEL = 
::Logger::WARN
DEFAULT_TIMEOUT = 
1.0
RUBY_EXT =

Shamelessly stolen from Rake

((RbConfig::CONFIG['ruby_install_name'] =~ /\.(com|cmd|exe|bat|rb|sh)$/) ?
      "" :
RbConfig::CONFIG['EXEEXT'])
RUBY = 
File.join(
RbConfig::CONFIG['bindir'],
RbConfig::CONFIG['ruby_install_name'] + RUBY_EXT).
sub(/.*\s.*/m, '"\&"')

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(*args) ⇒ Process

Returns a new instance of Process.



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# File 'lib/amberletters.rb', line 246

def initialize(*args)
  options         = if args.last.is_a?(Hash) then args.pop else {} end
  @command        = args
  @triggers       = []
  @blocker        = nil
  @input_buffer   = StringIO.new
  @output_buffer  = StringScanner.new("")
  @env            = options.fetch(:env) {{}}
  @cwd            = options.fetch(:cwd) {Dir.pwd}
  @logger   = options.fetch(:logger) {
    l = ::Logger.new($stdout)
    l.level = DEFAULT_LOG_LEVEL
    l
  }
  @state         = :not_started
  @shell         = options.fetch(:shell) { '/bin/sh' }
  @transcript    = options.fetch(:transcript) {
    t = Object.new
    def t.<<(*)
      # NOOP
    end
    t
  }
  @history = TranscriptHistoryBuffer.new(@transcript)
  @timeout = options.fetch(:timeout) { DEFAULT_TIMEOUT }

  ObjectSpace.define_finalizer(self) do
    kill!
  end
end

Instance Attribute Details

#blocker ⇒ Object

The Trigger currently being waited for, if any



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# File 'lib/amberletters.rb', line 232

def blocker
  @blocker
end

#command ⇒ Object (readonly)

Command to run in a subshell



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# File 'lib/amberletters.rb', line 231

def command
  @command
end

#cwd ⇒ Object (readonly)

Working directory for the command



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# File 'lib/amberletters.rb', line 236

def cwd
  @cwd
end

#input ⇒ Object (readonly)

Returns the value of attribute input.



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# File 'lib/amberletters.rb', line 237

def input
  @input
end

#input_buffer ⇒ Object (readonly)

Input waiting to be written to process



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# File 'lib/amberletters.rb', line 233

def input_buffer
  @input_buffer
end

#output ⇒ Object (readonly)

Returns the value of attribute output.



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# File 'lib/amberletters.rb', line 238

def output
  @output
end

#output_buffer ⇒ Object (readonly)

Output ready to be read from process



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# File 'lib/amberletters.rb', line 234

def output_buffer
  @output_buffer
end

#pid ⇒ Object (readonly)

Returns the value of attribute pid.



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# File 'lib/amberletters.rb', line 239

def pid
  @pid
end

#status ⇒ Object (readonly)

:not_started -> :running -> :ended -> :exited



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# File 'lib/amberletters.rb', line 235

def status
  @status
end

#timeout ⇒ Object

Returns the value of attribute timeout.



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

def timeout
  @timeout
end

Instance Method Details

#add_blocking_trigger(event, *args, &block) ⇒ Object 



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# File 'lib/amberletters.rb', line 319

def add_blocking_trigger(event, *args, &block)
  t = add_trigger(event, *args, &block)
  t.time_to_live = 1
  @logger.debug "waiting for #{t}"
  self.blocker = t
  catchup_trigger!(t)
  t
end

#add_nonblocking_trigger(event, *args, &block) ⇒ Object 



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# File 'lib/amberletters.rb', line 292

def add_nonblocking_trigger(event, *args, &block)
  t = add_trigger(event, *args, &block)
  catchup_trigger!(t)
  t
end

#add_trigger(event, *args, &block) ⇒ Object 



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# File 'lib/amberletters.rb', line 298

def add_trigger(event, *args, &block)
  t = build_trigger(event, *args, &block)
  triggers << t
  @logger.debug "added trigger on #{t}"
  t
end

#alive? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/amberletters.rb', line 357

def alive?
  ::Process.kill(0, @pid)
  true
rescue Errno::ESRCH, Errno::ENOENT
  false
end

#blocked? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/amberletters.rb', line 364

def blocked?
  @blocker
end

#ended? ⇒ Boolean

Have we seen the end marker yet?

Returns:

  • (Boolean) 


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# File 'lib/amberletters.rb', line 381

def ended?
  @state == :ended
end

#exited? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/amberletters.rb', line 376

def exited?
  @state == :exited
end

#flush_output_buffer! ⇒ Object 



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# File 'lib/amberletters.rb', line 345

def flush_output_buffer!
  @logger.debug "flushing output buffer"
  @output_buffer.terminate
end

#kill!(signal = "TERM") ⇒ Object 



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# File 'lib/amberletters.rb', line 350

def kill!(signal="TERM")
  handle_child_exit do
    @logger.info "Killing process #{@pid}"
    ::Process.kill(signal, @pid)
  end
end

#not_started? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/amberletters.rb', line 372

def not_started?
  @state == :not_started
end

#on(event, *args, &block) ⇒ Object 



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# File 'lib/amberletters.rb', line 277

def on(event, *args, &block)
  add_nonblocking_trigger(event, *args, &block)
end

#prepend_trigger(event, *args, &block) ⇒ Object 



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# File 'lib/amberletters.rb', line 311

def prepend_trigger(event, *args, &block)
  t = build_trigger(event, *args, &block)
  triggers.unshift(t)
  @logger.debug "prepended trigger on #{t}"
  t
end

#remove_trigger(t) ⇒ Object 



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# File 'lib/amberletters.rb', line 305

def remove_trigger(t)
  triggers.delete(t)
  @logger.debug "removed trigger on #{t}"
  t
end

#running? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/amberletters.rb', line 368

def running?
  @state == :running
end

#start! ⇒ Object

Raises:



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# File 'lib/amberletters.rb', line 328

def start!
  raise StateError, "Already started!" unless not_started?
  @logger.debug "installing end marker handler for #{END_MARKER}"
  prepend_trigger(:output, /#{END_MARKER}/, :exclusive => false, :time_to_live => 1) do |process, data|
    handle_end_marker
  end
  handle_child_exit do
    cmd = wrapped_command
    @logger.debug "executing #{cmd.join(' ')}"
    merge_environment(@env) do
      @output, @input, @pid = PTY.spawn(*cmd)
    end
    @state = :running
    @logger.debug "spawned pid #{@pid}; in: #{@input.inspect}; out: #{@output.inspect}"
  end
end

#time ⇒ Object 



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# File 'lib/amberletters.rb', line 385

def time
  Time.now
end

#to_s ⇒ Object 



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# File 'lib/amberletters.rb', line 389

def to_s
  "Process<pid: #{pid}; in: #{input.inspect}; out: #{output.inspect}>"
end

#wait_for(event, *args, &block) ⇒ Object 



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# File 'lib/amberletters.rb', line 281

def wait_for(event, *args, &block)
  raise "Already waiting for #{blocker}" if blocker
  t = add_blocking_trigger(event, *args, &block)
  @logger.debug "Entering wait cycle for #{event}"
  process_events
rescue
  unblock!
  triggers.delete(t)
  raise
end