Class: Async::Container::Generic

Inherits:
Object
  • Object
show all
Defined in:
lib/async/container/generic.rb

Overview

A base class for implementing containers.

Direct Known Subclasses

Forked, Threaded

Constant Summary collapse

UNNAMED = 
"Unnamed"

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(policy: Policy::DEFAULT, **options) ⇒ Generic

Initialize the container.



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# File 'lib/async/container/generic.rb', line 48

def initialize(policy: Policy::DEFAULT, **options)
	@group = Group.new(**options)
	@stopping = false
	
	@state = {}
	
	@policy = policy
	@statistics = @policy.make_statistics
	@keyed = {}
end

Instance Attribute Details

#group ⇒ Object (readonly)

Returns the value of attribute group.



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# File 'lib/async/container/generic.rb', line 60

def group
  @group
end

#policy ⇒ Object

Returns the value of attribute policy.



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# File 'lib/async/container/generic.rb', line 71

def policy
  @policy
end

#state ⇒ Object (readonly)

Returns the value of attribute state.



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# File 'lib/async/container/generic.rb', line 68

def state
  @state
end

#statistics ⇒ Object

Statistics relating to the behavior of children instances.



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# File 'lib/async/container/generic.rb', line 87

def statistics
  @statistics
end

#The group of running children instances.(groupofrunningchildreninstances.) ⇒ Object (readonly) 



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# File 'lib/async/container/generic.rb', line 60

attr :group

Class Method Details

.run ⇒ Object

Run a new container.



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# File 'lib/async/container/generic.rb', line 38

def self.run(...)
	self.new.run(...)
end

Instance Method Details

#[](key) ⇒ Object

Look up a child process by key. A key could be a symbol, a file path, or something else which the child instance represents.



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# File 'lib/async/container/generic.rb', line 81

def [] key
	@keyed[key]&.value
end

#async(**options, &block) ⇒ Object

Deprecated.

Please use #spawn or run instead.



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# File 'lib/async/container/generic.rb', line 315

def async(**options, &block)
	# warn "#{self.class}##{__method__} is deprecated, please use `spawn` or `run` instead.", uplevel: 1
	
	require "async"
	
	spawn(**options) do |instance|
		Async(instance, &block)
	end
end

#failed? ⇒ Boolean

Whether any failures have occurred within the container.

Returns:

  • (Boolean) 


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# File 'lib/async/container/generic.rb', line 91

def failed?
	@statistics.failed?
end

#interrupt ⇒ Object

Gracefully interrupt all child instances.



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# File 'lib/async/container/generic.rb', line 119

def interrupt
	@group.interrupt
end

#key?(key) ⇒ Boolean

Whether a child instance exists for the given key.

Returns:

  • (Boolean) 


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# File 'lib/async/container/generic.rb', line 354

def key?(key)
	if key
		@keyed.key?(key)
	end
end

#mark?(key) ⇒ Boolean

Mark the container’s keyed instance which ensures that it won’t be discarded.

Returns:

  • (Boolean) 


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# File 'lib/async/container/generic.rb', line 341

def mark?(key)
	if key
		if value = @keyed[key]
			value.mark!
			
			return true
		end
	end
	
	return false
end

#reload ⇒ Object

Reload the container’s keyed instances.



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# File 'lib/async/container/generic.rb', line 326

def reload
	@keyed.each_value(&:clear!)
	
	yield
	
	dirty = false
	
	@keyed.delete_if do |key, value|
		value.stop? && (dirty = true)
	end
	
	return dirty
end

#run(count: Container.processor_count, **options, &block) ⇒ Object

Run multiple instances of the same block in the container.



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# File 'lib/async/container/generic.rb', line 306

def run(count: Container.processor_count, **options, &block)
	count.times do
		spawn(**options, &block)
	end
	
	return self
end

#running? ⇒ Boolean

Whether the container has running children instances.

Returns:

  • (Boolean) 


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# File 'lib/async/container/generic.rb', line 96

def running?
	@group.running?
end

#size ⇒ Object 



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# File 'lib/async/container/generic.rb', line 63

def size
	@group.size
end

#sleep(duration = nil) ⇒ Object

Sleep until some state change occurs or the specified duration elapses.



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# File 'lib/async/container/generic.rb', line 109

def sleep(duration = nil)
	@group.sleep(duration)
end

#spawn(name: nil, restart: false, key: nil, health_check_timeout: nil, startup_timeout: nil, &block) ⇒ Object

Spawn a child instance into the container.



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# File 'lib/async/container/generic.rb', line 212

def spawn(name: nil, restart: false, key: nil, health_check_timeout: nil, startup_timeout: nil, &block)
	name ||= UNNAMED
	
	if mark?(key)
		Console.debug(self, "Reusing existing child.", child: {key: key, name: name})
		return false
	end
	
	@statistics.spawn!
	
	fiber do
		until @stopping
			Console.debug(self, "Starting child...", child: {key: key, name: name, restart: restart, health_check_timeout: health_check_timeout}, statistics: @statistics)
			
			child = self.start(name, &block)
			state = insert(key, child)
			
			# Notify policy of spawn
			begin
				@policy.child_spawn(self, child, name: name, key: key)
			rescue => error
				Console.error(self, "Policy error in child_spawn!", exception: error)
			end
			
			Console.debug(self, "Started child.", child: child, spawn: {key: key, restart: restart, health_check_timeout: health_check_timeout}, statistics: @statistics)
			
			# If a health check or startup timeout is specified, we will monitor the child process and terminate it if it does not update its state within the specified time.
			if health_check_timeout || startup_timeout
				age_clock = state[:age] = Clock.start
			end
			
			status = nil
			
			begin
				status = @group.wait_for(child) do |message|
					case message
					when :health_check!
						if state[:ready]
							# If a health check timeout is specified, we will monitor the child process and terminate it if it does not update its state within the specified time.
							if health_check_timeout
								if health_check_timeout < age_clock.total
									health_check_failed(child, age_clock, health_check_timeout)
								end
							end
						else
							# If a startup timeout is specified, we will monitor the child process and terminate it if it does not become ready within the specified time.
							if startup_timeout
								if startup_timeout < age_clock.total
									startup_failed(child, age_clock, startup_timeout)
								end
							end
						end
					else
						state.update(message)
						
						# Reset the age clock if the child has become ready:
						if state[:ready]
							age_clock&.reset!
						end
					end
				end
			rescue => error
				Console.error(self, "Error during child process management!", exception: error, stopping: @stopping)
			ensure
				delete(key, child)
			end
			
			if status&.success?
				Console.debug(self, "Child exited successfully.", status: status, stopping: @stopping)
			else
				@statistics.failure!
				Console.error(self, "Child exited with error!", status: status, stopping: @stopping)
			end
			
			# Notify policy of exit (after statistics are updated):
			begin
				@policy.child_exit(self, child, status, name: name, key: key)
			rescue => error
				Console.error(self, "Policy error in child_exit!", exception: error)
			end
			
			if restart && !@stopping
				@statistics.restart!
			else
				break
			end
		end
	end.resume
	
	return true
end

#status?(flag) ⇒ Boolean

Returns true if all children instances have the specified status flag set. e.g. ‘:ready`. This state is updated by the process readiness protocol mechanism. See Notify::Client for more details.

Returns:

  • (Boolean) 


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# File 'lib/async/container/generic.rb', line 127

def status?(flag)
	# This also returns true if all processes have exited/failed:
	@state.all?{|_, state| state[flag]}
end

#stop(timeout = true) ⇒ Object

Stop the children instances.



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# File 'lib/async/container/generic.rb', line 160

def stop(timeout = true)
	if @stopping
		Console.warn(self, "Container is already stopping!")
		return
	end
	
	Console.info(self, "Stopping container...", timeout: timeout)
	@stopping = true
	@group.stop(timeout)
	
	if @group.running?
		Console.warn(self, "Group is still running after stopping it!")
	else
		Console.info(self, "Group has stopped.")
	end
rescue => error
	Console.error(self, "Error while stopping container!", exception: error)
	raise
end

#stopping? ⇒ Boolean

Whether the container is currently stopping.

Returns:

  • (Boolean) 


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# File 'lib/async/container/generic.rb', line 102

def stopping?
	@stopping
end

#The policy for managing child lifecycle events.=(policy) ⇒ Object 



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# File 'lib/async/container/generic.rb', line 71

attr_accessor :policy

#The state of each child instance.=(stateofeachchildinstance. = (value)) ⇒ Object 



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# File 'lib/async/container/generic.rb', line 68

attr :state

#to_s ⇒ Object

A human readable representation of the container.



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# File 'lib/async/container/generic.rb', line 75

def to_s
	"#{self.class} with #{@statistics.spawns} spawns and #{@statistics.failures} failures."
end

#wait ⇒ Object

Wait until all spawned tasks are completed.



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# File 'lib/async/container/generic.rb', line 114

def wait
	@group.wait
end

#wait_until_ready ⇒ Object

Wait until all the children instances have indicated that they are ready.



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# File 'lib/async/container/generic.rb', line 134

def wait_until_ready
	while true
		Console.debug(self) do |buffer|
			buffer.puts "Waiting for ready:"
			@state.each do |child, state|
				buffer.puts "\t#{child.inspect}: #{state}"
			end
		end
		
		self.sleep
		
		if self.status?(:ready)
			Console.debug(self) do |buffer|
				buffer.puts "All ready:"
				@state.each do |child, state|
					buffer.puts "\t#{child.inspect}: #{state}"
				end
			end
			
			return true
		end
	end
end