out_rdkafka2: add patch for new version of rdkafka

Signed-off-by: Thomas Tych <thomas.tych@gmail.com>

README.md

@@ -509,7 +509,6 @@ You need to install rdkafka gem.
       partition_key         (string) :default => 'partition'
       partition_key_key     (string) :default => 'partition_key'
       message_key_key       (string) :default => 'message_key'
-      default_topic         (string) :default => nil
       use_default_for_unknown_topic           (bool) :default => false
       use_default_for_unknown_partition_error (bool) :default => false
       default_partition_key (string) :default => nil

lib/fluent/plugin/out_rdkafka2.rb

@@ -5,48 +5,17 @@
 
 require 'rdkafka'
 
-# This is required for `rdkafka` version >= 0.12.0
-# Overriding the close method in order to provide a time limit for when it should be forcibly closed
-class Rdkafka::Producer::Client
-  # return false if producer is forcefully closed, otherwise return true
-  def close(timeout=nil)
-    return unless @native
-
-    # Indicate to polling thread that we're closing
-    @polling_thread[:closing] = true
-    # Wait for the polling thread to finish up
-    thread = @polling_thread.join(timeout)
-
-    Rdkafka::Bindings.rd_kafka_destroy(@native)
-
-    @native = nil
-
-    return !thread.nil?
-  end
-end
-
-class Rdkafka::Producer
-  # return false if producer is forcefully closed, otherwise return true
-  def close(timeout = nil)
-    rdkafka_version = Rdkafka::VERSION || '0.0.0'
-    # Rdkafka version >= 0.12.0 changed its internals
-    if Gem::Version::create(rdkafka_version) >= Gem::Version.create('0.12.0')
-      ObjectSpace.undefine_finalizer(self)
-
-      return @client.close(timeout)
-    end
-
-    @closing = true
-    # Wait for the polling thread to finish up
-    # If the broker isn't alive, the thread doesn't exit
-    if timeout
-      thr = @polling_thread.join(timeout)
-      return !!thr
-    else
-      @polling_thread.join
-      return true
-    end
+begin
+  rdkafka_version = Gem::Version::create(Rdkafka::VERSION)
+  if rdkafka_version < Gem::Version.create('0.12.0')
+    require_relative 'rdkafka_patch/0_11_0'
+  elsif rdkafka_version == Gem::Version.create('0.12.0')
+    require_relative 'rdkafka_patch/0_12_0'
+  elsif rdkafka_version >= Gem::Version.create('0.14.0')
+    require_relative 'rdkafka_patch/0_14_0'
   end
+rescue LoadError, NameError
+  raise "unable to patch rdkafka."
 end
 
 module Fluent::Plugin

lib/fluent/plugin/rdkafka_patch/0_11_0.rb

@@ -0,0 +1,15 @@
+class Rdkafka::Producer
+  # return false if producer is forcefully closed, otherwise return true
+  def close(timeout = nil)
+    @closing = true
+    # Wait for the polling thread to finish up
+    # If the broker isn't alive, the thread doesn't exit
+    if timeout
+      thr = @polling_thread.join(timeout)
+      return !!thr
+    else
+      @polling_thread.join
+      return true
+    end
+  end
+end

lib/fluent/plugin/rdkafka_patch/0_12_0.rb

@@ -0,0 +1,27 @@
+# This is required for `rdkafka` version >= 0.12.0
+# Overriding the close method in order to provide a time limit for when it should be forcibly closed
+class Rdkafka::Producer::Client
+  # return false if producer is forcefully closed, otherwise return true
+  def close(timeout=nil)
+    return unless @native
+
+    # Indicate to polling thread that we're closing
+    @polling_thread[:closing] = true
+    # Wait for the polling thread to finish up
+    thread = @polling_thread.join(timeout)
+
+    Rdkafka::Bindings.rd_kafka_destroy(@native)
+
+    @native = nil
+
+    return !thread.nil?
+  end
+end
+
+class Rdkafka::Producer
+  def close(timeout = nil)
+    ObjectSpace.undefine_finalizer(self)
+
+    return @client.close(timeout)
+  end
+end

lib/fluent/plugin/rdkafka_patch/0_14_0.rb

@@ -0,0 +1,44 @@
+class Rdkafka::NativeKafka
+  # return false if producer is forcefully closed, otherwise return true
+  def close(timeout=nil, object_id=nil)
+    return true if closed?
+
+    synchronize do
+      # Indicate to the outside world that we are closing
+      @closing = true
+
+      thread_status = :unknown
+      if @polling_thread
+        # Indicate to polling thread that we're closing
+        @polling_thread[:closing] = true
+
+        # Wait for the polling thread to finish up,
+        # this can be aborted in practice if this
+        # code runs from a finalizer.
+        thread_status = @polling_thread.join(timeout)
+      end
+
+      # Destroy the client after locking both mutexes
+      @poll_mutex.lock
+
+      # This check prevents a race condition, where we would enter the close in two threads
+      # and after unlocking the primary one that hold the lock but finished, ours would be unlocked
+      # and would continue to run, trying to destroy inner twice
+      if @inner
+        Rdkafka::Bindings.rd_kafka_destroy(@inner)
+        @inner = nil
+        @opaque = nil
+      end
+
+      !thread_status.nil?
+    end
+  end
+end
+
+class Rdkafka::Producer
+  def close(timeout = nil)
+    return true if closed?
+    ObjectSpace.undefine_finalizer(self)
+    @native_kafka.close(timeout)
+  end
+end