`class Group`

Manages a group of running processes.

Definitions

`def initialize(health_check_interval: 1.0)`

Initialize an empty group.

Signature

parameter　health_check_interval　Numeric | Nil: The (biggest) interval at which health checks are performed.

Implementation

def initialize(health_check_interval: 1.0)
	@health_check_interval = health_check_interval
	
	# The running fibers, indexed by IO:
	@running = {}
	
	# This queue allows us to wait for processes to complete, without spawning new processes as a result.
	@queue = nil
end

`def inspect`

Signature

returns　String: A human-readable representation of the group.

Implementation

def inspect
	"#<#{self.class} running=#{@running.size}>"
end

`attr :running`

Signature

attribute　Hash(IO, Fiber): the running tasks, indexed by IO.

`def size`

Signature

returns　Integer: The number of running processes.

Implementation

def size
	@running.size
end

`def running?`

Whether the group contains any running processes.

Signature

returns　Boolean

Implementation

def running?
	@running.any?
end

`def any?`

Whether the group contains any running processes.

Signature

returns　Boolean

Implementation

def any?
	@running.any?
end

`def empty?`

Whether the group is empty.

Signature

returns　Boolean

Implementation

def empty?
	@running.empty?
end

`def sleep(duration)`

Sleep for at most the specified duration until some state change occurs.

Implementation

def sleep(duration)
	self.resume
	self.suspend
	
	self.wait_for_children(duration)
end

`def wait`

Begin any outstanding queued processes and wait for them indefinitely.

Implementation

def wait
	self.resume
	
	with_health_checks do |duration|
		self.wait_for_children(duration)
	end
end

`def health_check!`

Perform a health check on all running processes.

Implementation

def health_check!
	@running.each_value do |fiber|
		fiber.resume(:health_check!)
	end
end

`def interrupt`

Interrupt all running processes. This resumes the controlling fiber with an instance of Interrupt = ::Interrupt.

Implementation

def interrupt
	Console.info(self, "Sending interrupt to #{@running.size} running processes...")
	@running.each_value do |fiber|
		fiber.resume(Interrupt)
	end
end

`def terminate`

Terminate all running processes. This resumes the controlling fiber with an instance of class Async::Container::Terminate.

Implementation

def terminate
	Console.info(self, "Sending terminate to #{@running.size} running processes...")
	@running.each_value do |fiber|
		fiber.resume(Terminate)
	end
end

`def kill`

Kill all running processes. This resumes the controlling fiber with an instance of class Async::Container::Kill.

Implementation

def kill
	Console.info(self, "Sending kill to #{@running.size} running processes...")
	@running.each_value do |fiber|
		fiber.resume(Kill)
	end
end

`def stop(graceful = true, interrupt_timeout: INTERRUPT_TIMEOUT, terminate_timeout: TERMINATE_TIMEOUT)`

Stop all child processes with a multi-phase shutdown sequence.

A graceful shutdown performs the following sequence:

Send SIGINT and wait up to interrupt_timeout seconds
Send SIGTERM and wait up to terminate_timeout seconds
Send SIGKILL and wait indefinitely for process cleanup

If graceful is false, skips the SIGINT phase and goes directly to SIGTERM → SIGKILL.

Signature

parameter　graceful　Boolean: Whether to send SIGINT first or skip directly to SIGTERM.
parameter　interrupt_timeout　Numeric | Nil: Time to wait after SIGINT before escalating to SIGTERM.
parameter　terminate_timeout　Numeric | Nil: Time to wait after SIGTERM before escalating to SIGKILL.

Implementation

def stop(graceful = true, interrupt_timeout: INTERRUPT_TIMEOUT, terminate_timeout: TERMINATE_TIMEOUT)
	case graceful
	when true
		# Use defaults.
	when false
		interrupt_timeout = nil
	when Numeric
		interrupt_timeout = graceful
		terminate_timeout = graceful
	end
	
	Console.debug(self, "Stopping all processes...", interrupt_timeout: interrupt_timeout, terminate_timeout: terminate_timeout)
	
	# If a timeout is specified, interrupt the children first:
	if interrupt_timeout
		clock = Async::Clock.start
		
		# Interrupt the children:
		self.interrupt
		
		# Wait for the children to exit:
		self.wait_for_exit(clock, interrupt_timeout)
	end
	
	if terminate_timeout
		clock = Async::Clock.start
		
		# If the children are still running, terminate them:
		self.terminate
		
		# Wait for the children to exit:
		self.wait_for_exit(clock, terminate_timeout)
	end
	
	if any?
		self.kill
		self.wait
	end
end

`def wait_for(channel)`

Wait for a message in the specified class Async::Container::Channel.

Implementation

def wait_for(channel)
	io = channel.in
	
	@running[io] = Fiber.current
	
	while @running.key?(io)
		# Wait for some event on the channel:
		result = Fiber.yield
		
		if result == Interrupt
			channel.interrupt!
		elsif result == Terminate
			channel.terminate!
		elsif result == Kill
			channel.kill!
		elsif result
			yield result
		elsif message = channel.receive
			yield message
		else
			# Wait for the channel to exit:
			return channel.wait
		end
	end
ensure
	@running.delete(io)
end

`def select(duration)`

Wait for a child process to exit OR a signal to be received.

Implementation

def select(duration)
	::Thread.handle_interrupt(SignalException => :immediate) do
		readable, _, _ = ::IO.select(@running.keys, nil, nil, duration)
		
		return readable
	end
end