Class: Zold::ThreadPool

Inherits:
Object
  • Object
show all
Defined in:
lib/zold/thread_pool.rb

Overview

Thread pool

Instance Method Summary collapse

Constructor Details

#initialize(title, log: Log::NULL) ⇒ ThreadPool

Returns a new instance of ThreadPool.



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# File 'lib/zold/thread_pool.rb', line 34

def initialize(title, log: Log::NULL)
  @title = title
  @log = log
  @threads = []
  @start = Time.now
end

Instance Method Details

#add ⇒ Object

Add a new thread



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# File 'lib/zold/thread_pool.rb', line 70

def add
  raise 'Block must be given to start()' unless block_given?
  latch = Concurrent::CountDownLatch.new(1)
  thread = Thread.start do
    Thread.current.name = @title
    VerboseThread.new(@log).run do
      latch.count_down
      yield
    end
  end
  latch.wait
  Thread.current.thread_variable_set(
    :kids,
    (Thread.current.thread_variable_get(:kids) || []) + [thread]
  )
  @threads << thread
end

#count ⇒ Object

How many threads are in there



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# File 'lib/zold/thread_pool.rb', line 122

def count
  @threads.count
end

#exists?(name) ⇒ Boolean

A thread with this name exists?

Returns:

  • (Boolean) 


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# File 'lib/zold/thread_pool.rb', line 127

def exists?(name)
  !@threads.find { |t| t.name == name }.nil?
end

#join(sec) ⇒ Object 



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# File 'lib/zold/thread_pool.rb', line 88

def join(sec)
  @threads.each { |t| t.join(sec) }
end

#kill ⇒ Object

Kill them all immediately and close the pool



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# File 'lib/zold/thread_pool.rb', line 93

def kill
  if @threads.empty?
    @log.debug("Thread pool \"#{@title}\" terminated with no threads")
    return
  end
  @log.debug("Stopping \"#{@title}\" thread pool with #{@threads.count} threads: \
#{@threads.map { |t| "#{t.name}/#{t.status}" }.join(', ')}...")
  start = Time.new
  begin
    @threads.each do |t|
      t.join(0.1)
    end
  ensure
    @threads.each do |t|
      (t.thread_variable_get(:kids) || []).each(&:kill)
      t.kill
      sleep(0.001) while t.alive? # I believe it's a bug in Ruby, this line fixes it
      Thread.current.thread_variable_set(
        :kids,
        (Thread.current.thread_variable_get(:kids) || []) - [t]
      )
    end
    @log.debug("Thread pool \"#{@title}\" terminated all threads in #{Age.new(start)}, \
it was alive for #{Age.new(@start)}: #{@threads.map { |t| "#{t.name}/#{t.status}" }.join(', ')}")
    @threads.clear
  end
end

#run(threads, set = (0..threads - 1).to_a) ⇒ Object

Run this code in many threads



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# File 'lib/zold/thread_pool.rb', line 42

def run(threads, set = (0..threads - 1).to_a)
  raise "Number of threads #{threads} has to be positive" unless threads.positive?
  list = set.dup
  total = [threads, set.count].min
  if total == 1
    list.each_with_index { |r, i| yield(r, i) }
  elsif total.positive?
    idx = Concurrent::AtomicFixnum.new
    mutex = Mutex.new
    latch = Concurrent::CountDownLatch.new(total)
    total.times do |i|
      add do
        Thread.current.name = "#{@title}-#{i}"
        loop do
          r = mutex.synchronize { list.pop }
          break if r.nil?
          yield(r, idx.increment - 1)
        end
      ensure
        latch.count_down
      end
    end
    latch.wait
    kill
  end
end

#to_json ⇒ Object

As a hash map



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# File 'lib/zold/thread_pool.rb', line 132

def to_json
  @threads.map do |t|
    {
      name: t.name,
      status: t.status,
      alive: t.alive?,
      vars: Hash[t.thread_variables.map { |v| [v.to_s, t.thread_variable_get(v)] }]
    }
  end
end

#to_s ⇒ Object

As a text



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# File 'lib/zold/thread_pool.rb', line 144

def to_s
  @threads.map do |t|
    [
      "#{t.name}: status=#{t.status}; alive=#{t.alive?}",
      'Vars: ' + t.thread_variables.map { |v| "#{v}=\"#{t.thread_variable_get(v)}\"" }.join('; '),
      t.backtrace.nil? ? 'NO BACKTRACE' : "  #{t.backtrace.join("\n  ")}"
    ].join("\n")
  end
end