future_response.rb in routemaster-drain-2.4.0

- old
+ new

@@ -1,32 +1,18 @@
-require 'thread/pool'
-require 'thread/future'
+require 'concurrent/future'
+require 'concurrent/executor/cached_thread_pool'
 require 'singleton'
 require 'delegate'
 
 module Routemaster
   module Responses
-    # A pool of threads, used for parallel/future request processing.
-    class Pool < SimpleDelegator
-      include Singleton
-
-      def initialize
-        Thread.pool(5, 20).tap do |p|
-          # TODO: configurable pool size and trim timeout?
-          p.auto_trim!
-          p.idle_trim! 10 # 10 seconds
-          super p
-        end
-      end
-    end
-
     class FutureResponse
       extend Forwardable
 
       # The `block` is expected to return a {Response}
       def initialize(&block)
-        @future = Pool.instance.future(&block)
+        @future = Concurrent::Future.execute(executor: Pool.current, &block)
       end
 
       # @!attribute status
       # @return [Integer]
       # Delegated to the `block`'s return value.
@@ -39,8 +25,42 @@
       # @return [Hashie::Mash]
       # Delegated to the `block`'s return value.
 
       delegate :value => :@future
       delegate %i(status headers body) => :value
+      delegate :respond_to_missing? => :value
+      
+      def method_missing(m, *args, &block)
+        value.public_send(m, *args, &block)
+      end
+
+      def value
+        @future.value.tap do
+          raise @future.reason if @future.rejected?
+        end
+      end
+
+      module Pool
+        LOCK = Mutex.new
+
+        def self.current
+          LOCK.synchronize do
+            @pool ||= _build_pool
+          end
+        end
+
+        def self.reset
+          LOCK.synchronize do
+            return unless @pool
+            @pool.tap(&:shutdown).wait_for_termination
+            @pool = nil
+          end
+          self
+        end
+
+        def self._build_pool
+          Concurrent::CachedThreadPool.new(min_length: 5, max_length: 20, max_queue: 0, fallback_policy: :caller_runs)
+        end
+      end
     end
   end
 end