Class: RobustThread

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

Constant Summary collapse

VALID_CALLBACKS = 
[:before_init, :before_yield, :after_yield, :after_join, :before_exit]

Class Attribute Summary collapse

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(opts = {}, &block) ⇒ RobustThread

Create a new RobustThread (see README)



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# File 'lib/robustthread.rb', line 19

def initialize(opts={}, &block)
  self.class.send :init_exit_handler
  args = opts[:args] or []
  self.class.send :do_before_init
  @thread = Thread.new(*args) do |*targs|
    begin
      self.class.send :do_before_yield
      block.call(*targs)
      self.class.send :do_after_yield
    rescue Exception => e
      @exception = e
      self.class.send :handle_exception, e
    end
    self.class.log "#{self.label.inspect} exited cleanly"
  end
  self.label = opts[:label] || @thread.inspect
  self.class.group << self
end

Class Attribute Details

.callbacks ⇒ Object

Returns the value of attribute callbacks.



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# File 'lib/robustthread.rb', line 40

def callbacks
  @callbacks
end

.exit_handler_initialized ⇒ Object

Returns the value of attribute exit_handler_initialized.



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# File 'lib/robustthread.rb', line 40

def exit_handler_initialized
  @exit_handler_initialized
end

.logger ⇒ Object

Logger object (see README)



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# File 'lib/robustthread.rb', line 44

def logger
  @logger
end

.say_goodnight ⇒ Object

Returns the value of attribute say_goodnight.



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# File 'lib/robustthread.rb', line 40

def say_goodnight
  @say_goodnight
end

Instance Attribute Details

#exception ⇒ Object (readonly)

If the Thread takes a poopie…



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# File 'lib/robustthread.rb', line 14

def exception
  @exception
end

#label ⇒ Object

An identifier



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# File 'lib/robustthread.rb', line 16

def label
  @label
end

#thread ⇒ Object (readonly)

The Thread object, brah



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# File 'lib/robustthread.rb', line 12

def thread
  @thread
end

Class Method Details

.add_callback(sym, &block) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/robustthread.rb', line 94

def add_callback(sym, &block)
  sym = sym.to_sym
  raise ArgumentError, "Invalid callback #{sym.inspect}" unless VALID_CALLBACKS.include? sym
  self.callbacks ||= {}
  self.callbacks[sym] ||= []
  self.callbacks[sym] << block
end

.exception_handler(&block) ⇒ Object

Set exception handler



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# File 'lib/robustthread.rb', line 85

def exception_handler(&block)
  unless block.arity == 1
    raise ArgumentError, "Bad arity for exception handler. It may only accept a single argument"
  end
  @exception_handler = block
end

.group ⇒ Object

The collection of RobustThread objects



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# File 'lib/robustthread.rb', line 54

def group
  @group ||= [] 
end

.log(msg, level = :info) ⇒ Object

Simple log interface



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# File 'lib/robustthread.rb', line 49

def log(msg, level=:info)
  self.logger.send level, "#{self}: " + msg
end

.loop(opts = {}, &block) ⇒ Object

Loop an activity and exit it cleanly (see README)



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# File 'lib/robustthread.rb', line 59

def loop(opts={}, &block)
  sleep_seconds = opts.delete(:seconds) || 2
  self.new(opts) do |*args|
    Kernel.loop do
      break if self.say_goodnight
      block.call(*args)
      # We want to sleep for the right amount of time, but we also don't
      # want to wait until the sleep is done if our exit handler has been
      # called so we iterate over a loop, sleeping only 0.1 and checking
      # each iteration whether we need to die, and the timeout is a noop
      # indicating we need to continue.
      begin
        Timeout.timeout(sleep_seconds) do
          Kernel.loop do
            break if self.say_goodnight
            sleep 0.1
          end
        end
      rescue Timeout::Error
        # OK
      end
    end
  end
end