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.



48
49
50
51
52
53
54
55
56
57
 
# 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.



60
61
62
 
# File 'lib/async/container/generic.rb', line 60

def group
  @group
end

#policy ⇒ Object

Returns the value of attribute policy.



71
72
73
 
# File 'lib/async/container/generic.rb', line 71

def policy
  @policy
end

#state ⇒ Object (readonly)

Returns the value of attribute state.



68
69
70
 
# File 'lib/async/container/generic.rb', line 68

def state
  @state
end

#statistics ⇒ Object

Statistics relating to the behavior of children instances.



87
88
89
 
# File 'lib/async/container/generic.rb', line 87

def statistics
  @statistics
end

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



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

attr :group

Class Method Details

.run ⇒ Object

Run a new container.



38
39
40
 
# 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.



81
82
83
 
# 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.



319
320
321
322
323
324
325
326
327
 
# File 'lib/async/container/generic.rb', line 319

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) 


91
92
93
 
# File 'lib/async/container/generic.rb', line 91

def failed?
	@statistics.failed?
end

#interrupt ⇒ Object

Gracefully interrupt all child instances.



119
120
121
122
123
124
125
 
# File 'lib/async/container/generic.rb', line 119

def interrupt
	# We must enter the stopping state before signalling the children. Interrupting a child causes it to drain and exit, but the main run loop will respawn any child that exits while `restart: true` and the container is not stopping (see the `restart && !@stopping` gate in `#run`). Without setting this flag, an interrupted child immediately respawns, so the container never drains and `#wait` never returns.
	#
	# This matters most for `Hybrid` containers: a `SIGINT`/`SIGTERM` delivered to a fork is translated into a call to `#interrupt` on the inner threaded container, which typically runs with `restart: true` (the default for `async-service` managed services). If `#interrupt` did not set this flag, the inner threads would drain, exit, and respawn in a loop, so a single signal would never terminate the fork. Setting `@stopping = true` here makes `#interrupt` behave as the start of a graceful shutdown: children drain and exit, are not respawned, and the fork terminates - consistent with how `Forked` and `Threaded` containers handle a single interrupt.
	@stopping = true
	@group.interrupt
end

#key?(key) ⇒ Boolean

Whether a child instance exists for the given key.

Returns:

  • (Boolean) 


358
359
360
361
362
 
# File 'lib/async/container/generic.rb', line 358

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) 


345
346
347
348
349
350
351
352
353
354
355
 
# File 'lib/async/container/generic.rb', line 345

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.



330
331
332
333
334
335
336
337
338
339
340
341
342
 
# File 'lib/async/container/generic.rb', line 330

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.



310
311
312
313
314
315
316
 
# File 'lib/async/container/generic.rb', line 310

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) 


96
97
98
 
# File 'lib/async/container/generic.rb', line 96

def running?
	@group.running?
end

#size ⇒ Object 



63
64
65
 
# 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.



109
110
111
 
# 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.



216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
 
# File 'lib/async/container/generic.rb', line 216

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) 


131
132
133
134
 
# File 'lib/async/container/generic.rb', line 131

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.



164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
 
# File 'lib/async/container/generic.rb', line 164

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) 


102
103
104
 
# File 'lib/async/container/generic.rb', line 102

def stopping?
	@stopping
end

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



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

attr_accessor :policy

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



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

attr :state

#to_s ⇒ Object

A human readable representation of the container.



75
76
77
 
# 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.



114
115
116
 
# 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.



138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
 
# File 'lib/async/container/generic.rb', line 138

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