#2872

Committed 08 Jun 2014 06:00PM UTC coverage: 77.573% (-11.7%) from 89.319%

Build # #2872

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Updated badges with new repo location.

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/lib/concurrent/executor/ruby_thread_pool_executor.rb

require 'thread'

require_relative 'executor'
require 'concurrent/atomic/event'
require 'concurrent/executor/ruby_thread_pool_worker'

module Concurrent

  # @!macro thread_pool_executor
  class RubyThreadPoolExecutor
    include RubyExecutor

    # Default maximum number of threads that will be created in the pool.
    DEFAULT_MAX_POOL_SIZE = 2**15 # 32768

    # Default minimum number of threads that will be retained in the pool.
    DEFAULT_MIN_POOL_SIZE = 0

    # Default maximum number of tasks that may be added to the task queue.
    DEFAULT_MAX_QUEUE_SIZE = 0

    # Default maximum number of seconds a thread in the pool may remain idle
    # before being reclaimed.
    DEFAULT_THREAD_IDLETIMEOUT = 60

    # The set of possible overflow policies that may be set at thread pool creation.
    OVERFLOW_POLICIES = [:abort, :discard, :caller_runs]

    # The maximum number of threads that may be created in the pool.
    attr_reader :max_length

    # The minimum number of threads that may be retained in the pool.
    attr_reader :min_length

    # The largest number of threads that have been created in the pool since construction.
    attr_reader :largest_length

    # The number of tasks that have been scheduled for execution on the pool since construction.
    attr_reader :scheduled_task_count

    # The number of tasks that have been completed by the pool since construction.
    attr_reader :completed_task_count

    # The number of seconds that a thread may be idle before being reclaimed.
    attr_reader :idletime

    # The maximum number of tasks that may be waiting in the work queue at any one time.
    # When the queue size reaches `max_queue` subsequent tasks will be rejected in
    # accordance with the configured `overflow_policy`.
    attr_reader :max_queue

    # The policy defining how rejected tasks (tasks received once the queue size reaches
    # the configured `max_queue`) are handled. Must be one of the values specified in
    # `OVERFLOW_POLICIES`.
    attr_reader :overflow_policy

    # Create a new thread pool.
    #
    # @param [Hash] opts the options which configure the thread pool
    #
    # @option opts [Integer] :max_threads (DEFAULT_MAX_POOL_SIZE) the maximum
    #   number of threads to be created
    # @option opts [Integer] :min_threads (DEFAULT_MIN_POOL_SIZE) the minimum
    #   number of threads to be retained
    # @option opts [Integer] :idletime (DEFAULT_THREAD_IDLETIMEOUT) the maximum
    #   number of seconds a thread may be idle before being reclaimed
    # @option opts [Integer] :max_queue (DEFAULT_MAX_QUEUE_SIZE) the maximum
    #   number of tasks allowed in the work queue at any one time; a value of
    #   zero means the queue may grow without bounnd
    # @option opts [Symbol] :overflow_policy (:abort) the policy for handling new
    #   tasks that are received when the queue size has reached `max_queue`
    #
    # @raise [ArgumentError] if `:max_threads` is less than one
    # @raise [ArgumentError] if `:min_threads` is less than zero
    # @raise [ArgumentError] if `:overflow_policy` is not one of the values specified
    #   in `OVERFLOW_POLICIES`
    #
    # @see http://docs.oracle.com/javase/7/docs/api/java/util/concurrent/ThreadPoolExecutor.html
    def initialize(opts = {})
      @min_length = opts.fetch(:min_threads, DEFAULT_MIN_POOL_SIZE).to_i
      @max_length = opts.fetch(:max_threads, DEFAULT_MAX_POOL_SIZE).to_i
      @idletime = opts.fetch(:idletime, DEFAULT_THREAD_IDLETIMEOUT).to_i
      @max_queue = opts.fetch(:max_queue, DEFAULT_MAX_QUEUE_SIZE).to_i
      @overflow_policy = opts.fetch(:overflow_policy, :abort)

      raise ArgumentError.new('max_threads must be greater than zero') if @max_length <= 0
      raise ArgumentError.new('min_threads cannot be less than zero') if @min_length < 0
      raise ArgumentError.new("#{overflow_policy} is not a valid overflow policy") unless OVERFLOW_POLICIES.include?(@overflow_policy)

      init_executor

      @pool = []
      @queue = Queue.new
      @scheduled_task_count = 0
      @completed_task_count = 0
      @largest_length = 0

      @gc_interval = opts.fetch(:gc_interval, 1).to_i # undocumented
      @last_gc_time = Time.now.to_f - [1.0, (@gc_interval * 2.0)].max
    end

    def can_overflow?
      @max_queue != 0
    end

    # The number of threads currently in the pool.
    #
    # @return [Integer] the length
    def length
      mutex.synchronize{ running? ? @pool.length : 0 }
    end
    alias_method :current_length, :length

    # The number of tasks in the queue awaiting execution.
    #
    # @return [Integer] the queue_length
    def queue_length
      mutex.synchronize{ running? ? @queue.length : 0 }
    end

    # Number of tasks that may be enqueued before reaching `max_queue` and rejecting
    # new tasks. A value of -1 indicates that the queue may grow without bound.
    #
    # @return [Integer] the remaining_capacity
    def remaining_capacity
      mutex.synchronize { @max_queue == 0 ? -1 : @max_queue - @queue.length }
    end

    # Returns an array with the status of each thread in the pool
    #
    # This method is deprecated and will be removed soon.
    def status
      warn '[DEPRECATED] `status` is deprecated and will be removed soon.'
      mutex.synchronize { @pool.collect { |worker| worker.status } }
    end

    # Run on task completion.
    #
    # @!visibility private
    def on_end_task
      mutex.synchronize do
        @completed_task_count += 1 #if success
        break unless running?
      end
    end

    # Run when a thread worker exits.
    #
    # @!visibility private
    def on_worker_exit(worker)
      mutex.synchronize do
        @pool.delete(worker)
        if @pool.empty? && ! running?
          stop_event.set
          stopped_event.set
        end
      end
    end

    protected

    # @!visibility private
    def execute(*args, &task)
      prune_pool
      if ensure_capacity?
        @scheduled_task_count += 1
        @queue << [args, task]
      else
        handle_overflow(*args, &task) if @max_queue != 0 && @queue.length >= @max_queue
      end
    end

    # @!visibility private
    def shutdown_execution
      @queue.clear
      if @pool.empty?
        stopped_event.set
      else
        @pool.length.times{ @queue << :stop }
      end
    end

    # @!visibility private
    def kill_execution
      @queue.clear
      drain_pool
    end

    # Check the thread pool configuration and determine if the pool
    # has enought capacity to handle the request. Will grow the size
    # of the pool if necessary.
    #
    # @return [Boolean] true if the pool has enough capacity else false
    #
    # @!visibility private
    def ensure_capacity?
      additional = 0
      capacity = true

      if @pool.size < @min_length
        additional = @min_length - @pool.size
      elsif @queue.empty? && @queue.num_waiting >= 1
        additional = 0
      elsif @pool.size == 0 && @min_length == 0
        additional = 1
      elsif @pool.size < @max_length || @max_length == 0
        additional = 1
      elsif @max_queue == 0 || @queue.size < @max_queue
        additional = 0
      else
        capacity = false
      end

      additional.times do
        @pool << create_worker_thread
      end

      if additional > 0
        @largest_length = [@largest_length, @pool.length].max
      end

      capacity
    end

    # Handler which executes the `overflow_policy` once the queue size
    # reaches `max_queue`.
    #
    # @param [Array] args the arguments to the task which is being handled.
    #
    # @!visibility private
    def handle_overflow(*args)
      case @overflow_policy
      when :abort
        raise RejectedExecutionError
      when :discard
        false
      when :caller_runs
        begin
          yield(*args)
        rescue => ex
          # let it fail
          log DEBUG, ex
        end
        true
      end
    end

    # Scan all threads in the pool and reclaim any that are dead or
    # have been idle too long. Will check the last time the pool was
    # pruned and only run if the configured garbage collection
    # interval has passed.
    #
    # @!visibility private
    def prune_pool
      if Time.now.to_f - @gc_interval >= @last_gc_time
        @pool.delete_if do |worker|
          worker.dead? ||
            (@idletime == 0 ? false : Time.now.to_f - @idletime > worker.last_activity)
        end
        @last_gc_time = Time.now.to_f
      end
    end

    # Reclaim all threads in the pool.
    #
    # @!visibility private
    def drain_pool
      @pool.each {|worker| worker.kill }
      @pool.clear
    end

    # Create a single worker thread to be added to the pool.
    #
    # @return [Thread] the new thread.
    #
    # @!visibility private
    def create_worker_thread
      wrkr = RubyThreadPoolWorker.new(@queue, self)
      Thread.new(wrkr, self) do |worker, parent|
        Thread.current.abort_on_exception = false
        worker.run
        parent.on_worker_exit(worker)
      end
      return wrkr
    end
  end
end

1	require 'thread'	1✔
2
3	require_relative 'executor'	1✔
4	require 'concurrent/atomic/event'	1✔
5	require 'concurrent/executor/ruby_thread_pool_worker'	1✔
6
7	module Concurrent	1✔
8
9	# @!macro thread_pool_executor
10	class RubyThreadPoolExecutor	1✔
11	include RubyExecutor	1✔
12
13	# Default maximum number of threads that will be created in the pool.
14	DEFAULT_MAX_POOL_SIZE = 2**15 # 32768	1✔
15
16	# Default minimum number of threads that will be retained in the pool.
17	DEFAULT_MIN_POOL_SIZE = 0	1✔
18
19	# Default maximum number of tasks that may be added to the task queue.
20	DEFAULT_MAX_QUEUE_SIZE = 0	1✔
21
22	# Default maximum number of seconds a thread in the pool may remain idle
23	# before being reclaimed.
24	DEFAULT_THREAD_IDLETIMEOUT = 60	1✔
25
26	# The set of possible overflow policies that may be set at thread pool creation.
27	OVERFLOW_POLICIES = [:abort, :discard, :caller_runs]	1✔
28
29	# The maximum number of threads that may be created in the pool.
30	attr_reader :max_length	1✔
31
32	# The minimum number of threads that may be retained in the pool.
33	attr_reader :min_length	1✔
34
35	# The largest number of threads that have been created in the pool since construction.
36	attr_reader :largest_length	1✔
37
38	# The number of tasks that have been scheduled for execution on the pool since construction.
39	attr_reader :scheduled_task_count	1✔
40
41	# The number of tasks that have been completed by the pool since construction.
42	attr_reader :completed_task_count	1✔
43
44	# The number of seconds that a thread may be idle before being reclaimed.
45	attr_reader :idletime	1✔
46
47	# The maximum number of tasks that may be waiting in the work queue at any one time.
48	# When the queue size reaches `max_queue` subsequent tasks will be rejected in
49	# accordance with the configured `overflow_policy`.
50	attr_reader :max_queue	1✔
51
52	# The policy defining how rejected tasks (tasks received once the queue size reaches
53	# the configured `max_queue`) are handled. Must be one of the values specified in
54	# `OVERFLOW_POLICIES`.
55	attr_reader :overflow_policy	1✔
56
57	# Create a new thread pool.
58	#
59	# @param [Hash] opts the options which configure the thread pool
60	#
61	# @option opts [Integer] :max_threads (DEFAULT_MAX_POOL_SIZE) the maximum
62	# number of threads to be created
63	# @option opts [Integer] :min_threads (DEFAULT_MIN_POOL_SIZE) the minimum
64	# number of threads to be retained
65	# @option opts [Integer] :idletime (DEFAULT_THREAD_IDLETIMEOUT) the maximum
66	# number of seconds a thread may be idle before being reclaimed
67	# @option opts [Integer] :max_queue (DEFAULT_MAX_QUEUE_SIZE) the maximum
68	# number of tasks allowed in the work queue at any one time; a value of
69	# zero means the queue may grow without bounnd
70	# @option opts [Symbol] :overflow_policy (:abort) the policy for handling new
71	# tasks that are received when the queue size has reached `max_queue`
72	#
73	# @raise [ArgumentError] if `:max_threads` is less than one
74	# @raise [ArgumentError] if `:min_threads` is less than zero
75	# @raise [ArgumentError] if `:overflow_policy` is not one of the values specified
76	# in `OVERFLOW_POLICIES`
77	#
78	# @see http://docs.oracle.com/javase/7/docs/api/java/util/concurrent/ThreadPoolExecutor.html
79	def initialize(opts = {})	1✔
80	@min_length = opts.fetch(:min_threads, DEFAULT_MIN_POOL_SIZE).to_i	180✔
81	@max_length = opts.fetch(:max_threads, DEFAULT_MAX_POOL_SIZE).to_i	180✔
82	@idletime = opts.fetch(:idletime, DEFAULT_THREAD_IDLETIMEOUT).to_i	180✔
83	@max_queue = opts.fetch(:max_queue, DEFAULT_MAX_QUEUE_SIZE).to_i	180✔
84	@overflow_policy = opts.fetch(:overflow_policy, :abort)	180✔
85
86	raise ArgumentError.new('max_threads must be greater than zero') if @max_length <= 0	180✔
87	raise ArgumentError.new('min_threads cannot be less than zero') if @min_length < 0	180✔
88	raise ArgumentError.new("#{overflow_policy} is not a valid overflow policy") unless OVERFLOW_POLICIES.include?(@overflow_policy)	180✔
89
90	init_executor	180✔
91
92	@pool = []	180✔
93	@queue = Queue.new	180✔
94	@scheduled_task_count = 0	180✔
95	@completed_task_count = 0	180✔
96	@largest_length = 0	180✔
97
98	@gc_interval = opts.fetch(:gc_interval, 1).to_i # undocumented	180✔
99	@last_gc_time = Time.now.to_f - [1.0, (@gc_interval * 2.0)].max	180✔
100	end
101
102	def can_overflow?	1✔
103	@max_queue != 0	×
104	end
105
106	# The number of threads currently in the pool.
107	#
108	# @return [Integer] the length
109	def length	1✔
110	mutex.synchronize{ running? ? @pool.length : 0 }	×
111	end
112	alias_method :current_length, :length	1✔
113
114	# The number of tasks in the queue awaiting execution.
115	#
116	# @return [Integer] the queue_length
117	def queue_length	1✔
118	mutex.synchronize{ running? ? @queue.length : 0 }	×
119	end
120
121	# Number of tasks that may be enqueued before reaching `max_queue` and rejecting
122	# new tasks. A value of -1 indicates that the queue may grow without bound.
123	#
124	# @return [Integer] the remaining_capacity
125	def remaining_capacity	1✔
126	mutex.synchronize { @max_queue == 0 ? -1 : @max_queue - @queue.length }	×
127	end
128
129	# Returns an array with the status of each thread in the pool
130	#
131	# This method is deprecated and will be removed soon.
132	def status	1✔
133	warn '[DEPRECATED] `status` is deprecated and will be removed soon.'	×
134	mutex.synchronize { @pool.collect { \|worker\| worker.status } }	×
135	end
136
137	# Run on task completion.
138	#
139	# @!visibility private
140	def on_end_task	1✔
141	mutex.synchronize do	1,336✔
142	@completed_task_count += 1 #if success	1,336✔
143	break unless running?	1,336✔
144	end
145	end
146
147	# Run when a thread worker exits.
148	#
149	# @!visibility private
150	def on_worker_exit(worker)	1✔
151	mutex.synchronize do	×
152	@pool.delete(worker)	×
153	if @pool.empty? && ! running?	×
154	stop_event.set	×
155	stopped_event.set	×
156	end
157	end
158	end
159
160	protected	1✔
161
162	# @!visibility private
163	def execute(*args, &task)	1✔
164	prune_pool	1,357✔
165	if ensure_capacity?	1,357✔
166	@scheduled_task_count += 1	1,357✔
167	@queue << [args, task]	1,357✔
168	else
169	handle_overflow(*args, &task) if @max_queue != 0 && @queue.length >= @max_queue	×
170	end
171	end
172
173	# @!visibility private
174	def shutdown_execution	1✔
175	@queue.clear	2✔
176	if @pool.empty?	2✔
177	stopped_event.set	2✔
178	else
179	@pool.length.times{ @queue << :stop }	×
180	end
181	end
182
183	# @!visibility private
184	def kill_execution	1✔
185	@queue.clear	×
186	drain_pool	×
187	end
188
189	# Check the thread pool configuration and determine if the pool
190	# has enought capacity to handle the request. Will grow the size
191	# of the pool if necessary.
192	#
193	# @return [Boolean] true if the pool has enough capacity else false
194	#
195	# @!visibility private
196	def ensure_capacity?	1✔
197	additional = 0	1,357✔
198	capacity = true	1,357✔
199
200	if @pool.size < @min_length	1,357✔
201	additional = @min_length - @pool.size	98✔
202	elsif @queue.empty? && @queue.num_waiting >= 1	1,259✔
203	additional = 0	27✔
204	elsif @pool.size == 0 && @min_length == 0	1,232✔
205	additional = 1	×
206	elsif @pool.size < @max_length \|\| @max_length == 0	1,232✔
207	additional = 1	1,232✔
208	elsif @max_queue == 0 \|\| @queue.size < @max_queue	×
209	additional = 0	×
210	else
211	capacity = false	×
212	end
213
214	additional.times do	1,357✔
215	@pool << create_worker_thread	7,504✔
216	end
217
218	if additional > 0	1,357✔
219	@largest_length = [@largest_length, @pool.length].max	1,330✔
220	end
221
222	capacity	1,357✔
223	end
224
225	# Handler which executes the `overflow_policy` once the queue size
226	# reaches `max_queue`.
227	#
228	# @param [Array] args the arguments to the task which is being handled.
229	#
230	# @!visibility private
231	def handle_overflow(*args)	1✔
232	case @overflow_policy	×
233	when :abort
234	raise RejectedExecutionError	×
235	when :discard
236	false	×
237	when :caller_runs
238	begin
239	yield(*args)	×
240	rescue => ex
241	# let it fail
242	log DEBUG, ex	×
243	end
244	true	×
245	end
246	end
247
248	# Scan all threads in the pool and reclaim any that are dead or
249	# have been idle too long. Will check the last time the pool was
250	# pruned and only run if the configured garbage collection
251	# interval has passed.
252	#
253	# @!visibility private
254	def prune_pool	1✔
255	if Time.now.to_f - @gc_interval >= @last_gc_time	1,357✔
256	@pool.delete_if do \|worker\|	99✔
257	worker.dead? \|\|	64✔
258	(@idletime == 0 ? false : Time.now.to_f - @idletime > worker.last_activity)	64✔
259	end
260	@last_gc_time = Time.now.to_f	99✔
261	end
262	end
263
264	# Reclaim all threads in the pool.
265	#
266	# @!visibility private
267	def drain_pool	1✔
268	@pool.each {\|worker\| worker.kill }	×
269	@pool.clear	×
270	end
271
272	# Create a single worker thread to be added to the pool.
273	#
274	# @return [Thread] the new thread.
275	#
276	# @!visibility private
277	def create_worker_thread	1✔
278	wrkr = RubyThreadPoolWorker.new(@queue, self)	7,504✔
279	Thread.new(wrkr, self) do \|worker, parent\|	7,504✔
280	Thread.current.abort_on_exception = false	6,476✔
281	worker.run	6,476✔
282	parent.on_worker_exit(worker)	×
283	end
284	return wrkr	7,504✔
285	end
286	end
287	end

ruby-concurrency / concurrent-ruby / #2872

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