Issue #554 - Adding Farmers::Fork

lib/zold/node/farmers.rb

@@ -37,6 +37,10 @@ module Zold
   module Farmers
     # Plain and simple
     class Plain
+      def initialize(log: Log::NULL)
+        @log = log
+      end
+
       def up(score)
         score.next
       end
@@ -49,9 +53,8 @@ def initialize(log: Log::NULL)
       end
 
       def up(score)
-        if POSIX::Spawn::Child.new('ps', 'ax').out.include?(score.to_s.split(' ').take(4).join(' '))
-          raise "We are farming the score already: #{score}"
-        end
+        raise "We are farming the score already: #{score}" if
+          POSIX::Spawn::Child.new('ps', 'ax').out.include?(score.to_s.split(' ').take(4).join(' '))
         start = Time.now
         bin = File.expand_path(File.join(File.dirname(__FILE__), '../../../bin/zold'))
         raise "Zold binary not found at #{bin}" unless File.exist?(bin)
@@ -112,5 +115,30 @@ def kill(pid, start)
         @log.debug("No need to kill process ##{pid} since it's dead already: #{e.message}")
       end
     end
+
+    # In a child process using fork
+    class Fork
+      def initialize(log: Log::NULL)
+        @log = log
+      end
+
+      def up(score)
+        start = Time.now
+        stdin, stdout = IO.pipe
+        Process.fork do
+          score = score.next
+          stdout.puts "#{score}|#{Process.pid}"
+        end
+        Process.wait
+        stdout.close
+        output = stdin.read
+        buffer, pid = output.split('|')
+        after = Score.parse(buffer.strip)
+        stdin.close
+        @log.debug("Next score #{after.value}/#{after.strength} found in proc ##{pid.strip} \
+for #{after.host}:#{after.port} in #{Age.new(start)}: #{after.suffixes}")
+        after
+      end
+    end
   end
 end

test/node/test_farmers.rb

@@ -29,48 +29,46 @@
 class FarmersTest < Zold::Test
   def test_calculates_next_score
     before = Zold::Score.new(host: 'some-host', port: 9999, invoice: 'NOPREFIX4@ffffffffffffffff', strength: 3)
-    farmer = Zold::Farmers::Spawn.new(log: test_log)
-    after = farmer.up(before)
-    assert_equal(1, after.value)
-    assert(!after.expired?)
-    assert_equal('some-host', after.host)
-    assert_equal(9999, after.port)
+    [Zold::Farmers::Plain, Zold::Farmers::Spawn, Zold::Farmers::Fork].each do |farmer_class|
+      farmer = farmer_class.new(log: test_log)
+      after = farmer.up(before)
+      assert_equal(1, after.value)
+      assert(!after.expired?)
+      assert_equal('some-host', after.host)
+      assert_equal(9999, after.port)
+    end
   end
 
   def test_calculates_large_score
     log = TestLogger.new(test_log)
     thread = Thread.start do
-      farmer = Zold::Farmers::Spawn.new(log: log)
-      farmer.up(Zold::Score.new(host: 'a', port: 1, invoice: 'NOPREFIX4@ffffffffffffffff', strength: 20))
+      [Zold::Farmers::Spawn, Zold::Farmers::Fork].each do |farmer_class|
+        farmer = farmer_class.new(log: log)
+        farmer.up(Zold::Score.new(host: 'a', port: 1, invoice: 'NOPREFIX4@ffffffffffffffff', strength: 20))
+      end
     end
     assert_wait { !log.msgs.find { |m| m.include?('Scoring started') }.nil? }
     thread.kill
     thread.join
     assert(log.msgs.find { |m| m.include?('killed') })
   end
 
-  def test_calculates_next_score_plain
-    before = Zold::Score.new(host: 'some-host', port: 9999, invoice: 'NOPREFIX4@ffffffffffffffff', strength: 1)
-    farmer = Zold::Farmers::Plain.new
-    after = farmer.up(before)
-    assert_equal(1, after.value)
-    assert(!after.expired?)
-    assert_equal('some-host', after.host)
-    assert_equal(9999, after.port)
-  end
-
   def test_avoid_duplicate_processes
     log = TestLogger.new(test_log)
     time = Time.now
     thread = Thread.start do
-      farmer = Zold::Farmers::Spawn.new(log: log)
-      farmer.up(Zold::Score.new(time: time, host: 'a', port: 1, invoice: 'prefixone@ffffffffffffffff', strength: 20))
+      [Zold::Farmers::Spawn, Zold::Farmers::Fork].each do |farmer_class|
+        farmer = farmer_class.new(log: log)
+        farmer.up(Zold::Score.new(time: time, host: 'a', port: 1, invoice: 'prefixone@ffffffffffffffff', strength: 20))
+      end
     end
     assert_wait { !log.msgs.find { |m| m.include?('Scoring started') }.nil? }
     assert_raises do
-      Zold::Farmers::Spawn.new(log: log).up(
-        Zold::Score.new(time: time, host: 'a', port: 1, invoice: 'prefixtwo@ffffffffffffffff', strength: 20)
-      )
+      [Zold::Farmers::Spawn, Zold::Farmers::Fork].each do |farmer_class|
+        farmer_class.new(log: log).up(
+          Zold::Score.new(time: time, host: 'a', port: 1, invoice: 'prefixtwo@ffffffffffffffff', strength: 20)
+        )
+      end
     end
     thread.kill
     thread.join