Explicit specification of graceful shutdown behaviour.

examples/grace/server.rb

@@ -0,0 +1,72 @@
+#!/usr/bin/env ruby
+# frozen_string_literal: true
+
+# Released under the MIT License.
+# Copyright, 2024, by Samuel Williams.
+
+require '../../lib/async/container'
+require 'async/io/host_endpoint'
+
+Console.logger.debug!
+
+module SignalWrapper
+	def self.trap(signal, &block)
+		signal = signal
+
+		original = Signal.trap(signal) do
+			::Signal.trap(signal, original)
+			block.call
+		end
+	end
+end
+
+class Controller < Async::Container::Controller
+	def initialize(...)
+		super
+
+		@endpoint = Async::IO::Endpoint.tcp("localhost", 8080)
+		@bound_endpoint = nil
+	end
+
+	def start
+		Console.debug(self) {"Binding to #{@endpoint}"}
+		@bound_endpoint = Sync{@endpoint.bound}
+
+		super
+	end
+
+	def setup(container)
+		container.run count: 2, restart: true do |instance|
+			SignalWrapper.trap(:INT) do
+				Console.debug(self) {"Closing bound instance..."}
+				@bound_endpoint.close
+			end
+
+			Sync do |task|
+				Console.info(self) {"Starting bound instance..."}
+
+				instance.ready!
+
+				@bound_endpoint.accept do |peer|
+					while true
+						peer.write("#{Time.now.to_s.rjust(32)}: Hello World\n")
+						sleep 1
+					end
+				end
+			end
+		end
+	end
+
+	def stop(graceful = true)
+		super
+
+		if @bound_endpoint
+			@bound_endpoint.close
+			@bound_endpoint = nil
+		end
+	end
+end
+
+controller = Controller.new
+
+controller.run

lib/async/container/controller.rb

@@ -22,7 +22,7 @@ class Controller
 
 			# Initialize the controller.
 			# @parameter notify [Notify::Client] A client used for process readiness notifications.
-			def initialize(notify: Notify.open!, container_class: Container)
+			def initialize(notify: Notify.open!, container_class: Container, graceful: true)
 				@container = nil
 				@container_class = container_class
 
@@ -35,6 +35,8 @@ def initialize(notify: Notify.open!, container_class: Container)
 				trap(SIGHUP) do
 					self.restart
 				end
+
+				@graceful = graceful
 			end
 
 			# The state of the controller.
@@ -96,7 +98,7 @@ def start
 
 			# Stop the container if it's running.
 			# @parameter graceful [Boolean] Whether to give the children instances time to shut down or to kill them immediately.
-			def stop(graceful = true)
+			def stop(graceful = @graceful)
 				@container&.stop(graceful)
 				@container = nil
 			end
@@ -130,7 +132,7 @@ def restart
 				if container.failed?
 					@notify&.error!("Container failed to start!")
 
-					container.stop
+					container.stop(false)
 
 					raise SetupError, container
 				end
@@ -142,7 +144,7 @@ def restart
 
 				if old_container
 					Console.logger.debug(self, "Stopping old container...")
-					old_container&.stop
+					old_container&.stop(@graceful)
 				end
 
 				@notify&.ready!
@@ -211,11 +213,11 @@ def run
 					end
 				end
 			rescue Interrupt
-				self.stop(true)
+				self.stop
 			rescue Terminate
 				self.stop(false)
 			ensure
-				self.stop(true)
+				self.stop(false)
 
 				# Restore the interrupt handler:
 				Signal.trap(:INT, interrupt_action)

lib/async/container/group.rb

@@ -133,6 +133,7 @@ def wait_for(channel)
 			protected
 
 			def wait_for_children(duration = nil)
+				Console.debug(self, "Waiting for children...", duration: duration)
 				if !@running.empty?
 					# Maybe consider using a proper event loop here:
 					readable, _, _ = ::IO.select(@running.keys, nil, nil, duration)