autoname MRI threads

Author: AlexanderZagaynov

lib/concurrent/executor/ruby_thread_pool_executor.rb

@@ -131,6 +131,7 @@ def ns_initialize(opts)
       @scheduled_task_count = 0
       @completed_task_count = 0
       @largest_length       = 0
+      @workers_counter      = 0
       @ruby_pid             = $$ # detects if Ruby has forked
 
       @gc_interval  = opts.fetch(:gc_interval, @idletime / 2.0).to_i # undocumented
@@ -224,7 +225,8 @@ def ns_worker_died(worker)
     def ns_add_busy_worker
       return if @pool.size >= @max_length
 
-      @pool << (worker = Worker.new(self))
+      @workers_counter += 1
+      @pool << (worker = Worker.new(self, id: @workers_counter))
       @largest_length = @pool.length if @pool.length > @largest_length
       worker
     end
@@ -284,6 +286,7 @@ def ns_reset_if_forked
         @scheduled_task_count = 0
         @completed_task_count = 0
         @largest_length       = 0
+        @workers_counter      = 0
         @ruby_pid             = $$
       end
     end
@@ -292,11 +295,12 @@ def ns_reset_if_forked
     class Worker
       include Concern::Logging
 
-      def initialize(pool)
+      def initialize(pool, id: nil)
         # instance variables accessed only under pool's lock so no need to sync here again
         @queue  = Queue.new
         @pool   = pool
         @thread = create_worker @queue, pool, pool.idletime
+        @thread.name = [pool.name, self.class.name, id].compact.join('-')
       end
 
       def <<(message)

spec/concurrent/executor/ruby_thread_pool_executor_spec.rb

@@ -54,5 +54,37 @@ module Concurrent
         block.count_down
       end
     end
+
+    context 'threads naming' do
+      subject do
+        opts = { min_threads: 2 }
+        opts[:name] = pool_name if pool_name
+        described_class.new(opts)
+      end
+
+      let(:names) { Concurrent::Set.new }
+
+      before do
+        subject.post(names) { |names| names << Thread.current.name }
+        subject.post(names) { |names| names << Thread.current.name }
+        subject.shutdown
+        subject.wait_for_termination(pool_termination_timeout)
+        expect(names.size).to eq 2
+      end
+
+      context 'without pool name' do
+        let(:pool_name) { }
+        it 'sets counted name' do
+          expect(names.all? { |name| name =~ /^Concurrent.*Worker-\d+$/ }).to be true
+        end
+      end
+
+      context 'with pool name' do
+        let(:pool_name) { 'MyExecutor' }
+        it 'sets counted name' do
+          expect(names.all? { |name| name =~ /^MyExecutor-Concurrent.*Worker-\d+$/ }).to be true
+        end
+      end
+    end
   end
 end